Digital processing of film radiographs.

Initial clinical experience with a system for the digitization, processing, and display of film radiographs is described. Film is digitized using a high-intensity laser scanner; the recorded image data may then be subjected to a wide variety of processing options, with display of processed images on television monitors. The possibilities of clinical applications to processing and display of chest radiographs and film mammograms are described. A comparison of conventional analog subtraction and digitized film subtraction angiography indicated equivalent diagnostic capability, with the advantage of flexible, interactive image processing with the digital technique. A specially designed, energy-selective cassette permits dual-energy imaging from two films effectively exposed to different x-ray energy spectra. Dual-energy imaging may be capable of the characterization of body materials, including lung nodules, and useful for eliminating obscuring radiographic shadows overlying regions of interest.

Hiatus hernia causing CT gastric mass lesions.

Two cases of hiatus hernia causing a soft tissue mass involving the gastric fundus on CT scans are presented. These masses could be mistaken for pathologic processes if hiatus hernia is not included in the differential diagnosis. Methods for resolving such diagnostic problems are discussed.

Ultrasonic contrast enhancement of tissue by encapsulated microbubbles.

Pilot studies have shown that gelatin encapsulated microbubbles (GEM) are readily demonstrable ultrasonic contrast agents. GEM injected into hepatic and renal blood vessels resulted in increased echogenicity of the parenchyma in normal rabbits. VS carcinoma implanted in the rabbit liver and kidney showed significantly different echogenicity from that of normal parenchyma following GEM injection. Echogenic bubbles were delivered to different regions by varying the size of GEM.

Radiographic blood pool contrast agents for vascular and tumor imaging with projection radiography and computed tomography.

An emulsion of Ethiodol and Pluronic was evaluated as a vascular (blood pool) imaging agent with both the GE experimental scanned projection radiography system and conventional computed tomography (CT), 475 mg iodine/kg body weight of emulsion, was injected into 11 rabbits with thigh muscle V2 carcinomas. Both projection radiography scans and CT scans visualized aorta, vena cava, pulmonary, and femoral vessels, and distorted vessels around tumors for 20 min after infusion. This persistent vascular visualization allowed CT scanning at multiple contiguous levels, which could be followed by reformatting in the sagittal and coronal planes. Following diatrizoate in identical iodine/kg doses, vascular visualization persisted for only 1 min after infusion. Blood pool agents are ideal for projection radiography systems and CT reformatting of vascular anatomy.

Cancer imaging by scanned projection radiography.

We have evaluated scanned projection radiography (SPR) for the diagnosis of cancer. Four rabbits with V2 thigh carcinomas and nine patients with a variety of malignant neoplasms were studied with a GE CT/T 8800 scanner modified for SPR. Images were made before injection of intravenous contrast medium, and additional scans were taken after injection. Temporal subtraction was then performed on the digitized data. Rabbit thigh V2 carcinomas and human lung, liver, and extremity neoplasms were visualized. Contrast enhancement was phasic with early vessel demonstration and subsequent visualization of low density central areas of tumoral necrosis. Liver metastases appeared as poorly defined areas of low density. Because of the combination of high contrast sensitivity plus capability of imaging large tissue volumes on one scan, SPR may be valuable in cancer screening.

Double-contrast esophagrams. The prone technique.

The authors describe a simple method for obtaining double-contrast images of the lower esophagus with the patient in a prone position. This technique has a high success rate, allows repeated imaging, and is easily incorporated into routine upper gastrointestinal studies. Diagnostic double-contrast studies were obtained in 78% of 28 patients. Ten abnormalities, including a Mallory-Weiss tear, were demonstrated. Single-contrast esophagrams, performed immediately afterwards, demonstrated only six abnormalities.