Showing papers in "Radiology in 1998"
2,787 citations
TL;DR: The volumetric score showed better reproducibility than the traditional score, and its variability was considerably less than the score increase in untreated patients after 1 year.
Abstract: PURPOSE: To assess the variability and reproducibility of a volumetric calcium score calculated with electron-bean computed tomographic (CT) scans of coronary arteries. MATERIALS AND METHODS: Two sets of electron-beam CT scans were obtained in patients with coronary calcification (group A) or known risk factors for coronary arterial disease (group B). The second set or scans was obtained after a brief interval (group A, n = 52) or after 1 year with no risk modification (group B, n = 27). Traditional (plaque area and attenuation) and volumetric calcium scores were calculated for each patient and lesion. RESULTS: The median percentage change for individual lesions in group A was 13% for the volumetric and 19% for the traditional score. The overall reduction in error with the volumetric score was 40% (P < .001). The median percentage change for group A patient totals was 9% for the volumetric and 15% for the traditional score (P < .001). In group B patients, the median volumetric score increased by 44% after...
761 citations
TL;DR: The D values primarily reflect overall brain water content and the A sigma values are more sensitive to tissue microstructure (e.g., white matter packing and myelination), which reveal information and not apparent on T1- and T2-weighted images.
Abstract: PURPOSE: To establish quantitative standards for the directionally averaged water apparent diffusion coefficient (D) and quantitative diffusion anisotropy (A sigma) of normal brains in newborns by using diffusion tensor magnetic resonance (MR) imaging. MATERIALS AND METHODS: Diffusion tensor MR imaging was performed during the first 36 hours of life in 22 newborns (gestational age range, 31-41 weeks). Values of D and A sigma were measured in regions of interest chosen in the cortical gray matter, centrum semiovale, caudate nuclei, lentiform nuclei, thalami, internal capsules, and cerebellar hemispheres. RESULTS: The D values in the gray and white matter in newborns are considerably higher than those in adults. There is a striking correlation between gestational age and D, with D decreasing as gestational age increases. The A sigma values in the white matter in newborns are lower than those in adults. Values of A sigma show statistically significant correlations with gestational age only in the white matte...
659 citations
TL;DR: Screening US can depict small, early-stage, otherwise occult cancers similar in size and stage to mammographically identified nonpalpable cancers and smaller and lower in stage than palpable cancers in dense breasts.
Abstract: PURPOSE: To evaluate bilateral screening ultrasound (US) in the detection of otherwise occult masses and cancer in women with dense breasts and normal mammographic and physical examination findings. MATERIALS AND METHODS: Of 11,220 consecutive patients prospectively examined, all 3,626 women with dense breasts and normal mammographic and physical examination findings underwent physician-performed screening US. The size and stage of cancers detected with US alone were compared with those of cancers detected on mammograms, at physical examination, or both, in the remainder of the patients. RESULTS: In the group of 3,626 women, 11 surgically proved cancers in 11 women (prevalence, 0.30%) were identified with US alone. These cancers were not statistically significantly different in mean surgical size and stage from those of 61 nonpalpable, mammographically detected cancers and were smaller and lower in stage than 64 palpable cancers (P < .01) that were diagnosed in the remainder of the population. In the wome...
468 citations
TL;DR: In patients younger than 50 years, disk extrusion and sequestration, nerve root compression, end plate abnormalities, and osteoarthritis of the facet joints are rare and, therefore, may be predictive of low back pain in symptomatic patients.
Abstract: PURPOSE: To identify the magnetic resonance (MR) abnormalities of the lumbar spine that have a low prevalence in asymptomatic patients and thus determine the findings that are predictive of low back pain in symptomatic patients. MATERIALS AND METHODS: Sagittal T1-weighted and sagittal and axial T2-weighted MR images were obtained in 60 asymptomatic volunteers aged 20-50 years. The MR images were evaluated with regard to intervertebral disk abnormalities, end plate abnormalities, and osteoarthritis of the facet joints by two musculoskeletal radiologists independently. RESULTS: Disk bulging or disk protrusion was found in 42 (14%) and 48 (16%) of the intervertebral spaces in 37 (62%) and 40 (67%) subjects, respectively. High-signal-intensity zones were found commonly (in 23 [7.7%] and 25 [8.3%] of the intervertebral spaces in 19 (32%) and 20 (33%) subjects, respectively). Disk extrusions were less common (in 11 [3.7%] and 11 [3.7%] of the intervertebral spaces in 11 (18%) and 11 (18%) subjects, respectively...
