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Biomedical subjects

B Krug

Publications and source records attributed to B Krug.

At least 55 records · Page 3Linked to original sources
PubMed1998

[Magnetic resonance sialography. A new diagnostic method for imaging salivary duct patency].

The new technique of non-invasive magnetic resonance (MR) sialography was evaluated for normal and various pathologic conditions of the parotid gland. Ten volunteers and 15 patients with various symptomatic diseases of the parotid gland were tested in the present study. Diseases included pleomorphic adenoma, cystadenolymphoma, carcinoma ex pleomorphic adenoma, ductal carcinoma, adenoid cystic carcinoma, lymphoepithelial carcinoma, non-Hodgkin's lymphoma, sialolithiasis, sialadenitis, Heerfordt's syndrome and congenital duct ectasies. In addition to the usually performed T1 and T2 cross-sectional sequences a heavily weighted T2 sequence (TR 3600, TE 800) was performed and allowed depiction of a fluid-filled parotid duct. Results showed that the main parotid and primary branching ducts were depicted reliably in all normal cases and all patients, except one with sicca syndrome. Pathological conditions such as duct dilatations, duct strictures, obstructing duct calculus and irregular shapes and courses of the ductal system were demonstrable. While X-ray sialography obtained a higher resolution, only MR sialography was able to depict dilated ducts proximal from a complete obstruction, as well as all ductal cysts. Our findings show that MR sialography can be applied successfully to investigations of the parotid gland system. There have been no contraindications or complications to date because MR sialography is non-invasive. The technique will also allow the salivary ducts and lesions to be differentiated from the course of the facial nerve.

Constriction, Pathologic↗
PubMed1998

Highly sensitive DNA typing for detecting tumors transmitted by transplantation.

DNA typing of a variable number of tandem repeats (VNTRs) and of short tandem repeats (STRs) is a modern forensic method for the identification of biological material. In many cases, amplification by the polymerase chain reaction (PCR), especially of STRs, allows DNA typing of minute amounts of or degraded DNA. Here we describe the successful use of forensic DNA typing to clarify the origin of a malignant tumor. We report two cases of metastatic malignant melanoma of unknown origin that developed a few months after transplantation in two recipients of kidneys from the same donor. Fresh metastatic tissue and blood from the first recipient, reference DNA of the donor, and only paraffin-embedded tissue from the second recipient were available for analysis. To investigate whether the melanoma originated in the donor, DNA analysis of nine polymorphic loci was performed. The results of the analysis showed that, in both cases, the tumors were genetically different from the recipient DNA but matched the donor DNA. One incident of allele loss was attributed to a mutation event. We conclude that the metastatic melanoma in both recipients originated in the donor and was transmitted by renal transplantation.

Adult↗
PubMed1998

[Digital selenium radiography: a comparison of the picture quality of thoracic images in normal and reduced image formats based on the structural anatomical details].

PURPOSE: Is there a loss of information when using selenium radiographic images displayed with reduced image format compared to full format? METHOD: Digital selenium radiographic chest images in two planes were obtained in 35 patients for medical reasons. The digital data sets of each patient were separately displayed in full format on two different films and were printed in reduced format on one film. The format was reduced to 61% of the full format using an acquisition matrix of 2166 x 2488 pixels, an image display matrix of 4000 x 5000 pixels and a film format of 43 x 49 cm. All images were anonymously evaluated by four independent readers using a questionnaire concerning anatomic structures. RESULTS: Format reduction did not result in a loss of information in diagnostically relevant anatomic details. CONCLUSIONS: Displaying digital selenium radiographic data sets of thoracic view in two planes on one film presumably does not lead to a loss of diagnostic information. This procedure may help to reduce film costs.

Adult↗
PubMed1998

[Correlation of MRI and histopathological findings in inflammatory skin diseases].

