Biomedical subjects
Publications and source records attributed to D F Preston.
Three cases are presented in which hepatobiliary scans demonstrated extent and course of active bile extravasation. Correlation with computed tomography is demonstrated. The results of the examinations significantly influenced the direction of clinical care of all three patients. Hepatobiliary scanning is suggested for early evaluation of postoperative and post-traumatic complications involving the biliary system.
The increasing use of digitally formatted imaging systems requires high-quality interactive gray-scale computer raster graphics systems for the management, display, and analog film recording of digital image and alphanumeric information. These systems are a combination of computer hardware and software and implement a set of graphics protocols. This paper describes a set of interactive graphics protocols that has been developed for clinical use.
The continuing increase in diagnostic examinations using digitally formatted image instrumentation imposes new requirements on the acquisition, display, transmission, recording, and archiving of all diagnostic data. The fabrication decisions and initial clinical testing of a prototype on-line, decentralized digital image management system are described. With this system, raw digital data can be viewed by multiple users as soon as it is acquired by an acquisition node and transmitted to a display node. Radiologists and clinicians have given this system a favorable reception.
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Tc-99m pertechnetate scintigraphy was performed in a patient with Barrett's esophagus and a history of previous lye ingestion. Radionuclide uptake was present in the distal two-thirds of the esophagus and persisted after the drinking of water. This technique is simple and accurate and may be of significant benefit in determining the presence and extent of Barrett's esophagus, which carries an increased incidence of adenocarcinoma development. Examination of patients with chronic gastroesophageal reflux, using this technique, is advocated.
In the last decade diagnostic imaging departments, even those of moderate size, have experienced unprecedented growth. Much of this expansion can be attributed directly to technological developments, including systems for the acquisition of diagnostic images in digital format. In modern imaging departments, digital-based systems are quite common and are found across the specialities of nuclear medicine, ultrasound, transmission and emission computed tomography, and angiography. Nuclear magnetic resonance is the newest digital-based modality, and it appears destined to achieve its place in the diagnostic arsenal. These systems all have one trait in common, which is the topic of this paper. They offer the potential of increasing diagnostic accuracy by varying the methods used to process and display the acquired imaged data. We present the results of a nuclear medicine study designed to compare observer performance among five digital scintigraphic display modes. The observer's task was to detect artificially created lesions in brain scintigrams. Each mode is defined by a combination of an image processing function and a method of display. Using 40 trained observers, a receiver operating characteristic curve analysis was performed. The results support the use of color displays in nuclear medicine.
A study of the cost of recording and archiving digitally formatted diagnostic images is presented for an academic radiology department serving a 614-bed university hospital and a large outpatient population. The radiological examinations include computed tomography, nuclear medicine, ultrasound, and digital radiography. The archiving management strategies studied include the combined use of computer magnetic tapes, computer disc storage, and multiformat video film recordings. The estimated cost per patient for the archiving of digital diagnostic images is presented.
In 20 cases routine static bone scans were no value in the detection of delayed fracture healing. Using the 7.5-15 min net uptake of technetium labelled phosphate, disturbed fracture healing was detected in a series, of 37 cases. Normally healing fractures had an increase of 3 per cent per month and delayed unions less than half that amount. Non-unions had no net uptake.
A case report is presented in which an initial bone scan in a patient with Burkitt's lymphoma of the jaw was negative, with radiographic and subsequent biopsy proof of bone involvement. Follow-up scans after chemotherapy demonstrated increased activity in the jaw, presumably indicating interval healing.
A method of recording continuous gray-tone images on dry-process silver paper from raster-scan video signals is described. The Tektronix 4634 image-forming module uses a fiber-optic faceplate cathode-ray tube to couple the light output onto the recording paper. The latent image is heat developed and presented in sheet form. An initial comparison between dry silver paper and conventional film for video-generated computed tomography and nuclear medicine examinations, shows little apparent difference in image quality. Considerable cost savings are possible when using dry silver paper. Additional cost savings are possible if multiple images can be recorded on each dry silver sheet.
