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Biomedical subjects

H B Gehl

Publications and source records attributed to H B Gehl.

36 records · Page 2Linked to original sources
PubMed1995

[Differential diagnosis of commonplace upper abdominal symptoms: hepatic echinococcosis].

A 17-year-old girl from Turkey had for 6 years been suffering from right-sided upper abdominal symptoms not usually related to food intake. Treatment of suspected gastritis remained ineffective. Laboratory tests were unremarkable, except for an accelerated erythrocyte sedimentation rate (12/30 mm), eosinophilia (6.4%) and albumin concentration of 52.6 g/l. Upper abdominal sonography revealed a cyst, about 10 cm in diameter, in the right liver lobe. Computed tomography showed the 8 x 8.5 cm cyst which was septated at its caudal portion and compressed the vena cava for 5.6 cm. The antibody titre against echinococcus antigen was 1:3200. At laparotomy the echinococcal cyst was found to have extended to the left adrenal gland, renal fat capsule and left part of the diaphragm. There was a pressure necrosis on the right lateral aspect of the vena cava. The affected parts were resected and the patient quickly recovered. Postoperative treatment consisted of the administration of mebendazole (1.5 g daily) for 18 months. The patient had come from an area where echinococcal infection is endemic. The disease could have been quickly and easily diagnosed and cured if sonography had been undertaken early, sparing the patient major surgery.

Adolescent↗
PubMed1994

[MR tomography of acute pancreatitis: initial results].

Magnetic resonance imaging (MRI) was evaluated for its potential in assessment of acute pancreatitis compared to computed tomography (CT). 15 patients with acute pancreatitis were examined using a routine protocol including T1- and T2-weighted sequences and a fat-suppressed T1-weighted spin-echo sequence. Gadopentant-Dimeglumin (Gd-DTPA) was given. For comparison, plain and contrast-enhanced CT was performed prior to MRI. MRI proved to be superior to CT in detection of bleeding, duodenitis and ascites. MRI failed to detect concrements. These first results show that, considering the latest development in technology, MRI is not inferior to CT in diagnostic imaging of acute pancreatitis.

Acute Disease↗
PubMed1993

[Manganese dipyridoxal diphosphate as a new contrast medium in the MRT of benign and malignant pancreatic tumors: initial clinical findings].

MnDPDP is a new intracellular contrast medium of which 50% is excreted through the bile; its acceptability and effect on MR images was studied in 21 patients, 18 of whom had malignant and three benign tumours of the pancreas. Spin echo T1 images (SE-T1: TR = 500 ms; TE = 15 ms) showed a 20% increase in signal to noise ratio (S/N) (p = 0.059) and a 90% increase in contrast to noise ratio (C/N) (p = 0.0027). In gradient T1 images (GE-T1: TR = 100 ms; TE = 6 ms; flip angle = 70 degrees) there was an increase of S/N of 70% (p < 0.0001) and of the C/N of 200% (p < 0.0001). T2 weighted SE sequences were inferior to plain SE-T1 weighted sequences with regard to their S/N and C/N ratios. There were no significant clinical complications or biochemical changes in the blood or urine. A subjective side effect in three patients was a feeling of heat. MnDPDP is a well tolerated and effective contrast medium for MRT of pancreatic tumours.

Adenocarcinoma↗
PubMed1993

Mn-DPDP in MR imaging of pancreatic adenocarcinoma: initial clinical experience.

Manganese (II) N,N'-dipyridoxylethylenediamine-N,N'-diacetate 5,5'-bis(phosphate) (DPDP) was tested as a contrast agent for magnetic resonance imaging of pancreatic adenocarcinoma in 15 patients. At enhanced T1-weighted spin-echo (SE) and enhanced T1-weighted gradient-echo (GRE) imaging, statistically significant increases in signal-to-noise ratio (S/N) for the pancreas (21% and 92%, respectively) and contrast-to-noise ratio (C/N) (91% and 209%, respectively) were found. The C/N at enhanced T1-weighted SE imaging was superior to that at unenhanced imaging, including T2-weighted SE imaging (P = .001). Subjective image analysis showed that delineation of the pancreas and pancreatic tumors was clearly improved (P = .05) on enhanced T1-weighted SE and GRE images compared with on unenhanced T1- and T2-weighted images. The liver enhanced 19% at T1-weighted SE imaging and 90% at T1-weighted GRE imaging. There was a significantly higher S/N increase in hepatic parenchyma than in pancreatic tissue at enhanced T1-weighted GRE imaging (P = .0026) but not at enhanced T1-weighted SE imaging.