450 citations
TL;DR: As the first gadolinium-based blood pool agent in human trials, MS-325 has the potential to enhance both dynamic and steady-state MR angiograms and provides vascular signal enhancement superior to that provided with other agents.
Abstract: PURPOSE: To evaluate the protein-binding and signal enhancement characteristics of MS-325, a gadolinium-based magnetic resonance (MR) imaging blood pool agent that binds to albumin, and compare results with those obtained with existing gadolinium- and iron oxide-based agents. MATERIALS AND METHODS: Protein binding in human plasma was measured by means of ultrafiltration. T1 relaxation times (20 MHz) were measured in human plasma or ex vivo samples from rabbits and monkeys injected with 0.1 mmol of MS-325 per kilogram of body weight. Imaging (three-dimensional fast imaging with steady-state precession, or FISP) was performed at 1.0 T in phantoms, which contained varying concentrations of different agents, or rabbits after injection of 0.015-0.100 mmol/kg MS-325. RESULTS: MS-325 is 80%-96% bound in human plasma and exhibits a relaxivity approximately six to 10 times that of gadolinium diethylenetriaminepentaacetic acid (DTPA). Images of phantoms containing MS-325 were significantly brighter than those conta...
446 citations
TL;DR: In phantoms and humans, application of amplitude-modulated radio-frequency irradiation during the control image corrected for saturation across the whole brain and made possible cerebral blood flow imaging in multiple sections at arbitrary angles to the labeling plane.
Abstract: A method was evaluated to control for off-resonance saturation in noninvasive magnetic resonance imaging with continuous arterial spin labeling of cerebral blood flow. In phantoms and humans, application of amplitude-modulated radio-frequency irradiation during the control image corrected for saturation across the whole brain and made possible cerebral blood flow imaging in multiple sections at arbitrary angles to the labeling plane.
406 citations
TL;DR: Diffusion-weighted MR imaging provided excellent distinction between pathologic and benign vertebral compression fractures.
Abstract: PURPOSE: To evaluate the usefulness of diffusion-weighted magnetic resonance (MR) imaging of bone marrow for differentiating between benign and pathologic vertebral compression fractures. MATERIALS AND METHODS: Thirty patients with 39 vertebral compression fractures were examined with MR imaging. Diffusion-weighted MR imaging was performed with a steady-state free precession sequence in 22 acute benign osteoporotic and/or traumatic fractures and 17 pathologic compression fractures. Biplanar radiographs, T1-weighted spin-echo (SE) MR images, and short inversion time inversion-recovery (STIR) MR images were available for all patients. The signal intensity characteristics were analyzed qualitatively and quantitatively (bone marrow contrast ratios and signal-to-noise ratios) for all sequences. RESULTS: At diffusion-weighted MR imaging, all benign vertebral compression fractures were hypo- to isointense to adjacent normal vertebral bodies. Pathologic compression fractures were hyperintense to normal vertebral ...
404 citations
TL;DR: FDG PET has a high sensitivity and specificity for detection of colorectal carcinomas (primary and liver metastases) and appears to be superior to CT in the staging of primary coloreCTal carcinoma.
Abstract: PURPOSE: To evaluate the diagnostic usefulness of positron emission tomography (PET) with fluorine-18 fluorodeoxyglucose (FDG) in patients with primary colorectal carcinomas. MATERIALS AND METHODS: Forty-eight patients with biopsy-proved (n = 44) or high clinical suspicion for (n = 4) colorectal cancer underwent whole-body PET after intravenous administration of 10 mCi (370 MBq) of FDG. FDG PET results were correlated with computed tomographic (CT), surgical, and histopathologic findings. RESULTS: PET depicted all known intraluminal carcinomas in 37 patients (including two in situ carcinomas) (sensitivity, 100%), but findings were false-positive in four of seven patients without cancer (three with inflammatory bowel conditions, one who had undergone polypectomy). Specificity was 43% (three of seven patients); positive predictive value, 90% (37 of 41 patients); and negative predictive value, 100% (three of three patients). No FDG accumulation was noted in 35 hyperplastic polyps. FDG PET depicted lymph node...
