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Biomedical subjects

A G Mattar

Publications and source records attributed to A G Mattar.

32 records · Page 2Linked to original sources
PubMed1981

Ventilation imaging with Kr-81m. A comparison with Xe-133.

Sixty-five patients with suspected pulmonary embolism were studied prospectively with both Kr-81m and Xe-133 ventilation imaging and Tc-99m MAA perfusion imaging. The krypton images, perfusion scintigrams and chest radiographs were read independently of the xenon images, perfusion scintigrams and chest radiographs by three observers. The studies of 53 patients were interpreted as normal or as indicative of a low or intermediate probability for pulmonary embolism with both gases. One study indicated intermediate probability with Xe-133 due to diffuse, severe xenon retention but low probability with Kr-81m because of close ventilation-perfusion correspondence. The studies of 9 patients indicated a high probability of embolism with both gases, while those of two additional patients (one with emboli at angiography) indicated a high probability only with Kr-81m. While essential agreement between Xe-133 and Kr-81m ventilation imaging was found in most patients, the significant difference in interpretation in 2 of 11 patients with probable pulmonary embolism suggests that a controlled, prospective trial with pulmonary angiography is warranted before Kr-81m is employed for routine clinical use.

Humans↗
PubMed1979

Interpretation of indeterminate lung scintigrams.

Lung scintigrams and pulmonary angiograms of 111 patients with suspected pulmonary embolism who had matching perfusion defects and radiographic abnormalities (infiltrate, atelectasis, or effusion) were reviewed. In 14 patients perfusion defects were substantially smaller than the corresponding radiographic opacity; only 1 (7%) had pulmonary embolism. In 77 the opacities and perfusion defects were of similar size; the abnormality was due to embolism in 20 (26%). In 18 patients perfusion defects were substantially larger than the radiographic opacities and were not associated with matching ventilation abnormalities; of these, 16 (89%) had pulmonary embolism. Evaluation of the relative size of perfusion defects and radiographic abnormalities occurring in the same region improves the ability of lung scintigrams to predict pulmonary emboli.

Adult↗
PubMed1979

Ventilation-perfusion studies in suspected pulmonary embolism.

The results of ventilation-perfusion (V-Q) imaging and pulmonary angiography were retrospectively analyzed in 146 patients with suspected pulmonary embolism (PE) to define the frequency of PE associated with various scintigraphic patterns. When the radionuclide images demonstrated at least two moderate-sized or one large area of V-Q mismatch, the probability of PE was 92%. However, only one of three patients with a single moderate-sized V-Q mismatch had PE, while small V-Q mismatches were not associated with PE in any of 19 patients. Matched V-Q abnormalities in lung regions that were radiographically normal were infrequently due to PE (4.8%). When a perfusion defect was substantially smaller than a corresponding radiographic abnormality, the frequency of PE was low (7.7%). Conversely, when a perfusion defect was substantially larger than the corresponding radiographic abnormality, there was a high probability of PE (87%). Matched perfusion and radiographic abnormalities indicated an intermediate probability of PE (27%). Patients with suspected pulmonary embolism may be classified into groups with low, intermediate, or high probability of pulmonary embolism on the basis of size and number of perfusion defects and a careful comparison of perfusion defects with ventilatory and radiographic findings.

Angiography↗
PubMed1978

Malformation of the cerebral cortex with heterotopia of the gray matter.

Developmental malformation of the cerebral cortex with heterotopia of the gray matter is a rare condition. It can present as unilateral megalencephaly, a localized mass, or focal cortical dysplasia. Four histologically confirmed cases are described in this report, and the findings from computed tomography as well as from other radiological diagnostic procedures are discussed.

Brain Neoplasms↗
PubMed1978

Intracranial pearly tumors: the roles of computed tomography, angiography, and pneumoencephalography.

The findings is computed tomography (CT) and other radiological examinations in nine histologically proven cases of intracranial pearly tumors are presented. The CT findings include a low density lesion with no enhancement after contrast medium injection and in some cases a lesser degree of mass effect than would be expected from the size and site of such lesions. Pneumoencephalography is superior to CT in detecting suprasellar pearly tumors when they are isodense with the cerebrospinal fluid.

Adult↗
PubMed1977

Case report: chronic graphite granulomatous abscess simulating a brain tumor.

