Biomedical subjects

Mathias Goyen

Publications and source records attributed to Mathias Goyen.

45 records · Page 3Linked to original sources

PubMed2002

[Arterial vascular screening with whole body MR angiography].

Atherosclerosis represents a frequent health problem in developed countries. Although a systemic disease, the diagnostic approach to atherosclerosis has remained segmental. Largely, this approach has been a reflection of limitations inherent to the imaging techniques used. Recently, whole-body MR angiography has become possible allowing the display of the arterial vasculature from the supraaortic arteries to the distal run-off vessels in merely 72 seconds. The technique provides images quality comparable to catheter angiography. The advantage of this approach relates to its potential in detecting vascular pathologies in regions which would have remained unexamined with conventional diagnostic management. Thus, the outlined strategy of whole-body MR angiography mirrors the systemic nature of atherosclerosis and can be used as a noninvasive comprehensive screen for arterial disease screening.

Arterial Occlusive Diseases↗

PubMed2002

Whole-body MRI using a rolling table platform for the detection of bone metastases.

The aim of this study was to compare the results of whole-body MRI using a recently developed rolling table platform with findings of nuclear scintigraphy in patients with bone metastases. Twenty-six patients with known or suspected bone metastases who had undergone radionuclide scintigraphy were examined by MRI. Patients were placed on a rolling table platform with integrated phased-array surface coils [BodySURF (system for unlimited field of view)] capable of pulling the patient through the isocenter of the magnet. Using a five-station approach three different image sets (T1-weighted gradient recalled echo, half-Fourier acquired single-shot turbo spin echo, and short tau inversion recovery) were collected in the coronal plane. In addition, the spine was imaged in the sagittal plane. The MRI findings were compared with the results obtained by scintigraphy. The whole-body MR examination lasting merely 40 min was feasible in all 26 patients. The MRI revealed excellent correlation with scintigraphy regarding metastatic lesions. A total of 60 regions with metastatic lesions were identified on bone scintigraphy. Fifty-three regions were detected on identical locations by MRI. The regions missed by MRI were located mainly in ribs and skull. The MRI could identify additional bone metastases in spine, pelvis, and femur. The MRI screening for bone metastases correlated well with bone scintigraphy. Use of the rolling table platform permits rapid imaging based on three different contrast mechanisms of the entire skeletal system.

Adult↗

PubMed2002

MR angiography for assessment of peripheral vascular disease.

Contrast-enhanced 3D MRA is emerging as a powerful noninvasive imaging modality for the assessment of patients with PVD. Its clinical utility using current technology has already been well established, and the continuous development of hard- and software will likely result in significantly improved performance. Thus, Gd-enhanced MRA is likely to emerge as the dominant noninvasive imaging modality for PVD worldwide.

Contrast Media↗

PubMed2002

Right-lobe living related liver transplantation: evaluation of a comprehensive magnetic resonance imaging protocol for assessing potential donors.

The purpose of this study was to determine the practicability and diagnostic accuracy of a magnetic resonance (MR) protocol capable of replacing computed tomography, catheter angiography, and endoscopic retrograde cholangiopancreatography for the presurgical evaluation of potential liver donors before right hepatectomy. MR imaging (MRI) was performed on a 1.5 T scanner using a phased-array torso surface coil for signal reception. The following image sets were collected: axial two-dimensional (2D) T1-weighted fast low angle shot (FLASH), axial 2D T2-weighted half-Fourier acquisition single-shot turbo-spin-echo (HASTE) with fat saturation, coronal MR cholangio-pancreatography (MRCP) based on 2D multisection HASTE and single-section single-shot rapid acquisition with relaxation enhancement (RARE) imaging, dynamic contrast-enhanced three-dimensional (3D) FLASH, and contrast-enhanced T1-weighted FLASH. 3D FLASH data sets were collected before and after an intravenous administration of Multihance (gadobenate dimeglumine, Gd-BOPTA; Bracco, Milano, Italy), 0.2 mmol/kg of body weight. Thirty-eight potential liver donors were assessed by means of MRI. Twenty patients also underwent digital subtraction angiography (DSA). Of these, 16 patients underwent liver harvesting. MR angiography (MRA) data sets correlated with DSA results, and MRCP results correlated with intraoperative findings. Patients were excluded as potential donors based on insufficient liver mass of the left hepatic lobe (n = 5) or presence of hepatic pathological states (n = 9) seen at MRI, such as hemangiomas, focal nodular hyperplasias, or hepatic steatosis. MRCP showed the biliary system to the level of the first hepatic side branch. Dilated ducts were present in 4 patients. MRA depiction of hepatic arterial morphological characteristics correlated with catheter angiography results in all 20 patients: Three left hepatic arteries originating from the left gastric artery, three aberrant right hepatic arteries originating from the superior mesenteric artery, and two aberrant origins of both hepatic arteries and one common hepatic artery originating from the superior mesenteric artery were correctly identified on MRA. Similarly, the portal venous system was fully assessed on MRA. A comprehensive assessment of the hepatic parenchyma, biliary and pancreatic ductal system, and hepatic arterial, portal, and venous systems can be accomplished using the outlined protocol.

Adult↗

PubMed2002

Optimization of contrast dosage for gadobenate dimeglumine-enhanced high-resolution whole-body 3D magnetic resonance angiography.

