Showing papers in "Radiology in 1999"
TL;DR: The shape of the time-signal intensity curve is an important criterion in differentiating benign and malignant enhancing lesions in dynamic breast MR imaging and a type III time course is a strong indicator of malignancy and is independent of other criteria.
Abstract: PURPOSE: To assess the relevance of the signal intensity time course for the differential diagnosis of enhancing lesions in dynamic magnetic resonance (MR) imaging of the breast. MATERIALS AND METHODS: Two hundred sixty-six breast lesions were examined with a two-dimensional dynamic MR imaging series and subtraction postprocessing. Time–signal intensity curves of the lesions were obtained and classified according to their shapes as type I, which was steady enhancement; type II, plateau of signal intensity; or type III, washout of signal intensity. Enhancement rates and curve types of benign and malignant lesions were compared. RESULTS: There were 101 malignant and 165 benign lesions. The distribution of curve types for breast cancers was type I, 8.9%; type II, 33.6%; and type III, 57.4%. The distribution of curve types for benign lesions was type I, 83.0%; type II, 11.5%; and type III, 5.5%. The distributions proved significantly different (χ2 = 139.6; P < .001). The diagnostic indices for signal intensit...
1,302 citations
TL;DR: RF ablation results in a higher rate of complete necrosis and requires fewer treatment sessions than percutaneous ethanol injection, however, the complication rate is higher with RF ablation than with percutaneously ethanol injection.
Abstract: PURPOSE: To compare the effectiveness of radio-frequency (RF) ablation with that of percutaneous ethanol injection in the treatment of small hepatocellular carcinoma (HCC). MATERIALS AND METHODS: Eighty-six patients with 112 small (≤3-cm-diameter) HCCs underwent RF ablation (42 patients with 52 tumors) or percutaneous ethanol injection (44 patients with 60 tumors). Therapeutic efficacy was evaluated with dual-phase spiral computed tomography performed at least 4 months after treatment. RESULTS: Complete necrosis was achieved in 47 of 52 tumors with RF ablation (90%) and in 48 of 60 tumors with percutaneous ethanol injection (80%). These results were obtained with an average of 1.2 sessions per tumor with RF ablation and 4.8 sessions per tumor with percutaneous ethanol injection. One major complication (hemothorax that required drainage) and four minor complications (intraperitoneal bleeding, hemobilia, pleural effusion, cholecystitis) occurred in patients treated with RF ablation; no complications occurre...
1,181 citations
TL;DR: Catheter-directed thrombolysis is safe and effective for treatment of symptomatic lower extremity deep venous thrombosis (DVT), andysis grade was predictive of 1-year patency rate.
Abstract: PURPOSE: To evaluate catheter-directed thrombolysis for treatment of symptomatic lower extremity deep venous thrombosis (DVT). MATERIALS AND METHODS: From a registry of patients (n = 473) with symptomatic lower limb DVT, results of 312 urokinase infusions in 303 limbs of 287 patients (137 male and 150 female patients; mean age, 47.5 years) were analyzed. DVT symptoms were acute (≤10 days) in 188 (66%) patients, chronic (>10 days) in 45 (16%), and acute and chronic in 54 (19%). A history of DVT existed in 90 (31%). Lysis grades were calculated by using venographic results. RESULTS: Iliofemoral DVT (n = 221 [71%]) and femoral-popliteal DVT (n = 79 [25%]) were treated with urokinase infusions (mean, 7.8 million IU) for a mean of 53.4 hours. After thrombolysis, 99 iliac and five femoral vein lesions were treated with stents. Grade III (complete) lysis was achieved in 96 (31%) infusions; grade II (50%–99% lysis), in 162 (52%); and grade I (<50% lysis), in 54 (17%). For acute thrombosis, grade III lysis occurre...
817 citations
TL;DR: Although the average CT numbers obtained with different scanners were distributed widely, the calculated fat areas were almost identical, suggesting this method might be a practical and standardized method at CT.