Brain abscess can develop at the site of retained intracranial foreign bodies many years after the injury. This report describes a 6 1/2-year-old child who presented with recurrent severe headaches and a focal seizure of the right upper extremity. Skull X-ray was normal. Computed tomography of the head showed a mass in the left temporoparietal region with a central area of high density and contrast enhancement, thought to be a neoplasm. The mass was seen on the radionuclide brain scan and was avascular on angiography. Craniotomy revealed a foreign body granuloma with a small abscess cavity and a retained piece of pencil graphite. No one in the family could recall if the child had had such an injury.

Brain↗
PubMed1977

Sensitivity of radionuclide brain imaging and computerized transaxial tomography in detecting tumors of the posterior fossa: concise communication.

In a series of 25 patients with histologically proven mass lesions of the posterior fossa, computerized transaxial tomography (CTT) and radionuclide (RN) brain imaging detected 23 (92%) and 22 (88%) of the 25 tumors, respectively. In this small group of patients, the difference is not statistically significant. When the results of both techniques were combined, the detection rate was 100%, which emphasizes the complementary value of the two procedures. The two lesions not detected by CTT were metastatic carcinomas, and contrast enhancement was not employed. The three lesions not detected by RN imaging were cystic. The results may represent underestimates of the true sensitivity of both techniques since the use of contrast enhancement with CTT and of posterior flow studies and magnified static RN images of the posterior fossa would probably improve the sensitivity of both tests.

Adolescent↗
PubMed1976

Obstructive airway disease associated with heterozygous alpha-1-antitrypsin deficiency.

Twenty-eight members of one family were investigated for the presence of pulmonary disease concurrent with variable (ZZ, MZ, or MS) degrees of alpha-1 antitrypsin deficiency. Three symptomatic siblings (2, ZZ; 1, MZ) had abnormal pulmonary scans and abnormal routine pulmonary function studies. Five asymptomatic heterozygotes, three of whom had never smoked and were the youngest studied, had distinctly abnormal closing volumes. Three of the five patients also had abnormal perfusion dynamics when scanning was done in the upright position. Pulmonary dysfunction occurs in asymptomatic heterozygotes but requires the use of sensitive techniques for its appreciation.

Adult↗
PubMed1976

Alteration of the cerebral bloodflow study due to reflux in internal jugular veins.

This paper considers abnormalities of flow patterns in the flow patterns in the cervical vasculature due to varying degrees of jugular venous reflux, and their influence on cerebral bloodflow studies. Two commonly encountered patterns are described. In the first group, the abnormal flow study resulted from reflux of the activity in the left internal jugular vein. In the second group, the observed abnormality resulted from reflux of the activity in the left internal jugular vein, followed by flow into the contralateral jugular vein, most probably through the transverse and sigmoid sinuses.

Aged↗
PubMed1976

Abnormal rapid-sequence imaging in a patient with subdural empyema: case report.

Static brain images in a patient with subdural empyema showed findings similar to those of a subdural hematoma. The rapid-sequence study, however, showed increased peripheral activity on the affected side. Since this finding suggested an inflammatory process, further neuroradiologic evaluation and immediate surgical treatment were undertaken. The significance of the rapid-sequence study in subdural empyema has not been reported previously.

Adult↗
PubMed1976

Primary and secondary carcinomata with focal nodular hyperplasia in a multinodular thyroid: case report.

A patient is described whose multinodular thyroid gland was found to have a primary papillary adenocarcinoma, a metastatic renal-cell carcinoma, and focal nodular hyperplasia. To our knowledge, this is the first case report of such an unusual combination. In a patient with known malignancy elsewhere, the possibility that a recent thyroid mass may be a metastasis should be considered.

Adenocarcinoma↗
PubMed1975

Visualization of pancreatic pseudocyst.

In a 44-year-old woman, a pancreatic pseudocyst was demonstrated on delayed images obtained up to 8 days after the intravenous administration of 0.250 mCi 75Se-selenomethionine. The initial routine pancreas image study failed to visualize both the pancreas and the pancreatic pseudocyst. The diagnosis was confirmed at surgery and the fluid of the pancreatic pseudocyst contained 0.73% of the injected dose of the radioselenium.

Adult↗