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This study evaluated the usefulness of T2-weighted and gadolinium-enhanced T1-weighted magnetic resonance (MR) images correlated with patients' menopausal status in assessing the depth of myometrial invasion in stage I endometrial carcinoma. MR images of 46 patients with stage I endometrial carcinoma were retrospectively reviewed. Twenty-five patients were premenopausal, and 21 were postmenopausal. The staging accuracy without regard to menopausal status was 59% for T2-weighted images and 61% for gadolinium-enhanced T1-weighted images. However, when staging accuracy was evaluated separately in the premenopausal and postmenopausal patient groups, T2-weighted imaging had an accuracy of 80% in the premenopausal group and gadolinium-enhanced T1-weighted imaging had an accuracy of 81% in the postmenopausal group. Therefore, T2-weighted imaging was more accurate in premenopausal patients and gadolinium-enhanced T1-weighted imaging was more accurate in postmenopausal patients. The overall accuracy of staging with MR imaging improved to 80% when patients' menopausal status was considered. Therefore, menopausal status should be considered when T2-weighted and gadolinium-enhanced T1-weighted MR images are used to stage early endometrial carcinoma.

Liquid phase ultraviolet irradiation in the presence of benzophenone as a photosensitizer and barium hydroxide as a pH controller were used to graft the mixtures of acrylic acid and acrylamide to a polypropylene surface. The surface of the grafted polypropylene samples were characterized by Fourier transform infrared spectroscopy-attenuated total reflectance, electron spectroscopy for chemical analysis, scanning electron microscopy, and a contact angle meter. The pH value of the reaction medium that produced the graft with equal molar ratio was found to be ∼ 3.77. The optimal reaction condition was found at a monomer feed of 25%, a reaction time of 30 min, and a benzophenone concentration of 1%. Surface tension of the samples increased to a value of 40 dyn cm−1 due to the graft of the hydrophilic monomers. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 72: 251–256, 1999

To evaluate the computed tomographic (CT) features of systemic lupus erythematosus (SLE) in patients with acute abdominal pain. Special emphasis was placed on the analysis of ischemic bowel disease.The authors retrospectively reviewed the images from 39 abdominal CT examinations performed in 33 patients with SLE and acute abdominal pain. Images were evaluated for bowel wall changes, mesenteric changes, fluid collection, retroperitoneal lymphadenopathy, peritoneal enhancement, and hepatomegaly as well as for changes in other abdominal organs. Ischemic bowel disease was diagnosed if at least three of the following signs were seen: bowel wall thickening, target sign, dilatation of intestinal segments, engorgement of mesenteric vessels, and increased attenuation of mesenteric fat.Thirty-one (79%) of the 39 examinations had CT findings diagnostic of ischemic bowel disease, including symmetric bowel wall thickening (n = 29), target sign (n = 26), and mesenteric vascular engorgement and haziness (n = 31). In 24 cases, bowel wall thickening was multifocal, with variable length, and did not appear to be confined to a single vascular territory.The most common CT finding in patients with SLE and acute abdominal pain is ischemic bowel disease. CT is useful for detecting the primary cause of gastrointestinal symptoms, planning treatment, and monitoring for infarction or perforation.

PURPOSE: To correlate the findings of nonossifying fibroma at magnetic resonance (MR) imaging with those at pathologic examination. MATERIALS AND METHODS: In 19 patients (age range, 8-25 years; mean age, 14 years) with pathologically proved nonossifying fibroma, MR images were analyzed for signal intensity and patterns of contrast enhancement. Findings at MR imaging and biopsy were correlated. RESULTS: On T1-weighted images, all nonossifying fibromas had low signal intensity compared with that of skeletal muscle. On T2-weighted images, 15 lesions (79%) were hypointense and four (21%) were hyperintense. On gadolinium-enhanced images, intense contrast enhancement was seen throughout 15 lesions (heterogeneous pattern in 12 and homogeneous in three) and in the margins and septa in four. Extensive hypercellular fibrous tissue and hemosiderin seen at pathologic examination were depicted with low signal intensity on T2-weighted MR images. CONCLUSION: The distinguishing features of nonossifying fibroma included hypointensity and septation on T2-weighted images. Signal intensity on T1- and T2-weighted MR images and the patterns of contrast enhancement were dependent on the amounts of hypercellular fibrous tissue, hemosiderin, hemorrhage, collagen, foamy histiocytes, and bone trabeculae.

