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Biomedical subjects

N Alazraki

Publications and source records attributed to N Alazraki.

At least 55 records · Page 3Linked to original sources
PubMed1990

Reversibility bull's-eye: a new polar bull's-eye map to quantify reversibility of stress-induced SPECT thallium-201 myocardial perfusion defects.

Myocardial ischemia is currently interpreted from SPECT thallium-201 (201Tl) tomograms by the subjective visual finding of stress-induced perfusion defects which "normalize" or "reverse" by 4 hr. Thus, we have developed a computer method to quantify and display the three-dimensional distribution of reversible segments. Circumferential profiles generated from the short axis slices are normalized to the reference area in the stress study. The stress is subtracted from the normalized delayed data, and then displayed as a polar bull's-eye plot so that positive values show areas that have "reversed" or "improved." Patient profiles are compared to means and standard deviations of reversibility for all pixels determined from the Emory normal male files. Criteria for reversibility were developed from studies of 42 male patients found to have 48 defects, as determined by the consensus of five blinded expert observers. There was computer agreement with the experts on 25 of 31 relatively fixed and 14 of 17 reversible defects. Our preliminary results indicate that this new method promises to aid observers to more consistently identify and quantify the reversibility of SPECT 201Tl myocardial perfusion defects.

Adult↗
PubMed1989

Hepatic localization of Tc-99m MAA during lower extremity venography.

Hepatic localization of macroaggregated albumin particles has been observed previously in both superior and inferior vena cava obstruction. These reports have described focal regional hepatic uptake in porta hepatis or the left hepatic lobe in cases of SVC and IVC obstruction as well as global hepatic uptake in IVC obstruction. In this report of an unusual case of hepatic uptake of MAA during lower extremity venography, the entire liver and lungs were simultaneously visualized, presumably due to portal-to-systemic collateral flow pathways in the presence of inferior vena cava obstruction.

Humans↗
PubMed1988

Effect of body posture on radionuclide measurements of gastric emptying.

The purpose of this investigation was to compare the effect of body posture on gastric emptying measurements of radiolabeled meals. Eight healthy male subjects were studied on four separate days. During each study subjects were fed a standardized meal of beef stew labeled with technetium-99m sulfur colloid, and orange juice. Measurements of solid-phase gastric emptying rates were obtained by a gamma camera. Subjects were studied in the lying, sitting, standing, or combined sitting-standing postures. The results demonstrated that the lying position significantly slowed gastric emptying compared to all other positions. Conversely, a decrease in emptying times of 51% and 35% occurred in the combined sitting-standing position compared to the lying and sitting position. These results support a marked effect of body posture on the radionuclide measurement of gastric emptying.

Adult↗
PubMed1988

Radioimmunodetection of human melanoma with indium-111-labeled monoclonal antibody.

The purpose of the study was threefold: (1) to evaluate the efficacy of an 111In-labeled murine monoclonal antibody (ZME-018) directed against a heavy molecular weight melanoma associated glycoprotein in localizing metastatic disease; (2) to determine the effect of unlabeled antibody mass (2.5, 5, 10, 20, and 40 mg) on labeled antibody blood clearance, biodistribution and lesion detection; (3) to estimate radiation dosimetry. Twenty-five patients with previously documented disease received an intravenous infusion of 2.5 to 40 mg of monoclonal antibody with 1 mg of the antibody labeled with 5 mCi of 111In. There were no acute reactions. Patients were scanned without computer enhancement or background subtraction techniques at 24 and 72 hr after injection. Imaging detected tumor in 14/18 (78%) patients with active disease, identified 24/44 (77%) of lesions greater than 1 cm and changed or specifically directed patient management in 22% (4/18) patients with tumor. There was a prolongation in blood clearance associated with decreased liver and spleen activity following administration of 20 and 40 mg of antibody compared to the three lower antibody dose levels. Assuming a biodistribution similar to [111In]ZME-018, the radiation dose delivered to normal tissues by [90Y]ZME-018 would restrict its use as a routine vehicle for radioimmunotherapy; however, it may be possible to deliver substantial tumor doses in selected patients.