Abstract: The authors estimated abdominal fat distribution on the basis of measurements at computed tomography (CT). The attenuation range for fat tissue was defined as the interval within the mean plus or minus 2 SDs considered to be individual variation. Fat areas found with this method were closely correlated with those obtained by means of the computed planimetric method or with a fixed attenuation range from -190 to -30 HU as the standard of reference. Although the average CT numbers obtained with different scanners were distributed widely, the calculated fat areas were almost identical. This method might be a practical and standardized method at CT.
797 citations
TL;DR: In this paper, T1-weighted fast low-angle shot MR imaging of the breast was performed before and after administration of gadopentetate dimeglumine and histopathologic analysis revealed 143 benign and 405 malignant lesions.
Abstract: PURPOSE: To determine if magnetic resonance (MR) imaging can help determine the therapeutic approach in women with breast cancer. MATERIALS AND METHODS: Preoperative contrast-enhanced MR imaging of the breast was performed in 463 patients with probably benign lesions (n = 63), suspicious lesions (n = 230), or lesions highly suggestive of malignancy (n = 170) per established clinical, mammographic, and/or ultrasonographic (US) criteria. T1-weighted fast low-angle shot MR imaging was performed before and after administration of gadopentetate dimeglumine. MR imaging findings were correlated with other imaging results and histopathologic findings. Special attention was paid to multifocality and multicentricity. RESULTS: Histopathologic analysis revealed 143 benign and 405 malignant lesions. The sensitivity, specificity, and accuracy were 58%, 76%, and 62% for clinical examination; 86%, 32%, and 72% for conventional mammography; 75%, 80%, and 76% for US; and 93%, 65%, and 85% for contrast-enhanced MR imaging. ...
658 citations
TL;DR: pooled point estimates of diagnostic performance and summary ROC curves indicated that PET was significantly more accurate than CT for demonstration of nodal metastases (P < .001), and PET is superior to CT for mediastinal staging of non-small cell lung cancer, independent of performance index or clinical context of PET imaging.
Abstract: PURPOSE: To meta-analytically compare 2-[fluorine 18]fluoro-2-deoxy-d-glucose positron emission tomography (PET) and computed tomography (CT) for the demonstration of mediastinal nodal metastases in patients with non–small cell lung cancer. MATERIALS AND METHODS: English-language reports on the diagnostic performance of PET (14 studies, 514 patients) and/or CT (29 studies, 2,226 patients) for demonstration of mediastinal nodal metastases from NSCLC were selected by using the Medline database. In eligible studies, an objective diagnostic standard was used, data were presented to allow recalculation of contingency tables, and established diagnostic criteria were used for abnormal test results. Summary receiver operating characteristic (ROC) curves were calculated. RESULTS: Pooled point estimates of diagnostic performance and summary ROC curves indicated that PET was significantly more accurate than CT for demonstration of nodal metastases (P < .001). Mean sensitivity and specificity (± 95% CI) were 0.79 ± 0...
651 citations
TL;DR: Echo-planar perfusion imaging is useful in the preoperative assessment of tumor grade and in providing diagnostic information not available with conventional MR imaging.
Abstract: PURPOSE: To evaluate the role of T2*-weighted echo-planar perfusion imaging by using a first-pass gadopentetate dimeglumine technique to determine the association of magnetic resonance (MR) imaging–derived cerebral blood volume (CBV) maps with histopathologic grading of astrocytomas and to improve the accuracy of targeting of stereotactic biopsy. MATERIALS AND METHODS: MR imaging was performed in 29 patients by using a first-pass gadopentetate dimeglumine T2*-weighted echo-planar perfusion sequence followed by conventional imaging. The perfusion data were processed to obtain a color map of relative regional CBV. This information formed the basis for targeting the stereotactic biopsy. Relative CBV values were computed with a nondiffusible tracer model. The relative CBV of lesions was expressed as a percentage of the relative CBV of normal white matter. The maximum relative CBV of each lesion was correlated with the histopathologic grading of astrocytomas obtained from samples from stereotactic biopsy or vo...
587 citations
TL;DR: Diffusion-weighted MR imaging is highly accurate for diagnosing stroke within 6 hours of symptom onset and is superior to CT and conventional MR imaging.