Purpose: To determine the impact of stereotactic radiosurgery (SRS) on the clinical course, hormonal status, and follow-up CT/MRI scan of pituitary macroadenomas. Methods and Materials: From July 1988 to March 1996, 24 pituitary macroadenomas had been treated using 6 MV linear accelerator based SRS. They consisted of 11 (45.8%) prolactinomas, 2 (8.3%) growth hormone (GH)-secreting tumors, 1 (4.2%) Cushing’s disease, 8 (33.3%) nonsecreting (nonfunctioning: NF) tumors, and 2 (8.3%) mixed prolactin-growth hormone (PRL-GH)-secreting tumors (M:F = 12:12; aged 21–61 years). Postoperative irradiation was performed in all cases except for the instance of Cushing’s disease. The prescribed dose to tumor center varied from 10 to 27 Gy (mean 21.1 Gy) using a collimator size of 0.5 to 2.5 cm. The follow-up duration ranged from 13 to 89 months (mean 49.2 months). Results from these patients were compared to our results using conventional radiation. Results: Visual acuity and field defect were improved or became normal in 19 (79.2%) cases. Four (16.7%) remained unchanged after the treatment. One (4.1%) progressed 6 years after SRS and subsequently had repeat surgery with conventional boost irradiation. Of the 13 (46.4%) prolactinomas, including two mixed PRL-GH secreting tumors, 11 (84.1%) revealed normal hormonal levels within 1 year after SRS. In contrast, it took 2 years to become normal after conventional radiation therapy. In four GH-secreting tumors including two mixed PRL-GH secreting tumors, SRS and conventional methods showed similar responses. On follow-up imagings of the 21 patients, the mass was completely resolved in 4 (16.7%), including 3 PRLs and one NF, decreased in 11 (45.8%), and unchanged in 5 (16.7%) with central necrosis or cysts. One (4.2%) progressed and was reoperated 6 years after treatment. The complications related to SRS were comparable to those from conventional method. Conclusion: Radiosurgery can be used effectively in patients with pituitary adenoma. In this study, a more rapid hormonal and clinical response was achieved with radiosurgery than with conventional pituitary irradiation treatment.

Purpose: to investigate the utility of the resistive indices (RIs) of the epididymal and intratesticular arteries, and to establish diagnostic criteria for scrotal inflammatory disease on the basis of quantitative color Doppler sonography Material and Methods: We prospectively examined 29 consecutive patients with scrotal pain, and 15 normal control subjects. the RIs of the intratesticular and epididymal arteries were obtained from color Doppler sonographs Results: the RIs of the testicular artery in epididymoorchitis were significantly lower than those in normal control subjects and in epididymitis (p0.5). with a cut-off value of RI=0.5, sensitivity, specificity, accuracy, and positive and negative predictive values were 91%, 94%, 94%, 83%, and 77% respectively. the mean RI of the epididymal arteries in epididymitis and epididymoorchitis was 0.49±0.11. A high level of diagnostic accuracy in scrotal inflammatory disease was achieved when the RIs of the intratesticular and epididymal arteries were less than 0.5 and 0.7 respectively Conclusion: the RI of the intrascrotal artery would give a more objective evaluation than subjective assessment and could provide diagnostic criteria for scrotal inflammatory disease

Using the transient behavior of the photoconductive-gain mechanism, a signal gain in radiation detection with a-Si:H devices may be possible. The photoconductive gain mechanism in two types of hydrogenated amorphous silicon devices, p-i-n and n-i-n configurations, was investigated in connection with applications to radiation detection. Photoconductive gain was measured in two time scales: one for short pulses of visible light ( 2 . Various gain results are discussed in terms of the device structure, applied bias and dark-current density.

The purpose of this study was to describe the findings of MR imaging of fibrous dysplasia and to evaluate the correlation between radiologic and pathologic findings.MR images of 13 proven cases of fibrous dysplasia were analyzed for signal intensity, hypointense rind, internal septations, cystic changes, soft-tissue extension, and patterns of contrast enhancement.All cases of fibrous dysplasia showed low signal intensity on T1-weighted MR images. Five cases (38%) were hypointense on T2-weighted MR images, and the other eight cases (62%) were hyperintense. Hypointense rind was seen in 10 cases (77%); internal septations were seen in three cases (23%); and cystic changes was seen in two cases (15%). Soft-tissue extension was observed in four cases (31%), including one case (8%) with a pathologic fracture. After gadolinium infusion, central contrast enhancement was noted in eight cases (73%), and peripheral rim enhancement was noted in three cases (27%). Numerous bony trabeculae, confirmed pathologically, caused a hypointense signal intensity on T2-weighted images.Patients with fibrous dysplasia showed a correlation between radiologic and pathologic findings. Our results showed that T1-weighted images reveal fibrous dysplasia as hypointense, and T2-weighted images reveal fibrous dysplasia as either hyperintense or hypointense. Signal intensity on T1- and T2-weighted images and the degree of contrast enhancement on T1-weighted images depended on the amount and degree of bony trabeculae, cellularity, collagen, and cystic and hemorrhagic changes.