PURPOSE: Can spatial and contrast resolution be achieved with currently available MR devices for the successful assessment of inflammatory diseases of the skin? METHOD: High resolution MRI was performed in 20 patients with non-malignant diseases of the dermis and subcutis. The skin biopsies subsequent to the MR examinations were indicated for clinical reasons. The MR examinations were done in the location of later performed skin biopsies using a 1.0 Tesla system (Gyroscan T10 NT, Philips, Best, the Netherlands) and a surface coil of 7.5 cm inner diameter. Conventional spin-echo (SE-Sequenz)- and gradient-echo (GRE)-sequences were optimised to obtain maximum spatial resolution with a sufficient signal-to-noise ratio within a tolerable examination time. MR visualisation of histopathology was assessed by four readers using a questionnaire. RESULTS: In 15 of 20 cases, high resolution MRI allowed a correct classification of the visualised dermal and subcutaneous patterns, in accordance with the histological work-up of the corresponding specimen. Due to the still only suboptimal spatial and contrast resolution the structure of the epidermis could not be assessed adequately. Determination of contrast enhancement or non-enhancement after administration of intravenous contrast agent provided information on the degree of tissue perfusion in 19 patients, which complemented the morphological assessment. CONCLUSION: High resolution MRI allows to identify non-invasively histological main patterns of inflammatory skin diseases. However, final diagnosis often depends on higher microscopic resolution and special staining.

Adolescent↗
PubMed1998

[Endorectal MRI and ultrasonography in rectal tumors: correlation with histological staging].

PURPOSE: To compare the accuracy of high resolution endorectal magnetic resonance imaging (EMRI) and endorectal ultrasound (EUS) in the preoperative diagnostic of rectal tumours. PATIENTS AND METHODS: Twenty-one patients with known rectal tumours underwent MR imaging with an endorectal surface coil and EUS. Transversal EMR images were obtained using fast T2-weighted sequences and pre- and postcontrast T1-weighted images. EUS was performed using a 7.0 MHz transducer. Results of both methods were compared with specimens from the resected tumours. RESULTS: Rectal wall layers were reliably demonstrated with both methods in all patients. EMRI and EUS determined the depth of rectal wall invasion. EMRI and EUS agreed with pathologic findings in 16/21 cases, respectively. In one case each, both methods understaged one tumour. EMRI overstaged an adenoma as a T2-tumour. In three and four patients, respectively, no staging was possible due to technical problems. CONCLUSION: EMRI and EUS show comparable results in the preoperative T-staging of rectal tumours. Both techniques are not suitable for differentiating benign from malignant lymph nodes accurately. While EMRI is expensive and technically demanding, it allows an objective documentation of pathological findings which is less dependent on the examiner. Two important clinical conclusions can be drawn from the good results of T-staging: Adenomas and T1-tumours can be treated by local excision. In patients with advanced tumours (T3/T4) a neoadjuvant therapy can be initiated.

Adenoma↗
PubMed1998

High-resolution MR imaging of the cutis and subcutis. Histological correlation.

OBJECTIVE: To determine whether the spatial resolution that can be achieved with currently available MR devices is adequate for the evaluation of skin disease. MATERIAL AND METHODS: We correlated high-resolution MR images of the skin with dermatohistopathology in 26 patients. The examinations were carried out on a 1.0 T imager using a commercially available surface coil (ID 7.5 cm) and optimized SE and GE sequences. Image quality was assessed by four readers on a questionnaire. RESULTS: The visualization of the dermis, subcutaneous tissue, and muscle fascia allowed a pattern analysis that gave findings identical to those at dermatohistopathology. It was possible to distinguish septal from lobular panniculitis, and lipatrophia from sclerodermia. Images with contrast media infusion were useful in the differential diagnosis. CONCLUSION: High-resolution MR imaging may narrow down the differential diagnosis of various skin diseases and may help to reduce the number of skin biopsies on certain indications.

Adolescent↗
PubMed1997

[Effectiveness of preoperative diagnosis in scintigraphically cold thyroid nodule].

PURPOSE: To compare the diagnostic efficacy of different imaging procedures carried out in patients with scintigraphically cold thyroid nodules. METHODS: The preoperative imaging procedures carried out in all patients operated on for cold thyroid lesions at the Department of Surgery of the University of Cologne were recorded in prospective manner for 1 year. Special attention was paid to the difference between in-patient and out-patient management. Diagnostic accuracy was assessed by comparison with the intraoperative findings and histology. RESULTS: The combination of ultrasonography and fine needle aspiration cytology proved effective. Computed tomography should be reserved for the preoperative assessment of large thyroid tumors. Repeat examinations seldom gave additional information. CONCLUSION: Standardized preoperative investigations may be performed on an out-patient basis, provided attention is paid to quality assurance.