Abstract: PURPOSE: To evaluate the diagnostic accuracy of diffusion-weighted magnetic resonance (MR) imaging performed within 6 hours of the onset of stroke symptoms. MATERIALS AND METHODS: The authors reviewed the patient records and images from all patients hospitalized in a 10-month period in whom diffusion-weighted imaging was performed within 6 hours of the onset of strokelike symptoms (n = 22). Analyses included comparison of the initial interpretation of the diffusion-weighted images with the final clinical diagnosis; blinded reviews of computed tomographic (CT) scans and conventional and diffusion-weighted images; and determination of lesion contrast-to-noise ratios (CNRs). RESULTS: Diffusion-weighted images indicated stroke in 14 patients, all of whom had a final diagnosis of acute stroke. Diffusion-weighted images were negative in eight patients, all of whom had a final clinical diagnosis other than stroke (100% sensitivity, 100% specificity, χ2 = 23.00, P < .0001). Blinded reviews yielded 100% sensitivit...
575 citations
TL;DR: The addition of 3D MR spectroscopic imaging to MR imaging provides better detection and localization of prostate cancer in a sextant of the prostate than does use of MR imaging alone.
Abstract: PURPOSE: To assess the efficacy of combined magnetic resonance (MR) imaging and three-dimensional (3D) proton MR spectroscopic imaging in the detection and localization of prostate cancer. MATERIALS AND METHODS: MR imaging and 3D MR spectroscopic imaging examinations were performed in 53 patients with biopsy-proved prostate cancer and subsequent radical prostatectomy with step-section histopathologic examination. The prostate was divided into sextants. At MR imaging, the presence or absence of cancer in the peripheral zone of each sextant was assessed independently by two readers (readers 1 and 2) unaware of the findings at 3D MR spectroscopic imaging and histopathologic examination. At 3D MR spectroscopic imaging, cancer was diagnosed as possible if the ratio of choline plus creatine to citrate exceeded 2 SD above population norms or as definite if that ratio exceeded 3 SDs above the norm. RESULTS: On the basis of sextants, sensitivity and specificity, respectively, for MR imaging were 77% and 61% (reade...
561 citations
TL;DR: The true diffusion coefficient D and the perfusion fraction f were calculated and compared with the apparent diffusion coefficient (ADC) and it was found that perfusion contributes to the ADCs of abdominal organs and hepatic lesions.
Abstract: PURPOSE: To determine the true diffusion coefficients of abdominal organs and hepatic lesions with intravoxel incoherent motion (IVIM) echo-planar magnetic resonance (MR) imaging. MATERIALS AND METHODS: Seventy-eight patients suspected of having hepatic lesions were examined with IVIM echo-planar MR imaging at 1.5 T. There were 77 hepatic masses (27 hepatocellular carcinomas, 10 metastatic tumors, eight hemangiomas, and 32 cysts) in the 78 patients. The true diffusion coefficient D and the perfusion fraction f were calculated and compared with the apparent diffusion coefficient (ADC). RESULTS: Specific values of D were found for abdominal organs (liver, 0.72 × 10−3 mm2/sec; spleen, 0.80 × 10−3 mm2/sec; kidney, 1.38 × 10−3 mm2/sec; gallbladder, 2.82 × 10−3 mm2/sec) and for hepatic lesions (hepatocellular carcinoma, 1.02 × 10−3 mm2/sec; metastasis, 1.16 × 10−3 mm2/sec; hemangioma, 1.31 × 10−3 mm2/sec; cysts, 3.03 × 10−3 mm2/sec). The ADCs of solid organs and solid lesions were significantly higher than thei...
518 citations
TL;DR: Fat-saturated volumetric interpolated breath-hold images have quality comparable to that of conventional fat-s saturated 2D GRE images.
Abstract: PURPOSE: To compare a T1-weighted, three-dimensional (3D), gradient-echo (GRE) sequence for magnetic resonance (MR) imaging of the body (volumetric interpolated breath-hold examination, or VIBE) with a two-dimensional (2D) GRE breath-hold equivalent. MATERIALS AND METHODS: Twenty consecutive patients underwent 1.5-T MR imaging. The examinations included pre- and postcontrast (20 mL gadopentetate dimeglumine) fat-saturated 2D GRE breath-hold imaging and fat-saturated volumetric interpolated breath-hold imaging before, during (arterial phase), and after injection, with thin (2-mm source images) and thick (8-mm reconstruction images) sections. The three images were compared qualitatively and quantitatively (signal-to-noise ratio [SNR] and contrast-to-noise ratio [CNR]). RESULTS: Qualitatively, the 2-mm source images had poorer pancreatic edge definition on precontrast images compared with the other two data sets (P < .05). On gadolinium-enhanced images, scores for clarity of pancreatic edge, number of vessel...