RATIONALE AND OBJECTIVES With the use of localized, water-suppressed in vivo 1H magnetic resonance spectroscopy (MRS), the proton metabolic alterations of white matter in patients with closed head injury (CHI) and healthy controls are evaluated, and metabolic alterations with Glasgow Outcome Scale (GOS) scores are compared. METHODS Patients with CHI (n = 10) and healthy control subjects (n = 10) underwent MRS examinations using a stimulated-echo acquisition mode pulse sequence that provided 2 x 2 x 2 cm3 volume of interest in the left frontoparietal white matter. Proton metabolite ratios relative to creatine were obtained using a Marquart algorithm. RESULTS The specific feature in patients with CHI was significant decrease of N-acetylaspartate (NAA)/creatine ratio compared with normal controls. No clear correlation of other metabolite ratios such as choline/creatine and inositols creatine was established. The level of NAA/creatine ratio was significantly correlated with GOS. CONCLUSIONS Results of this preliminary study suggest that the reduction of NAA/creatine ratio may indicate neuronal loss in patients with CHI. The NAA/creatine ratio may serve as a metabolic criterion to predict the GOS of patients with CHI. Thus, in vivo 1H MRS may be a useful modality in the clinical evaluation of patients with CHI based on the proton metabolite concentrations of cerebral white matter.

RATIONALE AND OBJECTIVES To investigate postmortem metabolic and morphologic alterations in the dog brain thalamus and to contribute diagnostic aids in medicolegal science. METHODS A homogeneous group of 17 dogs was used for in vivo 1H magnetic resonance (MR) spectroscopy and electron microscopic studies, which were performed under intravenous and intramuscular anesthesia before and after the dogs were killed. All 1H MR spectroscopy and electron microscopy examinations were performed on a 1.5 T MR imaging/MR spectroscopy system using a stimulated-echo acquisition mode pulse sequence and an electron microscope, respectively. RESULTS The lactate resonance signal, which could be used as a criterion for tissue survival, appeared during the entire postmortem period. The lactate: creatine ratio significantly increased in the early postmortem metabolic process. The inositol: creatine ratio showed a mild gradual increase. However, the N-acetyl-aspartate: creatine and choline/creatine ratios generally were unchanged. The decomposition of proton metabolites was observed in the MR spectrum 48 hours postmortem. In the postmortem period, high power field (x10,000) electron microscopic results showed significant morphologic alterations of the thalamus, revealing nuclear pyknosis and perikaryal condensation, cytoplasmic vacuoles, clumping of nuclear chromatin, and destruction of cellular organelles and nuclear membrane. CONCLUSIONS Results suggest that the combination of 1H MR spectroscopy and electron microscopy may simultaneously provide good quality metabolic and morphologic information of cerebral tissue in the field of thanatochronology.

Captopril, an inhibitor of angiotensin I converting enzyme, has been shown to modify radiation damage and prevent radiation injury of normal tissue in rats and pigs. The present study was carried out to determine whether captopril would reduce radiation changes in the proximal small bowel in mice.Mice were subjected to whole body irradiation with 9 Gy or 15 Gy. Captopril was administered in drinking water at a regimen of 62.5 mg/kg/day (captopril group I) and 125 mg/kg/day (captopril group II), continuously from 7 days before irradiation to the end of each designed experiment. The jejunal damage was evaluated microscopically by crypt count per circumference and by histologic damage grading.Crypt number in the sham-irradiated control was 133 +/- 6.8/circumference. In both captopril group I and II, crypt numbers and histologic scores were not significantly different from those in the normal group. The 9 Gy and 15 Gy radiation alone groups showed significantly lower crypt counts and histologic scores compared with the sham-irradiated control group (p0.05). The groups exposed to 9 Gy radiation plus captopril I and II showed significantly higher crypt counts and lower histologic damage scores on the third day, and lower histologic damage scores on the fifth day compared with the 9 Gy radiation alone group (p0.05). The 15 Gy radiation plus captopril I and II groups had significantly higher crypt counts and lower histologic damage scores on the third day than those of the 15 Gy radiation alone group (p0.05). All mice of the 15 Gy radiation group succumbed to intestinal radiation death.Our results suggest that captopril provides protection from acute radiation damage to the jejunal mucosa in mice.

Rationale and objectives The authors assessed the effect of noise on the detectability of rib fractures by residents. Methods Eight radiology residents read chest posterior-anterior radiographs of 92 subjects with rib fracture(s) and 28 normal subjects to detect rib fracture(s) according to a five-point scale of confidence, under quiet and "noisy" conditions. Each individual's attitude toward noise was measured by a multiple-choice questionnaire. Results The readers were divided into two groups depending on the questionnaire result: group A readers were accustomed to a quiet environment, and group B readers were accustomed to noisy environments or were unaffected by noise. Group A's performance, measured by the area (Az) under the receiver operating characteristic (ROC) curve, was better in quiet conditions when compared with their performance in noisy conditions; however, the opposite tendency was observed for group B. There was a significant individual difference of performance in response to noise. Conclusion Effect of noise on the detection of rib fractures depends on an individual's attitude toward sound and noise.

