Biomedical subjects
Publications and source records attributed to M Goyen.
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.
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.
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.
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.
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.
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.
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.
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.
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.
Radiography of the pelvis may incidentally reveal a rare congenital anomaly called "pelvic digit" and it is important to be aware of its existence in order to differentiate it from acquired abnormalities due to trauma. A case of a pelvic digit with CT correlation is presented and the literature is reviewed.
BACKGROUND: Risk factors and especially the combination of multiple risk factors are associated with the development of atherosclerosis. Therefore, patients with an early manifestation of atherosclerotic disease are likely to show an extraordinary risk profile. We analysed the frequencies and severity of risk factors in young patients with manifest peripheral arterial occlusive disease as compared to old patients. METHODS: We analysed the risk profiles in 303 patients who were sent for interventional treatment of a symptomatic peripheral arterial occlusive disease. The risk profiles were described for different age groups (54 patients under 50 years of age, 194 patients from 51 to 74 years, 55 patients over 75 years). Multiple linear regression analysis and analysis of variance were performed to look for age-dependent effects. RESULTS: Elevated total cholesterol, and triglyceride levels and nicotine abuse were more frequent in patients younger than 50 years. Diabetes mellitus and hypertension were more frequent in patients older than 75 years. The different frequencies for smoking, diabetes mellitus and hypertension were age-related (p<0.05). Concerning laboratory parameters such as HDL- and LDL-cholesterol, fibrinogen, lipoprotein(a) and homocysteine there were no relevant age-related differences in frequency nor in absolute values with the exception of the hematocrit and uric acid. The coincidence with clinically manifest myocardial infarction was 11.15% in the patients under 50 years compared to 20.6% in those aged 51-74 years and 16.4% in those over 75 years, for cerebral stroke it was 5.6%, 17.5% and 14.5%, respectively. Patients under 50 years with peripheral arterial occlusive disease and a history of myocardial infarction were characterised by high levels of total cholesterol, triglyceride and lipoprotein(a). Excluding patients with prior myocardial infarction patients did not show any difference in risk profile between the three age groups. CONCLUSIONS: In a population suffering from manifest peripheral arterial occlusive disease the risk profile in patients under 50 years is not different from that in older patients. In contrast an additional myocardial infarction in such a population is associated with pathological lipid profiles.
We report about a 29 year old female who developed right-sided leg vein thrombosis over three levels. Thrombectomy was attempted followed by intravenous anticoagulation with heparin. The platelet count dropped acutely from 176,000/microliter to 11,000/microliter after the sixth day. A lung perfusion-ventilation-scintigraphy suggested recent pulmonary embolism by lateral, predominantly right-sided perfusion deficits. ACT scan of the pelvic region showed rethrombosis of the right common iliac vein. The clinical suspicion of heparin-induced thrombocytopenia (HIT) type II was confirmed by a positive heparin-induced platelet aggregation test and the detection of antibodies by heparin-platelet factor 4-ELISA. The patient was treated with lepirudin at body-weight-adapted dose. After recovery of the platelet count to 102,000/microliter within seven days the treatment was changed to Orgaran after exclusion of immunologic cross reactivity. An overlapping oral anticoagulation with Marcoumar was initiated. Although HIT type II usually develops over a few days, acute thrombopenia can also occur. There is therefore no safe diagnostic interval permitting a timely detection.
A dissection of the superficial femoral artery mainly occurs due to trauma or manipulation of the artery by means of interventional procedures. In contrast to dissections of the carotid arteries which are known to occur spontaneously we present the case of a stenosis of the superficial femoral artery that led to a dissection caused by the stenosis-jet. The dissection on the other hand caused an appositional thrombus which led to the embolic occlusion of the pedal-arteries. In case of peripheral embolisms in patients with or without history of peripheral arterial occlusion disease it is important to look for a causing arterial pathology preferably by duplex sonography.
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Since the development of percutaneous transluminal angioplasty several techniques such as laser or atherectomy devices have been developed for recanalization of peripheral arterial occlusions. In a first clinical study we investigated if also the application of intravascular ultrasound can be useful for recanalization of occluded peripheral arteries. We applied an ultrasound angioplasty device (ACOLYSIS, ANGIOSONICS, USA) in a percutaneous approach in 8 patients with peripheral arterial occlusions (7 femoro-popliteal segments, 1 external iliac artery-occlusion). All patients suffered from severe leg ischemia due to subacute thrombotic occlusions. The ultrasound transmitter was introduced and advanced under fluoroscopic guidance to the site of the lesion. After activation the ultrasound transmitter was slowly advanced into the occlusion easily creating a channel within the occlusive material. Depending on the length of the occlusion (5-16 cm) treatment times ranged from 120-480 s. To further reduce the mass of the occlusive material an aspiration thrombectomy was performed in all cases leading to a complete recanalization in 6 cases. In 2 cases a remaining stenosis was successfully dilated. Intra-vascular ultrasonic devices can be useful for recanalization of occluded peripheral arteries. With the use of high-energy ultrasound a selective injury of the occlusive material can be induced without damaging the surrounding arterial wall. This selectivity is based on the differences in elasticity between the atherosclerotic plaque and the media layers. Especially if thrombolytic therapy of longer peripheral arterial occlusions fails or is contraindicated ultrasound angioplasty may be a new approach for recanalization.
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Magnetic resonance angiography (MRA) has become firmly established within the scope of diagnostic imaging procedures for assessing many pathological conditions and, depending on the questions posed, is often used on its own or as a supplementary method. MRA allows the (non)-invasive visualization of the vasculature by using the effects of moving spins on the magnetic resonance signal. MRA techniques can be classified into two different techniques depending on how the contrast is achieved: Time-of-flight (TOF) and phase contrast (PC) methods. Both methods have advantages and limitations as an imaging technique. This article outlines the basic understanding of MRA as well as the recent rapid expansion in MRA acquisition and processing techniques.
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