Adult↗
PubMed1987

99mTc-MAG3, a new renal imaging agent: preliminary results in patients.

99mTc-mercaptoacetyltriglycine (MAG3) is a new renal radiopharmaceutical which has been shown to have biological properties similar to 131I-hippurate (OIH) in animals and volunteers. 99mTc-MAG3 has now been compared with 131I-orthoiodohippurate (OIH) in a group of patients with varying degrees of renal impairment. In all cases, the 99mTc-MAG3 images were superior regardless of serum creatinine. Selected examples are illustrated including scans and renogram curves in a normal volunteer, transplant patients with creatinines of 9.8 mg/dl and 2.6 mg/dl respectively, and a furosemide study in a patient with questionable obstruction. Our preliminary results suggest that 99mTc-MAG3 performs well in patients with impaired renal function and may well provide an acceptable replacement for OIH. A kit formulation has been developed and will soon be undergoing clinical evaluation.

Adult↗
PubMed1987

Technetium-99m imaging of bone trauma: reduced sensitivity caused by hydrocortisone in rabbits.

This study evaluates the effect of hydrocortisone on the sensitivity of 99mTc-scintigraphy for the detection of bone trauma in three groups of rabbits: a control group that received no hydrocortisone, a low-dose group that received 0.8 mg/kg/day, and a high-dose group that received 20 mg/kg/day. Scintigrams of the tibial diaphyses were obtained at 48 hr, 1 week, 2 weeks, and 3 weeks after surgical creation of a simulated fracture (a 1.5-mm hole in the cortex). The mean sensitivity for detecting fractures in control animals was 95% at 48 hr and 100% at all other times. Mean sensitivity for rabbits given the high dose of hydrocortisone was 41% at 48 hr. Mean sensitivity for the low-dose group was 75% at 48 hr, but this was not significantly different from the control group. Sensitivity in both groups treated with hydrocortisone improved with time. At 3 weeks, the mean was 93% in the low-dose group and 83% in the high-dose group. These data suggest that 99mTc scintigraphy may be less sensitive in detecting bone trauma in patients on glucocorticoid therapy than in patients in the general population.

Animals↗
PubMed1987

Radioimmunodetection of human melanoma with indium-111-labeled monoclonal antibodies.

Our purpose in conducting this study was to evaluate the efficacy of an 111In-labeled murine monoclonal antibody directed against a high-molecular-weight glycoprotein in localizing metastatic melanoma in 15 patients with previously documented disease and to determine the effect of antibody mass (2.5, 5.0, and 10.0 mg) on blood clearance, biodistribution, and lesion detection. Five mCi of 111In-antibody were infused over 1 hour, and patients were scanned at 24 and 72 hours after injection without computer enhancement or background subtraction techniques. No significant differences in the organ distribution, urine excretion, or plasma disappearance curves were noted at the three antibody dose levels. There were no acute reactions. The scan detected tumor in 9 of 12 (75%) patients with active disease, and 26 of 33 (79%) lesions greater than 1 cm. Patient management in 3 of 15 (20%) of patients studied was changed as a result.

Adult↗
PubMed1986

Effect of synthetic prostaglandin E1 analog on gastric emptying of meals in man.

Forty-five subjects with healed duodenal ulcer were administered either a placebo or a low-dose or high-dose regimen of misoprostol, a synthetic PGE1 analog, in a double-blind, random, parallel-group design to assess the effect of this prostaglandin compound on the gastric emptying of liquid-solid meals. A dual-radionuclide technique to measure liquid- and solid-phase gastric emptying rates of physiological meals by external gamma camera imaging was used. All subjects had a pretreatment control (baseline) evaluation, followed one week later by a treatment-influenced emptying study. The results demonstrated that misoprostol did not significantly alter gastric emptying of either liquids or solids; however, these results cannot be extrapolated to other prostaglandin compounds because of the diverse and sometimes paradoxical effects of different prostaglandins on gastric motility.

