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Biomedical subjects

N Karstaedt

Publications and source records attributed to N Karstaedt.

35 records · Page 2Linked to original sources
PubMed1985

Superior vena caval obstruction: detection using CT.

A review of 210 chest computed tomographic (CT) examinations demonstrating upper chest masses revealed 16 cases of superior vena caval obstruction (SVCO); 11 of these were clinically occult. Two of the occult cases subsequently became clinically evident. Contrast-enhanced chest CT permits the diagnosis of clinically occult SVCO and should be considered in patients with upper chest masses, even in the absence of any physical signs of SVCO.

Aged↗
PubMed1984

Computed tomography for evaluation of mediastinal lymph nodes in lung cancer: correlation with surgical staging.

Computed tomography (CT) of the chest (late model) was done preoperatively in 56 candidates for resection of lung cancer. Precise borders for each node region were defined by the American Thoracic Society modification of the classification of the American Joint Committee for Cancer Staging and were used to "map" nodes seen on CT and nodes removed surgically. Metastatic involvement of mediastinal nodes was proven by mediastinoscopy in 11 patients; nodes were removed from multiple regions at thoracotomy in 45 patients. The mediastinum was clearly delineated by CT in 46 patients with determinate scans and was judged normal in 32 (CT-negative scans) and abnormal in 14 (CT-positive scans). A node was considered metastatically involved if it measured greater than 1.5 cm in diameter. Positive nodes were found at surgical staging in 3 of 32 patients with CT-negative scans and in all patients with CT-positive scans. Thus, for the 46 patients with determinate scans, sensitivity was 82%, specificity was 100%, and accuracy (true positive and true negative) was 93%. The high accuracy of CT in these patients suggests that mediastinoscopy is not necessary before thoracotomy in the patient with a CT-negative scan, but that for the patient with a CT-positive or CT-indeterminate scan, the indications for mediastinoscopy remain the same.

Adenocarcinoma↗
PubMed1983

Nuclear magnetic resonance imaging.

Nuclear magnetic resonance imaging has reached the point at which it is clear that such images will have a definite role in clinical practice. This article reviews the basic physical principles of nuclear magnetic resonance imaging, its current uses in disorders of the central nervous system, and its potential future applications in this field. The technique is also compared with computed tomography and positron emission tomography. Because nuclear magnetic resonance imaging is still in its infancy and its potential is great, definitive statements on present clinical use are difficult. Continual change and expansion of the role of nuclear magnetic resonance imaging in clinical practice in the next few years should be the rule.

Brain Neoplasms↗
PubMed1982

Cystic neoplasms of the pancreas: CT and sonography.

Cystic neoplasms of the pancreas are pathologically divided into macrocystic adenomas and microcystic adenomas, the former are considered a premalignant lesion and the latter without malignant potential. Five cases of cystic neoplasms are presented and the sonographic and/or computed tomographic features of microcystic and macrocystic adenoma are compared. A specific diagnosis can at times be suggested based on the computed tomography and sonography findings. In the proper clinical setting microcystic adenoma should be considered in the differential diagnosis of a pancreatic mass seen on sonography and computed tomography. Preoperative biopsy with appropriate pathologic staining can be performed and aid in directing appropriate therapy.

Adenocarcinoma↗
PubMed1981

Computed tomography of gastric neoplasms.

The authors analyzed the clinical and CT findings in 100 normal subjects and 31 patients with gastric disease to determine the significance of thickening of the gastric wall. Ninety per cent of the normal individuals had a wall thickness less than 1 cm with adequate distension of the lumen. Twenty-nine of the 31 patients with gastric disease (94%) had a wall thickness greater than 1 cm. Adenocarcinoma and lymphoma could not be reliably distinguished based solely on the pattern of gastric wall involvement, although most lymphomas had a lobular luminal contour while advanced adenocarcinomas had flattened inner margins. All 4 leiomyosarcomas were seen as large extragastric masses, and some had calcification or central necrosis. CT was helpful in assessing metastatic spread in 25 patients. While it could not distinguish between neoplastic and inflammatory disease or among histological types of tumor, it was a sensitive detector of gastric disease.

Adenocarcinoma↗
PubMed1978

Computed tomography of the adrenal gland.

Computed tomography (CT) easily and accurately demonstrates both the normal and abnormal adrenal gland. The normal adrenal gland can be seen in almost 95% of patients. With this technique, 29 of 29 proved adrenal masses were demonstrated; one case of bilateral adrenal hyperplasia could not be recognized, another showed equivocal enlargement. CT is an excellent screening and often definitive radiologic test of evaluating the adrenal gland.

Adrenal Gland Diseases↗
PubMedDate not supplied

Prolonged hepatic enhancement on computed tomography in a case of hepatic lymphoma.

