Showing papers in "Journal of Computer Assisted Tomography in 2007"
TL;DR: The DWI of the prostate at 3T MRI using a phased-array coil was useful for the differentiation of malignant and benign tissues in the TZ and PZ.
Abstract: Objective: To evaluate prospectively the use of apparent diffusion coefficients (ADCs) for the differentiation of malignant and benign tissue in the transition (TZ) and peripheral (PZ) zones of the prostate diffusion-weighted imaging (DWI) at 3 T magnetic resonance imaging (MRI) using a phased-array coil. Methods: The DWI at 3-T MRI was performed on a total of 35 patients before radical prostatectomy. A single-shot echo-planar imaging DWI technique with b = 0 and b = 1000 s/mm 2 was used. The ADC values were measured in both benign and malignant tissues in the PZ and TZ using regions of interest. Differences between PZ and TZ ADC values were estimated using a paired Student t test. Presumed ADC cutoff values in the PZ and TZ for the diagnosis of cancer were assessed by receiver operating characteristic analysis. Results: The ADC values of malignant tissues were significantly lower than those of benign tissues in the PZ and TZ (P<0.001; 1.32 ± 0.24 × 10 -3 mm 2 /s vs 1.97 ± 0.25 × 10 -3 mm 2 /s, and 1.37 ±0.29 x 10 -3 mm 2 /s vs 1.79 ± 0.19 × 10 -3 mm 2 /s, respectively). For tumor diagnosis, cutoff values of 1.67 x 10 -3 mm 2 /s (PZ) and 1.61 x 10 -3 mm 2 /s (TZ) resulted in sensitivities and specificities of 94% and 91% and 90% and 84%, respectively. Conclusions: The DWI of the prostate at 3T MRI using a phased-array coil was useful for the differentiation of malignant and benign tissues in the TZ and PZ.
132 citations
TL;DR: The 3.0-T phased-array MRI is equivalent to the 1.5-T endorectal MRI in evaluating local staging accuracy for prostate cancer without significant loss of imaging quality.
Abstract: Objective: To retrospectively evaluate local staging accuracy for prostate cancer at 3.0-T magnetic resonance imaging (MRI) by comparing with that at 1.5-T MRI. Methods: Two groups, each consisting of 54 patients, were included by matching for age, prostate specific antigen, and Gleason score. Before radical prostatectomy, 1 group underwent 3.0-T MRI using a phased-array coil, and the other 1.5-T MRI using an endorectal coil. T2-weighted MR images at 3.0 and 1.5 T were analyzed in consensus by 2 radiologists, and their staging accuracy was compared with histology. Artifact and overall image quality were compared at both 3.0 and 1.5 T. Results: Accuracy for T3 stage at 3.0 and 1.5 T were 72% (39/54) and 70% (38/54), respectively (P > 0.05). The 3.0-T MRI had a lower incidence of MR artifacts than the 1.5-T MRI (P 0.05). Conclusions: The 3.0-T phased-array MRI is equivalent to the 1.5-T endorectal MRI in evaluating local staging accuracy for prostate cancer without significant loss of imaging quality.
108 citations
TL;DR: Flow-sensitive 3-dimensional magnetic resonance imaging at 3 T and advanced3-dimensional visualization were used to visualize local and global vascular hemodynamics in the thoracic aorta and revealed considerable changes in local blood flow characteristics, compared with normal volunteers.
Abstract: Flow-sensitive 3-dimensional magnetic resonance imaging at 3 T and advanced 3-dimensional visualization were used to visualize local and global vascular hemodynamics in the thoracic aorta. In patients with pathological geometric alterations of the thoracic aorta, this technique revealed considerable changes in local blood flow characteristics, compared with normal volunteers. Specifically, relatively small geometric changes, such as a partially thrombosed aortic arch or a mild aneurysm of the ascending aorta, resulted in major disturbances of local blood flow patterns within and even further downstream to the pathology.
105 citations
TL;DR: In a retrospective review, 3 (3.8%) of 78 patients developed recurrent posterior reversible encephalopathy syndrome, and multiple organ dysfunction syndrome developed during the hospital course of all admissions.
Abstract: In a retrospective review, 3 (3.8%) of 78 patients developed recurrent posterior reversible encephalopathy syndrome. Underlying clinical conditions included sickle cell disease, antibody-positive autoimmune disease, and allogeneic bone marrow transplantation. Infection (bacterial/viral) was suspected or documented in both episodes in all 3 patients. Evidence of endothelial injury (schistocyte formation and increased lactate dehydrogenase) was documented in all patients, and multiple organ dysfunction syndrome developed during the hospital course of all admissions.
96 citations
TL;DR: The 64 MDCT is a promising technique for the detection and preoperative staging of gastric cancer and its accuracy for determination of lymph node metastasis is promising.
Abstract: Objective: To assess the accuracy of 64 multidetector-row computed tomography (MDCT) in the diagnosis and staging of gastric cancer. Methods: This study was approved by the institutional review board, and the patients involved gave informed consent. Forty-four patients (34 men and 10 women; mean age, 57 years) with gastric carcinoma underwent preoperative 64 MDCT (SOMATOM Sensation 64; Siemens Medical System, Forchheim, Germany; slice collimation, 0.6 mm; slice width, 5 mm; feed/rotation, 23 mm; pitch factor, 1.2; kernel, B30f; and gantry speed, 0.5 second per rotation). Gastric distension was achieved by ingestion of 8 g of effervescent granules. Scanning was performed during arterial and portal phases, as determined with bolus tracking and automated triggering technique after intravenous administration of 100 mL of contrast materials (4 mL/s). All computed tomography scans were retrospectively reviewed by 2 radiologists. Each tumor was staged according to the TNM classification system. All patients underwent surgery. Computed tomography results were compared with histological staging of tumor invasion depth and regional lymph node metastasis. Results: The accuracy of 64 MDCT for detection of gastric cancer was 90% (18/20) and 100% (24/24) in early and advanced gastric cancer, respectively, with an overall detection rate of 95% (42/44). Its accuracy for determination of tumor penetration depth was 89% (16/18) and 88% (21/24) in early and advanced gastric cancer, respectively, with an overall accuracy of 88% (37/42). Its accuracy for determination of lymph node metastasis was 90% (18/20) and 71% (17/24) in early and advanced gastric cancer, respectively, with an overall accuracy of 80% (35/44). Conclusions: The 64 MDCT is a promising technique for the detection and preoperative staging of gastric cancer.