403 citations
TL;DR: In asymptomatic adults aged 65 years or older, that risk of incident stroke was associated with two US features: hypoechoic internal carotid arterial plaque and an estimated internal carotin arterial stenosis of 50%-100%.
Abstract: PURPOSE: To investigate the association between incident (first) stroke and the echogenicity of internal carotid arterial plaque at ultrasonography (US). MATERIALS AND METHODS: A cohort of 4, 886 individuals who, at baseline, were 65 years of age or older and without symptoms of cerebrovascular disease was followed up for an average of 3.3 years. Baseline clinical findings were from color Doppler and duplex US studies of the carotid arteries and a record of traditional risk factors: age, sex, presence of diabetes mellitus, pack-years of cigarette smoking, presence of hypertension, elevated systolic and diastolic blood pressure, elevated low-density lipoprotein cholesterol level. RESULTS: Incident strokes, excluding hemorrhagic strokes and strokes of cardiac origin, were seen in 104 individuals (2.1%) at risk. Age- and sex-adjusted odds ratios for incident stroke were significant for hypoechoic plaque (odds ratio, 2.53; 95% CI, 1,42,4.53). After controlling for risk factors in a Cox proportional hazards mo...
397 citations
TL;DR: Simultaneous RF application to a cluster of three closely spaced internally cooled electrodes enables a larger volume of coagulation in ex vivo liver, in vivo tissues, and hepatic colorectal metastases than previously reported.
Abstract: PURPOSE: To evaluate whether coagulation necrosis achievable with radio-frequency (RF) ablation can be increased by using a cluster of closely spaced electrodes. MATERIALS AND METHODS: RF was applied to ex vivo liver (n = 68), in vivo liver (n = 12), and in vivo muscle (n = 15) by using a cluster array of three separate internally cooled electrodes spaced 0.5 cm apart. The diameter of coagulation necrosis achieved with optimal RF deposition (1,400-2,150 peak mA) for 5-60 minutes of RF application was determined for electrode tip lengths of 1.5-3.0 cm and compared with that obtained by using a single electrode and otherwise similar technique. Ten patients with solitary intrahepatic colorectal metastases were also treated by using cluster electrode RF ablation. RESULTS: In ex vivo liver, simultaneous RF application to electrode clusters for 15, 30, and 45 minutes produced 4.7 cm +/- 0.1, 6.2 cm +/- 0.1, and 7.0 cm +/- 0.2 of coagulation necrosis, respectively. In in vivo liver and muscle, RF applied to elec...
TL;DR: Age is a minor determinant of mammographic sensitivity in women aged 40 years or older and sensitivity is substantially decreased with the combination of higher breast density and estrogen replacement therapy use, and there was not a notable shift in cancer outcomes in the groups with lower mammography sensitivity.
Abstract: PURPOSE: To examine how common patient factors affect screening mammographic sensitivity and cancer stage at diagnosis. MATERIALS AND METHODS: The authors used a population-based database of 183,134 screening mammograms and a statewide tumor registry to identify 807 breast cancers detected at screening mammography. RESULTS: Sensitivity varied significantly with ethnicity, use of estrogen replacement therapy, mammographic breast density, and age. Sensitivity was 54% (13 of 24) in women younger than 40 years, 77% (121 of 157) in women aged 40-49 years, 78% (224 of 286) in women aged 50-64 years, and 81% (277 of 340) in women older than 64 years. Sensitivity was 68% (162 of 237) for dense breasts and 85% (302 of 356) for nondense breasts and 74% (180 of 244) in estrogen replacement therapy users and 81% (417 of 513) in nonusers. Sensitivity was most markedly reduced with the combination of dense breasts and estrogen replacement therapy use; there was little difference when only one factor was present. Median...
TL;DR: Uterine arterial embolization is an effective therapy in the management of symptomatic leiomyomas and may prove to be a valuable alternative to myomectomy, hysterectom, or other surgical procedures.
