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Biomedical subjects

D Tscholakoff

Publications and source records attributed to D Tscholakoff.

At least 55 records · Page 3Linked to original sources
PubMed1989

Course of cerebral lesions in a patient with periarteritis nodosa studied by magnetic resonance imaging.

The course is reported of a patient with periarteritis nodosa who initially presented with neurological symptoms. Multiple cerebral lesions were documented by the first magnetic resonance imaging (MRI) investigation. The majority of these had disappeared completely in the follow-up MRI studies. In contrast to neurological improvement the patient eventually died due to multiorgan failure. Postmortem histological examination revealed no pathological findings in the brain except one single necrotic area already known from MRI. Remissions of histological and angiographic alterations in periarteritis nodosa have been described as "local healing" leading to fibrosis and scarring. Our findings suggest that restitutio ad integrum may occur, at least in cerebral lesions.

Adult↗
PubMed1989

Sonography of unusual extratesticular lesions.

Sonograms of seven patients with extratesticular lesions are presented because of their relatively rare occurrence or unusual sonographic pattern. The sonographic appearance of a malignant extratesticular liposarcoma is described. Infected sebaceous glands and slow-growing malignant tumors of the spermatic cord are demonstrated as possible problems in differential diagnosis. Extratesticular septated cysts or fluid collections surrounding the spermatic cord are documented as complications in hemophilia and acute pancreatitis. These entities are presented because of their differential diagnostic challenge compared with more common disorders such as infected hydroceles and hernias.

Adult↗
PubMed1989

[Hepatic and splenic abscesses in immunosuppressed patients].

Morphologic characteristics of hepatosplenic abscesses using ultrasound and CT examinations in 13 immunosuppressed patients are presented. Additionally, the results of diagnostic ultrasound and CT guided biopsy procedures (n = 13) are reported. On sonograms, bacterial abscesses were exclusively hypoechoic lesions whereas patients with mycotic abscesses showed additionally target lesions and lesions presenting a "wheels-within-wheels" appearance. Thus, with some limitations, us might help to differentiate between fungal and bacterial abscesses. On CT, all patients presented uniformly with hypodense lesions. Follow-up ultrasound studies showed these abscesses over periods as long as 24 months; biopsy proved some of these as fibrotic lesions without vital bacteria or fungi.

Abscess↗
PubMed1989

Invasive pulmonary aspergillosis: evaluation with MR imaging.

Eleven patients with suspected invasive pulmonary aspergillosis underwent magnetic resonance (MR) imaging. Images were obtained with standard spin-echo sequences and electrocardiographic triggering before and after intravenous administration of gadolinium diethylenetriaminepentaacetic acid. Thirty-seven of 48 lesions seen on MR images were nodular infiltrates; 34 of these had a targetlike appearance, with hypointense centers and iso- or hyperintense rims. Twenty-three of 37 nodular lesions contained areas of hyperintensity on T1-weighted images. All 37 had enhanced rims on postcontrast MR images. The remaining 11 lesions were segmental infiltrates, seven of which were predominantly hyperintense on T1-weighted images. In one patient with nodular lesions, MR imaging findings were correlated with those from pathologic analysis of a resected upper lobe. Areas of hyperintensity corresponded to subacute hemorrhage permeated by Aspergillus organisms. The authors believe that the typical targetlike appearance of nodular lesions on MR images and the potential that MR imaging has to reveal hemorrhagic content will prove useful in the early diagnosis of invasive pulmonary aspergillosis.

Aspergillosis↗
PubMed1989

Optimal needle size for renal biopsy: in vitro and in vivo evaluation.

To evaluate the success and complication rates of small (16- and 18- gauge) needles in biopsy of the kidney, the authors performed in vitro biopsy in a cadaveric kidney and in vivo renal biopsy in 141 patients. Best results were obtained with a 16-gauge modified Menghini needle. In vitro, 9.7 +/- 5.7 (mean +/- standard deviation) glomeruli were retrieved, and the average length of tissue cores was 17.8 mm +/- 8.2. In vivo, 10.63 +/- 6.64 intact glomeruli were retrieved, and a definitive histologic diagnosis was achieved in 86% of patients. The frequency of major complications with this needle was 3.5%, and of minor complications, 5.8%. No major complications occurred after biopsy was performed with 18-gauge needles of the same design. However, the retrieval rate of glomeruli with these smaller needles was insufficient. An 18-gauge needle with two cutting edges yielded tissue cores of 11.0 mm +/- 3.5 in length. In vitro, 6.6 +/- 2.3 glomeruli were retrieved; in vivo, 9.92 +/- 6.65. A definitive histologic diagnosis was achieved with this needle in 75% of patients, and rates of 7.1% for major complications and 10.7% for minor complications were encountered.