RATIONALE AND OBJECTIVES The authors analyzed opinions regarding how a radiologist should answer a patient's or patient's family's questions about radiologic results. METHODS Questionnaires were obtained in a university hospital from 135 physicians of various specialties, including radiologists, and 501 nonphysicians, such as medical students, nurses, patients, families of patients, and hospital personnel. The questionnaire included three questions, each with five choices. The first question concerned a normal result, the second a minor abnormality, and the third a major abnormality. The five choices in each question consisted of two suggestive answers to patients' inquiries and three excuses for the refusal of immediate answers. Respondents were asked to choose the single most desirable and the single least desirable answer. RESULTS Approximately 50% of all physicians believed that a radiologist should refer the patient to his or her physician rather than to give a suggestive answer to a patient with an abnormality. Considerably fewer physicians had a similar opinion in cases involving a patient with normal results. Patients and the families of patients believed that a radiologist should give at least a suggestive answer in any circumstances where the patient is agitated to know the result. Radiologists were reluctant to convey any information regardless of the test result. CONCLUSIONS Physicians had significantly different opinions from patients and the families of patients, and radiologists preferred to keep their traditional role of referral physician.

We reviewed CT of four patients with surgically proved bowel infarction secondary to superior mesenteric vein (SMV) thrombosis. Pathologic correlation was available in all patients. Three patients had thrombus in both portal vein and proximal SMV and the remaining patient had thrombus that was seen only in the peripheral branches of the SMV. Contrast-enhanced CT showed a segmental distribution of marked concentric bowel wall thickening in all four patients. Two patients also showed zones of different attenuation in the bowel wall, which were caused by varying degrees of edema and hemorrhage in the submucosa. Dense peripheral enhancement of the bowel wall was present in one patient. Other CT findings included ascites and mesenteric changes such as edema and vascular engorgement. The combination of thrombus in the SMV with bowel wall thickening strongly suggests bowel infarction and, therefore, warrants initiation of appropriate therapy.

A case is presented in which massive retroperitoneal hemorrhage from the left first lumbar artery complicating a percutaneous renal biopsy was successfully controlled by superselective embolization with microcoils. An anterior radiculomedullary artery (artery of Adamkiewicz) originated from the lumbar artery. To minimize the risk of ischemic damage to the spinal cord from embolization, the extravasating branch of the lumbar artery had to be superselectively catheterized using a 3-F coaxial catheter system. Computed tomography (CT) scan localized the hematoma within the left posterior pararenal space in the retroperitoneal space.

We report a case of eosinophilic cholangitis, with US, CT, and cholangiographic findings. The lesion showed marked wall thickening of cystic and common bile ducts on US and CT together with mild diffuse narrowing of the common duct on cholangiography.

Results of Monte Carlo simulations on amorphous silicon based X-ray imaging arrays are described. In order to investigate the characteristics of amorphous silicon X-ray imaging devices and to provide the optimum design parameters, Monte Carlo simulations were performed. Monte Carlo simulation codes for the authors' purpose were developed and various combinations of X-ray peak voltages, aluminum filter thicknesses, CsI(Tl) thicknesses, and amorphous silicon photodiode pixel sizes were tested in connection with detection efficiency and spatial resolution of the amorphous silicon based X-ray imager. With usual CsI(Tl) thickness of 300 /spl mu/m/spl sim/500 /spl mu/m, detection efficiency was in the range of 70%/spl sim/95% and energy absorption efficiency was in the range of 40%/spl sim/70% for 60 kVp/spl sim/120 kVp X-rays. From the simulations it was found that amorphous silicon pixel size and CsI(Tl) thickness were the most important parameters which determine the resolution of the imager. By use of the authors' simulation results they could provide proper combinations of CsI(Tl) thicknesses and pixels sizes for optimum sensitivity and resolution.

A new optimization method was investigated. This method is distinguished from other existing optimization methods by additional constraints and reduction of unknown variables. It was tested on two ideal cases and the potential of the idea could be verified.

The use of carbon dioxide (CO2) as a vascular contrast agent has increased significantly since the introduction of digital subtraction angiography. To optimize the injection of CO2 for digital subtraction angiography, we evaluated the gas dispersion patterns from differing catheter designs, gas flow dynamics, and the influence of vessel size and inclination on luminal gas filling.A circulatory system model was constructed and perfused with 36% glycerin solution at a rate of 1.08 to 1.13 liters per minutes (pulse rate 72 beats/minute, pressure 90-111 mm Hg). Fifty milliliters of CO2 was rapidly injected into the vascular tube of the model (diameter 6.4-15.9 mm) at an inclination of 0 degrees to 45 degrees via a catheter, and imaged digitally in a cross-table lateral projection. The dispersal patterns of gas bubbles from the halo, pigtail, and end-hole catheters were evaluated as well as the degree of luminal gas filling.The halo and end-hole catheters produced continuous gas flow with homogeneous density. The pigtail catheter produced smaller bubbles with inhomogeneous density. Luminal gas filling was incomplete, with a residual fluid level posteriorly regardless of the size and inclination of the tube. At 0 degrees inclination, gas filling was greater with the 6.4-mm tube than with the 15.9-mm tube. With an inclination of 0 degrees to 15 degrees, gas filling was significantly improved for the larger tubes. On dispersal, CO2 bubbles rapidly coalesced and moved forward along the anterior aspect of the tube. The frontal motion of the bubble was parabolic in configuration.The halo and end-hole catheters provide more homogeneous gas density than the pigtail catheter. Gas filling was incomplete regardless of catheter design, vessel size, or inclination. Inclination improves gas filling in vessels12.7 mm in diameter.

