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Biomedical subjects

M Goyen

Publications and source records attributed to M Goyen.

At least 19 recordsLinked to original sources
PubMed2002

[MR Angiography: First choice for diagnosis of the arterial vascular system].

Contrast medium-enhanced, 3D MR angiography enables an extensive and diagnostically accurate evaluation of arterial vessels in the neck, thorax, abdomen, and limbs. Advances in the field of MR apparatus technology and the introduction of contrast-medium enhanced MR angiographic techniques have made this development possible. Contrast medium-enhanced MR angiography combines the intravenous bolus administration of a paramagnetic contrast medium with the rapid acquisition of 3D datasets. The possibilities for obtaining data in the thorax and abdomen within one breath-hold, the resulting high contrast between vessel lumen and surrounding soft tissue as well as the inherent 3D nature of the images allow for diagnostically relevant image quality. In many centers contrast-enhanced 3D MR angiography has widely replaced the conventional digital subtraction roentgenography for the clarification of pathologies in arterial vessels. This review presents a survey of the technical background of contrast medium eýnhanced 3D MRA. In addition, the spectrum of indications is given and discussed on the basis of clinical examples.

Arteries↗
PubMed2001

Rapid magnetic resonance angiography for detection of atherosclerosis.

BACKGROUND: Choice of treatment for atherosclerosis depends on various clinical factors and radiological techniques. We aimed to assess the diagnostic accuracy of a new three-dimensional magnetic resonance angiography (3D MRA) strategy for the display of arterial vasculature from supra-aortic arteries to distal runoff vessels in 72 s. METHODS: We examined five healthy volunteers and six patients over 6 weeks. Conventional digital subtraction angiography (DSA) was available as reference standard in all six patients. Magnetic resonance imaging was done on a commercially available 1.5 Tesla scanner. The imaging technique was based on the acquisition of five 3D data sets in rapid succession with an optimum single injection protocol. FINDINGS: Compared with conventional catheter angiography, according to the findings of two independent and masked readers, whole-body MRA had overall sensitivities of 91% (95% CI 0.76-0.98) and 94% (0.8-0.99), and specificities of 93% (0.85-0.97) and 90% (0.82-0.96) for the detection of substantial vascular disease (luminal narrowing >50%), interobserver agreement for assessment of whole-body magnetic angiograms was very good (kappa=0.94; 95% CI 0.9-0.98). INTERPRETATION: The technique provides a comprehensive non-invasive approach for morphological screening assessment of the arterial vasculature from supra-aortic arteries to the distal runoff arteries.

Adult↗
PubMed2001

Dynamic 3D MR angiography of the pulmonary arteries in under four seconds.

Although 3D MRA has been shown to provide excellent depiction of the pulmonary arterial tree, its clinical use has been limited due to lengthy breath-holding requirements. Employing the newest gradient generation (1.5 T MR system, amplitude of 40 mT/m and a slew rate of 200 mT/m/msec), we evaluated a technique permitting the dynamic acquisition of 3D data sets of the entire pulmonary tree in under 4 seconds. Coronal image sets were collected using a repetition time of 1.64 msec and an echo time of 0.6 msec, resulting in an acquisition time of 3.74 seconds. Three volunteers and eight dyspneic patients with known or suspected pulmonary embolism underwent MRI of the pulmonary arteries. The pulmonary arterial tree was visible to a subsegmental level in all examined subjects. Regarding the presence of pulmonary emboli in four patients, there was complete concordance between MR angiographic findings and those of corroborative studies. We conclude that diagnostic MRA of the pulmonary vasculature can be obtained even in patients with severe respiratory distress.

Dyspnea↗
PubMed2001

Pulmonary arteriovenous malformation: Characterization with time-resolved ultrafast 3D MR angiography.

To avoid potentially deadly consequences from paradoxical emboli, early detection and accurate characterization of pulmonary arteriovenous malformations (AVMs) is highly desirable. We report on a patient with a suspected pulmonary AVM who underwent ultrafast time-resolved 3D MR angiography of the pulmonary arteries. The case documents the suitability of the MRA technique as a noninvasive alternative to computed tomographic angiography and digital subtraction angiography for accurate pre-therapeutic characterization of pulmonary AVMs.

Arteriovenous Malformations↗
PubMed2001

Improved multi-station peripheral MR angiography with a dedicated vascular coil.