82 citations
TL;DR: Bismuth in-plane shielding for routine thoracic MDCT decreased radiation dose to the breast without qualitative changes in image quality, and radiosensitive superficial organs specifically must be protected with shielding.
Abstract: Objective: The purpose of our study was to determine the breast radiation dose when performing routine thoracic multidetector computed tomography (MDCT). We also evaluated dose reduction and the effect on image quality of using a bismuth breast shield when performing thoracic MDCT. Material and Methods: The dose reduction achievable by shielding the adult (18 years or older) female breasts was studied in 50 women who underwent routine thoracic MDCT. All examinations were performed with a 16-MDCT scanner (Sensation Cardiac 16; Siemens Medical Solutions). To compare the shielded/unshielded breast dose, the examination was performed with (right breast) and without (left breast) breast shielding in all patients. With this technique, the superficial breast doses were calculated. To determine the average glandular breast radiation dose, we imaged an anthropomorphic dosimetric phantom into which calibrated dosimeters were placed to measure the dose to breast. The phantom was imaged using the same protocol. Radiation doses to the breasts with and without the breast shielding were measured and compared using the Student t test. Results: In the qualitative evaluation of the MDCT scans, all were considered to be of diagnostic quality. We did not see any differences in quality between the shielded and unshielded lung. The mean radiation doses to the breasts with the shield and to those without the shield were 8.6 ± 2.33 versus 14.46 ± 3.94 mGy, respectively. The breast shield enabled a 40.53% decrease in radiation dose to the breast. The difference between the dose received by the breasts with and that received by the breasts without bismuth shielding was significant, with a P value of less than 0.001. Conclusions: Bismuth in-plane shielding for routine thoracic MDCT decreased radiation dose to the breast without qualitative changes in image quality. The other radiosensitive superficial organs (eg, testes and thyroid gland) specifically must be protected with shielding.
80 citations
TL;DR: Metal oxide semiconductor field effect transistor (MOSFET) technology was applied during the scanning of a female anthropomorphic phantom to determine 20 organ doses delivered during clinical body computed tomography (CT) imaging protocols.
Abstract: Purpose To determine the organ doses and total body effective dose (ED) delivered to an anthropomorphic phantom by multidetector array computed tomography (MDCT) when using standard clinical adult body imaging protocols. Materials and methods Metal oxide semiconductor field effect transistor (MOSFET) technology was applied during the scanning of a female anthropomorphic phantom to determine 20 organ doses delivered during clinical body computed tomography (CT) imaging protocols. A 16-row MDCT scanner (LightSpeed, General Electric Healthcare, Milwaukee, Wis) was used. Effective dose was calculated as the sum of organ doses multiplied by a weighting factor determinant found in the International Commission on Radiological Protection Publication 60. Volume CT dose index and dose length product (DLP) values were recorded at the same time for the same scan. Results Effective dose (mSv) for body MDCT imaging protocols were as follows: standard chest CT, 6.80 +/- 0.6; pulmonary embolus CT, 13.7 +/- 0.4; gated coronary CT angiography, 20.6 +/- 0.4; standard abdomen and pelvic CT, 13.3 + 1.0; renal stone CT, 4.51 + 0.45. Effective dose calculated by direct organ measurements in the phantom was 14% to 37% greater than those determined by the DLP method. Conclusions Effective dose calculated by the DLP method underestimates ED as compared with direct organ measurements for the same CT examination. Organ doses and total body ED are higher than previously reported for MDCT clinical body imaging protocols.
77 citations
TL;DR: The MDCT exanimation with multiplanar images and 3-dimensional angiography is a noninvasive imaging technique that can be used with high accuracy in the diagnosis of median arcuate ligament syndrome.
Abstract: Objective We aimed to describe the clinical and multidetector computed tomography (MDCT) angiography findings of celiac, mesenteric, and renal artery entrapment by the median arcuate ligament. Materials and methods Patients (n = 453) who underwent MDCT abdominal aorta angiography in a period of 3 years were retrospectively reviewed for vascular compression by median arcuate ligament known as median arcuate ligament syndrome. The MDCT examinations were performed with 16-slice (n = 292) and 64-slice scanners (n = 161). The median arcuate ligament itself and adjacent vascular branches of abdominal aorta were assessed for compression by 2 different radiologists who are experienced on MDCT angiography more than 3 years. Both axial, multiplanar reformatted images and 3-dimensional angiographies were used for interpretation. Results Twelve patients were found to have clinically significant vessel entrapments by median arcuate ligament; 6 of them with celiac artery, 4 of them with renal artery, and 2 of them with both celiac and mesenteric artery involvement. Patients with celiac and mesenteric vessel entrapments presented with epigastric pain. All patients with renal artery entrapment had resistant hypertension. The MDCT showed the proximal narrowing caused by compression of median arcuate ligament. The proximal portions of renal arteries pulled down and in toward the aorta, with mild to moderate narrowing. Conclusions The MDCT exanimation with multiplanar images and 3-dimensional angiography is a noninvasive imaging technique that can be used with high accuracy in the diagnosis of median arcuate ligament syndrome.
76 citations
TL;DR: The reduction of total injection volume lowered the enhancement of thoracic great vessels and coronary arteries in 64-detector row cardiac CT, and the injection volume of at least 0.9 mL/kg body weight was necessary for a steady contrast enhancement in coronary arteries.
