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Biomedical subjects

G Layer

Publications and source records attributed to G Layer.

At least 37 records · Page 2Linked to original sources
PubMed1999

[Spiral CT of the head-neck area: the advantages of the early arterial phase in the detection of squamous-cell carcinomas].

PURPOSE: To determine if scanning in the arterial phase improves detection of squamous cell carcinomas in the pharynx and larynx. METHODS: In a prospective clinical study 20 patients with a pharyngeal or laryngeal carcinoma were examined with by spiral CT. 80 ml lopromid were intravenously injected as a bolus with a rate of 3 ml/sec. Two consecutive spiral CT scans were performed with start-delay times of 20 and 70 seconds respectively. Delineation and contrast enhancement of tumours, cervical lymph nodes and vessels were evaluated. The radiodensities (HU) of tumors, lymph nodes vessels, pharyngeal wall and muscle were measured. RESULTS: Comparing early and late start delay time scans tumor assessment in the early phase was better in 58%, less in 16% and equal in both scans in 26%. 82% of the pathologic lymph nodes had more peripheral enhancement than surrounding muscle tissue. During the arterial phase the measured radiodensities of the common carotid artery and jugular vein were significantly higher than in the second phase. CONCLUSION: Contrast-enhanced special CT permits accurate morphologic assessment (size, infiltration) of pharyngeal and supraglottic laryngeal squamous cell carcinoma, while pathologic lymph nodes already have a sufficient contrast enhancement for the detection.

Adult↗
PubMed1999

[MRT, CT and sonography in the preoperative assessment of the primary tumor spread in malignant pleural mesothelioma].

PURPOSE: Evaluation of the diagnostic value of the imaging modalities computed tomography (CT), magnetic resonance imaging (MRI), and thoracic sonography in the preoperative staging of malignant pleural mesothelioma. MATERIALS AND METHODS: The diagnostic accuracy of CT (n = 41), MRI (n = 24), and thoracic sonography (n = 37) were evaluated in 51 patients with histologically proven diffuse malignant pleural mesothelioma. Values of sensitivity, specificity, positive and negative predictive values, and accuracy were calculated for the assessment of the diaphragm, lung, thoracic wall, pericardial wall, myocardium, and (retro)peritoneal space. RESULTS: The accuracy rates for CT were 85%, 98%, 83%, 73%, 71%, and 83%. MRI had an accuracy of 71%, 92%, 71%, 83%, 71%, and 96%, the thoracic ultrasound examinations of 76%, 63%, 51%, 60%, 71%, and 89%. CONCLUSIONS: According to these results CT remains the method of choice in the preoperative assessment of T-stage of malignant pleural mesothelioma. MRI is of nearly the same value, but is not a must. Sonography may be supplementary method for operation planning.

Female↗
PubMed1999

[Portal contrast medium-enhanced spiral computed tomography of the liver--the correlation of radiological and intraoperative findings and the evaluation of resectability].

PURPOSE: To evaluate the accuracy of spiral computed tomography during arterial portography (SCTAP) in the detection, localization, and resectability of liver tumors in a correlative study between radiology and intraoperative findings. METHOD AND MATERIALS: Retrospectively, SCTAP images of 168 consecutive patients before liver tumor resection were analyzed. The SCTAP studies (100 ml lopromid 300 by automated injector with a flow of 3 ml/s; slice thickness, table feed and reconstruction index 5 mm each; scan-delay 30 s; 120 kV; 250 mAs) were evaluated for the detection, localization, and resectability of focal liver lesions by three experienced radiologists in consensus and were correlated with histopathological and intraoperative findings where available (59/168). RESULTS: The sensitivity of SCTAP for the detection of liver tumors was 91% for all lesions and 84% for lesions < 1 cm. The specificity was only 19% due to a high rate of false-positive lesions (30%) and preselection effects. Typical pitfalls in false positive lesions were inhomogeneous liver perfusion near the portal vein, the falciform ligament, and the gallbladder (19/42). In 30% of the patients SCTAP correctly diagnosed inoperability, in 23% the intraoperative tumor expansion was larger than expected from SCTAP images, which would have changed operability. CONCLUSION: The SCTAP has a high sensitivity in the detection and localization of liver tumors and is a valuable method in the preoperative diagnostic procedure. The method is limited by many false-positive lesions often due to inhomogeneous liver perfusion and the insufficient evaluation of local tumor spread. Therefore, SCTAP should be replaced by MRI in the near future.

Adult↗
PubMed1998

[TIPSS: technical and clinical results after 4 years].

