Geral W. Dietz

The effect of fatigue on resident performance.

Fourteen rested and fatigued residents read a set of 25 test radiographs on two separate occasions approximately one month apart. The radiographs were made with partial chest phantom using pulmonary nodules as test objects. Seven rested and 7 fatigued residents read the radiographs, and a month later the order of fatigue was reversed. Fatigued residents had worked a minimum of 15 consecutive hours before their interpretations. Performance did not deteriorate with fatigue, and the nodule detection rate was almost identical on both occasions.

Normal “Cupid's Bow” Contour of the Lower Lumbar Vertebrae

The inferior end plates of the 3d, 4th, and 5th lumbar vertebral bodies frequently have paired parasagittal concavities when viewed in the frontal projection. When viewed in the lateral projection, the concavities superimpose, lying in the posterior portion of the vertebral body. This normal contour of the end plate should not be confused with other vertebral body anomalies having clinical importance. The incidence and degree of end plate depression are discussed.

Subpulmonic Pneumothorax in Patients with Chronic Obstructive Pulmonary Disease

A spontaneous pneumothorax is occasionally seen under the lung on upright views, apparently due to subpulmonic trapping of pleural air by adhesions. This is most likely to occur in patients with chronic obstructive pulmonary disease (COPD), especially if they have extensive parenchymal scarring from previous tuberculosis. The authors describe 4 patients who had subpulmonic pneumothorax, severe COPD, and parenchymal scarring and presented in respiratory failure. None had other clinical symptoms suggesting pneumothorax. Radiologists should be aware of this condition, since it is potentially lethal.

Grid versus non-grid techniques for the detection of pulmonary nodules in a chest phantom.

A partial chest phantom was constructed to compare two commonly employed radiographic techniques, 70 kVp without a grid and 120 kVp with a grid, for the detection of pulmonary nodules. The phantom consisted of human ribs embedded in paraffin, the lungs of a dog injected with silicone rubber, a tissue equivalent wax heart and beeswax nodules. The nodules ranged in size from 3-7 mm. A series of 120 films was exposed, half with each technique, and the films were interpreted by three senior residents and seven staff radiologists. More nodules of all sizes except 3 mm were detected with the 120 kVp technique. The 3 mm nodules were rarely detected with either technique. The disadvantages of the 120 kVp technique were an approximate 50 percent increase in patient exposures and almost twice as many false-positive nodule detections.

The supraclavicular fossa

The presence of a supraclavicular fossa and the visibility of its floor on chest radiographs have been ignored in the radiological literature. In a study of 500 randomly selected chest radiographs, we could identify the floor of the fossa in 29% of patients. There is extreme normal variation in the visibility, depth, and symetry of the two sides. However, the fossa can occasionally stimulate a parenchymal lung abnormality such as a fluid level or an emphysematous bleb in the upper outer lung fields.