RATIONALE AND OBJECTIVES: To determine the optimal dose of gadobenate dimeglumine for diagnostic high-resolution whole-body 3D-MR angiography. METHODS: Ten healthy volunteers were examined three times with an ascending dose of Gd-BOPTA (0.1/0.2/0.3 mmol/kg BW). Three-dimensional data sets were collected with a rolling table platform (AngioSURF; MR-Innovation GmbH, Essen, Germany) which integrates the torso surface coil, using a 3D FLASH sequence at five stations from carotid arteries to the trifurcation vessels in 72 seconds. SNR- and contrast-to-noise-values were calculated for 30 segments per patient. For qualitative evaluation a 4-point-visualization scale was used. RESULTS: Overall, significantly (P < 0.05) higher signal-to-noise values and CNR values were determined for Gd-BOPTA at a dose of 0.2 and 0.3 mmol/kg compared with 0.1 mmol/kg. Similarly, the qualitative analysis demonstrated image quality to be superior with 0.2 and 0.3 mmol/kg compared with 0.1 mmol/kg (P < 0.05). Qualitative and quantitative assessment failed to demonstrate a statistically significant difference between 0.2 and 0.3 mmol/kg BW (P > 0.05). CONCLUSION: A dose of 0.2 mmol/kg BW Gd-BOPTA rendered diagnostic image quality in all vascular segments of all volunteers.

Adult↗

PubMed2002

Contrast-enhanced magnetic resonance imaging (MS-325) in a murine model of systemic lupus erythematosus.

RATIONALE AND OBJECTIVES: To investigate whether inflammatory activity can be evaluated by MRI with an intravascular compound (MS-325) in Desoxyribonuclease I (Dnase1)-deficient mice, which show classical symptoms of systemic lupus erythematosus. METHODS: Dnase1-deficient and normal mice (both groups n = 10) underwent MRI with a body weight adapted dose of MS-325 on a 1.5 T whole body scanner equipped with a dedicated surface coil. MR images of the kidneys and the aorta and signal to noise ratios prior and post contrast administration were compared with histopathology in all animals. RESULTS: Dnase1-knockout mice demonstrated aortic-wall enhancement and inhomogeneous-renal enhancement with significantly higher SNR values corresponding to microscopically proved inflammatory changes (P < 0.05). CONCLUSION: MS-325-enhanced MRI appears to be a sensitive tool for the detection of renal and vascular involvement in this animal model. In addition, this method may facilitate assessment of therapeutic approaches in patients with SLE in the future.

Animals↗

PubMed2002

Whole-body three-dimensional MR angiography with a rolling table platform: initial clinical experience.

A technique for performing whole-body magnetic resonance (MR) angiography with multi-station three-dimensional MR angiography by using a self-developed rolling table platform that integrates the surface coil was evaluated in three volunteers and 10 patients. Use of the surface coil resulted in high signal-to-noise and contrast-to-noise ratios, which translated into sensitivity and specificity of 95.3% and 95.2%, respectively, for detection of significant stenoses (luminal narrowing, >50%) in lower extremity peripheral vascular disease.

Adult↗

PubMed2002

Assessment of ventricular function with single breath-hold real-time steady-state free precession cine MR imaging.

OBJECTIVE: The aim of our study was to evaluate whether a recently developed real-time steady-state free precession (trueFISP) cine sequence could be used to assess left ventricular function in a single breath-hold. CONCLUSION: Using real-time trueFISP permits one to assess left ventricular function in a single breath-hold. The dramatic reduction in data acquisition time does require some compromises. The temporal and spatial resolutions of images obtained with real-time trueFISP were considerably lower than those achieved with segmented trueFISP. Further reduction of the TR or the use of sensitivity encoding could improve temporal resolution and eliminate other limitations of real-time trueFISP.

Adult↗

PubMed2001

Visualization of swallowing using real-time TrueFISP MR fluoroscopy.

The aim of this study was to evaluate the ability of different real-time true fast imaging with steady precession (TrueFISP) sequences regarding their ability to depict the swallowing process and delineate oropharyngeal pathologies in patients with dysphagia. Real-time TrueFISP visualization of swallowing was performed in 8 volunteers and 6 patients with dysphagia using a 1.5 T scanner (Magnetom Sonata, Siemens, Erlangen Germany) equipped with high-performance gradients (amplitude 40 mT/m). Image quality of four different real-time TrueFISP sequences (TR 2.2-3.0 ms, TE 1.1-1.5 ms, matrix 63 x 128-135 x 256, field of view 250 mm(2), acquisition time per image 139-405 ms) was evaluated. Water, yoghurt, and semolina pudding were assessed as oral contrast agents. Functional exploration of the oropharyngeal apparatus was best possible using the fastest real-time TrueFISP sequence (TR 2.2 ms, TE 1.1 ms, matrix 63 x 128). Increased acquisition time resulted in blurring of anatomical structures. As the image contrast of TrueFISP sequences depends on T2/T1 properties, all tested foodstuff were well suited as oral contrast agents, but image quality was best using semolina pudding. Real-time visualization of swallowing is possible using real-time TrueFISP sequences in conjunction with oral contrast agents. For the functional exploration of swallowing high temporal resolution is more crucial than spatial resolution.

Adult↗