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Biomedical subjects

M G Velchik

Publications and source records attributed to M G Velchik.

At least 37 records · Page 2Linked to original sources
PubMed1988

Ventilation abnormalities associated with pulmonary embolism.

A retrospective analysis of 2035 lung images performed over approximately 5 years revealed abnormal ventilation coexisting with pulmonary embolism in 18 patients. Matching ventilation perfusion defects may be associated with pulmonary embolism without infarction. In patients with a high clinical suspicion of acute pulmonary embolism and matching V/Q abnormalities, an angiogram may be necessary to definitely exclude the diagnosis.

Humans↗
PubMed1988

Renal allografts: prospective analysis of Doppler sonography.

Fifty-six consecutively transplanted renal allografts were prospectively evaluated with serial Doppler sonographic examinations. Thirty-eight episodes of transplant rejection in 32 patients (63% proved pathologically) and 24 episodes of acute tubular necrosis (ATN) in 24 patients were encountered. The Doppler spectral waveform was characterized by means of the pulsatility index (PI), systolic/diastolic ratio (SDR), diastolic/systolic ratio (SDR), diastolic/systolic ratio (DSR), and resistive index (RI). Accuracy was optimized with use of top normal values as follows: PI = 1.8, SDR = 4.0, DSR = 0.25, RI = 0.75. There were no significant differences in the indices for those patients undergoing rejection versus those with ATN. The sensitivity for predicting transplant rejection was adversely affected by the history of either ATN or a previous rejection episode in the same allograft. Comparison with concurrent radionuclide examinations revealed similar sensitivities for rejection with scintigraphy and sonography. Differentiation of ATN from rejection was more reliable with scintigraphy than with sonography.

Acute Kidney Injury↗
PubMed1988

Indium-111-labeled white blood cells in the detection of osteomyelitis complicated by a pre-existing condition.

Forty-six patients (23M, 23F) ranging in age from 19 to 79 yr with a clinical history of a nonunion fracture, surgery, diabetes or a soft-tissue infection were studied with [111In]oxine WBCs to detect osteomyelitis. There were 27 true-positive, nine true-negative, two false-positive and one false-negative. The false-positives and the false-negative occurred in patients with soft-tissue infections overlying the area of interest. All diagnoses were confirmed by intraoperative bone biopsies and cultures. Bone biopsy and scan were performed within 2 days of each other in 39 patients. The overall sensitivity was 97% (27/28), specificity, 82% (9/11) and the diagnostic accuracy, 92% (36/39). The remaining seven patients had negative [111In]WBC scans several months after positive bone biopsies and definite antibiotic treatment. This suggests that [In]WBC scans become negative after appropriate therapy is undertaken. Interobserver data was obtained from four nuclear physicians of varying experience blinded to clinical information. A high degree of agreement was found in over 90% of the cases. This study demonstrates the utility of [111In]WBC scans in the diagnosis and follow-up of complicated osteomyelitis and a high level of interobserver agreement in scan interpretation.

Adult↗
PubMed1987

The cholescintigraphic pattern of small bowel obstruction.

An elderly patient presenting with acute abdominal pain, nausea, and vomiting underwent a hepatobiliary scan. This demonstrated normal filling of the gallbladder but dilatation of the small bowel, which was found to correspond radiographically to partial small bowel obstruction.

Aged↗
PubMed1987

Photon absorptiometry.

Recently, there has been a renewed interest in the detection and treatment of osteoporosis. This paper is a review of the merits and limitations of the various noninvasive modalities currently available for the measurement of bone mineral density with special emphasis placed upon the nuclear medicine techniques of single-photon and dual-photon absorptiometry. The clinicians should come away with an understanding of the relative advantages and disadvantages of photon absorptiometry and its optimal clinical application.

Bone and Bones↗
PubMed1986

Visualization of the uterus on evaluation of transplanted kidneys.

A vascular blush was noted in the pelvis during flow studies in two women with kidney transplants. The vascular structure was noted to be due to the uterus. In one patient, the activity in the area of the uterus could have been mistaken for excretion of agent into the bladder.

Diagnostic Errors↗
PubMed1986

Urine extravasation into the scrotum.

A case report demonstrating urine extravasation into the scrotum following renal transplantation is presented. An anatomic explanation of the pathway of urine drainage into the scrotum is offered with a brief discussion of extravasation following renal transplantation and its detection by scintigraphy.

Humans↗
PubMed1985

False-positive liver scan due to ascites.

Extrahepatic structures (breast, costal margin, kidney, pleural effusion, right lower lobe lung mass) may occasionally result in a false-positive liver scan by causing attenuation of the gamma rays emenating from the liver, thereby simulating an apparent intrahepatic lesion. A false-positive diagnosis of intrahepatic pathology may often be avoided by simple maneuvers such as elevating the breast, obtaining another projection, etc. A case of false-positive liver scan due to loculated ascites is presented in which these maneuvers failed to resolve the problem. Ultrasound or CT examination may be helpful in this circumstance due to the cross-sectional nature of the information they provide.

Ascites↗
PubMed1985

Quantitative analysis of liver function in percutaneous transhepatic biliary drainage patients.

The diagnostic usefulness of Tc-99m DISIDA cholescintigraphy as a predictor of eventual catheter and hepatic function in patients who have undergone percutaneous transhepatic biliary drainage (PTBD) for extrahepatic biliary obstruction was evaluated. Twenty-nine cholescintigrams were performed in 14 patients. The examinations were divided into two groups: Group A (N = 17), in which the patient's clinical status deteriorated within two to three days post-PTBD, and Group B (N = 12), in which the patients did well clinically post-PTBD. No significant difference between the two groups was demonstrated by visual analysis of the analog images or by analysis of serum bilirubin levels. A computer program, developed by the authors, quantitates several parameters of DISIDA kinetics, reflecting hepatic function based upon compartmental analysis. A significant difference (P less than .001) was demonstrated between the mean transport constants (blood clearance constant = k1; hepatic clearance constant = k2) for the two groups. It is concluded that serum bilirubin levels and visual inspection of analog images are inadequate independent predictors of hepatic function in patients post PTBD. The transport constants k1 and k2 are quantitative parameters of hepatic function that may be of prognostic value in patients post PTBD.

Adult↗