PURPOSE: Retrospective analysis of the technical and clinical results after transjugular portosystemic stent shunt (TIPSS) procedure. METHOD: Between 1992 and 1996 we tried to establish a TIPSS in 90 patients. The indications were: recurrent variceal haemorrhage (n = 74), refractory ascites (n = 12), hepatorenal syndrome (HRS) (n = 4). Due to advanced liver cirrhosis 16 patients suffered of severe renal dysfunction (HRS). 57 patients had ascites. RESULTS: TIPSS implantation was technically successful in 96.7% (1992-1994: 5.1%, 1995-1996: 100%) of the patients. Complications occurred in 14.9% (1992-1994: 25.6%, 1995-1996: 6.3%). TIPSS-associated mortality was 2.3% (1992-1994: 5.1%, 1995-1996: 0%). 76.1% of the patients required reinterventions. 85.3% of reinterventions were necessary in the first year after TIPSS placement. The survival rate without reintervention was 28%, 21% and 9% for Child A, B, and C patients, respectively. Recurrent variceal haemorrhage occurred in 12.7%. De novo hepatic encephalopathy developed in 13.8%. Ascites improved in 79.2% and renal function in 75% of the patients. CONCLUSION: TIPSS is an effective method to treat recurrent variceal haemorrhage, refractory ascites and HRS. Complication and mortality rate depend on the investigator's experience and on the technique used.

Adult↗
PubMed1998

[Quantitative evaluation of the suitability of magnetic resonance sequences for the detection of spinal bone marrow metastases of solid tumors].

AIM: To compare MR sequences for the examination of the bone marrow of the spine in the detection of skeletal metastases. METHODS: 20 standardised prospective studies of the cervical, thoracic or lumbar spine in patients with known skeletal metastases were evaluated quantitatively. Studies included T1w SE with and without intravenous contrast medium (CM) administration of Gd-DTPA, T2w TSE with and without frequence selective fat saturation (SPIR), opposed phase gradient echo (opGE) with and without intravenous CM administration of Gd-DTPA and T1w SE CM SPIR sequences. The quantitative parameters signal/noise ratio (SNR), contrast/noise ratio (CNR) and contrast were evaluated. RESULTS: OpGE with contrast showed the best results in SNR, CNR and C. Results were statistically significant. Good SNR and C also was found for T1w SE native. SPIR and T2w sequences were less sensitive. CONCLUSION: OpGE sequences are recommended for the detection of skeletal metastases of the spine.

Bone Marrow Neoplasms↗
PubMed1998

[Spiral CT and MRT of the operated Stanford-type-A aortic dissection: its course and complications].

PURPOSE: To demonstrate normal postoperative spiral CT and MRI findings and typical complications in patients with aortic repair after Stanford type A aortic dissection. METHODS: 24 patients with aortic repair after Stanford type A aortic dissection were followed up by spiral CT and MRI (0.5 Tesla). Presence of persistent dissection, progressive or new dissection, proximal and distal anastomosis, periprosthetic space, supraaortic vessels, thrombosis and dilatation of the true and false lumen were evaluated. RESULTS: The following postoperative complications were seen: three pseudoaneurysms which developed at the proximal anastomoses of the Dacron prosthesis in two cases and at the insertion site of the reimplanted left coronary artery after implantation of a composite graft (Bentall procedure) in one case; one re-dissection; one perforation of the false lumen; periprosthetic flow in one patient after surgical repair of type A dissection by the graft inclusion technique; progressive dilatation of the false lumen in 4 cases; dilatation of the aortic root in a Marfan patient after replacement of the ascending aorta. CONCLUSION: Precise knowledge of the surgical technique performed is crucial to accurate postoperative imaging evaluation. MRI is the method of choice in the postoperative follow-up of clinically stable patients with aortic dissections.

Aortic Dissection↗
PubMed1998

[MRI, CT and CT arterial portography in the diagnosis of malignant liver tumors in liver cirrhosis].

PURPOSE: To determine the value of magnetic resonance imaging (MRI), computed tomography (CT) and CT arterial portography (CTAP) in detecting malignant liver lesions in cirrhosis patients. MATERIALS AND METHODS: The radiological examinations (CT, MRI and CTAP) of 47 patients suffering from cirrhosis having undergone an orthotopic liver transplantation (OLTX) were analysed retrospectively. The number of detected liver lesions was compared with the results of the histopathological findings after OLTX. RESULTS: 13/21, 11/18 and 7/12 of the malignant lesions were detected by MRI, CT and CTAP respectively. In MRI one false positive case was shown, two in CT and three in CTAP. Almost the same lesions were identified by all three procedures. The examination of the liver with MRI and CT and CTAP did not bring additional information. Most of the lesions that were missed were less than 2 cm in diameter. CONCLUSIONS: The rate of detection of HCC in patients with cirrhosis was about 60%. MRI and CT yielded similar results.