Hepatic lymphoma is often very difficult to detect using any modality. A case of hepatic lymphoma appeared on rapid contrast infused CT as extremely prolonged and bizarre enhancement. The specific features included a widespread and aggressive appearance with a variable pattern of contrast enhancement. There was one localized area of apparent centripetal accumulation of contrast medium. The prolonged and irregular enhancement may be due to contrast medium "trapping" in interstitial spaces or even to the fact that a bolus technique was used.

Aged↗
PubMedDate not supplied

MR imaging of rhabdomyolysis.

The use of magnetic resonance (MR) imaging in two cases of rhabdomyolysis, one resulting from prolonged muscle compression and one from electrical burns, is described. The involved muscles were clearly demonstrated with MR. Recognition and assessment of the extent of rhabdomyolysis are important since life-threatening sequelae including severe metabolic disorders are possible. In one case, spin-echo and inversion-recovery MR imaging provided greater detail of muscle abnormalities than did 99mTc-pyrophosphate radionuclide scanning. Both cases illustrate the usefulness of MR in evaluation of skeletal muscle disorders.

Adult↗
PubMedDate not supplied

Design modification of dedicated MR breast coil.

We recently reported on a dedicated MR receiver coil for simultaneous breast imaging. We here describe a new design that has increased sensitivity and signal-to-noise ratio and has decreased the spatial variation of reception sensitivity seen with the original design. This breast coil is compatible with a 0.15 T resistive magnet utilizing separate transmit and receive coils and works as a plug-in replacement for the standard receiver coil. As with the original, the modified breast coil uses a triple coil structure. A central coil situated between the breasts consists of an inner loop in vertical plane and two outer loops facing outward at 45 degrees from horizontal. Two outer coils are situated lateral to each breast and consist of an outer loop in vertical plane and an inner loop facing inward at 65 degrees from horizontal plane. A two-chambered clear plastic box supports the coils and allows for accurate patient positioning. The modified coil is insensitive to heart and lung movement, eliminating motion artifacts produced by these organs, and further increasing image quality and resolution.

Breast↗
PubMedDate not supplied

Unusual presentation of cholelithiasis on T1-weighted MR imaging.

Cholelithiasis usually appears on magnetic resonance as a signal void contrasting with the high signal of surrounding bile. We describe the appearance of two intraluminal gallstones as high-signal areas on a heavily T1-weighted scan and, based on infrared spectroscopic analysis of the stones, believe the fatty-acid content of the stones accounts for this unusual result. Increased focal intraluminal signal on strongly T1-weighted sequences does not, therefore, preclude a diagnosis of cholelithiasis.

Aged↗
PubMedDate not supplied

MR imaging of anterior cruciate ligament repair.

Magnetic resonance (MR) imaging is an accurate means of analyzing disruptions of the native anterior cruciate ligament (ACL). Various techniques may be used to repair a disrupted ACL. A common repair is the MacIntosh lateral-substitution over-the-top repair in which a strip of fascia lata from the iliotibial band is used as a "neoligament." The results of 27 MR examinations of 17 athletes with this repair were analyzed to determine the appearance of the neoligament on MR. Thirteen of the 17 patients had returned to full athletic activity and four were capable of strenuous activity. Examinations were made at both 0.5 and 1.5 T in varied extents of external rotation from 0 to 20 degrees, and at variable time intervals after surgery from 1 to nearly 40 months. Only two patients clinically required postrepair arthroscopy, but both had normal repairs. Neoligaments were classified as well-defined (n = 6 studies), ill-defined (n = 10), and not discernible (n = 11), based on clarity of appearance. Reasons for this variable appearance include the variable presence of fibrous and fatty tissue investing the neoligament. We conclude that the normal neoligament, unlike the normal active ACL, has a variable appearance, including nonvisualization on MR and that criteria used in evaluating the native ligament will be inadequate to assess the repair.

Adolescent↗
PubMedDate not supplied

MR appearance of sternal hyperostosis.

Sternal hyperostosis is characterized by prominent new bone formation and fibrosis with less pronounced areas of granulation tissue and round cell infiltration. In previously reported cases the process involved not only the sternum but adjacent bony areas as well. Depending upon the extent of disease, acquiring biopsy material for histologic analysis can be difficult. We report a case of sternal hyperostosis involving the sternum exclusively and extensively. Magnetic resonance imaging was useful in directing biopsy for optimal histologic yield. This unusual case of sternal hyperostosis is believed to be the result of an inflammatory process.

Adult↗
PubMedDate not supplied

NMR: state of the art in medical imaging.

The future of NMR imaging in medicine seems bright. Absence of known biologic hazard, lack of moving parts, and ability to measure multiple tissue parameters should make it the study of choice in many clinical situations, while its ability to create detailed tomographic images in any plane, with both anatomic detail and tissue specificity, should revolutionize diagnostic radiology. The additional information gained about metabolic processes in vivo may well change our entire understanding of health and disease.

Magnetic Resonance Spectroscopy↗