Abstract: PURPOSE: To determine the effectiveness of uterine arterial embolization as a primary therapy in the management of symptomatic leiomyomas. MATERIALS AND METHODS: Uterine arterial embolization was performed in 53 patients (age range, 33-58 years) with menorrhagia, bulk-related symptoms (frequency of urination, sensation of pressure, sensation of mass), or both, due to leiomyomas. The effectiveness of this therapy in the control of symptoms and the patients' acceptance of the treatment were measured by means of the information from patient interviews 3 months after the procedure. RESULTS: Fifty-two (98%) of the 53 patients had technically successful procedures and were interviewed 3 months after embolization. Forty-six (88%) of these patients reported marked improvement in their abnormal bleeding. Twenty-nine (94%) of the 31 patients with bulk-related symptoms reported marked improvement in these symptoms. Follow-up ultrasonographic examinations showed a mean 46% reduction in uterine volume. Forty-one patie...
TL;DR: CT performed slightly better than MR imaging for all interpretative criteria, however, a high NPV was achieved only when a low size criterion was used and was therefore associated with a relatively low PPV.
Abstract: PURPOSE: To compare the abilities of magnetic resonance (MR) imaging and computed tomography (CT) in detection of lymph node metastasis from head and neck squamous cell carcinoma. MATERIALS AND METHODS: MR imaging and CT were performed with standard protocols in patients with known carcinoma of the oral cavity, oropharynx, hypopharynx, or larynx. Histopathologic examination was performed to validate imaging findings. Between 1991 and 1994, 213 patients undergoing 311 neck dissections were accrued at three institutions. RESULTS: For the upper jugular and spinal accessory regions, the areas under the receiver operating characteristic curves for combined information on size and internal abnormality were 0.80 for CT and 0.75 for MR imaging. Sensitivities, specificities, negative predictive values (NPVs), and positive predictive values (PPVs) were calculated for various size criteria with and without internal abnormality information. With use of a 1-cm size or an internal abnormality to indicate a positive nod...
TL;DR: Normal reference values for morphologic variants and diameter measurements of the circle of Willis specific to three dimensional time-of-flight MR angiography are determined.
Abstract: PURPOSE: To establish normal reference values for the presence of the anatomic variants of the circle of Willis and average diameters for its component vessels by using three-dimensional time-of-flight magnetic resonance (MR) angiography and to determine whether age- or sex-related differences exist in the circle's anatomy. MATERIALS AND METHODS: One hundred fifty volunteers were grouped according to age: those aged 20-25 years (n = 50) and those aged 60-88 years (n = 100). All subjects underwent three-dimensional time-of-flight MR angiography of the arterial circle at 1.5 T. The anatomic variants of the anterior and posterior parts of the circle were determined separately, the completeness of the entire circle was assessed, and the diameters of all component vessels were measured. RESULTS: On MR angiograms, 111 (74%) subjects demonstrated a complete anterior part of the circle, 78 (52%) demonstrated a complete posterior part of the circle, and 63 (42%) demonstrated an entirely complete circle of Willis (...
TL;DR: Perfusion CT not only allows early detection of cerebral ischemia but also yields valuable information about the extent of perfusion disturbances in ischemic territories.
Abstract: PURPOSE: To determine the value of perfusion computed tomography (CT) in a clinical study of patients with stroke and compare the results with single photon emission CT (SPECT) findings. MATERIALS AND METHODS: Perfusion CT was performed within 6 hours of symptom onset in 32 patients with possible stroke. Cerebral blood volume (CBV), cerebral blood flow (CBF), and time to peak contrast material enhancement were calculated on the basis of the CT results. Cerebral SPECT was also performed in a subgroup of 18 patients. Perfusion CT and SPECT findings were compared in a lesion-by-lesion analysis. Perfusion CT results were compared with follow-up CT and magnetic resonance imaging findings. RESULTS: Areas of reduced CBF were detected with the aid of perfusion CT in 25 of 28 patients with a proved infarct (sensitivity, 89%). The results of the CBF maps corresponded well to SPECT findings in 13 (81%) of 16 patients, but ischemia was located outside the scanning level in the other three patients and was therefore m...
TL;DR: Percutaneous biopsy of a nonpalpable breast mass with either US or stereotactic guidance is less expensive than surgery, but cost savings are greater with US-guided biopsy.