Adult↗
PubMed1998

[1H MR spectroscopy of the lumbar spine in diffuse osteopenia due to plasmacytoma or osteoporosis].

PURPOSE: To evaluate the role of in vivo 1H MR spectroscopic determination of relaxation times and of fat and water content to differentiate between infiltration of multiple myeloma or osteoporosis in patients with roentgenologic unclear demineralization of the lumbar spine. PATIENTS, MATERIALS AND METHODS: Ten patients each with osteoporotic reduction of bone mineral density (BMD), histologically proven multiple myeloma who showed only diffuse tumor manifestations without tumor compression fractures in the spine, and volunteers were investigated. Osteoporosis was confirmed by dual-energy X-ray absorptiometry (DXA) (Hologic QDR 2000 device, Siemens Medical Systems). The MR investigations were performed with a 1.5 T whole body system (Gyroscan S15/ACS II, Philips Medical Systems). Localized MR spectra from a cubic volume of about 8 cm3 were acquired by the PRESS technique. Chemical shift selective T1 relaxation times were obtained from an IR series, T2 was measured by variation of the interval between the first and the second echo in the volume selection scheme. Statistical analysis was done using the Kruskal-Wallis test and the Mann-Whitney test with the software SPSS. RESULTS: There were highly significant differences in T2 values and fat content between patients with osteoporosis and multiple myeloma. T2 values were decreased in osteoporosis (37 ms and 59 ms vs. 44 ms and 70 ms in plasmocytoma) and fat content was decreased in multiple myeloma (20% vs 31% and 34% in volunteers and osteoporosis). Between volunteers and patients with osteoporosis the differences in the T2 of the fat component was significantly different. CONCLUSIONS: In our preliminary experience MRS is helpful in the differential diagnosis of bony demineralization. It enables a differentiation between osteoporosis and diffuse multiple myeloma. T2 value measurements may be helpful in the diagnostic trial of osteoporosis.

Adult↗
PubMed1998

[Diagnosis of liver tumors--what is necessary for therapy planning?].

For the surgical treatment of liver tumors, two initial steps are necessary: functional operability must be proven and oncological and local inoperability must be ruled out. The diagnostic process consists of a series of steps, beginning with non-invasive procedures such as laboratory findings and sonography, continuing with CT, CTAP, laparoscopy in the case of hepatic cirrhosis, up to explorative laparotomy. The potential operability is re-checked after each step. Punction, MRI and scintigraphy are implemented in special cases. The early implementation of MRI is of particular value for the diagnosis of certain benign processes.

Diagnostic Imaging↗
PubMed1998

[Does angiographic localization of bleeding affect the management and mortality in gastrointestinal hemorrhage of unknown origin?].

PURPOSE: To evaluate the effect of angiography on patient management and mortality in patients with GIB of unknown origin. MATERIAL AND METHODS: 88 angiographies were performed in 74 patients with GIB of unknown origin (18 upper gastrointestinal tract [GIT]), 35 lower GIT. 21 unknown localisation) and were evaluated retrospectively in regard to the influence on patient management and clinical outcome. RESULTS: After unsuccessful endoscopic diagnosis, angiography shows a sensitivity of 60% in the acute phase of GIB. Once the GIB had stopped the sensitivity was 14%. Following angiographic localisation, patients were more commonly treated surgically (71% vs. 44.5%) and subsequently had a lower rate of persistent or recurring bleeding (15% vs. 37.5%) as well as a lower event related mortality (10.5% vs. 25%). Patients with angiographic localisation of the bleeding site had a better outcome than patients with unsuccessful bleeding localisation, with regard to both surgical (85% vs. 62.5%) and conservative (100% vs. 85%) treatment. CONCLUSION: Angiographic localisation should be attempted in all cases of unknown GI-bleeding after endoscopic methods have been unsuccessful or ambiguous, because such a procedure has a positive effect on patient management and outcome. Moreover, angiography also offers therapeutic options.

Adolescent↗
PubMed1998

[Aortic rupture and retroperitoneal bleeding im Behcet disease].

Although retroperitoneal hemorrhage is a rather seldom complication of Behçet's syndrome it is in no way unusual. Younger patients in particular those from the eastern Mediterranean or east Asian regions in whom a retroperitoneal hemorrhage or an aneurysm in the aorto-iliaco-femoral flow region has be diagnosed must be considered for the differential diagnosis of Behçet's syndrome. The consequences for the surgeon are resection deep into healthy tissue and in general an appropriately close follow-up with strict avoidance of arterial angiography.