TL;DR: Functional MR imaging can demonstrate the CNS pathway for acupuncture stimulation, which may shed light on the CNS mechanism of acupuncture analgesia and form a basis for future investigations of endogenous pain modulation circuits in the human brain.
Abstract: PURPOSE: To characterize the central nervous system (CNS) pathway for acupuncture stimulation in the human brain by using functional magnetic resonance (MR) imaging. MATERIALS AND METHODS: Functional MR imaging of the whole brain was performed in two groups of nine healthy subjects during four stimulation paradigms: real acupuncture at acupoints ST.36 (on the leg) and LI.4 (on the hand) and control stimulations (minimal acupuncture and superficial pricking on the leg). Stimulations were performed in semirandomized, balanced order nested within two experiments. Psychophysical responses (pain, De-Qi effect [characteristic acupuncture effect of needle-manipulation sensation], anxiety, and unpleasantness) and autonomic responses were assessed. Talairach coordinates–transformed imaging data were averaged for a group analysis. RESULTS: Acupuncture at LI.4 and ST.36 resulted in significantly higher scores for De-Qi and in substantial bradycardia. Acupuncture at both acupoints resulted in activation of the hypoth...
TL;DR: Preoperative thin-section MR imaging accurately indicates the tumor stage of rectal cancer and depth of extramural tumor infiltration and provides valuable information for identifying T3 tumors for preoperative adjuvant therapy in patients who are at high risk of failure of complete excision.
Abstract: PURPOSE: To evaluate the accuracy of thin-section magnetic resonance (MR) imaging (in-plane resolution, 0.6 × 0.6 mm) in the preoperative assessment of the depth of extramural tumor infiltration, which is a major prognostic indicator in rectal cancer. MATERIALS AND METHODS: In a prospective study of 28 consecutive patients, preoperative MR imaging was performed. The tumor stage according to the TNM classification system and the measured depth of extramural tumor invasion in matched MR images and histopathologic slices were compared. RESULTS: Preoperative MR imaging correctly indicated the histopathologic tumor stage in all 25 patients in whom comparisons were possible. The difference between the depth of extramural tumor measured on preoperative MR images and corresponding measurements on histopathologic slices of the resection specimen ranged from −5.0 mm to +5.5 mm (mean difference, +0.13 mm; 95% CI: −2.72, +2.98 mm), indicating good agreement. The mesorectal fascia, and the relation of the tumor to it,...
TL;DR: A very small recurrence may be observed at the level of the neck of the aneurysm at long-term follow-up angiography despite achieving total occlusion initially with detachable coils.
Abstract: PURPOSE: To evaluate the stability of aneurysm occlusion at follow-up angiography after endovascular treatment (EVT) with detachable coils in intracranial berry aneurysms. MATERIALS AND METHODS: A total of 203 berry aneurysms (<1.5 cm) were treated with EVT. Follow-up angiography at least 3 months later was performed in 169 cases. RESULTS: Complete occlusion of the aneurysm sac and neck was achieved in 148 aneurysms, subtotal occlusion in 18, and incomplete occlusion in three. Recurrence occurred between 3 and 40 months in 20 (14%) of the 148 totally occluded aneurysms. A second treatment was performed in five cases, was scheduled in one, and failed in one. The small neck remnant increased in size but did not require any retreatment in three cases, and the size of the neck remnant remained stable in 10 cases. Remnant regrowth occurred in six of the 18 subtotally occluded aneurysms. A second treatment was performed in three. Of the 169 cases, last follow-up angiography showed total occlusion in 133 cases, ...
TL;DR: MR imaging can delineate areas of altered blood flow, blood volume, and water mobility in hyperacute human stroke and Predictive models of tissue outcome may benefit by including computation of both relative cerebral blood flow and blood volume.