Adenocarcinoma↗
PubMed1992

[Late pulmonary changes following bleomycin administration in computed tomography. Nodular fibrosis mimicking a seminoma metastasis].

This is a case report of a patient with multiple metastases to the lung due to a seminoma, treated with a chemotherapeutic regimen containing bleomycin. The typical subpleural fibrosis of the lung related to bleomycin damage disappeared 6 months after the start of chemotherapy. 4 weeks later, a solitary nodule at a prior unchanged site of the lung appeared, mimicking recurrent metastasis. Explorative thoracotomy revealed a nodular fibrosis of the lung, representing a late reaction of the lung to chemotherapy damage.

Adult↗
PubMed1991

Pancreatic enhancement after low-dose infusion of Mn-DPDP.

Enhancement of the pancreas was demonstrated after low-dose (10 mumol/kg) infusion of a new contrast agent for magnetic resonance (MR) imaging, manganese dipyridoxal-diphosphate (Mn-DPDP). To the authors' knowledge, this has not been described previously. The enhancement reached a maximum of 98% +/- 13% (standard deviation) during a long period (greater than 6 hours). Mn-DPDP seems to have potential as a selective contrast agent in MR imaging of the pancreas.

Contrast Media↗
PubMed1990

[Dynamic contrast medium-aided ultrasound cavography in patients with a caval filter].

In 35 patients during 42 examinations, vena-caval blood flow was visualized by application of a new ultrasonic contrast medium (Echovist) via a dorsopedal vein. A caval filter had previously been implanted in 32 patients. In 94 out of 99 cases, application of the contrast medium allowed a diagnostically relevant enhancement of the echogenicity of the caval blood flow. In addition, the caval filters allowed altered flow geometry to be depicted in detail.

Adult↗
PubMed1990

[MR-angiography (MRA) in deep leg and pelvic venous thrombosis: a comparison with phlebography].

MRA by means of flow-phased gradient echo sequences is a valuable addition to phlebography for showing the extent of thrombosis in the veins of the pelvis and lower limbs. In eight out of 32 patients in whom the extent of deep vein thrombosis was not clearly shown by phlebography, it was possible to demonstrate the involvement of the inferior vena cava. Three of these patients had bilateral pelvic vein thrombosis. In seven out of 32 cases, thrombosis on the opposite side, which was not apparent clinically, could be demonstrated by MRA. Seven out of 32 patients showed involvement of the internal iliac vein. MRA is also valuable for observing the effect of treatment.

Adolescent↗
PubMed1990

[Imaging of penile vascular anastomoses using color-coded Doppler ultrasound: comparison with CW Doppler ultrasound and clinical aspects].

In fourteen patients undergoing surgical revascularization (11 with Hauri's, three with Virag's anastomosis) because of erectile dysfunction, the patency of vascular anastomosis was evaluated and visualized by color-coded-Doppler sonography (CCDS). Results were compared with continuous-wave Doppler (CWD) and clinical data. CCDS proved to be superior to CWD with regard to assessment of flow in the penile vessels and to applicability. Strength and direction of flow can be judged visually. Therefore, the nature of the imaged vessel (artery or vein, deep or dorsal artery) can be differentiated. There is a good correlation of CCDS and CWD in their evaluation of the patency of the anastomosis. CCDS showed higher accuracy in detecting deep cavernosal arteries.

Adult↗
PubMed1990

Color-coded image-directed Doppler sonography compared with digital subtraction angiography in the follow-up of percutaneous vascular endoprostheses.

Color-coded image-directed Doppler sonography (CCIDS) was used in the follow-up of self-expandable vascular endoprostheses and was compared with the results of digital subtraction angiography and Doppler pressure indices. The stents were implanted in iliac and femoral arteries or hemodialysis fistulae of 26 patients. The aim of the study was to evaluate the potential of the new imaging method to identify local flow patterns inside of vascular endoprostheses. The stents were identified by sonography in all cases; laminar flow was represented in CCIDS by homogeneous Doppler signals. In case of a distinctly reduced lumen, intravenous digital subtraction angiography (DSA) and CCIDS were both able to identify the stenotic process; however, CCIDS was superior in the demonstration of minute flow irregularities. No different flow patterns were detected in comparing recent with older vascular implants.