Abstract: PURPOSE: To determine the frequency with which ultrasonographically (US) guided core biopsy obviated diagnostic surgical biopsy of nonpalpable breast masses, to calculate the cost savings of diagnosis attributable to US-guided core biopsy, and to compare the costs of US-guided versus stereotactically guided core biopsy. MATERIALS AND METHODS: US-guided core biopsy was performed in 151 consecutive solitary, nonpalpable breast masses in 151 women (age range, 23-80 years) by using a 14-gauge automated gun and needle. Clinical follow-up data were obtained. Cost savings were assessed by using national Medicare reimbursement costs of +385 for US-guided core biopsy, +610 for stereotactic core biopsy, and +1,332 for needle localization and surgical biopsy. RESULTS: US-guided core biopsy obviated a surgical procedure in 128 (85%) of 151 women. The mean adjusted direct cost saving per US-guided core biopsy was +744 per case. Use of US-guided biopsy decreased the cost of diagnosis by 56% (+744/+1,332) over the cost ...
TL;DR: Moving-bed infusion-tracking MR angiography proved to be a robust technique, and image quality on maximum intensity projection images was comparable with that on conventional angiograms.
Abstract: PURPOSE: To evaluate a magnetic resonance (MR) angiographic technique for imaging of the peripheral arteries with gadolinium enhancement. MATERIALS AND METHODS: Moving-bed infusion-tracking MR angiograms were obtained in 15 healthy volunteers and in 28 patients with intermittent claudication before and during slow infusion of contrast material. Lower- and upper-leg and pelvic regions were imaged. Unenhanced images were subtracted from gadolinium-enhanced images, and maximum intensity projection images were generated. Image quality was evaluated subjectively and objectively, and maximum intensity projection images were compared with conventional angiograms, which served as the standard of reference. RESULTS: Moving-bed infusion-tracking MR angiography proved to be a robust technique, and image quality on maximum intensity projection images was comparable with that on conventional angiograms. Sensitivity and specificity for grading hemodynamically significant stenoses were 93% and 98%, respectively, with ex...
TL;DR: Half-Fourier RARE MRCP enables accurate evaluation of pancreaticobiliary disease and obviates ERCP in some patients.
Abstract: PURPOSE: To determine prospectively the clinical applications and diagnostic accuracy of half-Fourier rapid acquisition with relaxation enhancement (RARE) magnetic resonance (MR) cholangiopancreatography (MRCP) in a large patient population. MATERIALS AND METHODS: Breath-hold, heavily T2-weighted half-Fourier RARE MRCP was performed in 265 patients with suspected pancreaticobiliary disease and in 35 control patients without symptoms or signs referrable to the biliary tract or pancreatic duct. MRCP findings were correlated with those at direct cholangiography, pathologic examination, cross-sectional imaging, and clinical follow-up. RESULTS: Diagnostic MRCP examinations were obtained in 299 (99.7%) subjects. MRCP yielded an accuracy of 100% in determining the presence of pancreaticobiliary disease, the presence and level of biliary obstruction, and obstruction due to bile duct calculi. The accuracy of MRCP and MR imaging in determining the presence and level of malignant obstruction was 98.2%. MRCP obviated...
TL;DR: PET may provide more information about extranodal lymphoma than does incremental CT and in 13 patients, PET findings led to changes in tumor staging.
Abstract: PURPOSE: To evaluate use of functional imaging with positron emission tomography (PET) versus computed tomography (CT) for detection of extranodal lymphoma spread. MATERIALS AND METHODS: Eighty-one consecutive and previously untreated patients with malignant non-Hodgkin lymphoma (n = 43) or Hodgkin disease (n = 38) were examined with 2-[fluorine-18]fluoro-2-deoxy-D-glucose (FDG) PET and contrast material-enhanced CT. Concordant findings at both CT and FDG PET were regarded as actual locations of disease; discordant results were resolved on the basis of biopsy or follow-up results when possible. RESULTS: Forty-two lesions were identified at both PET and CT, and 19 were verified with biopsy results. PET demonstrated a further 24 lesions. Verification was possible in 15 of these lesions with biopsy (n = 10), magnetic resonance imaging (n = 1), scintigraphic (n = 1), or follow-up (n = 3) results. In 14 of these 15 lesions, PET findings were confirmed (bone marrow, nine; spleen, three; other, two). Seven lesio...