Abstract: Objective: To assess the influence of total injection volume on thoracic great vessels and coronary arteries enhancement in 64-detecter row computed tomography (CT) coronary angiography using low dose of contrast material. Methods: Sixty patients underwent cardiac CT (64 x 0.5 mm, 0.4 rot/s) using 40 mL of contrast material (350 mg of Iodine per milliliter) in 30 patients and 50 mL in 30 patients. Computed tomography densities (Hounsfield units) in ascending aorta, descending aorta, and main pulmonary artery were measured at every second with the time of CT data acquisition recorded in each reconstructed image. Computed tomography densities of proximal and distal coronary arteries were also measured. Differences in CT densities between 40 and 50 mL contrast material were assessed with the Student t test. In addition, the relation between the injection volume (mL) of contrast material per kilogram body weight and contrast enhancement in coronary arteries was studied. Results: The average attenuations in the ascending and descending aorta and coronary arteries were significantly lower in 40-mL group than in 50-mL group (<0.05). In addition, the average attenuations in the pulmonary artery were significantly lower in 40-mL group than 50-mL group (<0.01). Every patient with the total injection volume of more than 0.9 mL/kg body weight showed a contrast enhancement more than 250 Hounsfield units. Conclusions: The reduction of total injection volume lowered the enhancement of thoracic great vessels and coronary arteries in 64-detector row cardiac CT. The injection volume of at least 0.9 mL/kg body weight was necessary for a steady contrast enhancement in coronary arteries.
75 citations
TL;DR: In the present study, 56.2% of asymptomatic patients undergoing coronary MDCT angiography were found to have significant extracardiac pathology requiring additional workup, therefore it is essential that a radiologist should review the scans for abnormalities in structures other than the coronary arteries.
Abstract: PURPOSE: The purpose of the present study was to determine the prevalence of significant noncardiac findings in asymptomatic patients undergoing coronary multidetector computed tomography (MDCT) angiography. MATERIALS AND METHODS: A total of 258 consecutive participants, 202 (78.3%) men and 56 (21.7%) women, aged 54.38 +/- 7.9 years (range, 40-86 years), underwent CT of the coronary arteries. All examinations were performed with the 16-slice Brilliance CT scanner (Philips, Cleveland, Ohio) and electrocardiography triggering. Patients were scanned in the supine position twice, first without contrast medium to calculate the calcium score and then with contrast medium. RESULTS: One hundred forty-five patients (56.2%) were found to have a significant noncardiac abnormality on coronary MDCT angiography. Lung abnormalities were detected in 91 patients. Eleven patients had emphysema, 17 with bullae, 3 with interstitial lung disease, 3 with lung mass of more than 10 mm, and 64 with lung nodules. Pericardial abnormalities were identified in 10 patients (3.8%). Liver disease was detected in 12 patients (16.9%), including multiple cysts and echinococcal cyst, and 5 patients had liver mass. Adrenal masses were found in 8 patients (one with 2 masses). Bone abnormalities were found in 3 patients, one with sclerotic lesion in the vertebral body, one with osteolytic lesion in the fifth rib, and one with bilateral cervical rib. CONCLUSIONS: In the present study, 56.2% of asymptomatic patients undergoing coronary MDCT angiography were found to have significant extracardiac pathology requiring additional workup. Therefore it is essential that a radiologist should review the scans for abnormalities in structures other than the coronary arteries.
73 citations
TL;DR: The observations suggest that paired inspiratory/expiratory CT scans in the limited-lung excluding emphysema are sensitive for the evaluation of airway obstruction in COPD with emphySEma.
Abstract: Objectives: We examined the hypothesis that paired inspiratory/ expiratory computed tomography (CT) scans in a limited-lung area that excludes emphysema may provide a more accurate evaluation of peripheral airway obstruction in patients with chronic obstructive pulmonary disease (COPD) with emphysema. Materials and Methods: This study included 32 patients with COPD. The cross-sectional area between -500 and -1024 HU was segmented as whole-lung. The relative areas (RA) less than -950 HU for the whole-lung (RA <-950 ) were segmented as emphysema, and pixels less than -900 HU for the whole-lung (RA<-900) were segmented to evaluate air trapping. Next, the cross-sectional area between -500 and -950 HU that excludes emphysema was segmented as limited-lung, and pixels between -900 and -950 HU for the limited-lung (RA 900-950 ) were segmented. The changes in RA <-900 (RA <-900 -change) and RA 900-950 (RA 900-950 -change) between inspiration and expiration were calculated. Correlations between CT measurements and the results of pulmonary function tests (PFT) were evaluated. Results: There was no significant difference between the mean inspiratory RA <-950 and expiratory RA <-9-50 (P = 0.245), but the mean expiratory RA 900-950 decreased significantly compared with the mean inspiratory RA 900-950 (P<0.001). The correlation coefficients between PFT parameters and the RA 900-900 -change in the limited-lung without emphysema were higher than that of the RA <-900 -change in the whole-lung. Conclusions: The paired inspiratory/expiratory CT measurements in the limited-lung without emphysema correlated more closely with the PFTs. Our observations suggest that paired inspiratory/expiratory CT scans in the limited-lung excluding emphysema are sensitive for the evaluation of airway obstruction in COPD with emphysema.
TL;DR: FDG PET and PET-CT are useful in the imaging evaluation of patients with cholangiocarcinoma for detection of recurrent and metastatic disease and for assessment of treatment response.