Abstract: PURPOSE: To investigate additional information provided by maps of relative cerebral blood flow in functional magnetic resonance (MR) imaging of human hyperacute cerebral ischemic stroke. MATERIALS AND METHODS: Diffusion-weighted and hemodynamic MR imaging were performed in 23 patients less than 12 hours after the onset of symptoms. Maps of relative cerebral blood flow and tracer mean tissue transit time were computed, as were maps of apparent diffusion and relative cerebral blood volume. Acute lesion volumes on the maps were compared with follow-up imaging findings. RESULTS: In 15 of 23 subjects (65%), blood flow maps revealed hemodynamic abnormalities not visible on blood volume maps. A mismatch between initial blood flow and diffusion findings predicted growth of infarct more often (12 of 15 subjects with infarcts that grew) than did a mismatch between initial blood volume and diffusion findings (eight of 15). However, lesion volumes on blood volume and diffusion maps correlated better with eventual in...
TL;DR: The false-negative rate with LCNB was 1.2% in this study and 4.0% in the literature, and the presence of carcinoma in ADH and radial scar lesions was often underestimated.
Abstract: PURPOSE: To determine the rate and causes of false-negative findings and histologic underestimates at stereotactic biopsy of nonpalpable breast lesions. MATERIALS AND METHODS: Stereotactic, 14-gauge, automated, large-core needle biopsy (LCNB) was performed in 483 consecutive nonpalpable breast lesions. Excision was advised for the 143 carcinomas, 25 atypical ductal hyperplasia (ADH) lesions, and five radial scars. Mammographic follow-up was advised for the benign lesions without a repeat biopsy. RESULTS: Of the 310 benign lesions, 259 underwent mammographic follow-up at 6–85 months (median, 55 months) without repeat biopsy, 48 underwent repeat biopsy and three were lost to follow-up. On the basis of the histologic diagnosis of carcinoma at surgical biopsy, diagnosis with LCNB was not correct (ie, disease was underestimated at histologic examination) in 14 (58%) of 24 ADH lesions and two (40%) of five radial scars. Two (1.2%) of 161 lesions with a final diagnosis of carcinoma were benign at LCNB but malign...
TL;DR: Although US, CT, or MR imaging can be used in the pretreatment evaluation of endometrial cancer, contrast-enhanced MR imaging offers "one-stop" examination with the highest efficacy.
Abstract: PURPOSE: To apply a meta-analysis to compare the utility of computed tomography (CT), ultrasonography (US), and magnetic resonance (MR) imaging in staging endometrial cancer. MATERIALS AND METHODS: Data were obtained from a medline literature search and from manual reviews of article bibliographies. Articles were selected that included results in patients with proved endometrial cancer and imaging-histopathologic correlation and that presented data that allowed calculation of contingency tables. Data for the imaging evaluation of myometrial and cervical invasion were abstracted independently by two authors. Data on year of publication, International Federation of Gynecology and Obstetrics (FIGO) stage distribution, and methodologic quality were also collected. A subgroup analysis was performed to compare contrast medium–enhanced MR imaging with nonenhanced MR imaging, US, and CT. RESULTS: Six studies met the inclusion criteria for CT; 16, for US; and 25, for MR imaging. Summary receiver operating characte...
TL;DR: Perhaps, most important, a lesion placed into BI-RADS category 3 is highly predictive of benignity, and short-term interval follow-up as an alternative to biopsy would decrease the number of biopsies performed in benign lesions.
Abstract: PURPOSE: To determine the positive predictive value (PPV) of the American College of Radiology Breast Imaging Reporting and Data System (BI-RADS) categories 0, 2, 3, 4, and 5 by using BI-RADS terminology and by auditing data on needle localizations. MATERIALS AND METHODS: Between April 1991 and December 1996, 1,400 mammographically guided needle localizations were performed in 1,109 patients. Information entered into the mammographic database included where the initial mammography was performed (inside vs outside the institution), BI-RADS category, mammographic finding, and histopathologic findings. A recorded recommendation was available for 1,312 localizations in 1,097 patients, who composed the study population. RESULTS: The 1,312 localizations yielded 449 (34%) cancers (139 [31%] were ductal carcinoma in situ [DCIS]; 310 [69%] were invasive cancers) and 863 (66%) benign lesions. There were 15 (1%) category 0 lesions; the PPV was 13% (two of 15 lesions). There were 50 (4%) category 2 lesions; the PPV w...
