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Biomedical subjects

R E Koehler

Publications and source records attributed to R E Koehler.

At least 37 records · Page 2Linked to original sources
PubMed1990

Computer facilitation of the resident selection process.

A personal computer software system has been designed and implemented to facilitate the numerous complex tasks involved in the resident selection process. The computer tracks the status of each candidate, monitors each application for incomplete documentation, generates personalized correspondence, computes and maintains a scoring system based on evaluation by each Resident Selection Committee member, and provides various data printouts (eg, list of candidates by medical school; persons granted an interview; and ranking lists). Developed with the intent to share with the academic community, the system improves organization and accuracy, and notably decreases time spent by administrative assistants and staff members in the resident selection process.

Computer Systems↗
PubMed1988

Preoperative evaluation of abdominal aortic aneurysm by MR imaging with aortography correlation.

Sonography, computed tomography, and most recently, magnetic resonance imaging (MRI) have been advocated as noninvasive imaging methods for the preoperative evaluation of patients with abdominal aortic aneurysms (AAA). We prospectively assessed the value of MRI in this clinical setting. Twenty of 23 patients with AAA referred for evaluation with biplane aortography underwent MRI within 3 days of aortography. MR and angiographic studies were interpreted prospectively and independently and then the results were compared with each other and with the operative findings. All angiographically demonstrated infrarenal and suprarenal aneurysms except one were documented as such by MRI. The distal extent of the aneurysm on MRI agreed with that on angiography in all but 3 cases. MRI is an accurate method for assessing the size and extent of AAA and its relationship to the main renal artery origins. MRI is not accurate in detecting vascular obstructions or accessory renal arteries. Therefore, the usefulness of MRI and the need for aortography in preoperative assessment of AAA depends upon the specific information the surgeon requires prior to aneurysmectomy in a given patient.

Aorta, Abdominal↗
PubMed1987

Malignant hemangiopericytoma: computed tomography and magnetic resonance imaging.

Computed tomography and magnetic resonance imaging of a malignant hemangiopericytoma in a 58-year-old woman are described. The tumor was initially found in the abdomen and resected 34 years ago, but recurred 18 years later, followed by repeated recurrence and eventually metastasis to the lung and then to the liver. The lung nodules were round or oval, homogeneous, and well circumscribed while the massive tumor in the right lobe of the liver was poorly delineated with irregular areas of cystic necrosis. With proper setting of the repetition time and echo delay, the metastatic tumor became distinct from the uninvolved hepatic tissue on magnetic resonance imaging. In this case computed tomography and magnetic resonance imaging were complementary in evaluation of such a tumor.

Abdominal Neoplasms↗
PubMed1987

The case for radioprotective eyewear/facewear. Practical implications and suggestions.

Numerous eyeglass lens materials have been recommended for protection of radiologists' eyes from the cataractogenic effect of radiation during fluoroscopic procedures. For the most part, these lenses coincidentally attenuate x-ray beams because they contain elements of high atomic number that are added to increase refractive index. With a bean hardened to simulate scatter, direct transmission ratios were measured for 32 commercially available lens materials. Scatter to the eye, both through and around the glass lenses and secondary scatter to the eye from the radiologist's head, was determined with lenses mounted on a head phantom and a 1-cm3 ion chamber in the position of the eye. Transmission ratios for the various lenses ranged from 3% to 98% for an 80 kVp x-ray beam (HVL = 4.5 mm Al). Measurements with the head phantom in place show that secondarily scattered radiation from the fluoroscopist's head contributes significantly to ocular exposure. Optimal radiation protection of the eyes during fluoroscopy depends not only on eyeglasses with leaded glass, but also on shielding of sufficient size and shape to reduce exposure to the surrounding head.

Cataract↗
PubMed1987

Magnetic resonance imaging of the internal anatomy of the prostate gland.

Previous reports on the value of magnetic resonance imaging of the prostate have been conflicting and frequently pessimistic, in part because of inability to visualize internal prostatic anatomy. Multiple spin-echo sequences were used to determine a sequence that clearly delineated the internal prostatic anatomy in normal volunteers. A thin section, T2-weighted, spin-echo technique displayed the internal prostatic anatomy in great detail, including the central and peripheral zones, the prostatic urethra, and the periprostatic venous plexus. Accurate depiction of the zonal anatomy of the prostate is important in characterizing focal prostatic disease because the vast majority of carcinomas begin within the peripheral zone, whereas benign hypertrophy originates centrally.

Adult↗
PubMed1985

Hand-held real-time breast sonography.

The results of real-time hand-held sonographic breast examinations on 86 patients are presented. The technique is described in detail. Sonography was found to be a useful adjunct to the x-ray mammogram in three groups of patients: (1) patients with dense breasts and localized symptomatology or a suspicious area on x-ray mammogram; (2) patients with nonpalpable abnormalities discovered on x-ray mammogram; and (3) patients with palpable masses considered indeterminate on x-ray mammogram. The examination was also found useful for guiding needle aspiration biopsies, in patients with persistent nipple discharge, and in those with breast prostheses. Advantages of the hand-held real-time technique include supine positioning, the ability to flexibly orient the probe, improved resolution due to higher frequency transducers and the lack of compounding, and the ability to vary the amount of compression to assess tissue compliance and fixation. The disadvantage of decreased resolution in the near field can be overcome by attaching a detachable water-path step-off device to the transducer. Geometric distortion from the pressure of the transducer was not believed to be a problem. Hand-held sonographic technique is useful when attention can be directed to a specific area of the breast. The additional information provided results in fewer equivocal interpretations of the x-ray mammogram; however, it should not be used as a substitute for routine mammography.