Adult↗
PubMed1986

Evidence for a midgastric transverse band in humans.

When the solid fraction of a standardized meal is labeled with technetium 99m-sulfur colloid-labeled chicken liver and fed to human subjects, linear regions of decreased radioactivity that have the appearance of a band are identified on the scintillation camera images of the stomach. The band is not a peristaltic contraction because it persists in individual subjects after 4 h of imaging. The band has also been identified in the dog, pig, and monkey. It is transverse and midgastric in location. William Beaumont noted a similar band in his observations on Alexis St. Martin in 1833, and a transverse band was noted in autopsy specimens of food-filled human stomachs in 1919. However, the finding has been ignored in current gastrointestinal or radiologic textbooks because the band cannot be identified with conventional barium sulfate meals. The anatomic basis for the band and its role in regulating gastric emptying remain unclear.

Adult↗
PubMed1986

Uptake of 111In-labeled leukocytes by tumor.

The 111In-labeled leukocyte scan is a sensitive and specific technique for the detection and localization of abscesses. However, in reviewing an unselected series of 249 scans, six (2.3%) were false-positive cases in which leukocyte uptake by tumor mimicked an abscess. This represented 12% (6/51) with known tumor at the time of imaging. Five of the cases were primary or metastatic tumors to the soft tissues; the sixth was a skeletal metastasis. The intensity of tumor activity has been characterized as mild in the few cases of leukocyte uptake reported in the literature, suggesting that the degree of uptake is helpful in distinguishing tumor from abscess. In this study, however, variable degrees of tumor-associated activity were seen ranging from mild to very intense. These findings indicate that tumor accumulates labeled leukocytes more frequently than has been previously appreciated, that primary and metastatic neoplasms involving both the soft tissues and skeleton are involved, and that the intensity of uptake is not a reliable criterion to distinguish tumor from abscess.

Adult↗
PubMed1986

Advantage of indium-111 leukocytes over ultrasound in imaging an infected renal cyst.

Indium-111-labeled leukocyte scanning is a highly sensitive and specific method of detecting abscesses. This report describes a patient with polycystic kidneys and a single infected cyst. Ultrasound could not determine which cyst was infected, but the infected cyst could be localized by [111In]leukocyte imaging in conjunction with a [99mTc]DMSA renal scan. The two radionuclide studies were used to identify an infected renal cyst and direct ultrasound guided aspiration.

Adult↗
PubMed1985

Gastric emptying of combined liquid-solid meals in healed duodenal ulcer.

The gastric emptying rates of combined liquid and solid radioisotopically labeled meals in 47 healed duodenal ulcer subjects and 17 healthy control subjects are compared. No significant differences were found between the groups in emptying slopes and the emptying half-times or in the percent retention values at any of the counting intervals for either the liquid or solid meals. These results are compatible with the observation that the rapid gastric emptying in many patients with duodenal ulcer is associated with the disease and that healing results in a return to normal gastric emptying rates. However, since gastric emptying rates during active ulceration were not determined in our patients, a more definitive interpretation awaits a study comparing emptying rates obtained during and after healing of active ulceration in the same patient.

Adult↗
PubMed1985

Chronic osteomyelitis: monitoring by 99mTc phosphate and 67Ga citrate imaging.

Thirteen patients with chronic osteomyelitis, treated for 6 months with rifampin, had serial 99mTc phosphate and 67Ga scans to determine their value in assessing response to treatment. In patients who responded to treatment, gallium scans were deemed more accurate than 99mTc phosphate bone scans. The gallium scans, although still abnormal at the end of 6 months of antibiotic therapy, showed an improvement trend in all the responders except one in whom fracture recurred. Worsening or lack of improvement on gallium scans predicted active bone infection in five of six "clinical-failure" patients who had documented active bone infection. 67Ga scans eventually became normal in all patients who remained asymptomatic (excluding one with recurrent fracture). 99mTc phosphate scans became normal in only one of five clinical responders. All nonresponders had persistently abnormal scans, although after 6 months of therapy only four of seven showed worsening or no improvement on the scan. Therefore, 67Ga is preferred over 99mTc phosphate bone scans in the assessment of response to therapy in chronic bone infection. Clinical utility of the gallium scan is most significant in patients whose clinical assessment is uncertain, but routine use of this technique does not appear to be warranted. Gallium images are most valuable when obtained over a period of time, so that the trend of improvement versus nonimprovement is evident.

