Search PubMed⌕ Search

Biomedical subjects

A Alavi

Publications and source records attributed to A Alavi.

At least 343 records · Page 19Linked to original sources
PubMed1984

Variation of the spleen-liver activity ratio due to a change in position.

The ratio of splenic to hepatic activity in the posterior view of a Tc-99m SC liver-spleen scan has been used as an indicator of parenchymal disease. Analysis of liver-spleen scans from a series of patients acquired in both the supine and erect positions revealed that the spleen-liver ratio varied considerably with a change in the patient position. Qualitatively there was a shift of colloid from the liver to the spleen in five of 18 supine views and ten of 18 erect views. Quantitative analysis of 37 cases showed that the median erect spleen-liver ratio was 20% greater than the spleen-liver ratio observed in supine patients. Criteria for an abnormal spleen-liver ratio need to be established in each position.

Colloids↗
PubMed1984

Cold lesions on bone scan in pediatric neoplasms.

A retrospective examination of the bone scans of 425 pediatric oncology patients was undertaken to determine the incidence of photon-deficient (cold) lesions in this population. Eight patients (1.8%) had cold lesions due to a wide variety of tumors. Of the tumor types, six had not been previously reported to give cold lesions on bone scan. The appearance of the radiograph at the site of the cold lesion was normal in five of the eight patients. All but one of the patients had "hot spots" as well as a cold lesion. Follow-up scans showed resolution of the cold lesions in two cases and a change from cold to hot in one case. A review of the literature revealed eight cases of cold lesions on bone scan due to tumor in pediatric patients. The previous reports included five patients with neuroblastoma and three with osteosarcoma.

Adolescent↗
PubMed1984

Detection of sclerosing adenosis of the breast on a thallium scan.

Uptake of thallium in a patient with sclerosing adenosis of the breast was detected. Although thallium has been reported to accumulate in primary carcinoma of the thyroid, lung, and liver, detection of a breast lesion on a thallium scan has not been previously reported.

Coronary Disease↗
PubMed1984

Gallbladder carcinoma. Another cause of the distended photon-deficient gallbladder in cholescintigraphy.

A case report of an 82-year-old woman with carcinoma of the gallbladder is presented. Technetium-99m DISIDA cholescintigraphy demonstrated nonvisualization of the gallbladder, with a large photon-deficient region corresponding to the gallbladder fossa, with medial displacement of the common bile duct. Carcinoma of the gallbladder has not been previously described as a cause of this scintigraphic pattern.

Adenocarcinoma↗
PubMed1984

Indications for the treatment of deep venous thrombosis following total knee replacement.

The diagnosis of deep venous thrombosis in the lower extremity has usually been thought to mandate the initiation of anticoagulation therapy. However, there has been evidence to show that this approach may not be necessary for deep venous thrombosis at or distal to the knee, and that the risks of treatment may be greater than those of the thrombosis itself. One hundred and seventy-five patients who underwent total knee replacement were examined postoperatively by venography, plethysmography, fibrinogen scans, and ventilation-perfusion lung scans. We found that 126 (72 per cent) of them had small or large clots in the calf, and that only forty-nine (28 per cent) had no thrombi. Seventy-one (41 per cent) of the patients had small thrombi in the calf and fifty-five (31 per cent) had large thrombi in the calf. Six patients had thrombi in the thigh, all of which were associated with large thrombi in the calf. In only two patients, however, did clinically recognized pulmonary emboli develop, one in the group of patients without known thrombi and the other in a patient with a large iliofemoral thrombus. The ventilation-perfusion scans showed six asymptomatic pulmonary emboli that were not associated with the presence of either large or small thrombi in the calf. The fibrinogen scans that were done in the postoperative period were capable of revealing large but not small thrombi in the calf. The preoperative plethysmography did not aid in determining in which patients a large thrombus of the calf or thigh was likely to develop.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1983

Intracranial myeloid metaplasia: diagnosis by CT and Fe52 scans and treatment by cranial irradiation.

A patient with longstanding agnogenic myeloid metaplasia developed a progressive dementia. CT scanning demonstrated multiple intracranial masses, and a Fe52 bone marrow scan demonstrated erythroid activity within the masses and confirmed the suspicion of extra-medullary hematopoiesis. A potentially hazardous biopsy was avoided, and a course of cranial irradiation was administered, resulting in regression of the masses and clearing of the patient's dementia. Fe52 scintigraphy provides a specific and useful diagnostic approach which may eliminate the need for invasive procedures.

Brain↗
PubMed1983

Automated calculation of gallbladder ejection fraction.

We have developed a computer method which by automatically locating the border of the gallbladder in each image and subtracting a varying location-dependent background corresponding to the gallbladder border overcomes the difficulties associated with quantitating gallbladder contraction. These difficulties are attributable to significant and changing background activity, imprecise manual delineation of the gallbladder, and the changing position and shape of the gallbladder. Validation studies using a gallbladder phantom showed the method to be very accurate. No significant difference (P greater than 0.05) was observed between the expected and calculated ejection fractions. Ten patient studies were analyzed, with a resulting range of gallbladder ejection fractions of 22-79%. Excellent reproducibility was obtained with an average intraobserver coefficient of variation of 3.5%, and no statistically significant difference in interobserver measurements (P greater than 0.05). The regression line for interobserver measurements had a slope of 0.96 +/- 0.08, an intercept of 1.6 +/- 4.0%, and a correlation coefficient of 0.99. From these preliminary results we conclude that this method offers a reliable means of quantitating gallbladder contraction.