Abstract: Objectives We retrospectively assessed the diagnostic utility of dedicated positron emission tomography (PET) and hybrid PET-computed tomography (CT) scans with [F-18]fluorodeoxyglucose (FDG) in the imaging evaluation of patients with known or suspected recurrent and metastatic cholangiocarcinoma. Methods The study group included 24 patients (13 males and 11 females; age range, 34-75 years) with known or suspected recurrent and metastatic cholangiocarcinoma. We performed 8 dedicated PET scans (Siemens 953/A, Knoxville, Tenn) in 8 patients and 24 hybrid PET-CT scans (Siemens Biograph, Knoxville, Tenn) in 16 patients. Four patients underwent both pretreatment and posttreatment scans. Nonenhanced CT transmission scans were obtained for attenuation correction after administration of oral contrast material. PET images were obtained 60 minutes after the intravenous administration of 15 mCi (555 MBq) FDG. Prior treatments included surgery alone in 12 patients, surgery and chemotherapy in 6 patients, and surgery and combined chemoradiation therapy in 6 patients. Diagnostic validation was conducted through clinical and radiologic follow-up (2 months to 8 years). Results PET and CT were concordant in 18 patients. PET-CT correctly localized a hypermetabolic metastatic lesion in the anterior subdiaphragmatic fat instead of within the liver and was falsely negative in intrahepatic infiltrating type cholangiocarcinoma. PET was discordant with CT in 6 patients. PET was negative in an enlarged right cardiophrenic lymph node on CT, which remained stable for 1 year. In 1 patient, PET-CT scan showed hypermetabolic peritoneal disease in the right paracolic gutter without definite corresponding structural abnormalities, which was subsequently confirmed on a follow-up PET-CT scan performed 6 months after the initial study, at which time peritoneal nodular thickening was evident on concurrent CT. PET-CT documented the progression of locally recurrent and metastatic disease in another patient based on interval appearance of several new hypermetabolic lesions and significant increase in the standardized uptake values of the known lesions despite little interval change in the size and morphologic character of lesions on concurrent CT. It was also helpful in excluding metabolically active disease in patients with contrast enhancement at either surgical margin of hepatic resection site or focally within hepatic parenchyma and in an osseous lesion. Overall, based on the clinically relevant patient basis for detection of recurrent and metastatic cholangiocarcinoma, the sensitivity and specificity of PET (alone and combined with CT) were 94% and 100% and, for CT alone, were 82% and 43%, respectively. Conclusions FDG PET and PET-CT are useful in the imaging evaluation of patients with cholangiocarcinoma (except for infiltrating type) for detection of recurrent and metastatic disease and for assessment of treatment response. In particular, the combined structural and metabolic information of PET-CT enhances the diagnostic confidence in lesion characterization.
TL;DR: The stipple sign is helpful in demonstrating the areas of myonecrosis in type 2 rhabdomyolysis and, together with clinical and laboratory presentations, in reaching the correct diagnosis.
Abstract: Objective: Our purpose was to describe the magnetic resonance (MR) imaging and computed tomography (CT) findings in patients with rhabdomyolysis. Methods: The medical records and imaging studies of 10 patients (5 males, 5 females; age range, 14-60 years; mean age, 28.3 years) with rhabdomyolysis were retrospectively reviewed. Magnetic resonance imaging was available in 9 patients and CT in 2 patients. Results: Two distinct imaging types of rhabdomyolysis were observed. For type 1 rhabdomyolysis (n = 2), the affected muscles revealed homogeneously isointense to hyperintense on Tl-weighted, homogeneously hyperintense on T2-weighted and short-tau inversion recovery (STIR) images, and homogeneously enhanced on contrast-enhanced MR images. For type 2 rhabdomyolysis (n = 8), the affected muscles revealed homogeneously or heterogeneously isointense to hyperintense on Tl-weighted images, heterogeneously hyperintense on T2-weighted and STIR images, heterogeneously hypodense on CT images, and rim enhanced on contrast-enhanced MR and CT images with the presence of a specific presentation, named as the "stipple sign." Conclusions: Rhabdomyolysis is a clinical and biochemical syndrome comprising 2 distinct imaging types. Homogeneous signal changes and enhancement in the affected muscles advocate type 1 rhabdomyolysis. The stipple sign is helpful in demonstrating the areas of myonecrosis in type 2 rhabdomyolysis and, together with clinical and laboratory presentations, in reaching the correct diagnosis.
TL;DR: A subgroup of patients at very high risk for LAA thrombus may benefit from the high negative predictive value of cardiac MDCT, as compared with transesophageal echocardiography.
Abstract: Objective To determine the diagnostic performance of multidetector computed tomography (MDCT) for the detection of left atrial appendage (LAA) thrombus as compared with transesophageal echocardiography. Methods Multidetector computed tomography was evaluated in 43 patients qualitatively for the presence or absence of a filling defect in the LAA and compared with transesophageal echocardiography. Additionally, a ratio of the mean computed tomographic attenuation in the LAA apex to the mean computed tomographic attenuation in the aortic root was used for quantitative evaluation. Results A filling defect visualized in the LAA by MDCT corresponded to a sensitivity of 70% (7/10), a specificity of 82% (27/33), and a negative predictive value of 90% (27/30) for detection of LAA thrombus. When using quantitative parameters, MDCT demonstrated a sensitivity of 80% (8/10), a specificity of 73% (24/33), and a negative predictive value of 92% (24/26). Multidetector computed tomography was not able to differentiate LAA thrombus from spontaneous echo contrast by either visual evaluation or by quantitative parameters. Conclusions Multidetector computed tomography remains limited for the detection of LAA thrombus. However, a subgroup of patients at very high risk for LAA thrombus may benefit from the high negative predictive value of cardiac MDCT.
TL;DR: Magnetic resonance imaging is more sensitive than PET/CT for detecting local pelvic recurrence and peritoneal lesions of recurrent ovarian tumors.