Aorta, Abdominal↗
PubMed1997

[Xanthogranulomatous pyelonephritis with septic lung metastases and infiltration of the colon. Difficult preoperative differential pulmonary hypernephroma metastasis diagnosis].

Xanthogranulomatous pyelonephritis (XGP) is a rare and aggressive form of chronic pyelonephritis for which partial or complete nephrectomy is mandatory [1.2]. The diagnosis and, in particular, the differentiation from hypernephroma is mostly established by the histopathological examination only. We have reviewed the literature and present an unusual case of XGP with septic spreading into the lungs mimicking pulmonary metastasis and with an inflammatory infiltration of the descending colon.

Adult↗
PubMed1995

[Turbo-spin-echo sequences with selective fat suppression (SPIR) in the MRI of focal liver lesions at 0.5 tesla].

PURPOSE: The value of T2 weighted turbo-spin-echo sequences with selective fat suppression (TSE-SPIR) in the detection and differential diagnosis of focal liver lesions was compared to TSE sequences and conventional T1 weighted spin-echo (T1 SE) sequences at 0.5T. METHODS: In 50 patients with focal liver lesions T1 SE-TSE-, and TSE-SPIR sequences were performed. Two independent readers evaluated the sequences with regard to the image quality, fat suppression, and the number and conspicuity of liver lesions. Quantitative analysis was performed by tumour-liver contrast-to-noise (CNR) measurements. RESULTS: From a total of 118 liver lesions the T1 SE sequence, the TSE sequence, and the TSE-SPIR sequence showed 85.6%, 83.9%, and 91.5%, respectively (p < 0.05). The tumour-liver CNR of malignant liver lesions was 30.2-46.6% higher on the TSE-SPIR sequence compared to the TSE sequence (p < 0.01). With the exception of fat-containing lesions there was no significant difference of CNR in benign lesions on both TSE sequences. CONCLUSION: With regard to lesion detection the TSE-SPIR sequence is superior to the TSE sequence without fat suppression, whereas it is inferior to the TSE sequence in the differential diagnosis of benign and malignant lesions.

Adipose Tissue↗
PubMed1995

[Diagnostic imaging in primary hepatobiliary cystadenoma of the liver].

The clinical and radiological findings of 5 patients with a total of 7 hepatobiliary cystadenomas are reported. In all cases sonography and computed tomography were performed, in three cases angiography was carried out, and in one case magnetic resonance imaging was used. On sonography and computed tomography hepatobiliary cystadenomas exhibit relatively typical findings as a multicystic, space-occupying lesion with septation and papillary mucosal nodes; hence the diagnosis can be made preoperatively in most cases. For differential diagnosis, the malignant form, hepatobiliary cystadenocarcinoma has to be considered which can only be distinguished from the benign form by histology.

Adenoma, Bile Duct↗
PubMed1995

[Intra-arterial treatment of therapy-resistant residual tumors of the pelvis].

PURPOSE: Evaluation of intraarterial cancer treatment in recurrent pelvic tumors, which were resistent to other treatment modalities. PATIENTS AND METHODS: Ninety-seven patients suffering from pelvic recurrences originating from bladder (n = 40), rectum (n = 19), cervix (n = 21) oder other organs (n = 17) were treated by intraarterial chemotherapy (111 times) or transcatheter embolisation (52 times). RESULTS: Less than 20% of our patients had remission of the tumor burden but tumor symptoms (especially pain and bleeding) could be controlled in 35 to 87% of the patients. The main complication was a muscle necrosis after intraarterial chemotherapy because of recurrent bladder cancer. CONCLUSION: Intraarterial cancertherapy is a useful procedure for symptomatic treatment of tumor symptoms especially in case of bleeding. Local tumor control can only be achived in a minority of the patients.

Adult↗
PubMed1994

[The role of MRT in detecting the cause of therapy-refractory partial complex epilepsy].

MRT is of considerable significance in the investigation of epilepsy because of its ability to render soft tissue contrast for the demonstration of structural lesions. The present retrospective study consists of an analysis of MRT findings in operatively confirmed, circumscribed temporal tumours and in hippocampal sclerosis. The examinations were performed under standard conditions using T1- and T2-weighted spin-echo sequences of the head and coronal T2-weighted gradient-echo sequences of the brain stem. The diagnosis of tumours was extremely accurate (22/23) and specific (18/23) whereas hippocampal sclerosis could not be satisfactorily demonstrated (5/18). The use of intravenous contrast medium did not provide any advantages.

Adolescent↗