Studies on the accuracy of liver scintigraphy for the detection of metastases were assembled from 38 sources in the medical literature. An ROC curve was fitted to the observed values of sensitivity and specificity using an algorithm developed by Ogilvie and Creelman. This ROC curve fitted the data better than average sensitivity and specificity values in each of four subsets of the data. For the subset dealing with Tc-99m sulfur colloid scintigraphy, performed for detection of suspected metastases and containing data on 2800 scans from 17 independent series, it was not possible to reject the hypothesis that interobserver variation was entirely due to the use of different decision thresholds by the reporting clinicians. Thus the ROC curve obtained is a reasonable baseline estimate of the performance potentially achievable in today's clinical setting. Comparison of new reports with these data is possible, but is limited by the small sample sizes in most reported series.
We present a patient with crossed renal ectopia whose bone scan gave the appearance of unilateral hydronephrosis with contralateral absent or nonfunctioning kidney. An excretory urogram revealed crossed renal ectopia without obstruction. The axiom that unilateral absence of a kidney without previous nephrectomy should stimulate a search for ectopic kidney applies equally well to the bone scan as to the excretory urogram.
This report summarizes the experiences of the Oak Ridge Associated Universities Cooperative Group with the scanning of head and neck cancer using carrier-free gallium-67 citrate. Central nervous system and thyroid tumors and lymphomas were excluded. Fifty-six percent of primary head and neck tumors and their metastases were detected in 65 patients. The detection rates for primary and metastatic lesions were similar. Results of 1306 scans on patients with many types of cancer and suspicion of head and neck involvement indicate that a positive gallium scan was associated with tumor involvement five to nine times as often as no tumor, but a negative scan cannot reliably rule out involvement. In head and neck tumors, both primary and metastatic, lesions over 3 cm in diameter had a significantly higher detection rate than smaller lesions. Previous radiation or surgery did not affect accuracy.
An algorithmic approach for the evaluation of musculoskeletal tumors is proposed on the basis of a prospective comparison of different imaging techniques in 50 unselected patients. Conventional radiography was superior to other techniques in predicting the nature of primary bone tumors. Computed tomography proved the most effective method for assessing the extent of musculoskeletal tumors and therefore had a significant influence on management in 66% of patients studied. CT was more informative than angiography and also provided more anatomical detail than ultrasound. Radionuclide scanning was mainly of value in detecting unsuspected skeletal metastases in patients with apparently solitary skeletal lesions.
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In an attempt to define the role of scintiscanning in patients with a malignant melanoma, 349 liver, bone and brain scans in 136 patients have been reviewed. No patient with clinical Stage I or II disease was found to have occult metastases detected by scintiscans. All patients with proved positive scans demonstrated clinical symptoms consistent with the results of scintiscanning. Scintiscans in patients with a malignant melanoma are most effectively used to evaluate the symptomatic patient with Stage I or II disease and all patients with Stage III disease. Histologic verification of positive scans in patients with Stage I and II disease avoids unwarranted therapeutic decisions. There is, however, practical value in being able to predict accurately the absence of metastatic involvement. In only two of 249 examinations did the scans fail to detect metastases. A normal scan is a strong indicator of the absence of metastatic disease.
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The biodistribution of a lipid-soluble brominated female sex hormone, Br-77-labeled estrone, has been determined in dogs and rabbits. Following i.v. or intragastric administration, Br-77-labeled estrone localized in the gallbladder bile within 20-25 min. Fifty-six percent of the injected activity was found in the bile at 90 min. Breast tissue was imaged by scintillation camera in three female dogs with postpartum breast enlargement at 24 hr following i.v. injection. Analysis of digitized images revealed 50% more counts per pixel in stimulated female breast tissue than was in surrounding tissue. Increased Br-77 activity in the breast was associated with the presence of increased concentrations of estrogen receptors.