Biomedical subjects
Publications and source records attributed to D G Varma.
The computed tomography findings of large subcutaneous metastatic implants in the pelvic and inguinal regions from an epidermoid carcinoma of the esophagus are presented. To the best of the authors' knowledge, this appearance has not previously been reported.
Lipomas are frequently encountered benign tumors of adipose tissue origin. A lipoma generally develops in the superficial subcutaneous tissues but may occasionally be deep seated, growing between or within muscles. Deep-seated lipomas (excluding body cavities and viscera) have been termed infiltrating benign lipomas, of which there are two varieties--lipoma and angiolipoma. We wish to report three cases of infiltrating benign lipomas. Computed tomography scanning is the diagnostic modality of choice in the evaluation of these tumors.
A case of false-negative Tc-99m MDP bone scintigrams, taken at one and two weeks for pathologic fractures in a patient with metabolic bone disease and a super-scan appearance, is described. The patient had renal osteodystrophy, and postparathyroidectomy hypocalcemia. Postoperative seizures caused multiple pathologic fractures. Initial scans were negative for focal tracer localization in the presence of a continued super-scan appearance. After months of calcium and vitamin D replacement therapy, fracture sites became positive on Tc-99m MDP imaging. The observations in this case lend credence to the hypothesis of Tc-99m MDP binding by immature collagen in the production of a super scan in metabolic bone disease, as well as that of Tc-99m MDP chemisorption to calcium hydroxyapatite crystal in fracture healing. In addition, aluminum toxicity, common in chronic renal osteodystrophy, may have played a role in the delayed fracture healing.
A case of neurosarcoidosis with extensive involvement of both optic nerves and intracranial leptomeninges is reported. Computed tomography demonstrates diffuse enlargement of the optic nerves and extensive nodular contrast medium enhancement of the leptomeninges of the anterior and middle cranial fossae extending into the frontal convexity. Only one such case has been previously reported in the computed tomography literature. Marked therapeutic response was obtained clinically and demonstrated on a follow-up computed tomography after therapy with corticosteroids. Differential diagnosis of computed tomography findings is discussed.
A 68-year-old woman was admitted with atypical angina. A chest radiograph showed an anterior mediastinal mass that was confirmed on CT. The mass was relatively avascular and separate from the heart and great vessels. She underwent stress thallium testing that demonstrated no exercise-induced ischemia; however, an abnormal focus of thallium activity was present in the anterior mediastinum on stress and redistribution images. Cardiac catheterization demonstrated a normal left ventriculogram, coronary arteries and thoracic aorta. Subsequent surgery and pathologic examination revealed the mass to be a benign thymoma arising in the right lobe of the thymus gland.
Gray-scale sonographic examination of the maxillary sinuses of five normal volunteers and 12 patients with maxillary sinus disease was performed and correlated with other radiologic imaging modalities, clinical follow-up, and, in two cases, surgical findings. B-mode scanning is a rapid, potentially useful, nonionizing diagnostic modality for determining whether the maxillary sinuses contain fluid or are normally aerated. Sonography may also demonstrate mucosal thickening, focal soft tissue masses, and complex collections.
A case of multiple saccular cerebral aneurysms in association with a left-sided inferior vena cava and hemiazygos continuation is presented. To our knowledge, this association has not previously been recorded in the literature.
The computed tomography findings in two cases of xanthogranulomatous pyelonephritis are presented. There was diffuse involvement of the kidney in one case, with correlation with the pathologic specimen and microscopic findings. In the second case there was focal involvement of the kidney. Computed tomography greatly assisted in making a correct preoperative diagnosis and in assessing the degree of extrarenal involvement.
A case of a subpleural pulmonary hamartoma demonstrated by computed tomography is presented. The literature on subpleural pulmonary lesions demonstrated by computed tomography is reviewed. Although peripheral pulmonary hamartomas have been well documented, we believe this is the first demonstration of a subpleural location by computed tomography scanning. In the appropriate clinical setting, pulmonary hamartoma should be included in the differential diagnosis of subpleural lesions identified on computed tomography scanning of the chest.