TL;DR: Use of dual-phase helical CT improves prediction of resectability in patients with pancreatic cancer.
Abstract: PURPOSE: To evaluate the use of dual-phase helical computed tomography (CT) (with or without CT angiography) to assess resectability in patients suspected to have pancreatic cancer. MATERIALS AND METHODS: Tumor resectability was prospectively evaluated in 89 patients who later underwent surgery for suspected pancreatic cancer. Helical CT scans were obtained in the vascular phase and a phase of maximal hepatic enhancement. CT angiograms were produced with multiprojection volume reconstruction and maximum-intensity projection. CT results were correlated with surgical and histopathologic results. RESULTS: Helical CT allowed detection of pancreatic cancer in 74 of 76 cases (97%). There were six false-positive results (positive predictive value, 92%). For prediction of irresectability, helical CT had an accuracy of 91%, negative predictive value of 79%, and sensitivity of 91%. Helical CT allowed detection of liver metastases in 21 of 28 cases (75%), nodal involvement in 13 of 24 cases (54%), and vascular invasion in 35 of 40 cases (88%). CT angiography demonstrated 30 of the 35 cases of vascular invasion detected with helical CT (86%). CONCLUSION: Use of dual-phase helical CT improves prediction of resectability in patients with pancreatic cancer. CT angiography cannot show all of the findings seen on helical scans.
TL;DR: Reduction in cardiac output results in a substantial increase in peak aortic enhancement but not in peak hepatic enhancement, and as cardiac output decreases, the times to the arrival of the contrast medium bolus in the aorta and to peakAortic and hepatic Enhancement increase.
Abstract: PURPOSE: To investigate how reduction in cardiac output affects the magnitude and timing of aortic and hepatic contrast medium enhancement during abdominal computed tomography (CT). MATERIALS AND METHODS: Eight 20-30-kg pigs underwent CT before and after pharmacologic reduction of cardiac output (measured by means of thermodilution). Each CT study consisted of 53 dynamic images acquired every 5 seconds at a fixed level through the midliver after intravenous injection of contrast medium (concentration, 282 mg of iodine per milliliter; dose, 2 mL per kilogram of body weight; injection rate, 2 mL/sec). Curves of contrast medium enhancement versus time were measured. Changes in the magnitude and timing of aortic and hepatic enhancement were compared with the reduction in cardiac output. RESULTS: With reduction in cardiac output, the time from the injection start to the arrival of the contrast medium bolus in the aorta (P < .01) and the times from injection completion to peak aortic (P < .01) and peak hepatic ...
TL;DR: Pneumatosis, often linear or cystic in appearance, is seen with increased frequency in patients who are immunocompromised because of steroids, chemotherapy, radiation therapy, or AIDS, and in cases of chronic obstructive pulmonary disease, asthma, and cystic fibrosis.
Abstract: This review illustrates the changing paradigms in the understanding of the pathogenesis of pneumatosis intestinalis. Although many theories have been evoked, pragmatically there appear to be four major clinical and diagnostic imaging considerations. The most common and most emergent life-threatening cause of intramural bowel gas is the result of bowel necrosis due to bowel ischemia, infarction, necrotizing enterocolitis, neutropenic colitis, volvulus, and sepsis. In the stomach, intramural gas can be caused by emphysematous gastritis or ingestion of caustic agents. These situations represent surgical emergencies. Pneumatosis is found secondary to mucosal disruption presumably due to over-distention from peptic ulcer, pyloric stenosis, annular pancreas, and even to more distal obstruction. Disruption can also be caused by ulceration, erosions, or trauma, including the trauma of child abuse. Disruption can also be iatrogenic from intracatheter jejunal feeding tubes, stent perforation, sclerotherapy, or surgical or endoscopic trauma. In these cases, the gas may be focal or linear. Treatment depends on the extent of the disruption and the underlying cause. A more subtle form of mucosal disruption may occur due to mucosal erosions and also to defects in intestinal crypts secondary to acute and subclinical enteritides that allow intraluminal bacterial gas under pressure to percolate into the bowel wall layers, particularly the submucosa (29). Pneumatosis, often linear or cystic in appearance, is seen with increased frequency in patients who are immunocompromised because of steroids, chemotherapy, radiation therapy, or AIDS. In these cases, the pneumatosis may result from intraluminal bacterial gas entering the bowel wall due to increased mucosal permeability caused by defects in bowel wall lymphoid tissue. Clinical and imaging findings are important in the differentiation of this transient pneumatosis from fulminant life-threatening causes in this subset of patients. A pulmonary cause must still be considered in cases of chronic obstructive pulmonary disease, asthma, and cystic fibrosis. It can occur with barotrauma and after chest tube placement. It may relate to increased intrathoracic pressure associated with retching and vomiting. The possibility remains that occasionally the origin of pneumatosis intestinalis will remain cryptogenic--caused but unexplained.
