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Biomedical subjects

G Wilms

Publications and source records attributed to G Wilms.

At least 19 recordsLinked to original sources
PubMed1995

Thrombolytic therapy of peripheral arterial occlusion with recombinant staphylokinase.

BACKGROUND: Recombinant staphylokinase (STAR) induces fibrin-specific coronary artery recanalization in patients with evolving myocardial infarction. The present pilot study evaluates its thrombolytic efficacy, safety, fibrin specificity, and immunogenicity in patients with peripheral arterial occlusive disease. METHODS AND RESULTS: Thirty patients (37 to 86 years of age) with angiographically documented thromboembolic peripheral arterial occlusion of recent origin (21 +/- 5.5 days, mean +/- SEM) were treated with heparin and intra-arterial STAR given as a 1-mg bolus followed by a 0.5-mg/h infusion in 20 patients or as a 2-mg bolus followed by a 1-mg/h infusion in 10 subsequent patients. With 7.0 +/- 0.7 mg STAR infused over 8.7 +/- 1.0 hours, recanalization was complete in 25 patients, partial in 2, and absent in 3. Two major hemorrhagic complications occurred: one fatal hemorrhagic stroke and one hypovolemic shock caused by bleeding at the angiographic puncture site. Administration of STAR did not induce fibrinogen breakdown or a significant prolongation of template bleeding time. STAR-neutralizing activity and anti-STAR IgG were low at baseline, increased markedly from the second week on, and remained elevated for several months. CONCLUSIONS: Intra-arterial administration of STAR restores vessel patency in patients with peripheral arterial occlusion in the absence of fibrinogen degradation.

Female↗
PubMed1995

Characterisation of intracranial aneurysms with MR angiography.

The purpose of this study was to compare the accuracy of 3D time-of-flight (TOF) acquisitions in the characterisation of intracranial aneurysms. Fourteen patients with aneurysms proven on intra-arterial angiography were first studied with a 3D TOF acquisition. When the aneurysms were incompletely demonstrated, additional MR angiography (MRA) acquisitions were performed, including black-blood MRA, 2D TOF, phase-contrast and contrast-enhanced TOF.3D TOF MRA was sufficient for detection of the aneurysm in 13 of 14 cases and characterisation of the aneurysm was possible in 6. All the initial shortcomings of the TOF technique could be analysed and explained by means of additional MRA techniques. This study suggests that the combination of different MRA techniques offers new possibilities for noninvasive investigation of intracranial aneurysms.

Adult↗
PubMed1995

Magnetic resonance angiography of supratentorial tumours: comparison with selective digital subtraction angiography.

We compared magnetic resonance angiography (MRA) and intra-arterial digital subtraction angiography (IADSA) in the study of brain tumours and assessed the utility of gadolinium-enhanced MRA. We studied 17 patients with supratentorial brain tumors. The entire brain was imaged with multiple overlapping thin volume acquisitions. After IV injection of gadolinium-DTPA, a single thick-slab MRA acquisition was performed. Standard three-dimensional (3D-TOF) acquisitions (in six patients) and 3D-TOF with magnetization transfer prepulse and tilted optimisation nonsaturing radiofrequency excitation pulses (in 11 patients) were used. Displacement of the anterior cerebral artery, main stem and insular branches of the middle cerebral artery was seen well on unenhanced and contrast-enhanced MRA. Displacement of the lenticulostriate and anterior choroidal arteries was seen only once, after Gadolinium. Tumour encasement of the middle cerebral artery was demonstrated in one patient. Tumour vessels were seen in 2 of 8 cases before and 3 of 8 after gadolinium; Tumour hypervascularity was seen only after gadolinium, in 3 of 8 cases. Study of the veins was possible only on gadolinium-enhanced MRA. Displacement of the venous angle was seen in 4 of 7 patients in the frontal, and in all of 8 patients on the lateral projections. Early venous drainage was not seen. Patency of the dural venous sinuses was demonstrated in all patients, but in one neoplastic occlusion of a cortical vein was recognized.

Adult↗
PubMed1995

Uncommon posterior cranial fossa anomalies: MRI with clinical correlation.

The clinical and MRI findings in two cases of rhombencephalosynapsis (RS) and two of tectocerebellar dysraphia (TCD) with an associated occipital encephalocele were studied to elucidate the clinical picture and embryogenesis of these rare anomalies. To our knowledge, only one case of TCD [1] and four of RS [2, 3] examined by MRI during life have been reported. The clinical picture in the cases of RS was rather constant and there were similarities with TCD. Consideration of the embryogenesis of the neural tube suggests a temporal proximity of the abnormalities, with TCD arising at a slightly earlier time.