Delineation of small branch vessels can be crucial for assessing the peripheral arterial system of patients requiring surgical grafting. Thus signal-to-noise needs to be maximized. We evaluated the performance of a dedicated peripheral vascular coil in four subjects by comparing it to the body coil using DSA as the standard of reference. SNR and CNR values of the dedicated peripheral coil exceeded those obtained with the body coil by a mean of 398%, thus permitting improved delineation of the infrapopliteal arterial morphology.

Adult↗
PubMed2001

0.5 M Gd chelate (Magnevist) versus 1.0 M Gd chelate (Gadovist): dose-independent effect on image quality of pelvic three-dimensional MR-angiography.

To compare the effect on image quality of a 1.0 M gadolinium (Gd) chelate to that of a conventional 0.5 M Gd chelate, five healthy volunteers and seven patients with angiographically documented aorto-iliac disease underwent a mono-station three-dimensional magnetic resonance angiography (MRA) exam (Siemens SONATA, Erlangen, Germany) twice, once using Gadovist 1.0 and the other time using Magnevist as the contrast agent. All subjects received a fixed volume of Gadovist 1.0, corresponding to a dose between 0.1 and 0.15 mmol/kg body weight followed by a saline flush. For the Magnevist exam, the contrast agent volumes and flow rates were doubled. For both quantitative and qualitative analysis of the angiographic data sets, the arterial tree was divided into nine segments. 1 M Gadovist 1.0-enhanced three-dimensional MRA data sets were characterized by significantly higher signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) values compared to 0.5 M Magnevist-enhanced images. The data revealed mean SNR/CNR increases exceeding 70% (P < 0.01). Although there was no statistically significant difference in the rating of image quality (P > 0.05), the Gadovist 1.0 exam led to better delineation of the arterial morphology, especially of small vessels.

Adult↗
PubMed2001

[Modern diagnostic concepts in dissection and aortic occlusion].

For the diagnostic work-up of the aorta, non-invasive cross-sectional imaging techniques have almost replaced invasive catheter angiography. CT- and MR-angiography are supplemented by sonography which is used predominantly for the assessment of abdominal aortic aneurysm and dissections of the thoracic aorta. This review deals with the diagnostic approach to two disease entities involving the aorta: aortic dissection and aortic occlusion. Transoesophageal echocardiography (TEE), CT- and MR-angiography (MRA) are used in the assessment of aortic dissection. Published sensitivity and specificity values regarding the detection and classification of dissections into Stanford A and Stanford B range between 96-100% for all three modalities. Results for multislice CTA have not yet been reported, but can be expected to be at least as good. The ability to delineate additional information regarding the precise morphology of true and false lumen, entry and reentry-sites, the development of thrombus or paraaortic hematomas, as well as the assessment of aortic regurgitation or involvement of coronary arteries depend on the chosen technique. Reflecting the ability to collect functional imaging data, both TEE and MRA are superior to CTA in the assessment of aortic valve involvement, while TEE is the modality of choice for evaluation of coronary arteries. Sonography is of limited use in the assessment of abdominal dissections. For the evaluation of patients with suspected aortic occlusion both CTA and MRA represent the imaging modalities of choice. Both provide for a comprehensive and precise depiction of the underlying aortic morphology, the extent of collateral flow as well as delineation of distal run-off vessels. MRA should be employed in patients with impaired renal function as paramagnetic contrast agents are not nephrotoxic.

Aged↗
PubMed2001

[Contrast-enhanced 3D MR venography of central thoracic veins: preliminary experience].

PURPOSE: To evaluate the usefulness of three-dimensional (3D) gadolinium-enhanced magnetic resonance (MR) venography for evaluation of thoracic central veins. MATERIALS AND METHODS: Over a 4-month period, 14 patients with suspected central venous abnormalities were examined on a 1.5 T scanner (Magnetom Sonata, SIEMENS, Germany) by means of MR venography. A FLASH-3D sequence using the following parameters was employed: TR 1.6 ms, TE 0.6 ms, TA 3.74 s, flip: 15 degrees, slab thickness 110 mm, effective slice thickness: 2.75 mm, 40 partitions, FOV 360 mm, matrix 140 x 256. 10 s prior to imaging 20 ml of Gd-DOPTA (Multihance, BRACCO, Italy) were automatically injected (MEDRAD, Pittsburgh, USA) flushed by 20 ml of normal saline (flow 4 ml/s). Six 3D data sets were acquired in immediate succession in under 24 s. Results were corroborated with findings from duplex sonography. RESULTS: MR venograms were of diagnostic quality for all 14 patients. Compared to duplex sonography thromboses, post-thrombotic changes as well as functional compressions were reliably detected. Unsuspected findings were found in two patients. CONCLUSION: The outlined strategy allows for dynamic diagnostic imaging of central thoracic veins. Gadolinium-enhanced breath-hold 3D MR venography is easy to perform, well tolerated and highly accurate in assessing central venous pathology.

