Biomedical subjects

N Alazraki

Publications and source records attributed to N Alazraki.

At least 73 records · Page 4Linked to original sources

PubMed1985

Value of a 24-hour image (four-phase bone scan) in assessing osteomyelitis in patients with peripheral vascular disease.

The delayed images of the four-phase 99mTc phosphonate bone scan are compared with the delayed images of the three-phase study in patients with diabetes mellitus and/or peripheral vascular disease and suspected osteomyelitis. Three-phase bone imaging includes an immediate postinjection radionuclide angiogram, a blood-pool image, and delayed static images to 7 hr. The four-phase study adds a 24-hr static image. The scan is positive for osteomyelitis if images show progressively increasing lesion to background activity ratios over time. The results of analyzing 21 three- and four-phase bone scans in 17 patients were correlated with clinical course, cultures, and/or x-rays, gallium scans, and CT scans. The accuracy of four-phase bone imaging for diagnosing osteomyelitis was 85%; for three phase, 80%. Sensitivity for four phase was 80%; specificity was 87%. Sensitivity for three phase was 100%; specificity was 73%. Since overall accuracy of the four-phase study is slightly better than three phase, in these patients with diabetes mellitus and/or peripheral vascular disease, the addition of a 24-hr image, creating a four-phase bone scan, is recommended.

Diabetic Angiopathies↗

PubMed1985

Gastric emptying measurements: delayed and complex emptying patterns without appropriate correction.

Anteriorly acquired and geometric mean corrected gastric emptying curves of solids and liquid isotopic-labeled meals were compared in 37 subjects given 61 meals of three different sizes. Anterior data alone consistently and significantly underestimated solid-phase gastric emptying rates with all meal sizes when compared to geometric mean acquired data. However, with liquids there were only slight differences between anterior and anterior and posterior geometric mean corrected emptying-rates. The difference probably reflects greater attenuation of the 140 kev photon of 99mTc compared to the 247 keV photon of 111In. With anterior data alone, an apparent early delay in emptying of solids was present with all meal sizes and the resultant emptying curves were nonlinear in shape. Geometric mean correction resulted in the linearization of the solid-phase emptying curves and essentially eliminated the apparent delay in emptying or lag phase noted with the anterior data alone. Based on our results, geometric mean correction techniques are necessary for accurate assessment of radioisotopic-labeled solid meals.

Adult↗

PubMed1984

Failure of bone scanning to detect fractures in a woman on chronic steroid therapy.

Osteopenic bones in patients on chronic steroid therapy are often difficult to assess for occult fractures. Such patients are also at greater risk for fractures. Technetium 99m bone scan is currently thought to represent the most sensitive method of diagnosing these lesions. We present a case of failure of diagnosis of a subtle fracture by Tc-99m bone scan and speculate on the role of steroid therapy in the mechanism of this failure.

Adult↗

PubMed1984

Influence of meal weight and caloric content on gastric emptying of meals in man.

This study was designed to assess the relative influence of meal weight and caloric content on gastric emptying of liquid and solid meals in man. A dual radioisotopic method which permits noninvasive and simultaneous measurement of liquid- and solid-phase emptying by external gamma camera techniques was employed. Nine healthy volunteer subjects ingested 50-, 300-, and 900-g lettuce and water meals adjusted to either 68, 208, or 633 kcal with added salad oil. The following observations were made: (1) absolute emptying rates (grams of solid food emptied from the stomach per minute) increased directly and significantly with meal weight; (2) increasing meal total caloric content significantly slowed solid food gastric emptying but did not overcome the enhancing effect of meal weight; and (3) liquid emptying rates were uninfluenced by meal total kcal amount.

Energy Intake↗

PubMed1984

The effect of iatrogenic trauma on the bone scintigram: an animal study: concise communication.

An animal study was performed to assess the effect on the Tc-99m phosphate bone scintigram of injury by needle aspiration or drill hole to metaphyseal and diaphyseal areas in immature and mature bones. Results showed that in 12 immature rabbits such trauma to metaphyseal regions had no effect on the bone image. Similar metaphyseal trauma in two mature dogs showed definite abnormalities on the bone image, but in one mature rabbit, no abnormality could be identified by scintigram. Diaphyseal trauma always gave a definitely abnormal bone image. Extrapolation of these results to humans should be cautious, but it suggests that needling or drilling in metaphyseal regions in neonates or young children probably does not affect later bone images.

Age Factors↗

PubMed1984

Decreased sensitivity of early imaging with In-111 oxine-labeled leukocytes in detection of occult infection: concise communication.

Imaging with leukocytes labeled with indium-111 oxine is a sensitive technique for detecting sites of occult infection. Traditionally, imaging is performed 24 hr after injection. We undertook a prospective study of 35 patients (40 studies) with possible occult infection to see whether a 24-hr delay in imaging is really necessary. Patients were imaged at 1-4 hr and again at 24 hr after injection. The early images had a sensitivity of only 33%, compared with 95% for the 24-hr images. Of the seven studies that were positive on both early and delayed images, 71% had more intense uptake at 24 hr. There were no false-positive early images. We conclude that imaging 1-4 hr after injection with In-111 oxine-labeled leukocytes has a low sensitivity for detecting occult infection. However, a positive early image is specific for a site of infection.