Adult↗
PubMed1988

[Magnetic resonance tomography as a localization method in hyperparathyroidism].

Magnetic Resonance Imaging (MRT) was performed in 36 consecutive patients with hyperparathyroidism. MR tomograms of 31 patients were evaluated and compared with the results of operation and histology (n = 29). In the remaining 5 patients MR examination was not completed, due to claustrophobia or motion artefacts. MR examinations were performed in 2 superconductive magnets (0.5 and 1.5 Tesla). A surface coil with following spinecho sequences was used: SE: TR/TE: 550-700/15-30; 2000/22-100. All patients were subjected to additional sonography. Out of 28 parathyroid adenomas 25 were identified on MR tomograms (sensitivity: 73%, specificity: 90%). However, only 2 out of 6 hyperplastic parathyroid glands were localized on MR tomograms. Lesions missed on MR tomograms measured 15 mm and less in diameter. It is characteristic that parathyroid adenomas showed isointense MR signal to the thyroid (SE 550/30 and hyperintense MR signal to fat (SE 2000/100). Different signal intensities of the adenomas were observed in 25% of the cases. MR imaging is a valuable diagnostic method for preoperative localisation of parathyroid adenomas. We think that MR imaging should be performed when sonography and subtraction scintigraphy are not able to identify a suspected adenoma in the same location.

Adenoma↗
PubMed1988

[Ultrasound in terminal renal failure--etiologic conclusions?].

Using standard real time sonography, renal cortical echogenicity, renal length, intrarenal cystic structures and renal calculi were evaluated in 63 patients (30 men, 33 women) in end-stage renal parenchymal diseases (glomerulonephritis n = 21, diabetic glomerulosclerosis n = 9, analgesic nephropathy n = 14, chronic atrophic pyelonephritis n = 19). Patients with glomerulonephritis and diabetic glomerulosclerosis presented with larger kidneys and only slightly increased cortical echogenicity as compared to analgesic nephropathy and chronic atrophic pyelonephritis. In addition, intrarenal cystic structures were found in 50% of the patients with analgesic nephropathy and in 31% of the patients with pyelonephritis, compared with only 14% and 11% in patients with glomerulonephritis and diabetic glomerulosclerosis, respectively. Intrarenal calcifications were more frequent in pyelonephritis and analgesic nephropathy. In end-stage renal parenchymal disease, sonography might be able to distinguish between different types of renal medical disorders.

Adult↗
PubMed1988

[Diagnostic imaging of hemangiopericytomas].

Eight patients with histologically verified hemangiopericytomas were examined by conventional radiographic techniques (plain films, angiography including cavography) as well as by duplex sonography, CT and MRI. These imaging techniques detected solid tumors with cystic compartments. A typical computed tomographic finding was intensive contrast enhancement within the tumor. Duplex sonography revealed blood flow in the periphery of the tumor. In contrast to reports by other authors no tumor calcification was found by plain film radiography.

Abdominal Neoplasms↗
PubMed1988

Magnetic resonance imaging of the lower vertebral column in patients with multiple myeloma.

Eighteen patients with multiple myeloma (clinical stages 1-3) and a control group of 21 persons underwent magnetic resonance imaging (MRI) studies of the lower thoracic and lumbar spine. This was done to determine the potential benefit of MRI in addition to conventional radiographs, tomograms, computed tomography and nuclear scans. In addition to focal fatty replacement of normal hematopoietic marrow, which presented as focal hyperintense lesions on T1-weighted images (T1-WI) and on T2-weighted images (T2-WI), two types of myelomatous lesions were found: (1) focal areas with reduced signal intensity when compared with normal bone marrow on T1-WI and enhanced signal intensity on T2-WI, mainly found in untreated myelomas; and (2) focal areas of decreased signal intensity on T1-WI and on T2-WI, which were predominantly detected after previous radiation therapy. MRI surpassed conventional radiography in detecting abnormal focal marrow infiltration in 41 of 247 vertebrae. Radiographs identified only 11 of the 41 as pathologic, based on shape and structure of the vertebral bodies; however, 15 other collapsed vertebrae showed no signal abnormalities of the marrow on MR images. Discrimination of normals and abnormals by statistical analysis of intensity measurements of the bone marrow was not possible.