Adult↗
PubMed2001

Peripheral magnetic resonance angiography.

Peripheral vascular disease (PVD) is a common disorder in western society. Reflecting on the risks and costs of contrast arteriography, magnetic resonance angiography is a powerful noninvasive imaging modality for the diagnostic workup of patients with peripheral vascular disease. This article reviews the current state of the art of magnetic resonance angiography of the peripheral vasculature.

Contrast Media↗
PubMed2001

MR evaluation of ventricular function: true fast imaging with steady-state precession versus fast low-angle shot cine MR imaging: feasibility study.

Short- and long-axis cine magnetic resonance (MR) images were obtained with a standard fast low-angle shot, or FLASH, sequence and a first-generation true fast imaging with steady-state precession (FISP) sequence on a 1.5-T MR imager. Contrast-to-noise ratios and volumetric left ventricular measurements were compared for manual and automatic segmentation. True FISP images were associated with significantly (P<.01) higher contrast-to-noise ratios and allowed better detection of the endocardial border. True FISP images were provided with short acquisition times and excellent contrast between the myocardium and the ventricular lumen.

Adult↗
PubMed2001

Whole-body MR imaging in 30 seconds with real-time true FISP and a continuously rolling table platform: feasibility study.

A technique for whole-body magnetic resonance (MR) imaging in only 30 seconds was developed on the basis of a rolling table platform with integrated surface coils and real-time true fast imaging with steady-state precession. In five patients, all hepatic and pulmonary lesions with a diameter exceeding 8 mm were detected by using thoracic and abdominal helical computed tomography as the reference method. Whole-body MR imaging with real-time true fast imaging with steady-state precession is feasible and may be suitable for tumor screening and staging.

Adult↗
PubMed2000

Interventional therapy of vascular complications caused by the hemostatic puncture closure device angio-seal.

The hemostatic puncture closure device Angio-Seal is a quick, safe, and easy-to-use system, allowing rapid sealing of the vascular access site following coronary angiography and interventional procedures. It is advantageous for patients in whom early mobilization is desired and may therefore decrease hospital costs. Despite the documented low complication rate, there are some specific problems. Reporting on five cases, we describe problems in diagnosis and possible interventional therapy of Angio-Seal-associated complications such as stenosis, occlusion, or peripheral embolism. Our experience led to the concept of precise diagnosis in any patient with leg symptoms and early interventional treatment with the aim of complete removal of the intra-arterial parts of the Angio-Seal device. Any delay in diagnosis and treatment increases the risk of additional thrombotic occlusion. Spontaneous dissolution of the Angio-Seal sponge limits interventional possibilities of complete removal. Cathet. Cardiovasc. Intervent. 49:142-147, 2000.

Adult↗
PubMed2000

MR-angiography: the role of contrast agents.

Contrast-enhanced 3D MR angiography (MRA) permits comprehensive assessment of the supraaortic arteries as well as the arterial system in the chest, abdomen and lower extremities. 3D MRA combines intravenous injection of a non-nephrotoxic, paramagnetic, extracellular contrast agent that increases the signal intensity of blood by shortening its T1 value with the acquisition of a fast 3D data set. High contrast between the vascular lumen and surrounding tissues, inherent three-dimensionality and the ability to collect image data in the chest and abdomen under apnea conditions all contribute to excellent image quality. This review provides clinical applications of 3D MRA in the chest, abdomen and lower extremities based upon the available literature and several clinical examples.

Aorta, Abdominal↗
PubMed2000

[Hypothenar hammer syndrome: causes, sequelae and diagnostic aspects].