TL;DR: Whole-body PET was more accurate than thoracic CT, bone scintigraphy, and brain CT or MR imaging in staging bronchogenic carcinoma.
Abstract: PURPOSE: To compare the accuracies of whole-body 2-[fluorine 18]fluoro-2-deoxy-d-glucose (FDG) positron emission tomography (PET) and conventional imaging (thoracic computed tomography [CT], bone scintigraphy, and brain CT or magnetic resonance [MR] imaging) in staging bronchogenic carcinoma. MATERIALS AND METHODS: Within 20 months, 100 patients with newly diagnosed bronchogenic carcinoma underwent whole-body FDG PET and chest CT. Ninety of these patients underwent radionuclide bone scintigraphy, and 70 patients underwent brain CT or MR imaging. For each patient, all examinations were completed within 1 month. A radiologic stage was assigned by using PET and conventional imaging independently and was compared with the pathologic stage. The accuracy, sensitivity, specificity, and negative and positive predictive values were calculated. RESULTS: PET staging was accurate in 83 (83%) patients; conventional imaging staging was accurate in 65 (65%) patients (P < .005). Staging with mediastinal lymph nodes was c...
TL;DR: The data confirm that certain US features can help differentiate benign from malignant masses, however, practice and interpreter variability should be further explored before these criteria are generally applied to defer biopsy of solid masses.
Abstract: PURPOSE: To investigate the general applicability and interobserver variability of ultrasonographic (US) features in differentiating benign from malignant solid breast masses. MATERIALS AND METHODS...
TL;DR: The small iron-independent component R2', as compared with that of R2, is consistent with the hypothesis that R2' has higher iron-related specificity.
Abstract: PURPOSE: To determine the transverse relaxation rates R2 and R2′ from several gray matter regions and from frontal cortical white matter in healthy human brains in vivo and to determine the relationship between relaxation rates and iron concentration [Fe]. MATERIALS AND METHODS: Six healthy adults aged 19–42 years underwent thin-section gradient-echo sampling of free induction decay and echo magnetic resonance (MR) imaging at 3.0 T. Imaging covered the mesencephalon and basal ganglia. RESULTS: Relaxation rates (mean ± SD) were highest in globus pallidus (R2 = 25.8 seconds−1 ± 1.1, R2′ = 12.0 seconds−1 ± 2.1) and lowest in prefrontal cortex (R2 = 14.4 seconds−1 ± 1.8, R2′ = 3.4 seconds−1 ± 1.1). Frontal white matter measurements were as follows: R2 = 18.0 seconds−1 ± 1.2 and R2′ = 3.9 seconds−1 ± 1.2. For gray matter, both R2 and R2′ showed a strong correlation (r = 0.92, P < .001 and r = 0.90, P < .001, respectively) with [Fe]. Although the slopes of the regression lines for R2′ versus [Fe] and for R2 ver...
TL;DR: Tumor proteases can be used as molecular targets, allowing visualization of millimeter-sized tumors, and the development of this technology, probe design, and optical imaging systems hold promise for molecular imaging, cancer detection, and evaluation of treatment.
Abstract: PURPOSE: To build and test an optical imaging system that is sensitive to near-infrared fluorescent molecular probes activated by specific enzymes in tumor tissues in mice. MATERIALS AND METHODS: The imaging system consisted of a source that delivered 610–650-nm excitation light within a lighttight chamber, a 700-nm longpass filter for selecting near-infrared fluorescence emission photons from tissues, and a charge-coupled device (CCD) for recording images. The molecular probe was a biocompatible autoquenched near-infrared fluorescent compound that was activated by tumor-associated proteases for cathepsins B and H. Imaging experiments were performed 0–72 hours after intravenous injection of the probe in nude mice that bore human breast carcinoma (BT-20). RESULTS: The imaging system had a maximal spatial resolution of 60 μm, with a field of view of 14 cm2. The detection threshold of the nonquenched near-infrared fluorescent dye was subpicomolar in the imaging phantom experiments. In tissue, 250 pmol of flu...