Findings in 30 consecutive patients with pneumothorax were prospectively analyzed. All patients underwent supine anteroposterior (AP) and erect posteroanterior (PA) chest radiography. The interpleural distances were measured at three locations. Average interpleural distances on supine AP and erect PA radiographs were analyzed by means of correlation and linear regression analysis. The authors developed a formula that can be used to estimate the size of a pneumothorax on a supine AP chest radiograph.

The authors investigate whether there is a lateral effect of 1H-magnetic resonance spectroscopy (MRS) observable metabolite ratios between the symptomatic and the asymptomatic side in Parkinson's disease with unilateral symptoms.Localized in vivo 1H MRS was used to measure the metabolite levels in the symptomatic and the asymptomatic sides of the substantia nigra (SN) and putamen-globus pallidus (PG) in Parkinson's disease with unilateral symptom (n = 15). The metabolite ratios of N-acetylasparatate (NAA)/creatine (Cr), and choline-containing compounds (Cho)/Cr in the symptomatic side were compared with those in the asymptomatic side. According to the symptomatic duration, the authors evaluated whether there was a specific correlation between laterality and the clinical stage.Significant metabolic lateral effect of NAA/Cr ratio was established between the symptomatic and the asymptomatic sides of SN and PG in Parkinson's disease with unilateral symptoms (P = 0.03). The decreased NAA/Cr ratio was calculated in at least one of the selected regions in SN and PG, indicating neuronal loss. The main observations were that NAA/Cr ratios were reduced in the left symptomatic side (n = 7; P = 0.001) and reduced to a lesser degree in the right symptomatic side (n = 8; P = 0.03 [PG], P = 0.21 [SN]) and that there was no significant laterality of other metabolite ratios.On the basis of NAA/Cr ratios between the symptomatic and the asymptomatic sides, the present 1H MRS study shows a significant neuronal laterality in Parkinson's disease with unilateral symptoms. In vivo 1H MRS may provide a diagnostic marker for neuronal dysfunction in Parkinson's disease with unilateral symptoms.

Fifteen patients underwent computed tomography (CT)-guided contrast material localization of pulmonary nodules, with barium and indigo carmine stain used in five patients, iodized oil and indigo carmine stain in five, and water-soluble contrast material and indigo carmine stain in five before fluoroscopy-assisted thoracoscopic resection. Contrast material localization was successful in all cases, and the surgeon confirmed accurate localization, CT-guided contrast material localization is simple and useful for thoracoscopic resection.

RATIONALE AND OBJECTIVES The authors investigate alterations of proton T1 and T2 relaxation times and phosphorus metabolites of canine thigh muscle tissue after high dose x-ray irradiation by follow-up magnetic resonance imaging (MRI) and phosphorus-31 (31P) magnetic resonance spectroscopy (MRS). METHODS A group of 20 dogs was used for MRI and in vivo 31P MRS. Single doses of 5,000 and 10,000 cGy were delivered to the right thigh muscle of groups of 10 dogs each. All MRI and 31P MRS examinations were performed before irradiation and 1, 7, 14, 28, 42, and 56 days after irradiation. For measurement of T1, repetition time (TR) was measured at 300, 500, 1000, 1500, 2000 msec and echo time (TE) was fixed at 12 msec. Also, for measurement of T2, TE was measured at 20, 40, 60, and 80 msec and TR was fixed at 2000 msec. Image selected in vivo spectroscopy (ISIS) pulse sequence was used to obtain 31P MR spectra. Peak areas for each phosphorus metabolite were measured using a Marquart algorithm. RESULTS Magnetic resonance imaging signal began to change at 28 days after a single dose of 10,000 cGy, whereas there was no significant MRI signal change until 56 days after a single dose of 5,000 cGy. Also, extensive MRI signal changes were observed at 42 days after a single dose of 10,000 cGy. Significant correlation was established between T2 and a lapse of time although there was no correlation between T1 and a lapse of time. T2 value increased substantially corresponding to the time period after x-ray irradiation. Although MR spectral change was not observed until 42 days after a single dose of 5,000 cGy, it began at 14 days after a single dose of 10,000 cGy. And, significant MR spectral changes were observed at 28 and 42 days. Inorganic phosphate and phosphodiesters signal intensities increased while phosphocreatine signal intensity decreased. The pH value was 7.22 +/- 0.05 at control, and 6.98 +/- 0.04 at 42 days after a single dose of 10,000 cGy. CONCLUSIONS The postirradiation follow-up MRI and 31P MRS studies demonstrated that morphologic and metabolic changes were dependent upon the x-ray dose and a lapse of time.

