Although it is rare, the right atrium can be encroached on by abnormal mediastinal structures, including aortic aneurysms, carcinomas, hepatic cysts and diaphragmatic paralysis. Extrinsic compression of the right atrium causes significant hemodynamic compromise and can lead to fatal outcomes. We describe the case of a 66-year old man with a past history of pulmonary tuberculosis that had undergone right pneumonectomy 40 years previously. He then presented with signs and symptoms of right-sided heart failure. These new signs and symptoms were recognized to be secondary to extrinsic compression of the right atrium, which was due to late-onset postpneumonectomy empyema, and the signs and symptoms were successfully relieved by performing open drainage of the empyema.
Aortic Aneurysm ; Drainage ; Empyema ; Empyema, Pleural ; Fatal Outcome ; Heart ; Heart Atria ; Heart Failure ; Hemodynamics ; Pneumonectomy ; Respiratory Paralysis ; Tuberculosis, Pulmonary

PURPOSE: To compare free-breathing and respiratory-triggered diffusion-weighted imaging on 1.5-T MR system in the detection of hepatic lesions. MATERIALS AND METHODS: This single-institution study was approved by our institutional review board. Forty-seven patients (mean 57.9 year; M:F = 25:22) underwent hepatic MR imaging on 1.5-T MR system using both free-breathing and respiratory-triggered diffusion-weighted imaging (DWI) at a single examination. Two radiologists retrospectively reviewed respiratory-triggered and free-breathing sets (B50, B400, B800 diffusion weighted images and ADC map) in random order with a time interval of 2 weeks. Liver SNR and lesion-to-liver CNR of DWI were calculated measuring ROI. RESULTS: Total of 62 lesions (53 benign, 9 malignant) that included 32 cysts, 13 hemangiomas, 7 hepatocellular carcinomas (HCCs), 5 eosinophilic infiltration, 2 metastases, 1 eosinophilic abscess, focal nodular hyperplasia, and pseudolipoma of Glisson's capsule were reviewed by two reviewers. Though not reaching statistical significance, the overall lesion sensitivities were increased in respiratory-triggered DWI [reviewer1: reviewer2, 47/62(75.81%):45/62(72.58%)] than free-breathing DWI [44/62(70.97%):41/62(66.13%)]. Especially for smaller than 1 cm hepatic lesions, sensitivity of respiratory-triggered DWI [24/30(80%):21/30(70%)] was superior to free-breathing DWI [17/30(56.7%):15/30(50%)]. The diagnostic accuracy measuring the area under the ROC curve (Az value) of free-breathing and respiratory-triggered DWI was not statistically different. Liver SNR and lesion-to-liver CNR of respiratorytriggered DWI (87.6+/-41.4, 41.2+/-62.5) were higher than free-breathing DWI (38.8+/-13.6, 24.8+/-36.8) (p value <0.001, respectively). CONCLUSION: Respiratory-triggered diffusion-weighted MR imaging seemed to be better than free-breathing diffusion-weighted MR imaging on 1.5-T MR system for the detection of smaller than 1 cm lesions by providing high SNR and CNR.
Abscess ; Carcinoma, Hepatocellular ; Diffusion ; Eosinophils ; Ethics Committees, Research ; Focal Nodular Hyperplasia ; Hemangioma ; Humans ; Liver ; Neoplasm Metastasis ; Retrospective Studies ; ROC Curve

PURPOSE: To compare free-breathing and respiratory-triggered diffusion-weighted imaging on 1.5-T MR system in the detection of hepatic lesions. MATERIALS AND METHODS: This single-institution study was approved by our institutional review board. Forty-seven patients (mean 57.9 year; M:F = 25:22) underwent hepatic MR imaging on 1.5-T MR system using both free-breathing and respiratory-triggered diffusion-weighted imaging (DWI) at a single examination. Two radiologists retrospectively reviewed respiratory-triggered and free-breathing sets (B50, B400, B800 diffusion weighted images and ADC map) in random order with a time interval of 2 weeks. Liver SNR and lesion-to-liver CNR of DWI were calculated measuring ROI. RESULTS: Total of 62 lesions (53 benign, 9 malignant) that included 32 cysts, 13 hemangiomas, 7 hepatocellular carcinomas (HCCs), 5 eosinophilic infiltration, 2 metastases, 1 eosinophilic abscess, focal nodular hyperplasia, and pseudolipoma of Glisson's capsule were reviewed by two reviewers. Though not reaching statistical significance, the overall lesion sensitivities were increased in respiratory-triggered DWI [reviewer1: reviewer2, 47/62(75.81%):45/62(72.58%)] than free-breathing DWI [44/62(70.97%):41/62(66.13%)]. Especially for smaller than 1 cm hepatic lesions, sensitivity of respiratory-triggered DWI [24/30(80%):21/30(70%)] was superior to free-breathing DWI [17/30(56.7%):15/30(50%)]. The diagnostic accuracy measuring the area under the ROC curve (Az value) of free-breathing and respiratory-triggered DWI was not statistically different. Liver SNR and lesion-to-liver CNR of respiratorytriggered DWI (87.6+/-41.4, 41.2+/-62.5) were higher than free-breathing DWI (38.8+/-13.6, 24.8+/-36.8) (p value <0.001, respectively). CONCLUSION: Respiratory-triggered diffusion-weighted MR imaging seemed to be better than free-breathing diffusion-weighted MR imaging on 1.5-T MR system for the detection of smaller than 1 cm lesions by providing high SNR and CNR.
Abscess ; Carcinoma, Hepatocellular ; Diffusion ; Eosinophils ; Ethics Committees, Research ; Focal Nodular Hyperplasia ; Hemangioma ; Humans ; Liver ; Neoplasm Metastasis ; Retrospective Studies ; ROC Curve