TL;DR: Endovascular coil embolization seems to be a reliable technique, with good anatomic and clinical results, that provides protection against rebleeding of ruptured aneurysms.
Abstract: PURPOSE: To determine the types of aneurysm that may be treated endovascularly with platinum detachable coils. MATERIALS AND METHODS: Two hundred eight patients with 236 intracranial berry aneurysms underwent endovascular coil embolization; 150 patients had subarachnoid hemorrhage at the time of presentation. RESULTS: Treatment was performed in 182 patients with 203 (86%) aneurysms (86%). Follow-up angiograms were obtained at 3 months in 160 cases of aneurysm. A second procedure was performed in 18 (11%) of these cases, and a third was performed in one case. Final follow-up results in 152 aneurysms demonstrated total occlusion in 123 (81%) cases, subtotal occlusion in 26 (17%) cases, and incomplete occlusion in three (2%) cases. All patients with subtotally occluded aneurysm were scheduled for later angiographic follow-up and any indicated repeat treatment. Technique-related morbidity rate was 4% (seven patients with permanent neurologic deficits due to clotting). Technique-related mortality rate was 2% (...
TL;DR: Stereotactic, 11-gauge, directional, vacuum-assisted biopsy resulted in successful calcification retrieval in 106 (95%) of 112 cases and histologic underestimation was infrequent.
Abstract: PURPOSE: To determine the frequencies of calcification retrieval and histologic underestimates at stereotactic, 11-gauge, directional, vacuum-assisted breast biopsy. MATERIALS AND METHODS: Retrospective review of records revealed 112 calcific lesions in 80 women (aged 31-85 years) who underwent stereotactic, 11-gauge, directional, vacuum-assisted biopsy; a mean of 14 specimens per lesion were obtained. Calcification retrieval was defined as identification of calcifications on radiographs of specimens. Atypical ductal hyperplasia (ADH) underestimates were lesions that yielded ADH at stereotactic biopsy and carcinoma at surgery. Ductal carcinoma in situ (DCIS) underestimates were lesions that yielded DCIS at stereotactic biopsy and infiltrating carcinoma at surgery. Mammograms, stereotactic images, radiographs of specimens, and histologic findings were reviewed. RESULTS: Stereotactic, 11-gauge, directional, vacuum-assisted biopsy removed all calcifications in 51 (46%) lesions, some calcifications in 55 (49%...
TL;DR: A computer-based, physiologic model that may help predict organ-specific CT contrast medium enhancement for different injection protocols was developed and may have many clinical applications.
Abstract: PURPOSE: To develop a physiologic model of contrast medium enhancement by incorporating available physiologic data and contrast medium pharmacokinetics and to predict organ-specific contrast medium enhancement at computed tomography (CT) with various contrast medium injection protocols in patients of variable height and weight. MATERIALS AND METHODS: A computer-based, compartmental model of the cardiovascular system was generated by using human physiologic parameters and more than 100 differential equations to describe the transport of contrast medium. Blood volume, extracellular fluid volume, and regional blood flow were estimated from available data. Local structures were modeled mathematically to describe the distribution and dispersion of intravascularly administered iodinated contrast medium. A global model was formed by integrating regional circulation parameters with the models of local structures. Aortic and hepatic CT contrast-enhancement curves were simulated for three protocols and were compare...
TL;DR: AMI-227 is safe and may facilitate the differentiation of metastatic and benign nodes in patients with urologic and pelvic cancers.