Adult↗

PubMed1983

Evaluation of technetium-99m phosphate imaging for predicting skin ulcer healing.

We have developed criteria for radionuclide angiography to assess skin ulcer perfusion as an indicator of healing capacity. Twenty-six studies were performed on 21 consecutive patients with nonhealing ulcers of the lower leg; 20 mCi of technetium-99m phosphate was injected intravenously with immediate sequential scintillation camera imaging of the ulcer and surrounding area at 2 second intervals, followed by blood pool and delayed static images. Two radiologists without clinical bias graded the perfusion to the ulcer on the images as normal, increased, or reduced with respect to the opposite limb. Patients were either followed as outpatients for more than 10 days, as inpatients for at least 10 days, or both to determine whether ulcers showed clinical evidence of wound healing with optimal outpatient and in-hospital care. Of the 17 patients whose ulcers healed, imaging with technetium-99m phosphate predicted the outcome in 16. In nine patients the ulcers did not heal. This was correctly predicted by technetium-99m phosphate in eight of the patients. Overall, the sensitivity was 94 percent and the specificity was 89 percent. This technique appears to be a simple, reliable way to predict the microcirculatory adequacy for ulcer healing.

Diphosphates↗

PubMed1983

Renal gallium accumulation in the absence of renal pathology in patients with severe hepatocellular disease.

Visualization of Ga-67 citrate in the kidneys at 48 hours and 72 hours post injection is usually interpreted as evidence of renal pathology. In reviewing approximately 200 consecutive patients referred for gallium scans, 40 patients who also underwent liver/spleen Tc-99m sulfur colloid (SC) studies within one month of the gallium study were identified. Fourteen of these patients showed advanced hepatocellular dysfunction on the Tc-99m SC liver/spleen images. Of these 14 patients, nine had persistent renal accumulation of gallium at 48 or 72 hours. Five of these nine patients had no evidence of primary renal disease by clinical or postmortem examination and subsequent clinical information indicated that two additional patients probably had no significant renal pathology. Therefore, bilateral symmetrically increased renal uptake of gallium in patients with advanced hepatocellular disease should not necessarily be interpreted as evidence of renal pathology.

Adult↗

PubMed1982

The feasibility of performing 133Xe ventilation imaging following the perfusion study.

The 99mTC Compton scatter contribution from the perfusion lung study to the subsequent 133Xe ventilation scan was quantitated in 15 consecutive patients undergoing both studies. Maximum contribution during the wash-in phase occurred during the first 10 seconds; thereafter, 99mTc Compton scatter averaged less than 10% of the total counts accumulated for a 133Xe image. The contribution during wash-out gradually increased to a maximum of 36% at 4 minutes in a normal subject. The authors conclude that a properly performed 133Xe ventilation study may immediately follow the 99mTc perfusion lung scan without significant image degradation.

Aged↗

PubMed1981

Focal spinal abnormalities on bone scans in ankylosing spondylitis: a clue to the presence of fracture or pseudarthrosis.

Four cases of ankylosing spondylitis are presented in which radionuclide bone studies indicated focal abnormalities of the spine. In three patients, the area of abnormal nuclide uptake corresponded to a site of pseudarthrosis, and in the fourth an acute fracture was present. As such focal lesions on bone scans are unusual in cases of chronic ankylosing spondylitis in which a complication is not apparent, their presence can be a useful finding.

Aged↗

PubMed1980

Usefulness of gallium imaging in the evaluation of lung cancer.

The current enthusiasm for gallium (Ga) citrate as a tumor imaging agent reflects the need of clinical medicine for a good tumor imaging agent. To date, Ga-67 is probably the best tumor imaging agent available for clinical use. Initially, Ga-67 was investigated for its bone scanning potential. In this process, in 1969, Edwards and Hayes accidentally found that Ga-67 concentrated in soft tissue tumors, mainly lymphomas, in patients. Later studies reported the clinical experience with Ga-67 concentration in many different tumor types. Great variation was noted in the ability of different tumors to concentrate Ga-67. However, Ga-67 was most consistently and reliably taken up in lung tumors, with sensitivities of Ga imaging positivity in lung cancer ranging from 85 to 95%. Within the lung cancer group, squamous cell carcinoma consistently has been much more reliably positive than adenocarcinoma or alveolar cell carcinoma. Subsequent studies on Ga-67 led to the recognition of its preferential concentration in inflammatory lesions and abscess. These reports resulted in the clinical application of Ga-67 imaging as a diagnostic tool in the evaluation of patients with suspected abscesses. Mechanisms of Ga localization in tumor and inflammatory lesions are not currently well understood. Electron microscopic studies have revealed some information regarding the intracellular localization of Ga, but the mechanism by which it is taken up by the cell remains unproven, although several explanations have been suggested. The biodistribution of Ga-67 is responsible for the great difficulty experienced in interpreting Ga images of the abdomen, mainly because of the normal of the normal excretion in the bowel. Clinical studies have shown that the Ga scan can be used in the workup of patients with lung cancer as a sensitive tool in excluding the presence of mediastinal metastases. In some institutions, a negative Ga mediastinal scan in the presence of positive Ga uptake in the presumed primary tumor in patients with lung cancers has been used in lieu of a staging mediastinoscopy. Data regarding the thresholds of various factors which determine visibility of a lung tumor by Ga-67 imaging have been described in some detail. The factors include lesion size, depth in tissue, gallium concentration in tumor relative to background, type of film and instrumentation used, and count rates obtained. The data suggest the need for very high radiopharmaceutical concentrations in small tumors relative to background activity for identification of the tumor on an image.

