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Biomedical subjects

N A Yassa

Publications and source records attributed to N A Yassa.

14 recordsLinked to original sources
PubMed2001

Role of transrectal ultrasonography in evaluating the cause of azoospermia.

OBJECTIVE: To assess the role of transrectal ultrasonography in the investigation of azoospermia, a significant cause of infertility. METHODS: Over a 2-year period, 35 patients with azoospermia underwent an infertility workup, which included transrectal ultrasonography. RESULTS: Sonograms of 10 of the 35 patients were normal; 8 patients had enlarged seminal vesicles containing cysts, 6 had ejaculatory duct dilation, 5 had seminal vesicle calcification, 3 had seminal vesicle atrophy-hypoplasia and 3 patients had midline prostatic cysts. CONCLUSION: Transrectal sonography is a useful modality to evaluate seminal duct abnormalities, some of which may cause azoospermia.

Atrophy↗
PubMed1999

Ovarian vein thrombosis: a common incidental finding in patients who have undergone total abdominal hysterectomy and bilateral salpingo-oophorectomy with retroperitoneal lymph node dissection.

OBJECTIVE: Our objective was to use CT to determine the frequency of ovarian vein thrombosis in patients who have undergone total abdominal hysterectomy and bilateral salpingo-oophorectomy with retroperitoneal lymph node dissection. SUBJECTS AND METHODS: With contrast-enhanced conventional CT of the abdomen and pelvis, we ruled out recurrent malignant disease in 50 patients who in the previous 3-20 months had undergone total abdominal hysterectomy and bilateral salpingo-oophorectomy with retroperitoneal lymph node dissection. Thirty of these patients had ovarian cancer (60%), 15 (30%) had cervical cancer, and five (10%) had endometrial cancer. RESULTS: In 40 (80%) of the 50 patients, contrast-enhanced CT revealed ovarian vein thrombosis. No surrounding stranding to suggest phlebitis was seen in any of the patients. None of the patients reported symptoms that would suggest pulmonary embolism. CONCLUSION: Ovarian vein thrombosis is a common incidental finding in patients who have undergone total abdominal hysterectomy and bilateral salpingo-oophorectomy with retroperitoneal lymph node dissection. No treatment is necessary in cases uncomplicated by thrombophlebitis or pulmonary embolism.

Adult↗
PubMed1999

Perirenal lucency ("kidney sweat"): a new sign of renal failure.

OBJECTIVE: This study describes a new sonographic finding in renal failure: perirenal lucency, which we call the "kidney sweat" sign. MATERIALS AND METHODS: During 1 year at our institution, 502 renal sonograms were obtained. Sonography evaluated 330 patients with renal failure. All of the examinations were retrospectively analyzed. RESULTS: An extracapsular hypoechoic rim was present in 47 (14%) of the 330 patients with renal failure. The finding, when present, was always bilateral. The hypoechoic rim was not present in the remaining 283 patients with renal failure. Forty (85%) of the 47 patients had kidneys that were hyperechoic compared with the liver. Twenty-eight (60%) of the 47 patients had kidneys that were hyperechoic compared with the spleen. In 15 (32%) of the 47 patients, the kidneys were small. Ascites was present in 11 (23%) of the 47 patients. Of the 283 patients with renal failure whose sonograms did not show the hypoechoic rim, 76 patients had normal sonographic findings. The remaining 207 patients with renal failure who did not show the kidney sweat sign had hydronephrosis, stones, cysts, echogenic kidneys, small kidneys, or ascites. CONCLUSION: An extracapsular hypoechoic rim is found in patients with renal failure. We call this finding "kidney sweat." We believe, but cannot currently prove, that the kidney sweat sign represents edema. It is an additional sonographic finding in patients with renal failure.

Adult↗
PubMed1999

Iatrogenic bowel obstruction caused by balloon-inflated feeding tubes.

OBJECTIVE: To determine whether balloon-inflated feeding tubes may be a cause of bowel obstruction. METHODS: Evaluation of 10 patients with balloon-inflated feeding tubes who experienced cramping, nausea and vomiting. Conventional radiography of the abdomen was performed in all patients, a fluoroscopic barium examination in 6 patients, and computed tomographic scanning of the abdomen and pelvis in 4 patients. RESULTS: All patients had a bowel obstruction caused by the inflated balloon. Deflating the balloon relieved the obstructive symptoms immediately. CONCLUSION: Balloon-inflated feeding tubes can cause bowel obstruction.

Aged↗
PubMed1996

CT of focal hepatic injury due to surgical retractor.