TL;DR: The fractional distribution volumes of gadopentetate dimeglumine and 99mTc-DTPA are similar and indicate extracellular distribution in normal myocardium and intracellular as well as extrace cellular distribution in reperfused infarction.
Abstract: PURPOSE: To measure the fractional distribution volume of gadopentetate dimeglumine in normal and reperfused infarcted myocardium at magnetic resonance (MR) imaging by using the fractional distribution volume of technetium 99m–diethylenetriaminepentaacetic acid (DTPA) as an independent reference. MATERIALS AND METHODS: Rats were subjected to 1 hour of coronary artery occlusion and 1 hour of reperfusion before inversion-recovery echo-planar imaging or autoradiography. Regional change in relaxation rate (ΔR1) ratios for myocardium over blood were compared with radioactivity ratios for myocardium over blood after the injection of 99mTc-DTPA. RESULTS: Both ΔR1 and radioactivity ratios demonstrated equilibrium distribution and hence represent partition coefficients (λ). The fractional distribution volumes were greater in infarcted myocardium (0.90 ± 0.05 for gadopentetate dimeglumine and 0.89 ± 0.04 for 99mTc-DTPA) than in normal myocardium (0.23 ± 0.02 for gadopentetate dimeglumine and 0.16 ± 0.01 for 99mTc-D...
TL;DR: The addition of 3D MR spectroscopic imaging to MR imaging improves accuracy for less experienced readers and reduces interobserver variability in the diagnosis of ECE of prostate cancer.
Abstract: PURPOSE: To determine if the addition of three-dimensional (3D) proton magnetic resonance (MR) spectroscopic imaging to endorectal MR imaging helps diagnose extracapsular extension (ECE) of prostate cancer. MATERIALS AND METHODS: Endorectal MR imaging and 3D MR spectroscopic imaging were performed in 53 patients with prostate cancer before radical prostatectomy. MR imaging studies were evaluated by two independent readers unaware of histopathologic findings. The presence of ECE was graded on a five-point scale. At 3D MR spectroscopic imaging, cancer was diagnosed if the ratio of choline plus creatine to citrate was 2 or more SDs above normal. The accuracy of MR imaging alone was compared with that of combined MR imaging and 3D MR spectroscopic imaging, with use of the step-section histopathologic results as the standard of reference. RESULTS: For the less experienced reader, the addition of 3D MR spectroscopic imaging to MR imaging significantly improved accuracy (area under the receiver operating charact...
TL;DR: Most of the T1 and T2 findings appear to be related to changes in iron content and form and may possibly be used as indicators of such changes.
Abstract: PURPOSE: To investigate the potential of magnetic resonance imaging for identification and quantification of brain iron in healthy subjects, patients with Parkinson disease, and patients with multiple system atrophy. MATERIALS AND METHODS: Forty-nine subjects were studied at 1.5 T. Regional T1 and T2 values were compared among groups and also with histopathologic estimates of iron concentration. RESULTS: In healthy subjects, interregional T1 and T2 differences in the cortex and basal ganglia showed a good correlation with reported values for iron concentration, and intraregional variations were generally consistent with reported variability of iron concentration. Patients with multiple system atrophy had T1 and T2 shortening in the globus pallidus consistent with reported increases in ferritin-bound iron and changes in the putamen consistent with accumulation of hemosiderin (posterior portion) and neuromelanin (remainder). Both groups of patients had changes in the cortex that are consistent with decrease...
TL;DR: Except for NIPF, the various subtypes of idiopathic interstitial pneumonias often have a characteristic appearance that allows differentiation at thin-section CT.
