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Biomedical subjects

L Guhl

Publications and source records attributed to L Guhl.

At least 19 recordsLinked to original sources
PubMed1997

[Magnetic resonance tomography and magnetic resonance angiography in diagnosis of complicated popliteal artery aneurysm].

Regarding the frequency of aneurysms, the popliteal artery comes third behind the abdominal aorta and the iliac arteries. In up to 50% of cases a sudden limb-threatening thrombotic occlusion may occur. Early surgical intervention is the therapy of choice. We report the case of a 56-year-old patient whose popliteal aneurysms (PAs) in both legs had been bypassed with a venous graft some years previously. He presented with acute pain and tumescence in the left popliteal fossa combined with inflammatory symptoms. Neither ultrasonography nor DSA could distinguish between an extravascular inflammatory process, an anastomotic aneurysm and a partial reperfusion of the original PA due to a leaking anastomosis. The correct diagnosis was provided by MRI in combination with MRA, confirmed by the intraoperative findings. The value of MRA in the diagnostic imaging of the vasculature of the lower extremities is discussed and compared alternative methods.

Anastomosis, Surgical↗
PubMed1995

[Magnetic resonance tomography of the scrotum. Experiences with 129 patients].

In our study 129 patients underwent MR imaging for evaluation of the scrotum with spin-echo pulse sequence (proton density and T2-weighted images). The final diagnosis was confirmed by surgery in 54 patients. Our findings show that MRI is a powerful supplementary technique for scrotal imaging when ultrasound findings are unclear or are inconsistent with the clinical history. MRI can reduce the number of unnecessary exploratory operations on the testis, though surgery is unavoidable if the findings are equivocal. Differentiation and specification of tumours cannot be achieved by MRI, nor does it allow accurate evaluation of subacute torsion of the testis. In these cases dynamic MRT following intravenous administration of Gd-DTPA may improve the diagnostic accuracy.

Adolescent↗
PubMed1995

[Vena cava invasion in adrenal gland tumors: findings in nuclear magnetic resonance tomography].

In rare cases, large adrenal masses with a suspicion of malignancy exhibit tumor extension into the adrenal vein and inferior vena cava. When planning surgery, the relationship of the extension to the inferior vena cava is of decisive importance. We describe in two cases on the detection of a tumor thrombus in the inferior vena cava arising from a malignant adrenal mass by means of MR angiography (TOF, coronary 2D GRE images [FLASH], 3 slices acquired during 15 second apnea). The angiograms correlated well with the results of DSA venacavography and with the intraoperative findings. Thus, MRA has been demonstrated to be suitable for the certain proof of a venous tumor thrombus not only in cases of renal cell carcinomas but also in cases of malignant adrenal masses. The method should be applied whenever there is evidence of a venous involvement in the adrenal MR images.

Adenocarcinoma, Clear Cell↗
PubMed1994

[Clinical value of high-resolution magnetic resonance tomography in the staging of tumors of the oral cavity, the pharynx and the larynx].

In a prospective study 102 patients with malignant tumors of the tongue, oropharynx, hypopharynx, and larynx were staged by means of MRI. Special attention was directed at those tumour extensions that could influence the treatment strategy. The MR findings were correlated with the results of palpation, endoscopy, ultrasound, computerised tomography and histopathological findings. MRI showed a good delineation of pT2 to pT4 tumours. However, visualisation of small tumours in the soft palate, the tonsils, the pyriform sinuses and vocal cords was difficult. In conclusion our results suggest that in addition to endoscopy MRI is a valuable tool for the examination of tumours of tongue, oropharynx, hypopharynx and larynx.

Female↗
PubMed1993

[Magnetic resonance tomographic identification and characterization of renal space-occupying lesions using GE-sequences with application of Gd-DTPA].

In modern magnetic resonance imaging (MRI) gradient echo (GE) sequences have been shown to be superior to conventional spin echo (SE) sequences in characterising renal masses and staging renal tumours. In this study MRI was carried out in patients with renal masses (n = 97, histologically proven n = 43) using a fast GE-sequence (multislice technique, TR/TE 80/5 ms) and an i.v. bolus application of gadolinium (Gd)-DTPA mostly in axial, in selected cases additionally in coronal slice orientation. MRI findings were compared with those of contrast-enhanced CT (n = 56). The results demonstrated that MRI under Gd-DTPA has a reliably good image quality and can characterise renal masses safely. Compared with CT in multislice MRI problems of partial volume effects can be reduced; complex renal cysts can be differentiated more safely from solid tumours with unclear CT findings due to a significantly higher contrast enhancement in MRI.

