Biomedical subjects
Publications and source records attributed to B Bashist.
OBJECTIVE: The purpose of this study was to identify acute sigmoid diverticulitis as a cause of small-bowel obstruction and to describe the CT findings. CONCLUSION: CT scanning enabled accurate preoperative diagnosis of colonic diverticulitis as the cause of the small-bowel obstruction, thereby allowing proper management and surgical planning.
OBJECTIVE: We evaluated findings on contrast-enhanced abdominal CT scans that suggest obstruction of the superior vena cava, brachiocephalic vein, or subclavian vein. SUBJECTS AND METHODS: We conducted a retrospective review of 22 patients with superior vena caval, brachiocephalic vein, or subclavian vein obstruction and analyzed the upper abdominal images on a chest CT scan or an abdominal CT scan. We assessed collateral vessels in the upper abdomen to answer the following question: Did enhancement approach undiluted IV contrast or were there other findings? In the second part of our study, we conducted a prospective review of abdominal CT scans of 200 patients without known mediastinal disease or known upper extremity venous occlusion to determine the frequency of abnormal enhancement of these vessels in a healthy population. RESULTS: The groups of collateral vessels revealed on abdominal CT scans were azygos or hemiazygos veins, internal mammary veins, lateral thoracic and superficial thoracoabdominal veins, vertebral venous plexus veins, and small mediastinal collateral veins. In the retrospective series, one patient had focal enhancement of the liver and early inferior vena caval enhancement due to collateral vessels. In the prospective series, abdominal CT scans of two patients (1%) revealed dense undiluted enhancement of one or more groups of collateral vessels: One patient had an ipsilateral pacemaker, and the other patient had an anterior neck phlegmon to the upper mediastinum. Both conditions may have been factors in the revealing of the collateral vessels. Two other patients (1%) in the prospective series had mild to moderate vessel enhancement that was less than that from undiluted contrast material. In one of these patients, the enhancement was related to abdominal wall hyperemia after surgery. In the other patient, enhancement may have been the result of ipsilateral axillary nodes. CONCLUSION: On upper abdominal CT scans, dense undiluted contrast material in the collateral vessel groups that we studied suggests possible obstruction of the superior vena cava, brachiocephalic vein, or subclavian vein.
PURPOSE: To evaluate a magnetic resonance (MR) technique for depicting the kidneys and urinary tract. MATERIALS AND METHODS: Fourteen patients with urinary tract obstruction and 20 without obstructions were examined with a modified, heavily T2-weighted fast spin-echo pulse sequence (MR urography). In addition, six healthy volunteers underwent modified MR urography with intravenous administration of furosemide and ureteral compression prior to imaging. RESULTS: MR urography provided high-resolution images of the kidneys and urinary tract in all patients with obstruction with intact collecting systems. Anatomic anomalies were depicted in two patients. Intraluminal neoplasia was well demonstrated in both obstructed and nonobstructed systems (n = 4). Furosemide-enhanced MR urography provided fine anatomic and functional detail of both the kidneys and urinary tract (n = 6). CONCLUSION: MR urography may provide an alternative to more conventional urinary tract imaging techniques. It does not require ionizing radiation or iodinated contrast material. When combined with furosemide and ureteral compression, MR urography provides fine detail and reflects function.
Invasion of the main renal vein by transitional cell cancer of the renal pelvis is an infrequently reported event. No accurate clinical frequency of this phenomenon is available. Extensive invasion of the renal parenchyma by the tumor usually is present by the time it presents in the renal vein. This article represents but the second documenting main renal vein involvement depicted with computerized tomography in a patient with carcinoma of the renal pelvis.
OBJECTIVE: Imaging-directed fine-needle aspiration biopsy can be performed with or without immediate cytologic assessment (smears). We compared the results obtained immediately from cytologic smears with the results of cell-block analysis. We wished to determine the frequency of false-negative findings on cytologic smears in patients subsequently found to have malignant tumors by cell-block analysis. MATERIALS AND METHODS: We retrospectively reviewed the records for 100 consecutive biopsies performed between January 1986 and August 1987. In each case, specimens were obtained from both a 22-gauge and a 20-gauge notched needle placed in tandem. The study group consisted of 84 patients who had results of analyses of both cytologic smears and cell blocks available for review and who had clinical or surgical correlation. RESULTS: Sixty-four (76%) of the 84 biopsies yielded malignant tumor cells, 11 yielded evidence of a benign process, and nine were not diagnostic. Malignant tumor cells were seen on the cytologic smears in 55 (86%) of the 64 patients who had malignant tumors; in the other nine patients, the malignant tumors were indicated by the cell-block analysis only. Within the group of benign disorders, in only one case (9%) was the cell block diagnostic when the cytologic smear was not. CONCLUSION: Operators performing fine-needle aspiration biopsy should be aware of the limitations of immediate cytologic evaluation. Cell-block analysis of the aspirate remaining after the smears are made can be expected to increase the diagnostic accuracy in up to 14% of patients.
Therapeutic irradiation of the pelvis of a young female patient will result in loss of ovarian function. In a surgical technique termed ovarian transposition, the ovary is repositioned to the iliac fossa or paracolic gutter outside the radiation field. The computed tomographic (CT) scans and sonograms of five patients with cervical carcinoma who underwent this procedure were reviewed. The normal transposed ovary was of soft-tissue attenuation, often with one or more small cysts. Large cysts developed in the ovaries of three patients. One cyst was functional, another was due to a mesothelial inclusion cyst, and the third was most probably related to the transposition itself. Since the transposed ovary is difficult to palpate, CT or sonography can be used to demonstrate and follow up a cystic mass. Recognition of the appearance and location of the transposed ovary is important to avoid misinterpretation of a solid or cystic mass in patients who are at risk for tumor recurrence.