Adolescent↗
PubMed1997

Late results after resection of benign hepatic tumors: clinical and radiological findings.

The purpose of our work was to provide data on the recurrence of resected benign hepatic lesions and to evaluate the value of follow-up examinations in this group of patients. From August to October 1993, 75 patients who had been admitted for liver surgery for benign tumors between 1975 and 1993 were controlled by physical examinations, serological tests, US, and, in the case of equivocal US findings, by CT. The histological diagnoses of the operative specimen included hydatidosis in 43 patients, focal nodular hyperplasia (FNH) in 12 patients, liver cell adenoma in 8 patients, cavernous hemangioma in 8 patients, and congenital cyst in 4 patients. Hepatic scars were observed in 36 of the 75 patients. Four cases of intrahepatic recurrence and 1 case of intraperitoneal spread were observed in the 42 patients with recent hydatosis. Long-term postoperative controls (specific serological tests, US) are necessary in the management of patients with hydatid disease. Follow-up examinations are not indicated in asymptomatic patients who have been operated on for FNH, hemangioma, or congenital cysts.

Adult↗
PubMed1997

[Can digital selenium-based radiography in thoracic diagnosis replace the analog x-ray imaging technic?].

PURPOSE: To find out the diagnostic value of digital selenium radiography, we compared the image quality of chest x-ray images from 50 patients who had been examined via conventional chest x-ray and digital selenium radiography of the chest. METHOD: 50 patients with a malignant melanoma underwent chest x-ray within 3 months in conventional technique and with digital selenium radiography (Thoravision: Philips Medical Systems, Hamburg, Germany). In this period none of the patients showed a difference in respect of clinical status or radiological diagnosis. Simultaneous examinations on the same day were not performed to avoid unnecessary exposure to x-rays. The digital and conventional images were compared by 4 radiologists with regard to image quality by the detection of defined anatomic structures. RESULTS: Image quality of digital selenium radiography was considered superior to that of conventional chest x-rays in the mediastinum, the retrocardiac and retrodiaphragmatic areas, the superior and inferior lobes of the lung especially near the parietal pleura, and the chest wall. CONCLUSIONS: Compared to analogous techniques there is no loss of image information when employing digital selenium radiography in chest x-rays. On the contrary, new assessment criteria may be gained. We conclude that digital selenium radiography offers diagnostic advantages in chest x-ray examination.

Adult↗
PubMed1997

[Diagnostic value of digital projection radiography in comparison with conventional roentgen technique].

Digital projection radiography provides digital data in x-ray examinations, which used to be carried out by examinations screen-film system combinations. The technological basis and clinical performances of digital luminescent radiography (DLR) and digital radiography are reviewed. Digital projection radiography does not allow to reduce selenium exposure significantly, compared to screen-film system combinations. Digital luminescent radiography can be used for the entire spectrum of analogous projection radiography the only exception being extremely subtile structural changes. The clinical experiences with digital selenium radiography achieved so far in chest x-rays are promising and the technique is expected to be increasing used in other anatomic regions as well.

Humans↗
PubMed1997

Surgical therapy of malignant thymoma.

OBJECTIVE: To give a modern concept for treating tumours of the thymic gland. EXPERIMENTAL DESIGN: Retrospective analysis of all patients treated for thymic disease in the last 6 years with a mean follow-up of 22.3 months (range: 3-71 months). SETTING: All patients were admitted to the Department of Surgery of the University of Cologne with an average hospitalisation period of 14 days. Patients with myasthenia gravis were transferred to the intensive care unit postoperatively. PATIENTS: A total of 34 patients were treated by radical thymectomy. All patients had a routine chest roentgenogram and a computed tomography. In 13 patients a malignant tumour of the thymic gland was diagnosed. In 6 patients the main symptom was myasthenia gravis. INTERVENTIONS: All tumours were successfully resected by an upper median sternotomy which was extended through a Kocher incision (n = 2) or a complete sternotomy (n = 3). In one patient the tumour was unresectable. RESULTS: In four patients histological examination showed a thymic carcinoma and in 9 patients an invasive thymoma. Four patients died during follow-up period. Stage II to IV thymoma should receive postoperative radiotherapy and an additionally chemotherapy in stage IV. Cumulative survival rate for a five years follow-up independent of the tumour stage was 46%. CONCLUSIONS: Malignant tumours of the thymic gland are a rare entity and should be treated by radical resection of the tumour and the adjacent tissue. In stage II and III postoperative radiation can lower the risk of recurrence. In stage IV radiation should combined with chemotherapy. Long-term follow-up is mandatory.