Adolescent↗
PubMed1993

Intra- and perivesical tumor growth in preoperative staging of bladder cancer: the role of transrectal ultrasonography and high resolution magnetic resonance imaging.

Bladder tumors were staged preoperatively before and/or after M-VEC poly-chemotherapy using transrectal ultrasonography and magnetic resonance imaging in 46 patients. The resultant findings were each compared with histomorphologic results. The sensitivity of both methods compared with pathohistology was 88%. Using this technique, the degree of tumor invasion of the bladder wall could be evaluated and the appropriate therapy selected. Further applications included the monitoring of transurethral resection determine its adequacy as a treatment modality.

Adenocarcinoma↗
PubMed1993

Somatostatin receptor scintigraphy and magnetic resonance imaging in recurrent medullary thyroid carcinoma: a comparative study.

In a prospective study, 18 patients with recurrent medullary thyroid carcinoma (MTC) underwent magnetic resonance imaging (MRI) of the neck and mediastinum and somatostatin receptor scintigraphy (SRS) with 111In-labeled pentetreotide. In nine patients with macroscopic MTC, 17 corresponding lesions were found on MRI and SRS; in addition, 13 suspicious lesions were seen on SRS only. Histological confirmation was available for 19 metastatic lesions, showing MRI to be true positive in 13 metastases, SRS in 18. In minimal residual disease (n = 10), MRI and SRS were compared with the histological findings in three patients and with selective venous catheterization (SVC) in seven patients. Corresponding findings on MRI and SVC were seen in one of seven, whereas SRS and SVC showed concordant localization of tumor recurrence in five of seven. Histological examination demonstrated MTC tissue in one of three cases; MRI and SRS were false positive in one of three cases, while in the others the interpretation remained uncertain. In conclusion, SRS is a promising imaging modality for localization of MTC recurrence. MRI provides better spatial resolution and thus facilitates the planning of surgery for macroscopic metastases. In minimal residual disease, SRS turned out to be superior in detecting occult MTC recurrence, confirming SVC findings.

Adolescent↗
PubMed1993

[2D-time-of-flight MR angiography in the diagnosis of abdominal aorta aneurysms].

In abdominal aortic aneurysm ultrasonography, contrast-enhanced CT, and digital subtraction angiography (DSA) are the preoperative diagnostic methods of choice accepted today. It was the goal of this study to evaluate time-of-flight magnetic resonance angiography (MRA) in comparison with other radiographic procedures in different types of aneurysms. In 24 patients with proven aortic aneurysm, projection angiograms (MIP algorithm) of the abdominal aorta and pelvic arteries were performed using two-dimensional gradient echo multi slice sequence (FLASH, TE/TR = 10/51 ms; three slices; breathhold technique; flip angle = 30 degrees) in coronal orientation. In addition, renal arteries were imaged in axial slices. The information provided by MRA was comparable to that of DSA (perfused vascular lumen) and contrast-enhanced CT (alteration of vascular wall). Thus dilatation, thrombus, dissection, or inflammation could be analysed safely. Extension of the aneurysm to pelvic arteries could be evaluated in most cases by rotation of the projection angiograms; ostial renal artery disease could be visualized on axial slices. If further technical improvement of MRA is presupposed, this noninvasive method may completely replace the invasive procedures of contrast-enhanced CT and DSA in the future.

Aged↗
PubMed1993

[Preoperative assessment of depth of infiltration of rectal tumors by staging, endosonography and magnetic resonance tomography. A prospective study].

The choice of individual therapy for rectal tumours requires the pretherapeutic assessment of the depth of infiltration of the tumour. Fourty-four patients with rectal tumour were evaluated preoperatively by digital examination, endosonography and magnetic resonance imaging (MRI). Test results were compared with the postoperative histological examination. In digitally accessible tumours clinical staging had an accuracy rate of 85%. The sensitivity of endosonography was 83%, compared with 54% for MRI. Our findings suggest that endosonography may be more accurate as MRI, especially for rectal adenomas and early carcinomas.

