Interobserver discrepancies in distance measurements from lumbar spine CT scans.

Lumbar spine computed tomographic (CT) scans of 10 patients were examined independently at two levels by five experienced radiologists. At each level the minimum midline sagittal diameter was measured, and at each intervertebral space the left foramen was measured for its minimum diameter. Statistically significant differences were found between the measurements of different observers, differences that in a number of cases could have led to disagreement over whether or not stenosis was present. There were reasonably strong correlations between different observers' readings of midline sagittal diameters but generally not of foraminal diameters. Reasons for discrepancies between observers in spine CT measurements are reviewed briefly.

Pyogenic sacroiliitis. An absolute indication for computerized tomographic scanning.

Pyogenic sacroiliitis (PSI) resulted from direct injection of a foreign substance, pumice, in a 32-year-old woman and was complicated by iliopsoas abscess. The symptoms of PSI are unspecific, and similar complaints may accompany such conditions as herniated disc and arthritis. Results of physical examination may be misleading, especially if movements that stress the sacroiliac joint are omitted. Early roentgenograms are normal and rarely aid in the diagnosis. Scintiscanning with gallium and technetium may indicate an inflammatory pelvic focus. These methods lack specificity, however, and may underestimate the extent of disease. The computerized tomographic (CT) scan was effective in detecting interosseous gas with an associated soft tissue abscess. It also proved invaluable in precisely delineating the location and extent of the lesion in and around the sacroiliac joint, facilitating use of the most expeditious surgical approach. Through follow-up CT studies the course and end results of therapy can be objectively determined.

Computed tomography diagnosis of right aortic arch with an aberrant left innominate artery.

A patient whose chest computed tomography scan demonstrated a right-sided aortic arch with an aberrant retroesophageal left innominate artery is reported. There have been only isolated case reports of this developmental variation of the arch and great vessels. The demonstration of this anomaly by computed tomography scanning has never been previously reported.

Occult gastric bleeding demonstrated by bone scan and Tc-99m-DTPA renal scan.

A patient is described who had coagulopathy and clinically intermittent gastrointestinal bleeding. The bleeding site was clearly shown on renal and bone imaging performed at a time when the patient was considered clinically to have stopped bleeding. A bleeding gastric ulcer was subsequently demonstrated by radionuclide and contrast angiography, and at surgery.