Unusual exercise-related stress fractures. Two case reports.

We describe two unusual exercise-related stress fractures, one in the sacroiliac joint of a long distance runner, the other in the body of the scapulae of an above-knee amputee. Each were detected on a 2-hour delay bone scan. To our knowledge, neither have been described scintigraphically. The bilateral scapular fracture is an unreported entity, and the fractured SI joint is a very uncommon site for an overuse injury.

The Angle of Louis. A potential pitfall ("Louie's Hot Spot") in bone scan interpretation.

Evaluation of 100 consecutive Tc-99m MDP bone scans revealed in 36 patients a well defined area of increased accumulation of radiotracer at the Angle of Louis--the palpable ridge along the anterior surface of the sternum at the fibrocartilaginous junction of the sternum and manubrium. Twenty-five of the 36 patients had comparison radiographs; all were normal. None had sternal pain or a prior history of chest trauma. Increased uptake at the Angle of Louis ("Louie's Hot Spot") is a relatively common finding (36%) and should be recognized as a normal bone scan finding. It should not be confused with increased uptake due to an osseous abnormality, i.e., metastasis, degenerative disease, trauma, etc.

Suspected acute cholecystitis. Comparison of hepatobiliary scintigraphy versus ultrasonography.

One hundred ninety-five patients with suspected acute cholecystitis (AC) underwent both hepatobiliary scintigraphy (HBS) and static gray-scale ultrasonography (US) to assess the relative value of each imaging modality in this clinical setting. HBS was performed after the intravenous injection of 5 mCi Tc-99m iprofenin. Abnormal HBS indicative of AC visualized the common bile duct, but not the gallbladder, within 1 to 4 hours after tracer administration. Abnormal US indicative of AC demonstrated cholelithiasis and/or gallbladder wall edema. In this series, HBS surpassed US in sensitivity (98.3% versus 81.4%), specificity (90.2% versus 60.2%), predictive value of an abnormal test (91.4% versus 51.6%), and predictive value of a normal test (100% versus 92%), HBS should be the procedure of choice for the rapid detection of AC.

Efficacy of hepatobiliary imaging of acute abdominal pain: concise communication.

To assess prospectively the usefullness of hepatobiliary imaging in acute abdominal pain (72 hr or less), 36 patients were scintigraphed after intravenous injection of 5 mCi of Tc-99m p-isopropyl-iminodiacetic acid (PIPIDA). Before the procedure, the referring physician completed Part I of a questionnaire indicating his differential diagnosis, diagnostic confidence (expressed as a percentage), and therapeutic plan. Immediately after the test, the same physician, with knowledge of the results, completed Part II of the questionnaire indicating again his differential diagnosis, diagnostic confidence, and therapeutic plan. The impact of the imaging on the physician's diagnositic confidence was expressed as a log-likelihood-ratio (LLR). The mean LLR for this series was 1.48 +/- 0.93, with 33 of 36 (92%) patients demonstrating a LLR greater than 0.0. In 26 of 33 patients, a LLR greater than 1.0 was achieved; and in 11 of 36 patients, a change in the physician's therapeutic plan occurred, reflecting the considerable impact of hepatobiliary imaging on the decision-making process.