Tuberculosis of the rectum is a rare disease. A patient with a miliary pattern of pulmonary tuberculosis had a rectal lesion which proved to be tuberculosis. The patient subsequently developed several opportunistic infections characteristic of acquired immune deficiency syndrome. The clinical, endoscopic, radiologic, and histologic findings of this treatable lesion are presented.
ischemic colitis involving a limited segment of the proximal transverse colon in a young diabetic woman was identified and treated. Important clinical, radiographic, and histopathologic findings are detailed.
Absolute left ventricular volume has been calculated from gated blood pool studies by estimating an attenuation correction for left ventricular counts. We studied the physical basis of these corrections by evaluating x-ray photon attenuation from CT scans of the thorax (10 second scans, no gating). CT numbers were converted to linear attenuation coefficients (LACs) at 140 keV, and LACs from the center of the left ventricle or esophagus to the chest wall (40 degrees left anterior oblique position) were determined in 12 patients of various body habitus. The mean LACs were virtually identical (0.13 cm-1 +/- 0.02 cm-1 SD), but were less than the LAC of water (0.15 cm-1). However, the esophagus was 66% further from the chest wall than the center of the left ventricle. These results suggest that conventional methods overestimate attenuation and show that LAC variability between individuals can be large. Better methods of attenuation correction may improve count-based estimates of left ventricular volume.
Endometriosis of the bowel most often involves the sigmoid and rectosigmoid and appears as an intramural mass protruding into the lumen in a polypoid or constricting fashion. Occasionally there is an intraluminal mass without obvious intramural involvement. Endometriosis of bowel is rarely diagnosed at endoscopic biopsy. We present a patient with an intraluminal endometrioma with a positive endoscopic biopsy.
The computed tomography (CT) and ultrasound findings in 18 patients (35 kidneys) with non-Hodgkin lymphoma involving the kidneys are presented. Renal involvement was bilateral in 13 patients. The most common presentation was that of multiple intraparenchymal nodules (15 kidneys). Other types of involvement included direct invasion from contiguous retroperitoneal lymph node masses (nine kidneys), solitary renal masses (five kidneys), and diffuse infiltration (two kidneys). On CT most of the lesions were of homogeneous tissue density. Ultrasonographically the renal masses were hypoechoic. We believe that CT is the procedure of choice for the detection and follow-up of renal lymphoma.
Ten patients with intrathoracic goiters were evaluated by computed tomography (CT). In comparison with chest radiographs, CT showed additional features helpful in suggesting the correct diagnosis. These observations included: (1) clear continuity with the cervical thyroid gland (8/10 cases); (2) well defined borders (9/10); (3) punctate, coarse, or ringlike calcifications (8/10); (4) nonhomogeneity (9/10) often with discrete, nonenhancing, low-density areas (6/10); (5) precontrast attenuation values at least 15 H greater than adjacent muscles (4/10) with more than 25 H after contrast enhancement (8/8); and (6) characteristic patterns of goiter extension into mediastinum.
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One-hundred twenty-five cases of upper extremity internal arteriovenous and graft fistulas were reviewed. Clinical problems requiring study were poor fistula flow during dialysis, difficulty in cannulation, diminished graft pulsations, extremity edema or varicosities, the appearance of pulsatile or nonpulsatile masses in the graft or fistula, and distal ischemia. Angiography demonstrated venous occlusion (13 cases), venous stenosis at or near the anastomotic site (32 cases), thrombi within shunts (9 cases), venous aneurysms or pseudoaneurysms related to either proximal obstruction or traumatic dialysis (23 cases), distal venous overdistention due to proximal obstruction or overcirculation (15 cases), and radial artery steal of blood from the distal extremity (15 cases). The causes and predisposing factors leading to the complications are presented along with a discussion of the angiographic techniques that were used.
BACKGROUND: To determine whether computed tomography (CT) can satisfactorily diagnose and evaluate patients with suspected colonic obstruction. METHODS: Seventy-five patients with suspected colonic obstruction were evaluated prospectively by CT and compared with the gold standards of surgery and/or endoscopy in 65 patients, clinical course in nine, and contrast enema (CE) in one. A limited comparison between CT and CE (26) patients was also made in those patients who had both studies. RESULTS: CT successfully diagnosed colonic obstruction in 45 of 47 patients (96% sensitivity). Pseudo-obstruction was correctly diagnosed in 26 of 28 patients (93% specificity). CT correctly localized the point of obstruction in 44 of 47 patients (94%). CE successfully diagnosed obstruction in only 20 of 25 patients (80% sensitivity). CONCLUSION: In this study, CT proved to be a satisfactory modality in evaluating patients with suspected colonic obstruction. CT may in certain circumstances be preferable to the traditional CE in evaluating these patients.
Bronchial artery aneurysms are rare lesions. A case report is presented in which CT demonstrated a 7 cm enhancing mass that proved to be a mediastinal bronchial artery aneurysm. The aneurysm subsequently eroded into the esophagus, resulting in fatal exsanguination.
Intestinal obstruction due to a phytobezoar within a Meckel diverticulum is exceedingly rare, with only seven reported cases in the surgical literature. The most important precipitating factor is the ingestion of agents high in fiber and cellulose. Small bowel obstruction in all but one case was due to retrograde propagation of the bezoar into the small bowel lumen. We report the clinical and CT findings in such a patient following a vegetarian diet.