A standardized technique for lower limb radiography. Practice, applications, and error analysis.

The normal standing radiograph, which provides a view of the knee only, is prone to errors of parallax and poor control of patient positioning. A standardized radiographic procedure was developed to control these sources of error. Anteroposterior and lateral views of the lower limb (hip and knee) are obtained without moving the patient from a standardized position; this includes control of ankle position and limb rotation. To correct for parallax error, radiopaque markers are positioned between the patient and the x-ray source. The locations of bone landmarks and reference markers on the radiographs are digitized, and a software package provides a display of key parameters. Error analysis of the method confirmed that most angles were sensitive to contrived positional variations, especially limb rotation and knee flexion. Load distribution between limbs was not critical. The greatest error was random. Most angles were reproducible within +/- 1.3 degrees or less at 95% confidence.

Selective coronary arteriography.

The technique of selective coronary arteriography, as described originally by Sones, was employed in 255 patients. Successful catheterization of both coronary arteries was carried out in 88% of these patients, and in the last 100 examinations both coronary arteries were entered in 95 patients. Selective coronary arteriography is a useful diagnostic tool but is a potentially hazardous form of examination as we encountered four episodes of ventricular fibrillation in the present series.