OBJECTIVE: This study reports the CT appearance of changes in the liver due to retractor injury during surgery for upper gastrointestinal malignancy. SUBJECTS AND METHODS: Ten patients underwent CT examination of the abdomen before (n = 6) and after (n = 10) IV contrast enhancement 2-6 months after surgical resection of malignancy involving the gastric cardia. At each operation, a modified Weinberg's retractor was placed under the lateral segment of the left lobe of the liver to retract it and expose the esophagogastric junction. RESULTS: A sharply marginated, focal, hypodense lesion with no mass effect was shown in the lateral segment of the left lobe of the liver on unenhanced scans in six patients. Irregular enhancement was present after contrast injection in all 10 patients. All patients had a normal preoperative CT of the liver. No patient revealed clinical or laboratory evidence of liver metastasis or abscess. CONCLUSION: Focal hepatic injury due to intraoperative retraction has a typical location and CT appearance that can aid in recognition of the injury.

Aged↗
PubMed1992

Crossed renal ectopia. Correlative imaging.

Anatomic variants of the kidneys are often noted during renal scintigraphy and other imaging studies. These conditions have a variable effect on overall renal function and can cause confusion, both clinically and on initial imaging. The authors describe a case of unfused, crossed renal ectopia in an elderly woman that appeared to be an abdominal mass and was subsequently evaluated by computed tomography, ultrasound, and scintigraphy.

Aged↗
PubMed1988

Properties of electromagnetic field focusing probe.

The electromagnetic field focusing (EFF) apparatus consists of a radio frequency generator, solenoidal coil, and a hand-held or catheter probe. Applications such as aneurysm treatment, angioplasty, and neurosurgery in various models have been reported. The probe is operated in the near field (within one wavelength of an electromagnetic field source) of a coil inducing eddy currents in biological tissues, producing maximal convergence of the induced current at the probe tip. The probe produces very high temperatures depending on the wattage selected for the given radio frequency of output power. The high temperature can be used in cutting, cauterizing, or vaporizing. The EFF probe is comparable to different types of lasers and to bipolar and monopolar cautery. The EFF probe can be used with catheters or endoscopes. Objectives of this study were to determine what the thermal properties of the EFF probe are and how instrument parameters can be varied to obtain different temperatures in the tissue near the probe tip. In this study an F2 catheter was used as an insulated sheath and the tip of the guide wire was used as the probe tip. Different powers, wave forms, coil-to-probe distances, and probe-tip lengths were tested on a phantom that simulates tissue electrical properties. Some of the experiments were conducted under normal saline to simulate treatment of tissue with body fluids such as blood vessels or brain tissue under normal physiologic conditions. It is concluded that the EFF probe has the advantages of easy manipulation, relative safety, cost effectiveness, and a high degree of spatial control.(ABSTRACT TRUNCATED AT 250 WORDS)

Electrocoagulation↗
PubMed1988

Electromagnetic field focusing probe (EFFP)--a new angioplasty tool.

An electromagnetic field focusing probe (EFFP) consists of a radiofrequency generator, solenoidal coil, and a hand-held or catheter probe. The probe is operated in the near field (distance within one wave length of an electromagnetic field source) of a coil, which induces eddy current in a biological tissue. The induced eddy current is converged maximally at the tip of the probe upon contact of the tip with the tissue. The probe produces very high temperatures depending on the wattage selected. In this study, the EFFP was used to evaporate atheromatous plaques in human cadaver abdominal aorta specimens, which were then studied histologically. Gas produced by this technique was analyzed and the volume found to be related to power delivered, but in such small amounts as to be of no embolic significance. While temperature varied with wattage and time of application, it was maximal at the probe tip and easily controlled, resulting in clean obliteration of plaque.

Angioplasty, Balloon↗
PubMed1988

Precision surgery with an electromagnetically induced current convergence probe application in aneurysm treatment, angioplasty, and brain tumor resection in in vivo and in vitro models.

A hand-held probe, or one introduced through a catheter, rapidly produces an extremely high, tissue-vaporizing temperature in a precisely defined manner enabling surgeons or interventional radiologists to perform angioplasty, thrombose aneurysms, and vaporize tumors. The probe is operated in a near field of an inductive coil, and the current induced in the biologic tissue is converged maximally at the tip of the probe at the resonance frequency of both the inductor and the probe, producing a maximum temperature in excess of 1400 degrees C. Radio-frequency power controls the probe-tip temperature. The operation of the probe is comparable to that of a CO2 or YAG laser and is complementary to laser-surgical techniques. The low cost relative to lasers and simplicity of the device including its disposable components make the prospect of commercialization of this device promising.