Angiography, Digital Subtraction↗
PubMedDate not supplied

MR-guided placement of a temporary vena cava filter: technique and feasibility.

The purpose of this paper was to investigate the feasibility of MR-guided insertion of a temporary vena cava filter on an open low-field imager. In vivo procedures were performed on four anesthetized pigs using a common nonferromagnetic temporary vena cava filter and a special prototype guidewire developed for vascular interventions guided by low-field MRI. Breath-hold spoiled gradient-echo sequences (fast low-angle shot [FLASH]) with flow compensation were used for position monitoring of the passively visualized intravascular devices. Using the described technique and equipment, all steps of the procedure were feasible in the MR unit. Practicability of the procedure seems to be sufficient for clinical purposes but was inferior compared to the conventional technique of filter placement.

Animals↗
PubMedDate not supplied

Visualization of magnetic resonance-compatible needles at 1.5 and 0.2 Tesla.

PURPOSE: For two types of passively visualizable magnetic resonance (MR)-compatible needles, the size of susceptibility artifacts was investigated at 0.2 and 1.5 Tesla (T) and assessed regarding their suitability for needle visualization. METHODS: Phantom trials were performed using T1-weighted spin echo (SE), turbospin echo (TSE) and gradient echo (GE) sequences and different angles beta between the needles and the main magnetic field (B0). RESULTS: Depending on the needle angle beta and the applied pulse sequence, we found artifact diameters of 0-9.7 mm employing SE, of 1.7-9.4 mm employing TSE, and of 1.4-20.6 mm employing GE at 1.5 T. At 0.2 T, we found artifact diameters of 0-5.7 mm employing SE, of 0-6.3 mm employing TSE, and of 0-11.3 mm employing GE. CONCLUSION: Comparing artifact sizes at 1. 5 T and 0.2 T, low field strength is superior for passive visualization of the needles tested-especially if GE imaging is performed.

Artifacts↗
PubMedDate not supplied

Two-dimensional MR angiography in the evaluation of abdominal veins with gradient refocused sequences.

The purpose of this study was to demonstrate the potential role of gradient refocused magnetic resonance imaging as an angiographic method in the evaluation of abdominal veins. Fifteen patients with different venous disorders were examined using first order motion refocused gradient echo sequences (fast low angle shot) in sequential section acquisition technique. Twelve patients had abdominal tumors and three idiopathic thrombosis of abdominal veins. Magnetic resonance was superior to indirect splenoportography and mesentericoportography in evaluation of the abdominal veins in 8 of 10 cases. It was also superior to ultrasound in 3 of 7 cases and to dynamic CT in 2 of 11 cases. This resulted from a higher intrinsic contrast between flowing blood and stationary tissue. It is concluded that two-dimensional gradient refocused imaging may be a valuable angiographic method in the evaluation of abdominal veins.

Constriction, Pathologic↗
PubMedDate not supplied

Imaging of hemodialysis fistulas: limitations of MR angiography.

The clinical feasibility and utility of a three-dimensional (3D) MR angiography (MRA) were evaluated in 20 patients with hemodialysis fistulas. All patients had well functioning shunts and were imaged with a fast imaging in steady precision (FISP) flow rephased and flow dephased sequence. For comparison digital subtraction angiography and color-coded image directed Doppler sonography were used. Of 20 patients studied, 4 interrupted the MR examination due to pain in the shoulder of the extremity imaged. Of the 16 remaining fistulas only 2 were completely displayed on MR including feeding artery, anastomosis, and draining vein(s) on the MRA. Although 15 of 16 feeding arteries were shown by MRA, 10 of 16 draining veins and 14 of 16 anastomoses of the fistulas showed signal voids due to a lack of rephasing. Superimposing the MRA on the dephased images helped to demonstrate the shunt in another four patients having normal shunts. Thus, the utility of 3D MRA in imaging of hemodialysis fistulas is limited by technical problems and by patient's cooperation.

Adult↗