A mesothelial cyst of the round ligament is a rare cause of an inguinal mass. Clinically, it is frequently misdiagnosed as one of commoner diseases such as an inguinal hernia, femoral hernia, lipoma, and lymphadenopathy upon physical examination. Some previous reports elaborated the sonographic features of a mesothelial cyst of the round ligament. However, to our knowledge, few reports have described the CT features of a mesothelial cyst. We illustrated here the sonographic and multidetector CT features of a case of a mesothelial cyst of the round ligament that presented as an inguinal palpable mass and mimicked a metastasis in a patient with a Sertoli-Leydig cell tumor of the ovary.
Abdominal Neoplasms/*diagnosis/secondary ; Aged ; Contrast Media/diagnostic use ; Cysts/*radiography/*ultrasonography ; Diagnosis, Differential ; Epithelium/radiography/ultrasonography ; Female ; Humans ; Ovarian Neoplasms/*pathology ; Radiographic Image Enhancement/methods ; Round Ligament/*radiography/*ultrasonography ; Sertoli-Leydig Cell Tumor/*pathology ; Tomography, X-Ray Computed/methods

BACKGROUND/AIMS: Invasive coronary angiography remains the gold standard in the diagnosis of coronary artery disease. However, multidetector CT (MDCT) coronary angiography is an emerging technique that is available for the non-invasive detection of coronary artery stenoses. While the diagnostic accuracy of first generation MDCT is limited, recently released 64-slice MDCT has yielded promising results due to increased temporal and spatial resolution. The objective of this study was to investigate the diagnostic accuracy of non-invasive 64-slice MDCT for coronary artery disease. METHODS: One hundred one patients (63 males and 38 females; mean age, 63.7+/-10.5 years) undergoing conventional coronary angiography were included in this study. All coronary arteries, including the distal segments and side branches, were analyzed for the presence of significant stenosis (> or =50% diameter stenosis) and compared with of the quantitative coronary angiographic findings. RESULTS: Of the 1,440 coronary artery segments studied, 1,348 segments were assessed quantitatively by both MDCT and conventional coronary angiography (94%). Two hundred nine significant stenoses were detected by conventional coronary angiography. On a segment-based analysis, the senisitivity, specificity, and positive and negative predictive values of 64-slice MDCT were 96, 97, 85, and 99%, respectively. On a vessel-based analysis, the sensitivity, specificity, and positive and negative predictive values of 64-slice MDCT were 96, 97, 85, and 99%, respectively. The corresponding values obtained on a patient-based analysis were 100, 94, 97, and 100%, respectively. Coronary calcification was the major cause of false-positive findings. CONCLUSIONS: This study demonstrated that 64-slice MDCT coronary angiography is of similar accuracy as conventional coronary angiography for the detection of coronary artery disease. In selected groups of patients, 64-slice MDCT may replace the more invasive coronary angiography.
Constriction, Pathologic ; Coronary Angiography ; Coronary Artery Disease ; Coronary Stenosis ; Coronary Vessels ; Humans ; Male ; Sensitivity and Specificity

Solitary fibrous tumor (SFT) is a benign mesenchymal neoplasm of a spindle-cell origin, and it usually involves the pleura. It's occurrence in various organs of the body has recently been described. Meningeal SFT is very rare. Radiologically, it is a strongly enhancing solid mass and is undistinguishable from fibrous meningioma and hemangiopericytoma. Yet we report here on a case of SFT with massive cystic degeneration that arose from the meninges of the left occipital region.
Hemangiopericytoma ; Meninges* ; Meningioma ; Pleura ; Solitary Fibrous Tumors*