Aneurysm↗
PubMedDate not supplied

Gray-scale and color flow sonography of pancreatic ductal adenocarcinoma.

PURPOSE: Current sonographic technology has enhanced imaging. This study analyzes the sonographic findings in a large series of patients with pancreatic ductal adenocarcinoma. METHODS: The sonograms of 62 patients with pathologically confirmed pancreatic ductal adenocarcinoma were retrospectively analyzed. RESULTS: Tumors were an average of 4.5 x 3.5 cm in cross section. The largest lesion was 14.0 x 9.0 cm, and the smallest was 1.8 x 1.1 cm. Forty-three tumors (69%) were located in the head of the pancreas, 1 (2%) at the junction of the head and body, and 16 (26%) in the body or tail; 2 lesions (3%) were diffuse. Tumors were ovoid or spherical in 37 patients (60%) and irregular in 25 (40%). Forty tumors (65%) markedly deformed the shape of the gland. Six lesions (10%) caused no glandular contour abnormality and were visualized only because tumor echogenicity differed from that of the normal pancreas. Thirty-four tumors (55%) were homogeneously hypoechoic compared with the normal pancreas, 2 (3%) were homogeneously hyperechoic, 1 (2%) was isoechoic, and 25 (40%) had heterogeneous echotextures. Many of the heterogeneous tumors were predominantly hypoechoic with areas of varied echogenicity. Calcifications were noted in 4 patients (6%) and small intratumoral cystic areas in 9 patients (15%). Postobstructive pseudocysts were found in 4 patients (6%). Color Doppler flow information was available for 19 patients; internal flow was detected in only 1 tumor (5%). Vascular occlusion was found in 3 patients and circumferential vascular encasement in 8; the tumors in these patients were unresectable. Tumors were noted to touch vessels in another 6 patients. CONCLUSIONS: Current sonographic equipment allows the demonstration of new findings in pancreatic carcinoma. Color Doppler sonography can define tumor involvement of blood vessels and potentially affect clinical staging and treatment decisions.

Blood Flow Velocity↗
PubMedDate not supplied

Routine pre-contrast CT for liver lesion detection. A re-examination.

OBJECTIVE: Re-examination of routine pre-contrast computed tomography (CT) through liver. MATERIALS AND METHODS: 852 abdominal CTs including pre- and post-contrast images were retrospectively reviewed regarding detection of hepatic lesions. RESULTS: 103 cases demonstrated hepatic abnormalities. More liver lesions were identified post-contrast in 89; equal numbers were seen pre- and post-contrast in 10; more lesions were seen pre-contrast in one case. Tiny calcifications were detected only pre-contrast in three cases. CONCLUSIONS: Routine pre-contrast scanning through liver is not cost-effective.

Contrast Media↗
PubMedDate not supplied

Accuracy of CT in estimating extent of pancreatic necrosis.

The objective of this study was to determine whether nonenhancing pancreatic lesions are accurate in estimating pancreatic necrosis. Twenty-six consecutive abdominal computed tomography (CT) examinations performed over a 3-year period that met the CT criteria for pancreatic necrosis were reviewed. Follow-up CTs in three of 26 patients demonstrated pancreatic enhancement, indicating viable parenchyma, within the previously nonenhancing regions. All three patients had undergone surgical debridement in that area. Twenty-three cases demonstrated either no change or enlargement of the nonenhancing pancreatic lesions. Follow-up ranged from 1 week to 26 months. While CT is accurate in diagnosing pancreatic necrosis, lack of enhancement in CT may occasionally overestimate the extent of necrosis. Nonenhancing, viable but at-risk tissue may be present adjacent to frankly necrotic tissue. Surgical debridement may facilitate recovery of this viable tissue, which may enhance normally on follow-up CT.

Adolescent↗
PubMedDate not supplied

High-resolution CT pulmonary findings in adults with Gaucher's disease.

The purpose of this study was to illustrate high-resolution computed tomography (HRCT) findings in symptomatic adult Gaucher's disease patients. Five adult patients with Gaucher's disease experienced dyspnea. These patient were first evaluated by chest X-ray (CXR) followed by HRCT. The chest X-ray on one patient demonstrated a calcified granuloma. Two patients had interstitial disease only seen on HRCT, and two patients had a combination of interstitial and alveolar disease giving a mosaic pattern better illustrated on HRCT. HRCT can be used following CXR to evaluate lung pathology in symptomatic adult Gaucher's disease patients.

Aged↗