Abstract: Objective: To compare the diagnostic performances of magnetic resonance imaging (MRI) and positron emission tomography/ computed tomography (PET/CT) for the detection of recurrent ovarian tumor. Methods: Thirty-six patients who underwent primary cytoreductive surgery for ovarian carcinoma received both MRI and PET/CT for the evaluation of ovarian tumor recurrence. Recurrent ovarian tumors in abdomen and pelvis were classified based on site as follows: (1) local pelvic recurrence, (2) peritoneal lesion, (3) lymph nodal metastasis, and (4) distant metastasis. Patient-based and lesion-based analyses were retrospectively performed with the aim of detecting tumor recurrence. For the detection of recurrent ovarian tumors, we compared patient-based and lesion-based diagnostic accuracies of these 2 modalities using the McNemar test. Results: Histopathologic, clinical, and radiological follow-up findings revealed recurrent ovarian tumors in 35 sites of 22 patients. These 35 sites consisted of local pelvic recurrence (n = 15), peritoneal lesions (n = 14), lymph nodal metastasis (n = 4), and abdominal wall metastasis (n = 2). In detecting recurrent ovarian tumor, patient-based sensitivity and the accuracy of PET/CT and MRI were 73% and 91% (P 0.05), respectively. In addition, overall lesion-based sensitivity of PET/CT and MRI were 66% and 86%, respectively (P < 0.05). In detecting peritoneal lesions, overall lesion-based sensitivity and accuracy of PET/CT and MRI for peritoneal lesions were 43% and 86%, and 75% and 94%, respectively (P < 0.05). Conclusions: Magnetic resonance imaging is more sensitive than PET/CT for detecting local pelvic recurrence and peritoneal lesions of recurrent ovarian tumors.
TL;DR: Although the computed tomographic findings of benign and malignant cavitary nodules overlap, some computed tomography findings are useful for differentiating cavitary nodsules.
Abstract: Objective: To establish computed tomographic findings that enable accurate differentiation between malignant and benign cavitary lung nodules. Methods: Computed tomographic scans from 39 patients with malignant cavitary nodules and from 39 patients with benign cavitary nodules were independently assessed by 2 observers. They recorded the computed tomographic findings of both types of cavitary nodules and surrounding pulmonary parenchyma. The computed tomographic findings were then compared using x 2 test. Results: The notch was found in 29% of benign cavitary nodule cases and in 54% of malignant cavitary nodule cases (P < 0.01). An irregular internal wall was found in 26% of benign nodules and in 49% of malignant nodule cases (P < 0.01). A linear margin (P < 0.01), satellite nodule presence (P <0.01), bronchial wall thickening (P < 0.05), consolidation (P < 0.05), and ground-glass attenuation (P < 0.01) were significantly more frequent in benign cavitary nodules than in malignant ones. Conclusions: Although the computed tomographic findings of benign and malignant cavitary nodules overlap, some computed tomographic findings are useful for differentiating cavitary nodules.
TL;DR: Most appendiceal diverticulitis can be differentiated from usual acute appendicitis at computed tomography by visualization of the inflamed diverticulum.
Abstract: Objective: To describe the computed tomographic findings of appendiceal diverticulitis. Methods: Computed tomography (n = 20) and clinical findings in 23 patients with appendiceal diverticulitis were retrospectively reviewed and compared with those in 23 patients with usual acute appendicitis. Results: Computed tomography visualized the inflamed diverticula (up to 4 per patient) mostly as small (median, 7.5 mm) round cystic outpouchings at the distal appendix with contrast enhancement at the cyst wall in 16 (80%) patients with appendiceal diverticulitis. In 50% of appendiceal diverticulitis patients, computed tomographic diagnosis of accompanying appendicitis was false positive. Appendico-lith was rarely observed in the appendiceal diverticulitis group (5% vs 48%, P = 0.002). No significant difference was observed in the clinical findings except for the patient age (median, 45 vs 31 years; P= 0.001). Conclusions: Most appendiceal diverticulitis can be differentiated from usual acute appendicitis at computed tomography by visualization of the inflamed diverticulum.
TL;DR: In this article, the optimal timing of contrast material injection using a test bolus and a bolus-tracking technique was studied for electrocardiogram-gated computed tomographic angiography of the chest.
Abstract: Objective: Electrocardiogram-gated computed tomographic angiography is increasingly used in the differential diagnosis of acute chest pain. We studied the optimal timing of contrast material injection using a test bolus and a bolus-tracking technique. Materials and Methods: Thirty patients were prospectively included in the study. Volume and flow of high concentration contrast material were adapted to body weight. The scan delay was determined using either a test bolus or a bolus-tracking technique. Attenuation profiles of the different vascular districts were measured to evaluate the timing techniques. Results: In all the patients except for one, an adequate and homogeneous contrast enhancement of more than 200 Hounsfield units (HU) was achieved (285 ± 45 HU) in the different vascular districts. The pulmonary transit time in the test bolus group was 7 seconds (range, 4-11 seconds). Differences and variability of pulmonary and aortic enhancement were small in both groups (13 ± 48 HU vs −9 ± 21 HU), with differences of less than 70 HU over the craniocaudal range and very small intraindividual differences between pulmonary attenuation and systemic attenuation. Conclusions: Contrast administration regimens for electrocardiogramgated computed tomographic angiography of the chest can be optimized using the bolus-tracking method in the ascending aorta, with a short delay after trigger. Body weight adaptation of volume and injection rate of the contrast material results in a reliable simultaneous opacification of the pulmonary and systemic vasculature.
TL;DR: Improved urinary tract distension is obtained with single-bolus 3-phase CTU technique, and no significant differences between techniques in intrarenal collecting system opacification, ureteral distension, or ureTERal opacifying were identified.
Abstract: OBJECTIVE To compare urinary tract distension and opacification obtained with single-bolus 3-phase and split-bolus 2-phase multidetector row computed tomographic urography (CTU) techniques. METHODS Twenty-six single-bolus 3-phase CTU examinations were retrospectively compared with 26 split-bolus 2-phase examinations. Two readers reviewed excretory-phase imaging to record quantitative measurements of urinary tract distension and qualitative measurements of urinary tract opacification. RESULTS Single-bolus 3-phase CTU technique provided better overall urinary tract distension than did split-bolus 2-phase technique (P = 0.05). Single-bolus CTU images demonstrated superior lower pole and interpolar region intrarenal collecting system distension when compared with split-bolus CTU images (P < or = 0.04). Qualitative opacification scores for the lower urinary tract were significantly higher, using single-bolus technique for only 1 of 2 reviewers. No significant differences between techniques in intrarenal collecting system opacification, ureteral distension, or ureteral opacification were identified. CONCLUSIONS Improved urinary tract distension is obtained with single-bolus 3-phase CTU technique.