Parosteal osteosarcoma is an uncommon, low-grade malignant bone tumor and is found in an older age group than conventional osteosarcoma. We present a talar parosteal osteosarcoma that recurred twice in a 2-year-old child. To our knowledge, this is the youngest patient reported with a parosteal osteosarcoma. The talus is an unusual site for parosteal osteosarcoma. Inadequate resection due to a diagnosis of juxtacortical chondroma resulted in recurrence of the tumor. The age of the patient, the thick cartilaginous cap, and well-differentiated trabecular bone all contributed to the critical erroneous diagnosis.

Purpose: Our goal was to evaluate CT efficacy in differentiating gastrointestinal leiomyoma and leiomyosarcoma. Method: We retrospectively reviewed CT scans of 45 patients (21 men, 24 women, mean age 55 years) with surgically proven gastrointestinal leiomyomas (n = 21) and leiomyosarcomas (n = 24) with respect to size, contour, enhancing pattern, mesenteric fat infiltration, calcification, ulceration, regional lymphadenopathy, direct invasion, distant metastasis, and growth pattern after visual inspection by two radiologists in agreement. On the basis of these CT features, subjective diagnosis was also categorized into three groups (Group I: probably benign, Group II: probably malignant, Group III: diagnostic malignant). The results were compared with the final histopathologic diagnosis. Results: In addition to the features of direct invasion and distant metastasis suggesting diagnostic malignancy, the CT features favoring malignancy with statistical significance included larger size (>5 cm), lobulated contour, heterogeneous enhancement, mesenteric fat infiltration, ulceration, regional lymphadenopathy, and exophytic growth pattern (p < 0.005). However, calcification was not significant in differentiating the two entities (p = 0.25163). A subjective analysis revealed 89% sensitivity, 85% specificity, and 87% accuracy for diagnosis of leiomyosarcoma. Conclusion: CT features are useful in differentiating leiomyoma and leiomyosarcoma in gastrointestinal tract.

To evaluate the computed tomographic (CT) features of xanthogranulomatous cholecystitis (XGC) and to distinguish it from gallbladder carcinoma.Retrospective analysis was performed in 11 patients with XGC and 17 patients with gallbladder carcinoma in which the wall was thickened. The following CT features were analyzed: maximum wall thickness, intramural hypoattenuated nodules, mucosal line, patterns of wall thickening and enhancement, and the presence of stones. The changes outside the gallbladder were also compared.The mean thickness of the gallbladder wall was 1.8 cm in patients with XGC and 2.1 cm in patients with gallbladder carcinoma. Intramural hypoattenuated nodules were seen in all patients with XGC but in only seven patients with gallbladder carcinoma (P = .008). The mucosal line was observed in nine patients with XGC and in six with gallbladder carcinoma (P = .02). The gallbladder wall was more diffusely thickened in patients with XGC (10 of 11 patients) than in patients with gallbladder carcinoma (seven of 17 patients) (P = .01). The occurrence of changes outside the gallbladder did not differ statistically significantly.Because of a statistically significant overlap of CT features, only when intramural hypoattenuated nodules occupy a large area of the thickened gallbladder wall can the diagnosis of XGC be highly suggestive. The diagnosis of XGC at CT may indicate a less aggressive surgical approach.

The authors investigate: (1) whether there is a lateral effect of hydrogen (1H) magnetic resonance (MR) spectroscopy observable metabolite ratios between the right and the left prefrontal lobe in chronic schizophrenia; (2) whether there is a change of proton metabolite ratios in chronic schizophrenia after neuroleptic treatment; (3) whether there is a relation between changes in 1H MR spectra and the clinical assessment of Brief Psychiatric Rating Scale (BPRS); and (4) to investigate a hypofrontality hypothesis in schizophrenia in terms of neurochemical aspects.Localized in vivo 1H MR spectroscopy was used to measure the metabolite levels in the prefrontal lobes of control persons (n = 20) and of chronic patients before and after neuroleptic treatment (n = 34). The MR spectra of 8 cm3 voxels were compared with clinical assessment of BPRS in each subject.No significant metabolic lateral effect was established in both schizophrenia and control groups (P0.05). After neuroleptic treatment, chronic schizophrenic patients generally demonstrated a decrease of the complex of gamma-aminobutyric acid (GABA) and glutamate (Glu) containing (GABA + Glu)/creatine (Cr) ratio.The current follow-up 1H MR spectroscopy study shows a significant correlation between alterations of (GABA + Glu)/Cr ratio and BPRS, and supports a hypofrontality hypothesis in chronic schizophrenia. The reduction of (GABA + Glu)/Cr ratio after neuroleptic treatment may implicate the recovery of normal neuronal function in neurotransmitters. In vivo 1H MR spectroscopy may be a useful modality in follow-up evaluation of neuroleptic treatment in chronic schizophrenia.

