Majic S. Potsaid

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%.

The Clinical Use of 99mTc-Diphosphonate (HEDSPA)

Clinical experience in over 500 patients scanned with 99mTc-diphosphonate is discussed. In comparison with 18F scans and roentgen studies, 99mTc-diphosphonate has produced similar or better studies. Frequently, the diphosphonate scan is more sensitive, especially in the detection of metastases to bone. In addition, calcific soft-tissue deposits and urinary tract pathology have been visualized on 99mTc-diphosphonate scans. Scanning with 99mTc-diphosphonate is considered to be the most effective imaging modality available for determining the presence and extent of skeletal metastases.

99mTc-Diphosphonate Concentration in Primary Breast Carcinoma

In two patients with breast carcinoma images of the skeleton were obtained with 99mTc-diphosphonate. In both cases there was increased uptake of the scanning agent in the area of the breast mass.

Comparison of current radiologic approaches to the diagnosis of pancreatic disease.

Abstract To assess prospective accuracy and clarify indications for diagnostic study, 45 patients suspected clinically of having pancreatic disease were studied by conventional barium examination of the upper gastrointestinal tract, hypotonic duodenography, selective angiography and selenomethionine isotope scanning. Duodenography achieved 78 per cent, isotope scanning 72 per cent, conventional upper gastrointestinal examination 57 per cent, and angiography 55 per cent correct prospective diagnoses. Isotope scanning produced most (19 per cent) false-positive and angiography most (38 per cent) false-negative interpretations (most of those falsely negative on angiography occurred in patients with pancreatitis). Specific diagnostic procedures should be chosen on the basis of the provisional clinical diagnosis. The most appropriate approaches appear to be duodenography and angiography for pancreaticoduodenal cancer, scanning and angiography for cancer of the body and tail, conventional upper gastrointestinal ...

Radionuclide imaging of the spleen in suspected splenic injury.

Radiocolloid images of the spleen were obtained in 32 patients with suspected splenic trauma. Studies were positive in 11 of 12 patients who ultimately proved to have splenic injury and negative in 16 patients, one of whom proved to have splenic injury. Three studies were interpreted as equivocal, and no injury was confirmed. The results of the radionuclide procedure compared favorably with those of selective angiography. Thus although an abnormal radionuclide image is not specific for splenic injury, it is recommended as the primary method of evaluation for possible splenic trauma, with angiography reserved for unusual or equivocal cases.

Relative efficacy of radionuclide imaging and computed tomography of the brain.

Computed tomography (CT) with the EMI scanner has been demonstrated to possess a wide spectrum of capabilities in the diagnosis of suspected intracranial disease. This review of 418 dual CT and radionuclide (RN) brain images indicates that RN and CT are complementary in the diagnosis of cerebral infarction, but that CT has a greater capability in brain tumor detection. The classical RN static brain image does not detect cerebral atrophy, hydrocephalus or intraventricular hemorrhage; these conditions are clearly defined by CT.

Lung Perfusion Pattern Associated with Widespread Occlusion of the Pulmonary Vessels and Lymphatics

A case is reported of unusual lung perfusion changes in a patient with overwhelming occlusion of the pulmonary vessels and lymphatics. In addition to peripherally radiating irregular and linear perfusion defects, there are clearly demonstrated “fissure” hypoperfusion defects. Three major pathological processes appear to be important: fibrotic obliteration of the peripheral lung vessels, tumor microemboli, and Iyrnphangitic spread of tumor.

Iodine-125 labeled phenylphosphonic acid: A new radiopharmaceutical for long-term investigations of the skeleton

A skeletal seeking radiopharmaceutical labeled with a long-lived radionuclide was developed to evaluate regional bone formation and its subsequent resorption. The agent is [phosphonate (phenylmethylene hydroxy) bis]-I-125 or I-125 θPA. Tissue distribution studies in mice (N=16) showed approximately 40% of the administered dose to be retained by the skeleton up to 336 hours post IV injection. The percentage of the dose accumulated by the thyroid gland remained at less than 0.5%, indicating minimal deiodination of the I-125 θPA. Whole body retention studies in the same species revealed a triexponential release pattern with the longest component comprising 33% of the dose with a biologic half-life of 962 days. A fractured rat tibia model was studied with I-125 θPA and Tc-99m MDP. Chronic loss of the I-125 θPA relative to normal tibia was quantitated: five days (62.8%); 30 days (47.4%). Concomitant increased uptake of the Tc-99m MDP was observed at the fracture site relative to normal: five days (186%); 30 days (1,041%). The above data suggest that I-125 θPA can be utilized to measure acute bone formation and chronic resorption.

Radioisotopic “Subtraction” Scanning for Pancreatic Lesions

“Liver overlap”—inability to distinguish between hepatic and pancreatic radioactivity—frequently impairs 75Se selenomethionine pancreatic photoscans. This paper describes a technical innovation which successfully eliminates the problem. Se1enomethionine, an amino acid analogue, is rapidly accumulated in protein synthesizing tissues (1, 2). Pancreatic protein biosynthesis is so active that pancreatic uptake of selenomethionine exceeds that of any other organ (per gram of tissue) (3–5), and accordingly the material can be used for pancreatic photoscanning (6). Because of decreased digestive enzyme synthesis in neoplastic tissue (7) pancreatic tumors appear as “cold” areas (8–11). Since liver is also active in protein synthesis, formed simultaneously in conventional photoscans. Adequate pancreatic visualization is therefore present only when the two organs are sufficiently far apart for the scintillation detector to discriminate between them (8, 9) (Fig. 1). Since liver is often adjacent to (or actually supe...

A potential method for increasing pancreatic accumulation of 75Se selenomethionine.

Since the introduction of 75Se selenomethionine as an agent for pancreatic scanning (1), numerous protocols designed to increase pancreatic uptake of this amino acid analogue have been proposed (1–4). For the most part, these methods have not been substantiated by animal investigation, and, where they have been tested experimentally, no significant increase in pancreatic radioactivity has been found (5). During the past year we have been engaged in determining the effects of numerous hormonal, pharmacologic, and biologic influences on pancreatic amino acid accumulation. Of the agents so far studied, only ethionine has been found to significantly increase pancreatic concentration of 75Se selenomethionine. Ethionine, the ethyl analogue of methionine, has been used, in doses of 1 g/kg body weight, to produce experimental pancreatitis and other cytopathogenic effects in animals (6, 7). When given in smaller daily doses over a period of months, it is carcinogenic (8). We have found in rats that when 1 mg/kg bo...