Actuarial Analysis↗
PubMed1997

Yolk sac tumor of the anterior mediastinum: the role of palliative surgery.

Primary endodermal sinus tumor (yolk sac tumor) of the mediastinum is a very rare extragonadal germ-cell neoplasm. Most patients are young and male. Since initial description of the endodermal sinus tumor in 1959, this neoplasm has been found more and more frequently. alpha-Fetoprotein is an important tumor marker. The treatment consists of multimodal therapy. A combined approach with chemotherapy followed by surgical resection of residual tumor seems to be the optimal management of this tumor. Even a palliative surgical resection in advanced tumors is indicated. We describe the case of a patient with an advanced yolk sac tumor that was refractory to chemotherapy. This patient was treated by palliative surgical resection.

Adult↗
PubMed1996

[Postoperative follow-up in hepatic echinococcosis].

OBJECTIVE: To determine whether the monitoring of patients who have undergone surgical excision of hydatid cysts of the liver is useful. Furthermore, sonographic and computertomographic criteria of recurrent hydatid disease should be described. PATIENTS AND METHODS: Of 84 patients operated on for hepatic hydatid disease 42 (22 men, 20 women; mean age 44 [25-82] years) were examined between 6 months and 15 years post-operatively (median of 6 years) clinically, serologically (complement-fixation reaction, immunohaemagglutination) and by ultrasound. If the latter was positive, computed tomography was also performed. RESULTS: Recurrence of hydatid disease in the liver was diagnosed in three patients and in the peritoneal cavity in one patient. The demonstration of internal septa by solitary or multiple daughter cysts proved to be a reliable imaging criterion. CONCLUSION: Ultrasonography should be performed as a baseline test after surgical removal of hydatid cysts in the liver and specific antibody titres measured. This will make it easier to distinguish a recurrence from postoperative changes.

Adult↗
PubMed1996

Comparative study of rest technetium-99m sestamibi SPET and low-dose dobutamine stress echocardiography for the early assessment of myocardial viability after acute myocardial infarction: importance of the severity of the infarct-related stenosis.

Rest technetium-99m sestamibi single-photon emission tomography (SPET) has been shown to underestimate viability in some patients with chronic ischaemic myocardial dysfunction. The present study was designed to appraise the value of 99mTc-sestamibi as a viability tracer in patients with a recent myocardial infarction and to determine factors that might influence its accuracy in assessing infarct size. Therefore, rest 99mTc-sestamibi SPET, low-dose dobutamines stress echocardiography and quantitative coronary angiography were performed in 51 patients with a recent myocardial infarction. Perfusion activity and regional wall motion were scored semi-quantitatively using the same segmental division of the left ventricle. Assessment of 99mTc-sestamibi uptake as a marker of viability was performed by comparing a binary uptake score (viable=>50% vs necrotic =</=50% of the maximal tracer activity) with a binary wall motion classification during low-dose dobutamine infusion (viable=normal/hypokinetic vs necrotic=akinetic/dyskinetic). Infarct size, expressed as the number of segments with evidence of necrotic tissue, was significantly greater in the scintigraphic study than in the echocardiographic study (2.8+/-1.5 vs 2.2+/-1.3, P=0.006). This overestimation of infarct size by 99mTc-sestamibi was present only in patients with a severe infarct-related stenosis (% diameter stenosis >/=65%-100%) and particularly those with "late" reperfusion therapy (time delay >/=180 min). In patients without a severe infarct-related stenosis, 99mTc-sestamibi was able to accurately distinguish viable from necrotic segments. Thus, rest 99mTc-sestamibi scintigraphy early after acute myocardial infarction may underestimate residual viability within the infarct region, particularly in patients with low flow state coronary anatomy, as a result of a severe infarct-related stenosis and/or late reperfusion therapy.

Cardiotonic Agents↗
PubMed1996

Coronary flow reserve during coronary angioplasty in patients with a recent myocardial infarction: relation to stenosis and myocardial viability.