Cerebellum↗
PubMed1995

Time-of-flight MR angiography of the brain: comparison of acquisition techniques in healthy volunteers.

OBJECTIVE: The saturation phenomenon that limits vessel visibility in unenhanced time-of-flight MR angiograms can be overcome by the injection of MR contrast agents that shorten the T1 of the blood. Unlike the situation with unenhanced MR angiographic acquisitions, in which the MR parameters must be carefully adjusted to reduce saturation effects, optimization procedures for contrast-enhanced MR angiography focus on the acquired shortening of the T1 of the blood and the time evolution of the T1 over the entire measurement. To improve the quality of contrast-enhanced time-of-flight MR angiographic acquisitions in the brain, we compared different acquisition techniques that exploit shortening of the T1 of the blood. SUBJECTS AND METHODS: High-resolution MR angiographic examinations were done with a 1-T MR system for 12 healthy volunteers. Doses of 0.1 and 0.2 mmol of gadopentetate dimeglumine per kilogram of body weight were injected on two separate days to allow for identical timing of the comparative studies after contrast material injection. The effects of dose of contrast material, MR parameters (TR and flip angle), method of injecting the contrast material (monophasic, biphasic, or continuous slow injection), and K-space acquisition schemes (regular schemes versus collecting the central K-space lines near the beginning or the end of the acquisition) were studied. RESULTS: Higher doses provided better MR angiograms. The flip angle and the TR had to be adjusted on the basis of the Ernst equation and therefore depended on an estimation of the averaged T1 value over the entire measurement. Comparison of the different K-space acquisition schemes confirmed that the evolution of the T1 of the blood over the entire measurement time is important, especially for longer measurements. There was no noticeable difference between the MR angiograms acquired with monophasic or biphasic injections. These injection schemes provided more detailed MR angiograms than did continuous slow injection over the entire measurement. CONCLUSION: Our results show that the quality of contrast-enhanced MR angiograms can be remarkably increased when acquisition techniques that exploit the short T1 of the blood are used.

Adult↗
PubMed1995

The use of magnetic resonance angiography in stereotactic neurosurgery.

The authors discuss the advantages and disadvantages of the use of magnetic resonance (MR) angiography images in stereotactic neurosurgery. Current computer programs designed to assist the neurosurgeon in the planning of stereotactic neurosurgical interventions use intraarterial digital subtraction angiography images to visualize the blood vessels. Magnetic resonance angiography is a recent technique with a number of advantages over the digital subtraction method: it is less invasive and less prone to complications; it provides truly three-dimensional data sets that can be viewed from any direction; and it can visualize both stationary and flowing tissues with the same imaging device and localizer frame. Although digital subtraction images are still superior in contrast and vascular detail, state-of-the-art high-resolution MR angiography sequences provide sufficient vascular detail for planning surgery. Contrast-enhanced MR angiography images were acquired using adapted gradient-echo sequences to compensate for flow-induced distortions; postacquisition distortion correction was not necessary. Five methods to integrate and inspect a possible trajectory in the MR angiography data are discussed. Initial clinical experience with eight patients led to the conclusion that MR angiography is a valuable imaging modality that can be integrated reliably into a stereotactic neurosurgery planning procedure.

Adult↗
PubMed1995

External iliac artery fibrodysplasia.

We report a patient in the "atherosclerotic age" with symptomatic fibromuscular hyperplasia of both external iliac arteries. Our patient had a history of bilateral intermittent claudication secondary to a concentric narrowing of a long segment of both external iliac arteries. A typical associated involvement of both internal carotid arteries was present.

Carotid Artery, Internal↗
PubMed1995

[Spiral CT of the renal blood vessels].

Spiral CT angiography has been successfully applied to the detection and grading of renal artery stenoses. In this manuscript the technique, the diagnostic accuracy and the advantages and limitations of this new method are discussed.

Angiography↗
PubMed1995

[Spiral CT of cerebral aneurysms].

Spiral CT was performed in 9 patients with 13 cerebral aneurysms known from angiography. All lesions were detected by spiral CT, the smallest lesion measuring 3 mm in diameter. The neck of the aneurysm and the anatomical relations could be determined very accurately in all cases. Advantages of spiral CT over magnetic resonance angiography include: the short examination time, the independence of flow rate and cardiac output, and the excellent visualisation of calcification, thrombus and the bony landmarks. Disadvantages are the necessity of iodinated contrast media, the long postprocessing and reconstruction time and the possibility of overlap from bone and venous blood.