TL;DR: The MDCT was effective for evaluation of local invasion and lymph nodes metastasis of colorectal cancer and mesenteric vascular variations before laparoscopic surgery.
Abstract: Objective To evaluate local invasion and lymph nodes metastasis of colorectal cancer and mesenteric vascular variations using multidetector-row computed tomography (MDCT) before laparoscopic colorectal surgery. Methods Fifty-one patients with colorectal cancer underwent MDCT. The evaluation items were as follows: (1) local invasion; (2) detected lymph nodes evaluated by short-axis diameter, long-axis diameter, short/long axis diameter ratio, and computed tomography (CT) attenuation; and (3) visualization of mesenteric artery and vein by 3-dimensional-CT angiography. Results First, in the evaluation of local invasion, overall accuracy was 94.1%. Second, the point of 0.8 or greater in short/long-axis diameter ratio was best index for the diagnosis of metastatic lymph nodes. Using this index, the accuracy of the diagnosis per node was 80.5%. Third, 3-dimensional-CT angiography correctly demonstrated variations of the mesenteric artery and vein. Conclusions The MDCT was effective for evaluation of local invasion and lymph nodes metastasis of colorectal cancer and mesenteric vascular variations before laparoscopic surgery.
TL;DR: The findings suggest that DCE MRI can distinguish ovarian fibromas from uterine leiomyomas and should be used if sonography fails to show the origin of a pelvic mass.
Abstract: Purpose: The purpose of this study was to assess the accuracy of magnetic resonance imaging (MRI), particularly, dynamic MRI, in distinguishing ovarian fibromas from subserous uterine leiomyomas. Material and Methods: Fifteen ovarian fibromas and 15 subserous uterine leiomyomas were retrospectively reviewed. All MR examinations included dynamic contrast-enhanced (DCE) sequences. Morphological criteria (size, Tl and T2 signals, ovarian tissue, associated uterine leiomyoma, and pelvic fluid), arterial vessels, time-intensity curves (maximal enhancement and signal intensity at 30, 60, and 90 seconds), and signal intensity on delayed T 1-weighted images were compared between the 2 groups. Results: No significant difference in morphological criteria was noted between the 2 types of masses. Visualization of arterial vessels was more frequent in uterine leiomyomas than in ovarian fibromas (P = 0.002). The DCE MR enhancement rate was higher for uterine leiomyomas than for ovarian fibromas in terms of both maximal enhancement (P < 0.001) and enhancement rate at 30 (P = 0.009), 60 (P = 0.007), and 90 seconds (P = 0.0009). On delayed T I postcontrast sequence, no statistical difference exists between signal intensity of ovarian fibromas and uterine leiomyomas. Conclusion: Our findings suggest that DCE MRI can distinguish ovarian fibromas from uterine leiomyomas and should be used if sonography fails to show the origin of a pelvic mass.
TL;DR: The MDCT is very sensitive in detecting small osteolytic lesions in the spine, as compared with MRI and FDG-PET.
Abstract: Purpose: The aim of our study was to compare the efficacy of multidetector row computed tomography (MDCT) with magnetic resonance imaging (MRI) and fluorodeoxyglucose-positron emission tomography (FDG-PET) for detection of spinal bone marrow involvement in patients with multiple myeloma. Materials and Methods: Ten patients with multiple myeloma stage III underwent MDCT and MRI of the spine and FDG-PET. The number and location of lesions detected by 3 modalities were recorded, and a lesion-by-lesion analysis was completed, using McNemar test. For MDCT, image analysis was performed according to the type of lesion (established by Laroche et al), and the efficacy of lesion detection was compared with that of the MRI and FDG-PET. P values less than 0.05 were considered statistically significant. Results: The MDCT, MRI, and FDG-PET detected the following numbers of lesions: 102 of 140 vertebrae, 95 of 140 vertebrae, and 84 of 140 vertebrae, respectively. The difference between the abilities of MDCT and MRI to detect lesions was not statistically significant (P = 0.289). However, the difference in effectiveness between MDCT and FDG-PET was statistically significant (P < 0.001). For small osteolytic lesions, less than 5 mm, the difference in effectiveness between MDCT and MRI was also statistically significant (P = 0.031). Conclusions: The MDCT is very sensitive in detecting small osteolytic lesions in the spine, as compared with MRI and FDG-PET.
TL;DR: Focal peliosis hepatis showed various enhancement patterns on contrast-enhanced CT and MRI, depending on the histopathologic findings.
Abstract: Objective: To retrospectively evaluate the radiological findings in patients with focal peliosis hepatis and to correlate them with pathological findings. Methods: Eight patients with pathologically proven peliosis hepatis underwent ultrasonography (n = 6), computed tomography (CT; n = 8), and/or magnetic resonance imaging (MRI; n = 3). Two radiologists analyzed the images for the size, margin, echogenicity, presence of posterior acoustic enhancement, and enhancement pattern of the lesion. The enhancement patterns on CT or MRI were correlated with the pathological findings. Results: The average lesion size was 1.9 cm. On ultrasonography, 4 lesions were ill defined and low echoic compared with the hepatic parenchyma. Two lesions showed posterior acoustic enhancement. In 4 lesions, centripetal enhancement was observed on dynamic CT images. Two lesions showed homogeneously high and 2 showed persistently low enhancement patterns. On dynamic MR phases, 2 lesions showed strong and persistent enhancement. In 1 lesion, MR showed slow centripetal enhancement. In the 3 patients who showed a homogeneously high enhancement pattern on dynamic CT or MRI, microscopic examination demonstrated that the dilated sinusoids were filled with fresh blood cells. On the contrary, in 5 patients who showed a centripetal or persistently low enhancement pattern, their dilated sinusoids were filled with old stagnated blood. Conclusions: Focal peliosis hepatis showed various enhancement patterns on contrast-enhanced CT and MRI, depending on the histopathologic findings.
