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Biomedical subjects

M S Potsaid

Publications and source records attributed to M S Potsaid.

13 recordsLinked to original sources

Errors of interpretation as elicited by a quality audit of an emergency radiology facility.

A process-oriented quality care audit was performed in a large metropolitan hospital emergency radiology facility with an annual volume of over 50,000 examinations. One aspect of the audit dealt with errors found among interpretations by radiology residents, the initial interpreters of x-ray studies. Misinterpretations were identified by staff radiologists, who checked all examinations and countersigned the reports. Error rates were correlated with duration of training and were separated as to significance and whether the errors were false-negative (omission) or false-positive (commission). The false-positive to false-negative ratio was 27:73% which is in agreement with previous studies. For all cases of errors, the significance of change in interpretation was high in 20%, moderate in 29% and low in 51%. The effect of inadequate clinical history on the rate and significance of interpretation errors was also determined. When clinical information was inadequate, the significance was high in 27%, moderate in 40% and low in 33%.

Diagnostic Errors

Evaluation of left ventricular free wall asynergy due to coronary artery disease: use of an interlaced ECG-gated radiography system.

A new radiographic technique produces a high quality image of the chest at end systole and end diastole in a single radiograph. A preliminary study of this method for evaluating various degrees of segmental asynergy of the left ventricular free wall in 25 patients with coronary artery disease showed excellent correlation with left ventriculography (r = 0.88). The method showed a high sensitivity (94%) and specificity (96%). It seems potentially useful to increase the information gained from the chest radiograph in patients with cardiac disease.

Coronary Disease

The significance of augmented radiocolloid uptake by the spleen in patients with malignant melanoma.

Increase in splenic uptake of Tc-99m sulfur colloid was noted in 47 of 147 (32%) patients with cutaneous malignant melanoma early in the coure of disease. Patients with disseminated disease and/or clinical or laboratory evidence of hapatic dysfunction were excluded from study. Recurrence rate of 2 yr was higher for those patients with splenic scans demonstrating augmented uptake compared with patients having normal scans, 36% against 16% (p less than 0.02). These differences resulted from a much more favorable prognosis in women with normal scans contrasted with women with increased uptake, 6% against 26% (p less than 0.05). Women with increased splenic uptake, and all men regardless of scan status, seemed to have a higher rate of recurrence than women with normal spleen scans. Scan status may be an adjunctive prognostic marker in women.

Colloids

Quality assessment and assurance in diagnostic imaging. Theoretical and practical considerations and a quality audit of the excretory urogram.

Concepts necessary to an understanding of the basics of quality assurance audits are presented. Included are specific examples that bridged theory and practice by applying the protocol to a real-life diagnostic imaging situation. This method meets the present requirements of the Joint Commission of the Accrediation of Hospitals.

Costs and Cost Analysis

[32P] diphosphonate dose determination in patients with bone metastases from prostatic carcinoma.

In an initial safety study, phosphorus-32 (as diphosphonate) was administered intravenously to five patients with painful bone metastases from prostatic carcinoma; two patients received 9 mCi and three were given 3 mCi. Hematological, biochemical, ECG, x-ray, bone-scan data, and clinical observation, were followed for 2 mo. At both dose levels, bone-marrow depression was noted. One of the patients, who received 9 mCi, had only a slight dip in the levels of circulating white blood cells and platelets. The other 9-mCi patient was the only one with discrete metastases by bone scan; he had bone-marrow depression, from which he recovered, and was the only one of the five who had relief of bone pain.

Adenocarcinoma

Quality of bone scans compared with time between dose and scan.

The usual time interval between the administration of technetium-labeled bone-seeking radiopharmaceuticals and imaging varies among nuclear-medical departments. Pharmacokinetic data indicate that the interval could be as short as 2 hr. We have studied overall quality of bone detail in 280 bone scans performed at intervals varying from 2 to 5 hr following injection of technetium-99m diphosphonate. No significant qualitative difference was found between the studies performed at 2 hr and those done at later intervals.

Bone Diseases

Pharmacokinetics of technetium-99m diphosphonate.

Increased diagnostic information may be derived with Tc-99m diphosphonate from a detailed kinetic analysis of blood disappearance, urinary excretion, and quantitative assessment of skeletal uptake. Blood and urine determinations were studied in three populations: normal volunteers, patients with negative bone scans, and patients with positive bone scans. Quantitative imaging studies were performed in normal volunteers and patients with a scintillation camera interfaced to a computer. All subjects were scanned in the lower lumbar region up to 1 hr after Tc-99m diphosphonate administration. Blood levels exhibited a triexponential clearance pattern. Significant (p less than 0.05) differences were observed for the 5-min blood and 0-1 hr urine values among the various groups. The computer-generated images showed an initial early uptake in bone, kidneys and soft tissue. Thereafter, a parallel fall-off in activity was observed in kidney and soft tissue, with a concomitant increase in bone. Skeletal uptake was different for normal and diseased bone.

Adult

Improved method for quantitative bone scanning.

A quantitative gamma-camera technique is used to calculate the percentage of administered activity taken up by various areas of the skeleton. The method uses an external standard source of activity as a reference, and in addition presents the information in a new format, the Organ Uptake Image (OUI). Two cases of Paget's disease serve to illustrate the usefulness of this approach to quantitative bone imaging.

Aged

Improvement in visualization of hepatic lesions with upright views.

Standing scintiphoto views of the liver may provide improved visualization as compared with conventional supine liver images. This is partially due to decreased respiratory motion of the liver. The standing position is recommended if the supine liver scan appears normal in a patient suspected of metastatic disease.

Colloids

Accumulation of 99mTc-diphosphonate in four patients with hepatic neoplasm: case reports.

The accumulation of bone-seeking radiopharmaceuticals in extraosseous lesions has been reported in patients with myocardial infarctions, cerebral infarctions, and some soft-tissue tumors. While the precise mechanisms involved remain uncertain, the spectrum of abnormalities exhibiting such accumulation increases. In our laboratory, 99mTc-diphosphonate concentrated in four hepatic tumors (one cholangiocarcinoma and three metastases from colon carcinoma). This property of phosphate-related radiopharmaceuticals has not been reported previously. Awareness of the possibility of focal diphosphonate accumulation in the liver should help avoid confusion with right lower rib-cage metastasis or pleural effusion.

Adenocarcinoma