Abstract: PURPOSE: To evaluate the clinical and biologic safety of ultrasmall superparamagnetic iron oxide particles (AMI-227) as a contrast agent for magnetic resonance (MR) lymphography and to assess their efficacy for the differentiation of metastatic and benign nodes in patients with urologic and pelvic cancer. MATERIALS AND METHODS: Thirty adults suspected of having lymph node metastases underwent MR imaging before and 22-26 hours after intravenous infusion of AMI-227 (1.7 mg Fe/kg). Sixty histopathologically proved lymph nodes were analyzed on MR images, and 29 of these nodes were also analyzed quantitatively. RESULTS: AMI-227 was well tolerated with no major side effects. It allowed the detection of 10 additional nodes relative to those detected at MR imaging without AMI-227. None of the 27 metastatic nodes showed a decrease in signal intensity (SI) on AMI-227-enhanced images; nine of 27 metastatic nodes showed an increase in SI on T1-weighted images, probably resulting from altered capillary permeability in...
TL;DR: Emergency arterial embolization is a safe and effective means of control of primary postpartum hemorrhage and obviates high-risk surgery and allows maintenance of reproductive ability.
Abstract: PURPOSE: To prospectively evaluate the efficacy and safety of emergency selective arterial embolization in the management of intractable primary postpartum hemorrhage. MATERIALS AND METHODS: Twenty-seven consecutively seen women with life-threatening primary postpartum hemorrhage underwent uterine embolization. In all cases, hemostatic embolization was performed because of intractable hemorrhage that could not be controlled with vaginal packing and administration of uterotonic drugs. The mean hemoglobin level before embolization was 7.48 g/dL +/- 2.39 (74.8 g/L +/- 23.9) (1 standard deviation). Hysterectomy performed in two patients before embolization failed to stop the bleeding. RESULTS: Angiography revealed extravasation in nine patients and spasm of the branches of the internal iliac artery in five. The procedure consisted of embolization of uterine (n = 46), vaginal (n = 5), or ovarian (n = 2) arteries or anterior division of internal iliac arteries (n = 8). Immediate disappearance or dramatic diminu...
TL;DR: Annular tears and focal disk protrusions on MR images, with or without contrast enhancement, are frequently found in an asymptomatic population.
Abstract: PURPOSE: To evaluate the prevalence and radiologic findings of annular tear (especially of contrast material enhancement), bulging disk, and disk herniation on T2-weighted and gadolinium-enhanced T1-weighted magnetic resonance (MR) images in people without low back pain (LBP) or sciatica. MATERIALS AND METHODS: Thirty-six volunteers without LBP and/or sciatica (18 with no symptoms in their lifetime and 18 who were pain free for at least 6 months) were examined with sagittal and axial T2-weighted fast spin-echo (SE) and sagittal gadolinium-enhanced T1-weighted fast SE imaging. The prevalence and MR findings of bulging disk, focal protrusion, extrusion, and nonenhancing or enhancing annular tears were assessed. RESULTS: The prevalence of bulging disk and focal disk protrusion was 81% (29 volunteers) and 33% (12 volunteers), respectively. There were no extrusions. Twenty-eight annular tears were found in 20 patients (56%); 27 tears (96%) also showed contrast enhancement. CONCLUSION: Annular tears and focal d...
TL;DR: Use of injection rates above 2 mL/sec did not substantially increase hepatic peak enhancement but helped increase the magnitude of arterial enhancement and temporal separation of arterials and venous phases of enhancement for dual-phase spiral CT.
Abstract: PURPOSE: To investigate the effect of injection rate of contrast medium on aortic and hepatic peak enhancement at computed tomography. MATERIALS AND METHODS: Early pharmacokinetics of contrast enhancement was analyzed theoretically and simulated with a compartment model. Contrast enhancement curves were generated from the model at different injection rates (0.5-10.0 mL/sec). Time-enhancement curves were measured. The effect of contrast medium injection rate on the time and magnitude of peak enhancement was evaluated and validated empirically in pigs. RESULTS: Theoretic predictions and experimental results were in good agreement. Time to aortic peak enhancement was the sum of injection duration and bolus transfer time of contrast medium from the injection site to the aorta. Time to hepatic peak enhancement was the sum of injection duration and time to equilibrium. The magnitude of peak enhancement increased with the injection rate, but the increase was different in the aorta and liver. CONCLUSION: Use of i...