Abstract: PURPOSE: To determine whether idiopathic interstitial pneumonias can be differentiated on the basis of the pattern and distribution of abnormalities at thin-section computed tomography (CT). MATERIALS AND METHODS: Thin-section CT scans in 129 patients with histologically proved idiopathic interstitial pneumonia (35 with usual interstitial pneumonia [UIP], 24 with bronchiolitis obliterans organizing pneumonia [BOOP], 23 with desquamative interstitial pneumonia [DIP], 20 with acute interstitial pneumonia [AIP], and 27 with nonspecific interstitial pneumonia and fibrosis [NIPF]) were independently assessed by two observers without knowledge of clinical or histologic data. The observers recorded the abnormalities, diagnosis, and degree of confidence in their diagnosis. Differential diagnosis was limited to the five types of idiopathic interstitial pneumonia. RESULTS: The two observers made a correct diagnosis, on average, in 74 (57%) cases. On average, the correct diagnosis was made in 25 (71%) cases of UIP, ...
TL;DR: Systematic overestimation and moderate interobserver agreement may compromise subjective visual grading of emphysema, which suggests that subjectiveVisual grading should be supplemented with objective methods to achieve precise, reader-independent quantification of empysema.
Abstract: PURPOSE: To compare subjective visual grading of pulmonary emphysema with macroscopic morphometry and computed tomographic (CT) densitometry. MATERIALS AND METHODS: In 62 consecutive patients who underwent thin-section CT before surgical lung resection, emphysema was objectively quantified with computer-assisted macroscopic morphometry and CT densitometry. The percentage of lung macroscopically occupied by emphysema was compared with the percentage occupied on CT scans by pixels with attenuation values lower than a predefined threshold (CT densitometry). Three readers with varying degrees of expertise subjectively graded emphysema with visual assessment at two reading sessions. Data from objective quantification and subjective grading were analyzed with correlation coefficients, and interobserver and intraobserver agreement were calculated. RESULTS: Subjective grading of emphysema showed less agreement with the macroscopic reference standard results (r = 0.439–0.505; P < .05) than with objective CT densit...
TL;DR: Gray matter is mildly anisotropic in normal and early ischemic states, however, early white matter ischemia is associated with not only changes in trace ADC values but also significant changes in the anisotropy, or shape, of the water self-diffusion tensor.
Abstract: PURPOSE: To (a) determine the optimal choice of a scalar metric of anisotropy and (b) determine by means of magnetic resonance imaging if changes in diffusion anisotropy occurred in acute human ischemic stroke. MATERIALS AND METHODS: The full diffusion tensor over the entire brain was measured. To optimize the choice of a scalar anisotropy metric, the performances of scalar indices in simulated models and in a healthy volunteer were analyzed. The anisotropy, trace apparent diffusion coefficient (ADC), and eigenvalues of the diffusion tensor in lesions and contralateral normal brain were compared in 50 patients with stroke. RESULTS: Changes in anisotropy in patients were quantified by using fractional anisotropy because it provided the best performance in terms of contrast-to-noise ratio as a function of signal-to-noise ratio in simulations. The anisotropy of ischemic white matter decreased (P = .01). Changes in anisotropy in ischemic gray matter were not significant (P = .63). The trace ADC decreased for ...
TL;DR: Stepping-table digital subtraction contrast material-enhanced MR angiography has high accuracy compared with catheterAngiography in patients with arterio-occlusive disease of the aorta and outflow vessels and these preliminary study results suggest that this technique may ultimately provide a safe, noninvasive, and cost-effective alternative to catheter Angiography.
Abstract: PURPOSE: To compare stepping-table digital subtraction gadolinium-enhanced magnetic resonance (MR) angiography of the distal aorta and lower extremity arteries with conventional catheter digital subtraction x-ray angiography in patients with arterio-occlusive disease. MATERIALS AND METHODS: Twenty patients underwent both conventional catheter angiography and fast three-dimensional gadolinium-enhanced MR angiography of the aorta and outflow vessels at 1.5 T; the images were acquired in three consecutive imaging locations during a single infusion of a gadolinium chelate. RESULTS: Compared with catheter angiography, according to the findings of two blinded independent reviewers, MR angiography had sensitivities of 81% and 89% and specificities of 91% and 95%, respectively, for demonstration of insignificant (≤50%) stenosis versus significant (51%–100%) stenosis. For demonstration of occlusion, the sensitivity and specificity were 94% and 97%, respectively, by consensus. There was good interobserver correlati...