In order to efficiently plan non-spherical radiosurgical targets we have used computer-aided design optimization techniques with a fast dose model. A study of the spatial dose distribution for single or multiple non-coplanar arcs was carried out using a 18 cm diameter spherical head model. The dose distribution generated from the 3D dose computation algorithm can be represented by a simple analytic form. Two analytic dose models were developed to represent the dose for preset multiple non-coplanar arcs or a single arc: spherical and cylindrical. The spherical and cylindrical dose models compute dose quickly for each isocentre and single arc. Our approach then utilizes a computer-aided design optimization (CAD) with the use of two fast approximate dose models to determine the positions of isocentres and arcs. The implementation of CAD with fast dose models was demonstrated. While the fast dose models are only approximations of the true dose distribution, it is shown that this approximate model is sufficient to optimize isocentric position, collimator size and arc positions with CAD.

Rationale and Objectives. We in vestigated the proton metabolism of right prefrontal white matter in drug-naive, chronic schizophrenic patients (n=23), compared with healthy normal control subjects (n=10), by using localized, water-suppressed in vivo 1H magnetic resonance (MR) spectroscopy. Methods. All 1H MR spectroscopy examinations were performed on a 1.5-T MR imaging/MR spectroscopy system by using a point-resolved spectroscopy pulse sequence for localizd volumes of 2×2×2 cm3. Proton metabolite ratios relative to creatine (Cr) were obtained using a Marquart algorithm. Results. Drun-naive, chronic schizophrenic patients demonstrated a decrease in the N-acetylaspartate (NAA):Cr and choline (Cho):Cr ratios and an increase of the complex of γ-aminobutyric acid (GABA) and glutamate (Glu) containing ratio [(GABA+Glu):Cr] as compared with normal control subjects. Conclusion. Results suggest that the reduction of NAA and Cho may indicate neuronal dysfunction and that the elevation of GABA and Glu may play a role in chronic schizophrenia. 1H MR spectroscopy may be a useful modality in research and in the clinical evaluation of chronic schizophrenic patients.

Local recurrence of gastric carcinoma after surgery is defined as histologic evidence of a tumor in the surrounding tissues of the resected stomach. Compared with the large number of articles describing tumor recurrence after colectomy for colonic carcinoma, few reports have been published on the CT findings after gastrectomy. We illustrate the CT features of local tumor recurrence after gastrectomy in 36 patients in whom recurrence was confirmed pathologically or by definitive findings on CT scans.

The purpose of this study was to analyze the CT findings in 10 patients with abdominal actinomycosis to determine the appearance of lesions and the pattern of spread of the disease.We retrospectively reviewed the CT findings in 10 patients with pathologically proved actinomycosis. Involved areas were the pelvis (n = 4), greater omentum (n = 3), liver (n = 2), and kidney (n = 1). Contrast-enhanced (oral and IV) CT scans were available in all patients. Unenhanced CT scans were also available in six patients.CT scans showed mostly solid masses with focal areas of diminished attenuation in seven patients and mostly cystic masses with thickened walls in three. CT findings confirmed the infiltrative nature of the disease, showing its tendency to invade across tissue planes and boundaries. Dense inhomogeneous contrast enhancement in the walls or solid components of masses was seen in eight patients. Minimal lymphadenopathy was seen in only two patients.Although nonspecific, actinomycosis should be included in the differential diagnosis when CT scans show an infiltrative mass with unusual aggressiveness and dense inhomogeneous contrast enhancement, especially in patients with fever, leukocytosis, or long-term use of intrauterine contraceptive devices.

The work presented in the paper addresses a method for obtaining the optimal dose distribution for LINAC-based stereotactic radiosurgery. As many targets have nonspherical or irregular shapes and three-dimensional dose calculations included in dose optimisation, long computation times are required to determine the optimum isocentre separation and collimator sizes to shape the irregular target using the multiple-isocentre approach, by trial-and-error types of method. The simple approach, using a computer-aided design optimisation technique and a fast approximate dose model, has been developed to find the optimum isocentre positions and collimator sizes quickly and automatically. A spherical dose model has been developed to represent the dose for a standard arc system with a single isocentre. The implementation of computer-aided design algorithms with the spherical dose model and their application to several cases are discussed. It is shown that the spherical dose model gives dose distribution similar to that of the exact dose model, which makes this simple dose model more efficient, with computer-aided design optimisation, in finding optimum isocentre positions and collimator sizes used in stereotactic radiosurgery.