Gallium Radioisotopes↗

PubMed1978

Detection of porencephaly by cerebral dynamic scanning.

Routine cerebral dynamic scanning in two patients revealed unilateral focal areas of decreased radionuclide activity between the anterior and middle cerebral arteries; the subsequent brain scans were normal. Both patients were shown to have porencephaly by isotope cisternography and computed tomography (CT) scans. When a focal avascular area is noted on cerebral dynamic scanning in the presence of normal static images, the possibility of a porencephalic cyst should be considered.

Adult↗

PubMed1978

Enostosis of the spine.

Five patients with single sclerotic vertebral body lesions had serial radiographs demonstrating no change in size of the radiodensities. Radionuclide bone imaging, obtained in 4 of these patients, showed no increased radioisotopic uptake in the areas in question. The absence of growth of the lesions on follow-up radiographs and the presence of negative bone scans support the diagnosis of enostoses of the spine. It is important for the radiologist to realize that benign sclerosis of a single vertebral body may simulate skeletal metastasis.

Adult↗

PubMed1978

Rheumatoid arthritis and its variants: analysis of scintiphotographic, radiographic, and clinical examinations.

99mTc pyrophosphate radionuclide scans of the axial and appendicular skeletons in 23 patients with rheumatoid arthritis and 15 patients with systemic arthritic conditions were compared to clinical and radiographic examinations. The nuclear scan was the most sensitive indicator of active disease and correlated extremely well with the other methods. A pattern of abnormal radionuclide activity in rheumatoid arthritis consisting of a symmetric peripheral joint process can be distinguished from that of the rheumatoid variants which tend to have more central skeletal involvement and asymmetric peripheral articular involvement. The nuclear scan is less specific than the radiograph in its ability to distinguish among the clinical entities. However, documentation of scintigraphic activity often antedated radiographic or clinical abnormalities.

Adult↗

PubMed1978

A rapid method for the labeling of albumin microspheres with In-113 and In-111: concise communication.

A rapid and simple method for preparing microspheres labeled with In-113m or In-111 is described. The procedure requires 10 min and gives labeling yields approaching 100%. Biodistribution studies in rats, mice, and dogs show the product to be biologically stable, with approximately 90% of the injected dose localized in the lung at 1 hr postinjection. The convenient production of In-113m or In-111 albumin microspheres provides an alternate radiopharmaceutical to complement or substitute for Tc-99m microspheres in lung perfusion imaging and other circulation studies.

Animals↗

PubMed1977

Noninvasive determination of glomerular filtration rate using x-ray fluorescence.

Accurate glomerular filtration rates (GFR) can be calculated based on the infusion of small amounts of nonradioactive iothalamate and collection of plasma samples for assay by x-ray fluorescence. This innovation permits frequent clearance determinations in patients without the hazard of repeated radiation exposure and without the necessity of catheterization of the bladder for urine samples. Thus, the technique becomes feasible in children, transplant patients, and other needing accurate and frequent GFR determinations.

Animals↗

PubMed1976

Lack of gallium uptake in primary hepatic amyloidosis.

99mTc-sulfur colloid and 67Ga citrate hepatic scintigrams showed matching defects in a patient with diffuse primary amyloidosis. Amyloidosis should be added to the usual differential diagnosis of such matching lesions which includes cysts, fibrosis, most benign tumors, and occasional metastatic lesions which do not concentrate gallium.

Aged↗

PubMed1976

Intestinal concentration of 99mTc-pertechnetate into isolated loops of rat bowel.

In scanning patients for Meckel's diverticulum, the colon occasionally visualizes more rapidly than would be expected simply from gastric secretion and intestinal transit. To gain a better understanding of the intestinal physiology of pertechnetate and thereby to make a more intelligent interpretation of abdominal scans, segments of the gastrointestinal tract of Sprague-Dawley rats were isolated by transection between double ligations. After abdominal closure, the animals received an intravenous injection of 99mTcO4 and were killed at 30, 45, or 150 min after injection. Technetium concentrations in the stomach, colon, and appendiceal contents increased significantly with time after dosing, and after 30 min technetium could be clearly imaged in the stomach, upper small intestine, appendix, and colon. These results suggest that technetium is actively secreted by the intestinal mucosa. Additionally, the results indicate caution in the interpretation of scans in patients with suspected Meckel's diverticulum since, in the rat and probably in the human, significant amounts of technetium can accumulate in the gut apart from gastric secretion and intestinal transit.

Animals↗