TL;DR: In evaluating the biliary ductal extension of hilar cholangiocarcinoma, MDCT and MRC showed similar accuracies and agreements.
Abstract: Objective: To compare the diagnostic accuracy of multidetector computed tomography (MDCT) and magnetic resonance cholangiography (MRC) in evaluating the extent of biliary involvement of hilar cholangiocarcinoma. Methods: Images of 16-detector MDCT, MRC, and direct cholangiography of 33 patients with pathologically proven hilar cholangiocarcinoma were retrospectively interpreted independently by 2 radiologists according to the Bismuth classification. In the operated 14 patients, the diagnostic accuracies of MDCT and MRC were calculated according to surgical and pathological records. In nonoperated 19 patients, the agreement of MDCT and MRC with direct cholangiography was calculated. Results: In the operated patients, the diagnostic accuracy of MDCT was 64.3%, and that of MRC was 71.4%, without statistical difference (P = 0.93). In nonoperated patients, the agreement of MDCT with direct cholangiography was 73.7%, and that of MRC was 94.7%, without statistical difference (P = 0.58). Conclusions: In evaluating the biliary ductal extension of hilar cholangiocarcinoma, MDCT and MRC showed similar accuracies and agreements.
TL;DR: An additional imaging sign is described, the hyperintense ring sign on FLAIR images, which is distinct and is fairly sensitive and specific for DNET, and it is believed this sign is a helpful adjuvant to preoperatively diagnose these tumors.
Abstract: Purpose The aim of our study is to describe the hyperintense ring sign on fluid-attenuated inversion recovery (FLAIR) images in patients with dysembryoplastic neuroepithelial tumors (DNET), to discuss the radiopathologic correlation for this appearance, and to determine its role in preoperative diagnosis of DNETs. Materials and methods We retrospectively analyzed imaging features in 11 patients with pathological diagnosis of DNET. All patients had undergone surgery for refractory seizures. All had FLAIR imaging sequences performed on a 1.5-T magnetic resonance scanner. Clinical and pathological details in all cases were examined. Twenty-one age matched patients with pathologically confirmed low-grade glioma (n = 11), oligodendroglioma (n = 2), and ganglioglioma (n = 8) in similar locations acted as control cases. Ten patients had follow-up imaging. Results There were 11 patients with DNET (5 girls and 6 boys). The age of presentation varied from 4 to 18 years (average, 9 years 1 month). Tumors were located in the temporal (n = 5), frontal (n = 4), parietal (n = 1), and occipital (n = 1) lobes. In 9 patients (82% sensitivity), the FLAIR images showed a well-defined hyperintense ring around these tumors, either as a complete or incomplete ring. Among the 21 control cases, the hyperintense ring sign was seen in 2 cases (90% specificity): one with low-grade glioma and one with ganglioglioma. Pathological evaluation of the DNETs suggested the hyperintense ring might correspond to the presence of peripheral loose neuroglial elements. Postoperative imaging showed partial residual ring in 3 patients, all of whom had persistent seizures. One patient had recurrent DNET at second surgery. Conclusion Magnetic resonance imaging findings of DNET are well described. We describe an additional imaging sign, the hyperintense ring sign on FLAIR images, which is distinct and is fairly sensitive and specific for DNET. We believe this sign is a helpful adjuvant to preoperatively diagnose these tumors. The presence of this ring on postoperative imaging may indicate residual or recurrent tumor.
TL;DR: The PET/CT is a valuable modality for the follow-up of patients with breast cancer and elevated levels of tumor markers and person-based sensitivity was 96%, 88% and 96%, respectively.
Abstract: Objective: The value of combined positron emission tomography (PET)/computed tomography (CT) in the follow-up of patients with breast cancer with elevated tumor markers but without proven metastases or local recurrence was assessed. Methods: Thirty-four women underwent PET/CT. The PET and CT images were first analyzed separately; fused findings were then interpreted, blinded to the results of the other modalities. The results of CT, PET, and PET/CT were compared with each other and correlated to the final diagnosis. Results: The PET/CT identified 149 malignant foci in 24 patients (71%). The CT detected 96 of these foci in 18 patients, whereas PET identified 124 foci in 17 patients. Differences between CT and PET were not significant. Differences between PET/CT and CT (P < 0.01) and PET/CT and PET (P < 0.01) were significant. The person-based sensitivity of PET/CT, PET, and CT was 96%, 88% and 96%, respectively. Specificity of PET/CT, PET, and CT was 89%, 78%, and 78%, respectively. Conclusions: The PET/CT is a valuable modality for the follow-up of patients with breast cancer and elevated levels of tumor markers.
TL;DR: Patients with type A IMH and ULP, as revealed by initial and short-term follow-up CT examinations, should be carefully followed up with subsequent CT examination to monitor the development of an aortic aneurysm, which is a relatively common chronic complication of IMH.