Chronic Disease↗
PubMed1985

Detection of acute synthetic vascular graft infection with 111In-labeled leukocyte scanning: an animal study.

Synthetic vascular graft infection is characterized by late diagnosis due to indolent and nonspecific symptoms. Indium-111-labeled leukocyte imaging holds promise as a diagnostic tool to identify vascular graft infection, but reported data on its accuracy are somewhat sparse and conflicting. In this study, 13 mongrel dogs received Dacron aortic interposition grafts. Seven grafts were contaminated at the time of surgery by topical ATCC Staphylococcus aureus concentrated at 10(8) organisms/ml. Six control animals received no graft contamination. All infected animals were sacrificed on the second postoperative day after 111In leukocyte scanning. The results showed a sensitivity of 71%, specificity of 100%, and accuracy of 85% for the 111In leukocyte study in detecting early graft infections; false-positive leukocyte scans in the early postoperative period were not a problem as has been reported by others. These data indicate that leukocyte scanning for graft infection detection is likely to be clinically valuable.

Animals↗
PubMed1985

Assessment of skin ulcer healing capability by technetium-99m phosphate angiogram and blood-pool images.

The accuracy of radionuclide angiography and blood-pool imaging using [99mTc]-phosphate to assess skin ulcer perfusion as an indicator of healing capacity was determined in 50 studies performed on 45 patients with nonhealing ulcers of the lower extremities. Two nuclear medicine physicians without clinical bias, graded the perfusion of the ulcer on the images as normal, increased or reduced with respect to the opposite limb. Patients were followed closely with aggressive local wound care for at least 14 days. Of the 31 ulcers which healed, the radionuclide study correctly predicted 30; of the 19 ulcers which did not heal, 14 were correctly predicted. Eight patients had osteomyelitis; four of those healed and four did not. The radionuclide study predicted healing in seven. Excluding those patients with osteomyelitis, the sensitivity for the radionuclide angiogram and blood-pool image in predicting healing was 96%, specificity was 87%, and accuracy was 93%. This technique is a simple, reliable way to predict the microcirculatory adequacy for ulcer healing. Specificity is diminished in the presence of osteomyelitis.

Aged↗
PubMed1985

Indium 111-labeled leukocyte scanning for detection of prosthetic vascular graft infection.

Recent animal and human studies have suggested that positive indium 111-labeled leukocyte scans may help establish the diagnosis of vascular graft infection; however, there is little information available about the predictive value of both positive and negative leukocyte scans in larger groups of patients. In this study 31 indium 111 leukocyte scans were performed prior to definitive treatment in 21 patients with suspected vascular graft infections. Patients with more than one leukocyte scan performed had either anatomically distinct sites of infection or rescanning of a potentially infected site after definitive treatment. Scans were performed according to the method of Baker et al., attaching 500 muCi of indium 111 to leukocytes with imaging 24 hours later. All patients with positive scans underwent surgical exploration of the area of leukocyte accumulation, with documentation of purulence and culture of the graft. Patients with negative scans were treated as if scan results were indeterminate and underwent surgical exploration for usual clinical indications; if no exploration was performed, the patient was followed up closely for at least 1 year. Twelve of 12 positive scans showed purulence or culture evidence of infection with three different organisms; in 15 instances of negative scans, two operations were performed with one infection noted, whereas no patient without surgery has had a graft infection at 10 months follow-up. In addition to localizing graft infections, two scans demonstrated a nonvascular site of infection. Positive scans also helped determine the extent of infection along the graft, allowing better planning of the surgical procedure. These results indicate that indium 111-labeled leukocyte scans help document and localize prosthetic vascular graft infections.

Aged↗