Adult↗
PubMed1987

Magnetic resonance imaging of the spine in multiple myeloma.

The lower thoracic and lumbar spine of patients with multiple myeloma was examined by magnetic resonance imaging (MRI), plain radiography, and bone scintigraphy. Three independent investigators evaluated the power of these diagnostic methods to detect bone lesions in 192 vertebrae from 18 patients and in 60 vertebrae from 7 controls. 41 foci with abnormal signal intensity were detected by MRI; X-ray films showed osteolytic lesions in 4 vertebral bodies; and bone scanning was positive in 2 cases. The superiority of MRI in detecting myeloma-associated focal bone lesions was statistically significant, and in one case the lesions were confirmed at necropsy. Deviations in shape and height of vertebral bodies were slightly more easily visible on radiographs. Early detection of imminent medullary compressions in 2 patients led to successful radiotherapy before symptoms appeared.

Adult↗
PubMed1987

Proton NMR spectroscopy in canine myocardial infarction.

Proton NMR spectroscopy was used to study the relationship between proton relaxation times and other resonances in the proton spectra, such as lipids, creatine, and choline/carnitine in subacute (8-day-old) myocardial infarctions. Eight mongrel dogs received operative ligation of the left anterior descending coronary artery (four were permanently occluded, four were occluded for 1 h and reperfused) and were sacrificed 8 days later so that tissue samples could be prepared for NMR spectroscopy. The results of this study indicate that (for the core of infarcted tissue) the lipids do not contribute directly to the increased bulk relaxation times associated with myocardial infarction and that the lipid peaks (2.3, 1.2, 0.8 ppm) and creatine peak (3.0 ppm) are more specific to the kind of infarct than to the relaxation times. Therefore, analysis of the proton spectrum of myocardial tissue may serve as a method for tissue characterization.

Animals↗
PubMed1987

[Magnetic resonance tomography of the heart. Experimental study of a non-invasive characterization of myocardial tissue].

In this experimental study (canine heart) a variety of pathologic conditions of the myocardium were studied using ECG-triggered magnetic resonance imaging (MRI). The purpose of this study was to examine the MR appearance and the T2 relaxation times of occlusive and reperfused myocardial infarcts, of hypertrophic cardiomyopathy, and of cardiac transplants with and without acute cardiac allograft rejection. MR images were correlated with the results of histology and tissue water content. MRI identified normal myocardium with T2 values of 38 (+/- 4.3) msec. Myocardial infarcts and acute allograft rejection had significant (p less than 0.05) longer T2 values compared to normal myocardium. On the basis of T2 relaxation times no further differentiation among different pathologic entities was possible. Therefore, it is necessary to include morphologic criteria such as myocardial wall thickness, cardiac chamber size and intracavitary blood flow signal in the interpretation of cardiac MR tomograms.

Animals↗
PubMed1987

Measurement of canine left ventricular mass by using MR imaging.

This study assessed the capability of ECG-gated MR imaging for quantitating left ventricular mass by means of signal intensity-based and geometric methods for measuring left ventricular mass of normal dogs and dogs with left ventricular hypertrophy. Mass was measured on transverse images encompassing the left ventricle during both diastole and late systole. Partial-volume errors were minimized by measuring the length of the left ventricle on a sagittal image and weighting the mass of end slices accordingly. The range of postmortem left ventricular mass was 61-100 g. The linear relationship between postmortem left ventricular mass and mass measured via MR images correlated closely when MR imaging measurements were done at either end diastole (r = .94) or late systole (r = .94). The standard errors of the estimate were 13.7 and 14.7 g for images gated to end diastole and late systole, respectively. Inter- and intraobserver reproducibility showed excellent agreement (r = .93 and r = .89 for end diastole and r = .99 and r = .93 for late systole, respectively). Thus, left ventricular mass can be quantified accurately and reproducibly over a wide range of masses by using ECG-gated MR imaging.

Animals↗
PubMed1987

MR imaging in the diagnosis of pancreatic disease.