Cholecystokinin↗
PubMed1983

A case of microgastria in association with splenic-gonadal fusion.

Microgastria is a rare congenital anomaly usually associated with asplenia. In this 2 1/2-year-old presenting with left hydrocele and inguinal hernia multiple accessory spleens were found in the inguinal-scrotal region compatible with splenic-gonadal fusion. 99mTc-sulfur colloid scanning is helpful in microgastria searching for the presence of splenic tissue and in splenic-gonadal fusion for the location of accessory heterotopic spleens.

Abnormalities, Multiple↗
PubMed1983

A cognitive-motor network demonstrated by positron emission tomography.

The rate of local cerebral glucose metabolism was measured in subjects receiving a verbal (n = 4) and a spatial (n = 4) task. The verbal task produced greater metabolism in Wernicke's area relative to the right hemispheric homotopic region, whereas the spatial task produced greater metabolic activity in the right hemispheric homotopic region. Broca's area and its right hemisphere counterpart showed symmetrical activity during the verbal task, but there was a significant asymmetry to the right during the spatial task. Lateralized task effects were also obtained in the frontal eye fields, supporting a hypothesized neural network linking cognitive activity with motor orientation.

Adult↗
PubMed1983

NMR imaging of the abdomen at 0.12 T: initial clinical experience with a resistive magnet.

Forty-five patients with a variety of abdominal abnormalities and five normal volunteers were imaged on a 0.12 T resistive nuclear magnetic resonance system. Scans were obtained with saturation-recovery technique and short repetition times. The images reflected both proton density and T1 information. A variety of neoplastic and nonneoplastic disease processes involving the abdomen were imaged. Results suggest that clinically useful images clearly may be obtained at 0.12 T. In addition, saturation-recovery imaging with short repetition rates can detect a wide range of abdominal abnormalities.

Abdomen↗
PubMed1983

Fourier amplitude ratio: a new way to assess valvular regurgitation.

The stroke-volume ratio determined from the equilibrium gated blood-pool study has been utilized to assess valvular regurgitation, but it is difficult to get reproducible results using generally available equipment. We have developed a new approach utilizing the Fourier amplitude ratio of the left and right ventricles, which is easily implemented and reproducible. Initial clinical experience shows that 17 patients with valvular regurgitation were clearly distinguished from 30 patients without valve disease.

Aortic Valve Insufficiency↗
PubMed1983

Radioimmunodetection of human tumor xenografts by monoclonal antibodies.

Mouse IgG2a monoclonal antibodies with specific binding reactivity in vitro to human tumors of the gastrointestinal tract were radioiodinated and injected into immunosuppressed mice xenografted with human colon carcinoma tumors. The antibodies preferentially localized in tumor tissue compared to normal mouse tissue, as determined by differential tissue counting of radioactivity. Preferential antibody localization in tumor tissue was greatly enhanced when F(ab')2 fragments of the antibodies were used, and the fragments localized specifically only in those tumors that bind the antibodies in vitro and not in unrelated tumors. Radiolabeled fragments of an anti-hepatitis virus monoclonal antibody of the same isotype as the specific antibody did not localize in tumors. Tumors could be located by whole-body gamma-scintigraphy with radiolabeled specific antibody F(ab')2 fragments without background subtraction.

Animals↗
PubMed1983

Positron emission tomographic studies of sensory stimuli, cognitive processes and anxiety.

Research in detecting regional changes in brain metabolism related to functional activity is reviewed and supplemented by original results from positron emission tomography (PET) and the 18F-fluorodeoxyglucose method (FDG). A formula for calculating the value of local cerebral glucose metabolism (LCMRGlc) is discussed. Results concerning auditory stimulation suggest that metabolic responses are determined by the stimulus content and analysis strategy used by the subject rather than the side of stimulation. Tactile stimulation of the hand and fingers caused asymmetrical increases in LCMRGlc confirming topographic maps of the postcentral gyrus and other functional studies. Data from visually stimulated normal subjects show how the visual hemifields project to the opposite calcarine cortex. Studies of patients with hemianopsia or various field defects demonstrated that metabolic scanning can reveal alterations of cortical function not detectable by CT scan. Data obtained reveal the ability of metabolic mapping to subdivide the occipital cortex into distinct regions. Such measurements may also anticipate the course of visual recovery. Findings of increased overall right-hemispheric metabolism during the performance of verbal and spatial cognitive tasks are consistent with earlier results from right-handed males. Results for the frontal eye fields provide the first experimental evidence that lateralized metabolic activity, produced by cognitive tasks, causes similarly lateralized activity within a motor region. It is further demonstrated that FDG is able to provide information on such states as vigilance and anxiety.

Anxiety↗