Subcutaneous panniculitis-like T-cell lymphoma (SPTCL) is a rare cancer and it is widely regarded as being distinct from the other subtypes of peripheral T-cell lymphoma. SPTCL commonly presents with subcutaneous nodules that resembles panniculitis. The clinicopathologic features of SPTCL have recently been described. However, only a few cases with their CT and sonographic findings have been reported in the radiologic literature. We illustrate here the MR findings of this rare tumor in one case that presented with a popliteal mass.
Lymphoma, T-Cell* ; Lymphoma, T-Cell, Peripheral ; Panniculitis ; Subcutaneous Tissue ; T-Lymphocytes* ; Ultrasonography

We report here on a case of primary extraskeletal mesenchymal chondrosarcoma that arose from the pancreas. A 41-year-old man was evaluated by CT to find the cause of his abdominal pain. The CT scans showed a heterogeneously enhancing necrotic mass with numerous areas of coarse calcification, and this was located in the left side of the retroperitoneal space and involved the body and tail of the pancreas. Portal venography via the celiac axis also showed invasion of the splenic vein. Following excision of the mass, it was pathologically confirmed to be primary extraskeletal mesenchymal chondrosarcoma that arose from the pancreas.
Abdominal Pain/etiology ; Adult ; Chondrosarcoma, Mesenchymal/complications/*diagnosis/surgery ; Contrast Media/administration & dosage ; Diagnosis, Differential ; Humans ; Iohexol/analogs & derivatives/diagnostic use ; Male ; Necrosis ; Pancreas/pathology/radiography ; Pancreatic Neoplasms/complications/*diagnosis/surgery ; Portal Vein/radiography ; Radiographic Image Enhancement/methods ; Rare Diseases ; Retroperitoneal Space/radiography ; Splenic Vein/radiography ; Tomography, X-Ray Computed/methods

PURPOSE: To assess the therapeutic effect of Novalis radiosurgery for metastatic spinal tumors and evaluate the changes after treatment using MR imaging. MATERIALS AND METHODS: Between November 2003 and June 2005, 21 patients with metastatic spinal tumors underwent Novalis radiosurgery. Of these patients, the 7 with 13 metastatic spinal tumors who had undergone follow-up MR imaging were included in this study. The tumor locations were cervical spine in three, thoracic spine in four, lumbar spine in five and sacrum in one. During the first three months after Novalis radiosurgery, follow-up MRI was performed monthly and subsequently at 3-6-month intervals. On MR imaging, the volume of the tumors, the changes of their signal intensities and any changes in adjacent spinal cord were evaluated. RESULTS: Among the 13 lesions, 9 were decreased in volume (69.2%), 2 were stable (15.4%) and 2 were slightly increased. Seven of 9 lesions showed decreased signal intensity on T2 weighted images and 4 had compressive deformity. Two of 9 lesions had increased T2 signal intensity and tumor necrosis were detected on contrast-enhanced MR imaging. No changes in spinal cord were noted in any of the lesions. Those changes were detected on MRI obtained 1 month after Novalis surgery and the lesion sizes were gradually changed up to 3 months. CONCLUSION: Novalis radiosurgery was effective for the treatment of metastatic spinal tumor and the suppression of tumor growth. The estimation of therapeutic effect and detecting complication were precisely evaluated on MR imaging.
Congenital Abnormalities ; Follow-Up Studies ; Humans ; Magnetic Resonance Imaging ; Necrosis ; Radiation Oncology ; Radiosurgery* ; Sacrum ; Spinal Cord ; Spine

PURPOSE: We wanted to evaluate an acceptable compression rate of JPEG2000 for long term archiving of CT and MR images in PACS. MATERIALS AND METHODS: Nine CT images and 9 MR images that had small or minimal lesions were randomly selected from the PACS at our institute. All the images are compressed with rates of 5:1, 10:1, 20:1, 40:1 and 80:1 by the JPEG2000 compression protocol. Pairs of original and compressed images were compared by 9 radiologists who were working independently. We designed a JPEG2000 viewing program for comparing two images on one monitor system for performing easy and quick evaluation. All the observers performed the comparison study twice on 5 mega pixel grey scale LCD monitors and 2 mega pixel color LCD monitors, rspectively. The PSNR (Peak Signal to Noise Ratio) values were calculated for making quantitative comparisons. RESULTS: On MR and CT, all the images with 5:1 compression images showed no difference from the original images by all 9 observers and only one observer could detect a image difference on one CT image for 10:1 compression on only the 5 mega pixel monitor. For the 20:1 compression rate, clinically significant image deterioration was found in 50% of the images on the 5M pixel monitor study, and in 30% of the images on the 2M pixel monitor. PSNR values larger than 44 dB were calculated for all the compressed images. CONCLUSION: The clinically acceptable image compression rate for long term archiving by the JPEG2000 compression protocol is 10:1 for MR and CT, and if this is applied to PACS, it would reduce the cost and responsibility of the system.
Data Compression ; Noise