TI-201 myocardial scintigrams from 100 patients were reviewed for evidence of left ventricular aneurysms without prior knowledge of the clinical or angiographic data. Scintigraphic evidence of left ventricular aneurysms was considered present when TI-201 myocardial activity extended outward from the expected left ventricular contour in a region adjacent to an area of resting scintigraphic hypoperfusion. Scintigraphic findings suggestive of left ventricular aneurysm were detected in four patients, of whom three had angiographic evidence of left ventricular aneurysm. In the fourth patient, a dilated, akinetic left ventricular apex was present but an angiographic diagnosis of left ventricular aneurysm was not made. In three additional patients with angiographic evidence of left ventricular aneurysm, scintigraphic criteria for left ventricular aneurysm were absent. Although ungated TI-201 myocardial scintigraphy is an insensitive technique for the detection of left ventricular aneurysm, a characteristic scintigraphic pattern should suggest that a left ventricular aneurysm is present.
Radiologic evaluation of the patient with soft tissue sarcoma may include conventional radiography, scintigraphy, ultrasonography (US), computed tomography (CT), and magnetic resonance (MR) imaging. The radiologist also plays a critical role in the evaluation of the patient with soft tissue sarcoma by guiding and performing aspiration biopsies. This review discusses the use of radiological techniques to evaluate the primary lesion and to detect recurrences. In adults, soft tissue sarcoma most commonly occurs in the extremities, and this review emphasizes the role of MR imaging in the pre- and post-treatment evaluation of extremity soft tissue sarcomas. The role of imaging studies in the evaluation of soft tissue sarcomas in the abdomen, thorax, and the head and neck region is also discussed.
The authors retrospectively evaluated magnetic resonance images of the abdomen obtained in 52 consecutive patients. All cases included fast spin-echo (FSE) T2-weighted images acquired with a frequency-selective fat saturation technique. All imaging was performed with a 1.5-T unit. In 42 patients (81%), fat was not suppressed in the right anterior diaphragmatic region on the T2-weighted FSE images with fat suppression. In 11 (26%) of these 42 patients, subcutaneous fat adjacent to the unsuppressed anterior diaphragmatic fat was well suppressed. Hence, the fat in the diaphragmatic region mimicked fluid or peritoneal implants. The cause of the artifact appears to be the juxtaposition of liver, fat, and lung parenchymal air within a small anatomic space, creating a localized inhomogeneity of the magnetic field and susceptibility effects. Radiologists should be aware of this phenomenon to prevent confusion of an artifact with fluid or neoplasms.
The magnetic resonance imaging (MRI) and computed tomography (CT) appearance of 18 paravaginal cysts was reviewed. On MRI, serious cysts were hypointense on T1-weighted and hyperintense on T2-weighted images. Cysts presumed to contain proteinaceous material were hyperintense on T1-weighted and T2-weighted sequences while hemorrhagic cysts exhibited varying stages of hemorrhage. On CT, a high attenuation cyst was presumed to contain proteinaceous material or hemorrhage. MRI and CT examination may reveal paravaginal cysts; their varied appearance must be recognized to avoid confusion with other lesions.
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We describe the computed tomography (CT) appearance of an unusual, large retroperitoneal granular cell tumor and provide a 5-year follow-up. The tumor occurred in association with multiple, smaller, subcutaneous granular cell tumors. The CT findings were nonspecific, but the scans delineated the extent of the lesion and its relationship to adjacent vessels well. To our knowledge, this report is the first description of the CT appearance of retroperitoneal granular cell tumor in the medical literature.
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We retrospectively reviewed MR images of 32 histologically proven extracranial nerve sheath tumors (NSTs). There were 23 benign (10 neurofibromas, 13 schwannomas) and 9 malignant NSTs. On T1-weighted images (T1WIs) tumors were isointense or slightly hyperintense to muscle. On T2-weighted images (T2WIs) (11 lesions) and enhanced T1WIs (1 intraspinal lesion), a target pattern with peripheral hyperintense rim and central low intensity was seen in 12 of 23 (52%) benign NSTs (5 of 10 neurofibromas and 7 of 13 schwannomas). This pattern corresponded histologically to peripheral myxomatous tissue and central fibrocollagenous tissue. The pattern was absent in lesions with cystic, hemorrhagic, or necrotic degeneration. These tumors were hyperintense and variably inhomogenous on T2WIs. Malignant NSTs were hyperintense and variably inhomogenous on T2WIs and mimicked benign variably inhomogeneous lesions unless involvement of contiguous structures was visualized. A target pattern was not visible in malignant lesions. Magnetic resonance imaging cannot distinguish schwannomas from neurofibromas, and benign tumors may mimic malignant NSTs when cystic, hemorrhagic, and necrotic degeneration is present. A target pattern may be visualized in some benign NSTs, and evaluation of this sign with assessment of location and growth along nerves may help to avoid confusion with other lesions.