Adult↗
PubMed1984

Abdominal tuberculosis: CT findings.

The computed tomographic (CT) characteristics of intraabdominal tuberculosis are not specific. A recent article from South Africa proposed a set of criteria that included high density ascites and mesenteric involvement, consisting of thickening and adenopathy, as possible criteria for the diagnosis of tuberculous peritonitis by CT. Review of three additional cases of abdominal tuberculosis showing these findings supports the criteria defined in the earlier study. Although not definitive, these findings in the appropriate clinical setting should suggest the possibility of tuberculosis.

Adult↗
PubMed1984

Thrombophlebitis of the internal jugular vein: noninvasive imaging.

Internal jugular thrombophlebitis usually results from contiguous infection or central catheterization. Ultrasonography and CT allow rapid, noninvasive methods of confirming the diagnosis of this condition. Although the choice of modality has not been systematically examined, where local expertise exists for both, ultrasonography is less expensive and should provide adequate images.

Adult↗
PubMed1984

Gastrohepatic ligament: normal and pathologic CT anatomy.

In a review of 200 consecutive CT scans of the upper abdomen, the structures within the gastrohepatic ligament (GHL) were well seen in 182 (91%). In 85% of these 182 patients, the largest structure visible within the GHL was 6 mm or smaller. A total of 27 patients had a structure larger than 6 mm within the GHL; this finding could be explained in 13 by the presence of a normal anatomic variant. Of the 14 others, 12 had known tumor arising in or known to have spread to the upper abdomen. Two patients had no obvious explanation. Fourteen patients with cancers of the stomach (9 patients), pancreas (3 patients), and esophagus (2 patients) had 57 intact nodes that were evaluated pathologically. Of these 40/40 benign nodes and 10/17 malignant nodes were less than or equal to 8 mm in size. When anatomic variants are excluded, the finding of rounded structures greater than 8 mm in the GHL is a reliable indicator of left gastric node involvement by carcinoma or lymphoma or of coronary venous dilatation.

Humans↗
PubMed1983

Nodular duodenitis. Pathologic and clinical characteristics in patients with end-stage renal disease.

This prospective study evaluated the radiographic, endoscopic, histologic, and clinical characteristics of nodular duodenitis found in 17 of 50 (34%) patients with end-stage renal disease. By comparison, nodular duodenitis was noted in only 23 of 557 (4%) consecutive endoscopies in a general medical population. Endoscopic nodular duodenitis consisted of two or more nodules, 2.5-7.0 mm in diameter, with apical erythema, with or without tip erosions. Eight patients had nodules in the bulb only, eight had diffuse duodenal nodules, and a single patient had nodules only in the second portion of the duodenum. Single-contrast barium x-rays were sensitive in detecting the nodules only when they were 5 mm or greater in diameter. Some degree of inflammatory infiltrate was found in 14 of 17 (82%) of the patients with nodular duodenitis; 10 of 17 had a moderate to severe histologic grade compared to 3 of 18 (P = 0.015) patients with a normal endoscopic appearance to the duodenum. Several patients with endoscopic nodular duodenitis, in whom biopsies were taken both of the nodule and surrounding mucosa, were found to have a focal histologic lesion which consisted of villous blunting and thickening due to fibrosis and a chronic inflammatory infiltrate or lymphoid aggregate in the stroma. A higher incidence of peptic ulcers occurred in the nodular duodenitis group (3 of 17) compared to the remainder of the group (0 of 33) during a mean follow-up of 38 months (P = 0.03). Resolution of the nodules occurred in six patients following successful renal transplant (four patients) and following vagotomy and pyloroplasty (two patients).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1983

CT of the thorax in patients with achalasia.

The computed tomographic appearance of achalasia of the esophagus is described in three patients. The CT findings should enable one to suggest the diagnosis of achalasia even in those patients in whom this condition is not suspected. The final diagnosis can be confirmed by esophagography and manometric studies.

Adult↗
PubMed1983

Assessment of patients with failed gastric operations for morbid obesity.

The success of gastric restriction procedures for morbid obesity depends on a persistently small gastric pouch and stoma, an intact staple line, and, of equal importance, dietary compliance. Evaluation of patients with either excessive or inadequate weight loss should be directed at determining both the technical adequacy of the operation and the depth of understanding the patient has of his or her role in the success of the procedure. Because of the poor prognosis for weight loss, patients who are not likely to be complaint or who demonstrate a lack of understanding of the behavioral modification required to ensure the success of the procedure should not have reoperation, even if a large pouch or stoma or a disrupted staple line is seen on an upper gastrointestinal series.

Adult↗