MR imaging examinations of 20 patients with normal pancreas and of 38 patients with suspected pancreatic disease were analyzed retrospectively to evaluate the ability of MR imaging to depict the normal and abnormal pancreas, establish MR criteria for various pancreatic diseases, determine if MR imaging can distinguish among various pancreatic diseases, and compare the usefulness of MR imaging with CT. In all 20 patients with normal pancreas and in 34 of the 38 patients with suspected pancreatic disease excellent or good evaluation of the pancreas was achieved. A 0.35-T magnet (Diasonics MT/S) was used, and both T1- and T2-weighted images were needed. T1 and T2 relaxation times and MR signal intensities showed no specific pattern to allow consistent differentiation between normal and diseased pancreatic tissue or to distinguish between tumor and inflammation. In the 29 patients in whom MR and CT images could be compared, MR imaging and CT provided equivalent information in 20 (69%). In 4 patients (14%), MR imaging added information, and in 5 patients (17%) of cases, MR imaging yielded less information than CT. MR imaging of the pancreas was found to be superior to CT in selected instances, such as in the staging of pancreatic neoplasms (n = 4) and in the evaluation of pancreatic disease after surgery (n = 3). We conclude that, at present, MR imaging should not be used as the screening method for pancreatic disease but should be reserved as an adjunct when the information provided by CT is insufficient.

Adenocarcinoma↗
PubMed1987

Measurement of myocardial infarct size at early and late time intervals using MR imaging: an experimental study in dogs.

The current study assessed the capability of ECG-gated MR imaging to quantitate both the percentage of the left ventricle involved by acute myocardial infarction and the mass of acute myocardial infarction at 3 and 21 days after coronary occlusion in dogs. Infarct mass was measured from gated transverse MR images using computer-generated calculated-T2 images. T2 images provided accentuation of the boundary between infarcted and normal myocardium as well as objective, reproducible calculation of image voxels representing infarcted myocardium. Postmortem and in vivo MR infarct mass and percentage correlated closely at 3 days (r = .98, SEE = 0.73 g; r = .97, SEE = 1.2%), and 21 days (r = .94, SEE = 1.54 g; r = .95, SEE = 1.61%). Left ventricular mass, infarct mass, and percentage of infarct were measured on end-diastolic MR images. Infarct mass at 3 and 21 days was not significantly different, with a mean deviation of 0.63 g. There was close intra- and interobserver reproducibility (r = .99 and r = .90, respectively) for measurement of infarct mass. The quantitative technique employed for determining the mass of acute myocardial infarctions, based on the different T2 relaxation times of infarcted and normal myocardium, provides for objective analysis and reproducibility. With this technique, MR provides an accurate method for assessing the mass of acute infarcts and the percentage of the left ventricle involved by the infarct both early and late after coronary occlusion.

Animals↗
PubMed1987

[Occult and clinically suspected testicular tumor. Assessment using real-time sonography].

The diagnostic value of real-time-sonography was evaluated in 62 patients with suspected and occult testicular tumors. In 28 patients intratesticular tumors were identified on real-time-sonograms. In addition 7 clinically occult tumors were diagnosed by real-time-sonography. It was not possible to differentiate between orchitis and tumors on sonograms (3 cases). There was correlation only between the morphologic appearance of tumors on sonograms and the corresponding histology. Using high frequency transducers sonography proved to be an useful diagnostic modality to identify or to rule out occult intratesticular tumors.

Diagnosis, Differential↗
PubMed1987

[Sonography of the scrotal contents].

In 394 patients with various urological symptoms, the content of the scrotum was examined sonographically. 71 testicular lesions were found, 194 extratesticular pathologies were diagnosed. In 69% the enlargement of the testicle was due to a tumor, in 4 patients due to acute orchitis and in 3 patients due to acute torsion. An unilateral smaller sized testicle was found in chronic inflammation [5], cryptorchism [9], hypoplastic testicle [2] and after corticoid medication [1] and radiation therapy [1]. In normal sized testicles 8 tumors, 19 fibromas of the tunica albuginea, 2 scars after trauma and 1 haematoma were found sonographically. In 91% of patients with epididymitis the epididymis was enlarged. The echo structure was altered in 74%, in 13% abscesses were found. Sonography was useful in evaluation of scrotal herniation, especially when combined with hydroceles. Varicoceles were better detected and graduated by sonography than by clinical examination.

Genital Diseases, Male↗