Adult↗
PubMed1993

[Magnetic resonance tomographic findings in cardiac tumors].

After ultrasound, magnetic resonance imaging (MRI) is the second noninvasive powerful method of examining the heart. The findings in 9 patients with cardiac tumors are reported, who were examined by means of MRI: There was little variance in the MRI signal behavior (with only one exception), although the tumor population examined was very heterogeneous. The MRI techniques used (T1-weighted spin echo, steady-state gradient echo) seem to allow no better tumor specification than ultrasound. Wince multiplanar reconstruction is possible with MRI, tumor size, localization, and the borders of the cardiac neoplasms can be depicted. The cine technique provides dynamic information. In addition, this method allows reliable discrimination between the flow effects and true space-occupying lesions.

Adult↗
PubMed1992

[The evaluation of 2D- and 3D-"time of flight" magnetic resonance angiography (MRA) in the diagnosis of renal artery stenoses].

This study was carried out to evaluate time-of-flight RA in renal artery stenosis (RAS) in selected hypertensive patients (n = 41). In i.a. DSA studies, 10 unilateral, 8 bilateral RAS, and 4 unilateral RA occlusions were proven. MRA was done in coronal and axial 2D technique (FLASH), and in 3D technique (FISP) using GE-pulse sequences. DSA results were correlated with both 2D-individual slices, 2D- and 3D-MIP angiograms. Highest sensitivity and specificity was found for the axial 2D individual slice analysis (88%, 85% resp.), followed by the 3D-MIP MRA (78%, 80% resp.), and axial 2D-MIP MRA (73%, 79% resp.). MRA of renal arteries used in this study shows to be not adequate to DSA results due to many drawbacks. All MRA techniques, in particular the 3D-technique, tend to overestimate RAS occasionally pretending occlusions.

Adult↗
PubMed1992

[Magnetic resonance angiography of the renal veins and the vena cava inferior for the staging of renal cell carcinoma].

The staging of renal cell carcinoma (RCC) comprises exclusion of tumour expansion into the renal veins and the inferior vena cava (IVC). In 44 patients with RCC these vessels were examined using MRA on the basis of "time-of-flight" technique (coronal/axial 2D GE-flash-sequence, MIP-algorithm). The method was evaluated against contrast-enhanced CT and DSA in normal conditions and tumour-involved IVC (n = 12) and renal veins (n = 32) respectively. Following analysis of projection-angiograms (PA) and individual slices the results of MRA without contrast material included an information on vascular tumour extension that was identically safe as CT and DSA. In coronal slice orientation tumour extension into the vena cava was proven in 100%, and into the renal veins in 84%. Additional axial slices were necessary to demonstrate tumour extension into the renal veins in unclear cases. Single slices showed to be superior to PA for a correct identification of the size of the tumour thrombus.

Adult↗
PubMed1992

[Diagnosis of pulmonary sarcoidosis using high-resolution computed tomography].

This report deals with 24 patients with pulmonary manifestations of sarcoidosis who were examined by means of high-resolution computed tomography. The characteristic findings were rounded masses of all sizes and shapes. Other findings were ground glass opacities and thickened septal walls. In the advanced stage fibrous strands and intrapulmonary cavities could be seen. High-resolution tomography allows better detection of fine granulomas and better recognition of their anatomic relationship to the pulmonary substructures, facilitating differential diagnosis against other interstitial lung diseases.

Adolescent↗
PubMed1991

[MR angiography of the abdominal aorta: initial experience].

Flowing blood can be demonstrated as bright signal in MR-imaging resulting in MR-angiography (MRA). This study presents the results of MRA using the "time of flight"-effect in which projection angiograms along the longitudinal axis were established by a row of 2D-gradient echo (GE) images (FLASH) in breath-hold technique. The method was proven in 5 normal volunteers and evaluated against DSA in 21 patients with aortic diseases. The preliminary results demonstrate a satisfactory flow signal in the normally perfused aorta; thus occlusions, stenoses, and aneurysms could be defined clearly. In smaller vessels the signal was still insufficient. Diagnostic problems of vascular overlapping can be solved in most cases by rotating the angiograms, and by additional analysis of individual 2D-GE images. In the present form the quality of MRA is still inferior to that of DSA.

Angiography, Digital Subtraction↗