OBJECTIVES: In the present study, we examined post-stenotic coronary flow before and after percutaneous transluminal coronary angioplasty (PTCA) in patients with and without a recent myocardial infarction (MI) and related it to stenosis severity and residual viability. BACKGROUND: Post-stenotic coronary blood flow velocity reserve (CFVR) has been used with success to estimate functional stenosis severity in patients with stable angina. However, in patients with a recent MI, the impaired coronary vasodilator response of the reperfused myocardium may substantially alter the flow dynamics of the infarct-related artery. METHODS: Distal coronary flow velocities were recorded before and after PTCA in 36 patients at day 13 +/- 7 (mean +/- SD) after acute MI and in 38 patients without MI. The CFVR was assessed by the ratio of distal hyperemic to baseline average peak velocity, using a 0.014-in. Doppler guide wire. Stenosis severity was analyzed by quantitative coronary angiography, and infarct size was assessed scintigraphically. RESULTS: For similar angiographic stenosis severity, pre- and post-PTCA values of CFVR were significantly lower in patients with than without MI: 1.22 +/- 0.26 versus 1.50 +/- 0.45 before PTCA (p < 0.05) and 1.72 +/- 0.43 versus 2.21 +/- 0.74 after PTCA, respectively (p < 0.01). Although CFVR increased significantly (p < 0.0001) after angiographically successful PTCA in both study groups, abnormal CFVR (< or = 2.0) was still observed in 80% of patients with MI and in 44% of those without MI (MI vs. no MI, p = 0.001). Patients with an extensive infarction (relative infarct size > or = 50%) and those with a small infarction (relative infarct size < 50%) had comparable levels of post-PTCA CFVR (1.6 +/- 0.3 vs. 1.8 +/- 0.5, p = NS). Among a variety of factors, angiographic stenosis severity was the most important determinant of CFVR in both study groups. CONCLUSIONS: In patients with a recent MI, CFVR was significantly lower than in those without MI, both before and after PTCA. Besides the presence of this postreperfusion-related impairment of the coronary vasodilating response, CFVR was mainly influenced by stenosis severity and not by residual viability.

Adult↗
PubMed1996

[A prospective study to assess the need for requested radiological studies].

PURPOSE: What is the percentage of non-indicated examinations in the routine work of a radiologic university clinic? METHODS: From April 1st, 1994, to June 30th, 1994, all examinations carried out in the Radiology Department of the University Hospital of Cologne, Germany, were evaluated prospectively by the radiological medical staff using a questionnaire. The question was whether the examinations were medically indicated or not. Requests for examinations which were not carried out due to lacking indications were excluded from evaluation. The percentage of error was assessed by analysis of random samples assigned to the referring clinicians. RESULTS: 1400 (5.4%) of a total of 25718 examinations were considered by the radiological medical staff as "not indicated". A subsample analysis performed for validation gave an upper margin of a 95% confidence interval of about 13% for this rating. The percentage of non-indicated examinations was higher in conventional x-ray examinations and ultrasonography than in x-ray angiography, computed tomography and magnetic resonance tomography. Examinations during night time and weekend showed a higher percentage of lacking medical indications than examinations during daytime. CONCLUSIONS: Considering a university clinic concerned with educational work, the percentage of radiological examinations carried out without medical indication was tolerable. However, indications must be further improved by intensifying the communication with the referring clinicians and by elaborating a higher standard of radiological and clinical postgraduate training.

Diagnostic Tests, Routine↗
PubMed1996

Delineation of segmental liver anatomy. Comparison of ultrasonography, spiral CT and MR imaging for preoperative localization of focal liver lesions to specific hepatic segments.

PURPOSE: The purpose of this study was to determine the ability of noninvasive imaging methods to localize focal liver lesions to specific hepatic segments. MATERIAL AND METHODS: In a prospective study we evaluated 24 patients with hepatic masses with ultrasonography (US), spiral CT and MR imaging. RESULTS: The primary segmental location of the lesions was correct with US in 15 of 24 patients (63%), with CT in 21 of 24 patients (88%) and with MR imaging in 17 of 22 patients (77%). The full extent of the lesions was correctly described with US in 9 of 24 patients (38%), with CT in 16 of 24 patients (67%) and with MR in 12 of 22 patients (55%). CONCLUSION: Among the noninvasive imaging methods, CT provides the best information for determining the segmental location and planning the surgical approach to hepatic resections.

Contrast Media↗