We evaluated the CT of intestinal obstruction due to adhesions in 20 postoperative patients, with emphasis on early detection of strangulation. Ten patients with surgically proven strangulated obstruction (strangulation group) were compared with another ten patients (nonstrangulation group) in whom seven improved with conservative management and three had confirmed simple obstruction on surgical exploration. Beak-like luminal narrowing ("beak") was the most common CT finding at the obstructed site in both groups. The CT findings that suggested strangulated obstruction were serrated beaks, mesenteric edema or vascular engorgement, and moderate to severe bowel wall thickening. In contrast, simple obstruction could be assumed when the beak was smooth, there were no mesenteric changes, and the bowel wall was normal or mildly thickened. Computed tomography is a useful tool for detecting strangulation in patients with postoperative adhesive intestinal obstruction.

Purpose : The purpose of this study is to examine the frequency of posterior element injury in patients with traumatic thoraco-lumbar burst fractures and to evaluate the correlation between the MR imaging and CT findings. Materials and Methods : The MR images of 38 patients with 39 thoraco-lumbar burst fractures and the results of the CT examinations of 28 patients with 29 fractures were retrospectively analyzed. Both procedures were performed within two weeks of injury. Twenty-one males and 17 females were included ; their average age was 51.3 (range, 11-75) years. MR images were evaluated for injury to the posterior ligamentous complex, comprising the supraspinous ligament(SSL), the interspinous ligament(ISL), the flaval ligament(FL), and the capsule of facets. Analysis of the CT findings focused on the posterior bony elements of the lamina, pedicle, spinous process, and facet joint. Results : MR imaging revealed posterior ligamentous injuries in 18(46.2 %) of 39 burst fractures ; there was tearing of the ISL in 15 cases(38.5 %), of the SSL in 11(28.2 %), of the capsule of facets in 11(28.2 %), and of the FL in nine(23.1 %). Among the 29 burst fracture cases examined by CT, posterior bony injuries were detected in 13(44.8 % ). Lamina and facet joint fractures were detected in six cases(20.7 %), facet separation or dislocation in six(20.7%), and spinous process and pedicle fracture in one(3.4 %). In 29 burst fracture cases, both MRI and CT were performed. Among the 18 cases in which MR imaging revealed posterior ligamentous injuries, CT failed to demonstrate posterior element fractures in seven. On the other hand, among the 13 cases in which CT indicated posterior bony fractures, MR failed to reveal posterior ligamentous injuries in two. Conclusion : Posterior element injury is frequently found in patients with traumatic thoraco-lumbar burst fractures demonstrated by MR imaging(46.2 %) and CT(44.8 % ). Both MRI and CT are useful tools for the evaluation of posterior element injury, which determines the degree of instability of traumatic burst fracture.

Purpose : To analyze the radiologic findings of metastatic tumors of the breast. Materials and Methods : We retrospectively analyzed the findings of mammography (n=12), ultrasonography (n=9) and CT (n=4) of 13 patients with metastatic tumors of the breast. Methods for confirmation were biopsy (n=8) and clinical follow-up (n=5). The patient ’s ages ranged from 24 to 63 (mean 43) years. Results : Primary malignancies were contralateral breast cancer (n=3), non-Hodgkin ’s lymphoma (n=3), stomach cancer (n=2), uterine cervix cancer (n=1), laryngeal cancer (n=1), esophageal melanoma (n=1), ma-lignant thymoma (n=1), and lung cancer (n=1). Patterns of metastasis from contralateral breast cancer and the stomach cancer were diffuse and infiltrative, while metastasis from other cancers was of the focal mass-forming type. The radiologic findings of metastasis from contralateral breast cancer (n=3) were diffuse skin thickening and increased density or echogenicity in the medial aspect of the breast, while in cases involving metastasis from stomach cancer (n=2) radiographs revealed extensive skin thickening, increased density or echogenicity, lymphedema and ipsilateral lymphadenopathy in the left breast. In cases of metastatic tumors to the breast in which focal masses were seen on mammography (n=7), marginal spiculation or microcalcification of the tumors was not present. In six such cases, ultrasonography revealed well-defined margin, posterior acoustic shadowing or an irregular thick echogenic boundary was not seen. In two patients who underwent CT scanning, well-defined masses with moderate contrast enhancement were present. Conclusion : Radiographs of metastatic tumors to the breast from contralateral breast cancer and stomach cancer showed diffuse infiltration. The metastatic tumors with focal masses showed oval to round, smooth-marginated, well-defined masses without spiculation or microcalcification on mammography, and a well-defined mass without posterior acoustic shadowing or irregular thick echogenic boundary on ultrasonography.

A case of Kaposi's sarcoma involving the small bowel years after receiving a renal transplant is described. Immunosuppression had been achieved using cyclosporine A and prednisolone. Lesions extended from the duodenum to the ileum ; radiologically, they were demonstrated on small bowel follow-through study and computed tomography as multiple small nodular intraluminal masses with or without central umbilication, and endoscopically, were seen as intramural mucosal elevations with a central crater-like ulceration.