PURPOSE: To investigate the reasons and disease course of Hypothenar Hammer Syndrome. INTRODUCTION: Occlusion of the ulnar artery at the level of the hamate bone due to repetitive trauma to the hypothenar eminence is implicated as the cause of the rarely diagnosed hypothenar hammer syndrome (HHS). The thrombotic occlusion and the formation of an aneurysm of the ulnar artery and the superficial palmar arch with possible peripheral embolism of the digital arteries are a direct cause of the chronic damage to the vessel wall. Generally, HHS is diagnosed too late for recanalization to be a viable therapeutic option. METHODS: From 1996 to 1998 the diagnosis of an HHS was made in 8 patients at our hospital. Etiology, clinical settings and disease course were assessed. RESULTS: Our analysis suggests that HHS may be caused by a single severe trauma in addition to repetitive injuries. The pathogenesis of the syndrome is dependent on the vascular anatomy of the individual hand. Interindividual variations in the arterial supply of the affected hand influences the clinical symptomatology with possible masking of arterial occlusions. CONCLUSION: An exact investigation concerning the pathogenesis of HHS is a precondition for treating the disease and may help to establish HHS as an occupational disease. MR-angiography may be a new approach for assessing HHS.

Adult↗
PubMed2000

[Whole-body MRA on a rolling table platform (AngioSURF)].

PURPOSE: Development of a technique for whole-body MR angiography based on a rolling table platform and integration of a surface coil. MATERIAL AND METHODS: The developed rolling table platform AngioSURF (System for Unlimited Rolling Field-of-view) with integrated surface coil can be mounted on top of the original patient table of a Siemens Symphony System. Data acquisition was performed with a standard body array surface coil. The system was tested on three volunteers and one patient with angiographically documented vascular pathology. Data acquisition was performed with a 3D-FLASH-sequence (TR/TE 2.1/0.7 ms, flip angle: 20 degrees, FOV 40 x 40 cm, 80 partitions, matrix 512 x 420 with zero interpolation). Five data sets were collected in immediate succession during continuous injection of a paramagnetic contrast agent. Time of acquisition per data set was 10 seconds. Table repositioning was performed manually within 3 seconds. Thus the total acquisition time amounted to 72 seconds. RESULTS: No problems with handling occurred in any of the four cases. The excellent image quality enables detailed assessment of the displayed vascular territories. CONCLUSIONS: The rolling table platform with integrated surface coil (AngioSURF) allows diagnostic display of the arterial vascular system from supraaortic vessels to the distal trifurcation arteries in only 72 seconds.

Angiography↗
PubMed2000

Intravascular ultrasound angioplasty in peripheral arterial occlusion. Preliminary experience.

PURPOSE: To determine if ultrasound angioplasty in a percutaneous approach was capable of recanalizing occluded arteries in acute and subacute peripheral arterial occlusions. MATERIALS AND METHODS: We applied an ultrasound angioplasty device in a percutaneous approach in 9 patients with peripheral arterial occlusions. All patients suffered from severe leg ischemia due to subacute thrombotic occlusions. RESULTS: The ultrasound transmitter easily created a channel within the occlusive material. To further reduce the mass of the occlusive material, an aspiration thrombectomy was performed in all cases, leading to a complete recanalization in 7 cases. In 2 cases, a remaining stenosis was successfully dilated. CONCLUSION: Intravascular ultrasonic devices can be useful for recanalization of occluded peripheral arteries. In particular, if thrombolytic therapy of longer peripheral arterial occlusions fails or is contraindicated, ultrasound angioplasty may be a new approach for recanalization.

Acute Disease↗
PubMed2000

Improved peripheral MRA using multi-velocity-encoding phase contrast-enhanced MRA techniques.

Phase contrast MR angiography (PC-MRA) depends on phase shifts caused by blood flow. Generally, PC sequences employ one VENC (velocity-encoding) value for each encoded spatial direction to optimize the signal in major vessels during peak systolic flow. We compared a mono-(30) with a multi-(20/30/45) VENC-PC-MRA technique in 10 patients with peripheral arterial occlusive disease. In all patients, the multi-VENC-PC sequence enhanced the vascular signal in vessels with very different flow velocities in one measurement. Large fields-of-view can be measured in a relatively short examination time to obtain an overview of the peripheral arterial system of the patient when contrast-enhanced MRA is not possible.

Arterial Occlusive Diseases↗