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Biomedical subjects

J B Selby

Publications and source records attributed to J B Selby.

At least 37 records · Page 2Linked to original sources
PubMed1989

Insertion of subclavian hemodialysis catheters in difficult cases: value of fluoroscopy and angiographic techniques.

Double-lumen hemodialysis catheters designed to be placed via a subclavian vein approach have gained rapid acceptance over the past several years. Several studies have shown a significant rate of subclavian vein stenosis or occlusion after placement of these catheters. A large number of these patients require repeat placement of catheters with access often becoming increasingly difficult to obtain. Over the past 5 years, we have been asked to place 38 catheters in 34 patients that could not be placed at the bedside. Our procedure consists of obtaining a preliminary venogram to evaluate the reason for difficulty. The subclavian vein is then cannulated under direct fluoroscopic visualization while the peripheral venous line is injected with contrast material. Percutaneous angiographic techniques are then used to position the catheter. Satisfactory placement was obtained in all 38 cases. There were no complications, which is surprising considering the number of complications seen with the standard methods of insertion. This represents a new role for the interventional radiologist, one that can be important in minimizing the number of new dialysis sites in any one patient.

Angiography↗
PubMed1987

Clinical experience with technetium-99m DTPA aerosol with perfusion scintigraphy in suspected pulmonary embolism.

To evaluate the clinical value of radioaerosol imaging, 156 patients with suspected pulmonary embolism (PE) were studied. In 25 patients, a preperfusion xenon-133 (Xe-133) study was compared with a postperfusion study using Tc-99m DTPA aerosol. It was found that they were of equal value most of the time (56%), but that the aerosol study was more often helpful. Because of this, and the technical ease of using six standard views with radioaerosol, the series was completed using perfusion scintigraphy followed by radioaerosol images. In 19 patients the perfusion scintigraphy with Tc-99 macroaggregated albumin (Tc-99m MAA) was normal or nearly normal and no aerosol study was required. Tc-99m DTPA aerosol images were satisfactory when the count rate was at least twice and preferably three times that of the previous perfusion study. There were 17 studies (11%) classified as intermediate. There were 26 patients classified as high probability for PE, and angiographic or autopsy correlation was available in 14. All of the 14 proved to have PE. In the 113 patients classified as low probability, there were ten with angiographic or autopsy correlation. In the ten, there was one patient with a small pulmonary embolus found at autopsy. Clinical follow-up for over two months confirmed the absence of PE in the remainder of this group. Aerosol studies have proven technically easier to perform and a satisfactory substitute for xenon imaging in suspected PE.

Adult↗
PubMed1983

Imaging patterns with 99mTc-PIPIDA in evaluating abdominal pain.

A random retrospective review of hepatobiliary scans on 86 adult patients with abdominal pain revealed four distinct imaging patterns: normal, cystic duct obstruction, obstructive, and sick liver pattern. A normal pattern was found to exclude acute cholecystitis and was the pattern most frequently observed.

Abdomen↗
PubMed1982

Isotopic identification of intestinal strangulation.

A small series of eleven dogs prepared with a strangulating segment of jejunum demonstrated that a radionuclide, 99mTc-labelled albumin, concentrates in the lumen and bowel wall of the affected intestinal segment. Modern scanning equipment accurately localized the strangulating loop. This technique has the potential of identifying patients with intestinal obstruction, in whom strangulation is a factor, prior to the development of impaired arterial inflow and frank gangrene. These findings confirmed earlier obstructions that were reported when nuclear scanning instrumentation was less sophisticated. Identification of patients at risk for intestinal strangulation requires a high index of suspicion. Excruciating cramping abdominal pain out of proportion to physical findings, roentgenogram evidence, and laboratory studies should alert the physician to the possibility of intestinal ischemia and closed loop obstruction. Radionuclide scanning in such cases may be of assistance in defining or excluding the diagnosis of a strangulating mechanism. The test is simple, relatively economical, and represents a low risk procedure to patients. It would have no place when the classic physical and laboratory findings of intestinal infarction are present.

Animals↗
PubMed1979

The Anger camera and the pertechnetate ion in the routine evaluation of thyroid uptake and imaging.

The thyroid traps the pertechnetate ion and iodine in a similar manner. Thus, 99mTc-pertechnetate may be used for thyroid uptake studies (including stimulation and suppression tests)8 as well as imaging. Images are obtained after an intravenous administration of 2--4 mCi of 99mTc-pertechnetate, and the scan is preceded by a trapping index at 20 minutes, measured as the neck to thigh ratio. In 1973, we compared 99mTc-pertechnetate with 131I in diagnostic uptake and imaging studies of the thyroid gland in 100 patients. We have had experience with an additional 100 patients, and modified our procedure so that the Anger camera with pinhole collimator will adequately replace the standard scintillation probe. Using the camera alone, with the 99mTc-pertechnetate makes the study less expensive and briefer, with no loss of information. Routine use of the scan aids in distinguishing diffuse from localized diseases.

Evaluation Studies as Topic↗
PubMed1979

Scintiangiographic diagnosis of acute mesenteric venous thrombosis.

Scintiangiographic findings of prolonged mesenteric activity in a case of acute mesenteric thrombosis is described and 105 cases with abdominal scintiangiography are reviewed. Usual peak mesenteric blush occurred 5--15 sec after initial visualization of the aorta. Normal clearance of this activity was 15--30 sec. Future cases should confirm the importance of this observation in early diagnosis of mesenteric venous thrombosis.

Acute Disease↗
PubMed1977

"Hot spot" on hepatic scintigraphy and radionuclide venacavography.

Seven patients showing a localized area of increased uptake (hot spot) on 99mTc sulfur colloid liver scans are described. Four also had dynamic studies. In five patients the hot spot was associated with superior vena caval obstruction, in one it was associated with inferior vena caval obstruction, and in one with a hepatoma. Although a hot spot on static liver images usually indicates superior vena caval obstruction, the addition of radionuclide venacavography is recommended to confirm the diagnosis. A hot spot in the liver area in a radionuclide venogram of the lower limbs suggests inferior vena caval obstruction with collaterals via the liver.

Carcinoma, Hepatocellular↗
PubMed1975

The use of the 99mTc-pertechnetate neck/thigh ratio as a test of thyroid function.

A total of 100 patients were studied by standard thyroid function tests and the 99mTc-pertechnetate neck/thigh ratio was determined. This ratio or "trapping index" correlated closely with 131I uptake. The 99mTc test should be followed by scanning at 20 minutes to distinguish diffuse from localized thyroid disease. TSH stimulation and suppression studies can be done. It is recommended that this ratio be used in place of the standard 24-hour RAIU study, as it gives the same information at a saving in time, money, and radiation exposure.

Humans↗