Samuel J. Hessel

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The capacity of electrostatic imaging for edge enhancement and wide latitude recording can improve visualization in neuroradiologic studies using low differential absorption contrast agents. Gas myelography and pneumoencephalography show the most satisfactory improvement in visualization. Tomography combined with xerography enhances definition further, but(More)
The diagnostic yields and complication rates of closed lung biopsies were determined by responses to a questionnaire. Of 5,255 procedures reported, 30% were aspiration biopsies (AB), 7% tissue core biopsies (CB), 2% trephine biopsies (TR), 37% bronchial brush biopsies (BB), and 23% transbronchial biopsies (TB). Of these biopsies, 70% were done for suspected(More)
In this department 22% of examinations are interpreted independently by residents outside of normal hours. Staff radiologists review these studies in a process designed to train residents and assure appropriate radiologic consultation. The resident's written reports on 2,619 examinations were analyzed before and after staff review. Each film review session(More)
The detection of simulated pulmonary nodules was measured in three different situations that required: (1) reports of all significant chest findings (Free Search), (2) only reports of possible nodules (Nodule Search), or (3) evaluation of particular film locations as nodules (Specified Location). ROC curves from these conditions compared how accurately(More)
This study evaluated how accurately the chest film could be used to determine pulmonary capillary wedge pressure (PCW) in patients with chronic heart disease. Six experienced readers interpreted the erect posteroanterior chest radiographs of 50 patients whose measured PCWs ranged from 6 to 38 mm Hg. Direct numeric estimates of PCW from the films were(More)
Transvenous digital subtraction angiography was used before surgery to evaluate seven patients with chemical evidence of hyperparathyroidism. Digital subtraction angiography identified parathyroid adenomas in six of the seven patients. This technique is a sensitive, although not specific, method to identify small vascular tumors.
Preformed arterial collaterals are critical to renal parenchymal survival after acute total renal artery occlusion. This study was designed to delineate and quantify preformed collaterals and assess their response to vasodilators. A Swan-Ganz catheter induced a sudden, total occlusion of a renal artery sufficient to reduce distal arterial pressure to near(More)
The potential of ungated computed tomography (CT) to detect and quantify myocardial infarctions was assessed in 10 dogs. Twenty-seven in vivo CT examinations were performed at various time intervals (1 hr-20 days) after coronary artery occlusion. After intravenous contrast administration, CT delineated the infarcted myocardium in all 27 studies. The(More)