Biomedical subjects
Publications and source records attributed to B D Nguyen.
A case of silent extraperitoneal rectal perforation secondary to colonoscopic polypectomy is presented. Computed tomography (CT) demonstrated pathways of gas diffusion from the perirectal site to different compartments of the retroperitoneum, to the mediastinum and peritoneum.
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A double-pediatric kidney transplant recipient, who developed hypertension, was found to have unilateral renal artery stenosis. The stenosis was successfully assessed by single-dose 99mTc-diethylenetriaminepentaacetic acid renal scintigraphy, confirmed by renal arteriography, and treated by percutaneous transluminal angioplasty. This case illustrates the usefulness of Captopril-enhanced renography in screening en-bloc transplant patients suspected for renal vascular hypertension.
A case of renal granular cell carcinoma with inferior vena cava and right atrium involvement is presented. Spin-echo and single breath-hold gradient-recalled-echo magnetic resonance pulse sequences demonstrate a patchy flow signal within the cavoatrial thrombus. This pattern, in correlation with the histopathologic findings, represents tumoral neovascularity characteristic of renal carcinoma venous invasion, which was previously reported by angiography, computed tomography, and color Doppler duplex ultrasound.
A patient with a pelvic silicone prosthesis is presented. The sonographic and computed tomographic features in such patients can be confusing and incorrectly interpreted unless the radiologist knows that the prosthesis had been inserted as a radioprotective device.
A case of kappa light chain multiple myeloma with space-occupying hepatic plasmacytoma is presented. Magnetic resonance (MR) imaging shows an eccentric multiple-layer pattern of the liver mass and suggests malignancy. Differential diagnosis concerning the MR appearance of this rare hepatic tumor is discussed.
Technetium-99m sestamibi planar and single-photon-emission computed tomographic scintigraphy is useful in the diagnosis of parathyroid gland disease. To understand the various patterns of parathyroid disease, it is important to understand parathyroid embryology and anatomy. The spectrum of parathyroid disease demonstrated with Tc-99m sestamibi scintigraphy includes eutopic disease, ectopic disease, solitary adenoma, double or multiple adenomas, cystic adenoma, lipoadenoma, multiple endocrine neoplasia, hyperfunctioning parathyroid transplant, entities with atypical washout, and nonparathyroid entities that take up Tc-99m sestamibi. The diagnosis of parathyroid tumors with Tc-99m sestamibi scintigraphy is based on the difference in clearance rates between the thyroid and diseased parathyroid glands, and any condition that interferes with radiotracer clearance will limit the effectiveness of the study. The technique is most clearly indicated for the preoperative evaluation of recurrent or persistent hyperparathyroidism, but it is increasingly being used before the initial surgical exploration as well. Subtraction Tc-99m sestamibi and iodine-123 scintigraphy may be helpful in difficult cases. Parathyroid hyperplasia, multisite parathyroid disease, and concomitant thyroid and parathyroid disease remain potential hurdles for this scintigraphic technique, and optimal handling of these problems still relies heavily on the skill and experience of the endocrine surgeon.