Abstract: Objective To ascertain the incidence of acute and chronic complications of aortic intramural hematoma (IMH) and to analyze the predictors of the development of each complication. Materials and methods This retrospective study includes 107 consecutive patients diagnosed with aortic IMH by means of computed tomography (CT) during the period from January 1998 to December 2003 and followed up with serial CT examinations (median follow-up period, 320 days). There were 36 patients with type A and 71 with type B IMH. Initial and follow-up CT scans were reviewed, with special attention given to the development of complications, such as increase in the thickness of IMH, clinical and hemodynamic evolution requiring urgent surgery, and development of aortic dissection and/or aneurysm. If each complication developed within 30 days after the initial episode, we classified it as an acute complication; the others were classified as chronic complications. The time interval between the initial and the subsequent CT examination showing each complication was recorded. To identify the predictors of each complication, we analyzed the demographic and CT findings with regard to the following factors: age, sex, maximum thickness of the hematoma, maximum aortic diameter on initial CT examination, ulcerlike projection (ULP) on initial and follow-up CT examinations, and the degree of atherosclerosis. The Cox proportional hazards regression model with stepwise multivariate analyses was used to determine the significant predictors of each complication. Results Sixteen patients had acute complications consisting of aortic dissection (n = 7), aortic aneurysm (n = 6), and acute clinical and hemodynamic evolution requiring operation (n = 3). Three additional patients with aortic dissection (n = 1) and aneurysm (n = 2) underwent emergency surgery. Twenty-three patients with chronic complications had aortic dissection (n = 3), and aortic aneurysm (n = 20). Cox proportional hazards regression model revealed that the maximal diameter of involved aorta is the only significant predictor of the development of acute complications (P = 0.006), whereas the age (P = 0.040), type A IMH (P = 0.015), presence of ULP (P = 0.015), and newly developed ULP as revealed on follow-up CT examination (P = 0.032) were significant predictors of the development of chronic complications. With regard to the aortic dissection in 10 patients (9.3%; type A/B ratio, 5:5; median time interval, 34 days), Cox proportional hazards regression model revealed that the maximal thickness of the hematoma is the only significant predictor (P = 0.018). Twenty-one saccular and 5 fusiform aneurysms (24.3%) developed, as revealed on follow-up CT examinations (median time interval, 180 days). The presence of ULP (P = 0.030), type A (P = 0.038) and the maximal thickness of the hematoma (P = 0.017) were significant predictors for the development of an aneurysm. Conclusions The maximum thickness of a hematoma on the initial CT is the significant factor predicting the development of aortic dissection and aortic aneurysm. Patients with type A IMH and ULP, as revealed by initial and short-term follow-up CT examinations, should be carefully followed up with subsequent CT examination to monitor the development of an aortic aneurysm, which is a relatively common chronic complication of IMH.
TL;DR: The histological spectrum and imaging findings of the PEComas that involve the abdomen and pelvis are reviewed and discussed.
Abstract: Neoplasms of the perivascular epithelioid cell (PEComas) represent a recently described heterogeneous group of mesenchymal tumors characterized by the presence of specific histological, immunohistochemical, and ultrastructural findings. The PEComas encompass a family of neoplasms that include angiomyolipomas, clear cell sugar tumors, and lymphangioleiomyomatosis. The PEComas demonstrate a wide spectrum of clinicobiological behavior and imaging findings. Perivascular epithelioid cell, as the name implies, is a unique cell that is characterized by perivascular distribution and epithelioid morphology. Perivascular epithelioid cell consistently shows immunoreactivity to melanocytic and smooth muscle markers including HMB-45 and actin. Abdominopelvic PEComas are found at a variety of somatic and visceral locations including kidney, liver, pancreas, gastrointestinal tract, genitourinary tract, peritoneum, and retroperitoneum. A subset of patients with abdominopelvic PEComas manifests tuberous sclerosis complex. In this paper, we review the histological spectrum and discuss the imaging findings of the PEComas that involve the abdomen and pelvis.
TL;DR: In this article, the authors evaluated the incidence of lung metastases detected on thoracic computed tomography in patients with rectal cancer and assessed the association between the occurrence of pulmonary metastases and the stage of the rectal tumor.
Abstract: Purpose The aim of the study was to evaluate the incidence of pulmonary metastases detected on thoracic computed tomography in patients with rectal cancer and assess the association between the incidence of pulmonary metastases and the stage of the rectal tumor. Materials and methods Fifty-six consecutive patients who were diagnosed with rectal cancer over a 22-month period were included in the study. These patients had local tumor staging with a pelvic magnetic resonance imaging and staging computed tomographic scan of the chest and upper abdomen immediately after the magnetic resonance imaging. Two radiologists retrospectively reviewed all the thoracic imaging performed on these patients for the presence of metastases. The presence of a parenchymal lung nodule (greater than or equal to 1 cm if single and 0.5 cm if multiple) with a soft tissue component without calcification on lung and mediastinal window settings was considered positive for the presence of metastasis. All other patients were considered as not having any lung metastases. Results Of the 56 patients, 10 (17.9%) had evidence of pulmonary metastases on computed tomography. Of the 56 patients, there were 3 patients with stage T1, 24 with T2, 26 with T3, and 3 with stage T4 tumors. Of these 10 patients, 1 had a stage T2 tumor, 7 had T3, and 2 had stage T4 tumors. Statistical analysis using exact logistic regression showed the odds of getting lung metastases is an increasing function of tumor grade. Conclusions There is a high incidence of lung metastases in patients with rectal cancer, and thoracic computed tomographic scanning should be performed as part of a staging protocol in all patients before any form of treatment is planned. There is a higher incidence of lung metastases with higher T stage.
TL;DR: Imaging features of LPP on CT include bilateral and unilateral single and multifocal consolidation and ground opacity, and Sharply demarcated peribronchovascular foci of consolidation intermingled with ground glass opacity seem to be one of the most frequent CT appearances of L PP.
Abstract: Purpose To characterize the imaging features of Legionella pneumophila pneumonia (LPP). Subjects and methods Imaging findings of computed tomography (CT) in 38 cases of microbiologically or serologically determined LPP were analyzed and compared with those of 35 cases of Streptococcus pneumoniae pneumonia. Results In cases with LPP, abnormal opacities were distributed in a single lobe in 5 cases, in multiple lobes unilaterally in 10 cases, and multifocally and bilaterally in 23 cases. All cases showed consolidation and/or ground glass opacity in lung fields. Sharply demarcated peribronchovascular foci of consolidation intermingled with ground glass opacity were noted in 24 cases (24 of 38, 63%), whereas imaging features were seen in only 3 cases (3 of 35, 9%) of Streptococcus pneumoniae pneumonia. These CT patterns have nothing to do with clinical features such as age, sex, severity of disease, and time between onset of disease and CT examination. Conclusions Imaging features of LPP on CT include bilateral and unilateral single and multifocal consolidation and ground opacity. Sharply demarcated peribronchovascular foci of consolidation intermingled with ground glass opacity seem to be one of the most frequent CT appearances of LPP.