Cerebral Angiography↗
PubMed1994

Localized brain proton NMR spectroscopy in young adult phenylketonuria patients.

Localized proton magnetic resonance spectroscopy with short echo time (TE = 20 ms) was used to investigate biochemical changes in the cerebral white matter of 20 young adult patients (median 19 years) with phenylketonuria (PKU). Results were compared with those of a group of 12 age-matched healthy volunteers (median 25 years). Concentrations of N-acetyl-aspartate (NAA) and choline (Cho) relative to creatine (Cr) were unchanged. However, concentrations of inositol (Ins) relative to creatine were found to be significantly lower (P < 0.001) in the PKU patients (0.30 +/- 0.09 versus 0.57 +/- 0.17). Individual inositol concentrations did not correlate with age, diet, serum phenylalanine (Phe) levels or extent of pathological regions in the T2-weighted images. The lack of correlation with individual data suggests that the decreased inositol concentration could be related to a metabolic deficiency during fetal development. No signal from the phenyl ring protons of phenylalanine was detected in the PKU patients (phenylalanine serum concentration < or = 1.27 mM), which suggests that concentration of phenylalanine may be lower in brain than in serum.

Adolescent↗
PubMed1994

Gadodiamide injection at 0.1 and 0.3 mmol/kg body weight: a phase III double-blind, parallel, randomised clinical investigation of known or suspected central nervous system lesions at 1.5 T.

We studied 78 patients with clinically suspected central nervous system abnormalities (66 intracranial, 12 spinal) by MRI before and after administration of the nonionic contrast medium gadodiamide injection. A parallel, double-blind, randomised design was followed. Two dosages were used: 38 patients underwent studies with 0.1 mmol/kg body weight (b.w.) and 40 with 0.3 mmol/kg b.w. MRI showed abnormalities in 36 of the 38 patients receiving the lower dose and 39 of the 40 patients receiving the higher dose. In 3 patients from each group more lesions were seen following injection than before. The contrast medium improved the delineation of abnormal structures and assessment of tumour size and increased their signal intensity indices in both groups, but especially at the higher dose. Administration of gadodiamide injection provided more diagnostic information in about 75% of the patients, independently of the dose. There were no reports of discomfort, but 7 patients reported adverse events considered unrelated to the gadodiamide injection. The two doses were found to be equally safe and efficient for diagnosis.

Central Nervous System Diseases↗
PubMed1994

MR imaging of spondylitis with gadopentetate dimeglumine enhancement.

MR images of 17 patients with spondylitis were reviewed. T1 weighted spin-echo scans were obtained in 17 patients and proton density and T2 weighted scans were obtained in 15 patients. Unenhanced and gadopentetate dimeglumine enhanced scans were obtained in all patients. Five patients had pyogenic spondylitis, two patients tuberculous spondylitis, two patients fungal spondylitis and eight patients postoperative spondylitis. The four criteria described by Thrush and Enzmann were generally applicable in our study: 1) narrowing of the intervertebral disc; 2) cortical bone erosion; 3) abnormal signal in the adjacent vertebral bodies and 4) abnormal paraspinous or epidural soft tissue. In addition to plain sagittal T1 and T2 weighted images we suggest the routine administration of gadopentetate dimeglumine to assess the extent of the soft tissue mass and to differentiate postoperative spondylitis from a normal postoperative course, by showing disc enhancement. Disc enhancement occurs infrequently in the normal postoperative course. If it is associated with adjacent vertebral bone marrow changes it should be considered as postoperative spondylitis. A differential diagnosis between pyogenic, tuberculous, fungal and postoperative spondylitis was not possible although the pattern of enhancement in tuberculous spondylitis was different from the other cases of spondylitis.

Adult↗
PubMed1994

Iatrogenic spinal epidermoid tumour associated with tuberous sclerosis. A diagnostic pitfall.

We present a case of spinal epidermoid tumour that was probably caused by lumbar punctures. The tumour was detected on MRI in a child with tuberous sclerosis complaining of atypical low back pain. Preoperatively the tumour was considered to be a cystic astrocytoma of ependymoma of the conus terminalis. The association of tuberous sclerosis with a spinal tumour is rare but has been recorded in the literature. The diagnosis was an epidermoid tumour (E.T.). The MRI appearances were unusual for a spinal ET: the signal intensity changes were different from those reported in the literature and the presence of calcification and cavitation has not yet been reported. This case represents a diagnostic pitfall, since both entities were unrelated.

Child↗