Biomedical subjects

Stephan G Wetzel

Publications and source records attributed to Stephan G Wetzel.

At least 19 recordsLinked to original sources

PubMed2006

Diffusion-weighted imaging in stroke attributable to patent foramen ovale: significance of concomitant atrial septum aneurysm.

BACKGROUND AND PURPOSE: Patent foramen ovale (PFO) is an established cause of stroke in young patients without other determined etiologies (ie, cryptogenic stroke). The additional presence of atrial septum aneurysm (ASA) possibly increases stroke risk, but it remains undetermined which factors best predict thromboembolism in patients with PFO. Diffusion-weighted imaging (DWI) may help to distinguish the characteristics of cerebral embolism associated with different features of the interatrial septum in PFO stroke. METHODS: In a stroke databank-based cohort study, DWI and transthoracic/transesophageal echocardiography findings were assessed in 48 consecutive patients with cryptogenic ischemic stroke associated with PFO. The number, size, and distribution of acute ischemic lesions on DWI were correlated with PFO size, degree of interatrial right-to-left shunt (RLS), and the presence of ASA. RESULTS: Patients with PFO plus ASA combined more often had multiple acute DWI lesions (16 of 30, 53%) than those with PFO alone (3 of 18, 17%; P=0.01). This association remained significant after correction for PFO size, degree of RLS, and vascular risk factors in a logistic-regression analysis (P=0.04). No significant associations between DWI lesion characteristics and PFO size or degree of RLS were found. CONCLUSIONS: The presence of concomitant ASA is independently associated with multiple cerebral ischemic lesions in PFO stroke, which may indicate an increased embolic risk.

Adult↗

PubMed2006

Time-resolved 3D contrast-enhanced MRA with GRAPPA on a 1.5-T system for imaging of craniocervical vascular disease: initial experience.

INTRODUCTION: For three-dimensional (3D) imaging with magnetic resonance angiography (MRA) of the cerebral and cervical circulation, both a high temporal and a high spatial resolution with isovolumetric datasets are of interest. In an initial evaluation, we analyzed the potential of contrast-enhanced (CE) time-resolved 3D-MRA as an adjunct for neurovascular MR imaging. METHODS: In ten patients with various cerebrovascular disorders and vascularized tumors in the cervical circulation, high-speed MR acquisition using parallel imaging with the GeneRalized Autocalibrating Partially Parallel Acquisitions (GRAPPA) algorithm on a 1.5-T system with a temporal resolution of 1.5 s per dataset and a nearly isovolumetric spatial resolution was applied. The results were assessed and compared with those from conventional MRA and digital subtraction angiography (DSA). RESULTS: CE time-resolved 3D-MRA enabled the visualization and characterization of high-flow arteriovenous shunts in cases of vascular malformations or hypervascularized tumors. In steno-occlusive disease, the method provided valuable additional information about altered vessel perfusion compared to standard MRA techniques such as time-of-flight (TOF) MRA. The use of a nearly isovolumetric voxel size allowed a free-form interrogation of 3D datasets. Its comparatively low spatial resolution was found to be the major limitation. CONCLUSION: In this preliminary analysis, CE time-resolved 3D-MRA was revealed to be a promising complementary MRA sequence that enabled the visualization of contrast flow dynamics in various types of neurovascular disorders and vascularized cervical tumors.

Adult↗

PubMed2006

Combo acquisitions: balancing scan time reduction and image quality.

Recently a new technique for the combined acquisition of multicontrast images, termed "combo acquisition," was introduced. In combo acquisitions, the three concepts of 1) variable acquisition parameters, 2) k-space data sharing, and 3) multicontrast imaging are systematically integrated to reduce MRI scan time and improve data utilization in a clinical setting. In this study, two-contrast and three-contrast spin-echo (SE) and turbo spin-echo (TSE) combo acquisition protocols that were designed and optimized in simulation experiments were implemented on a 1.5 T clinical scanner. Phantom and human brain data from volunteers and patients were acquired. Scan time reductions of 25-52% were achieved compared to standard acquisitions, largely confirming the simulation results. We evaluated the resulting images by quantitatively analyzing the preservation of contrast and the signal-to-noise ratio (SNR). In addition, data sets for 10 clinical cases obtained with TSE combo and corresponding standard acquisitions were graded by two experienced neuroradiologists in terms of the level of artifacts and image quality for comparison. Only minor image degradation with the combo scans was observed, indicating an inherent trade-off between scan time reduction and image quality. The specific aspects of combo acquisitions with respect to motion, flow, and k-space data weighting are discussed.

Algorithms↗

PubMed2006

Mapping continuous neuronal activation without an ON-OFF paradigm: initial results of BOLD ceiling fMRI.

Standard functional magnetic resonance imaging (fMRI) requires alternations between activation (ON) and baseline (OFF) periods to map the haemodynamic response to neuronal activation. Consequently, standard fMRI cannot map continuous activations in conditions like tinnitus without an ON-OFF paradigm. We present a novel approach to fMRI that allows mapping of continuous neuronal activation. Compared with standard fMRI, we introduced the application of CO(2) as potent vasodilator. CO(2) induces a 'global' blood oxygenation level-dependent (BOLD) response. The neurovascular coupling in conjunction with the limited cerebral vasodilation implies a limitation or ceiling of the BOLD response. We hypothesize that active areas exhibit a reduced CO(2)-induced DeltaBOLD due to pre-existing 'local' task-induced BOLD response. This putative reduction in DeltaBOLD might be exploited for mapping of continuous neuronal activation. BOLD ceiling fMRI was tested in the auditory system. Six healthy subjects performed three runs: only continuous monaural auditory; only 10% CO(2); simultaneous auditory and CO(2) stimulation. First, we demonstrated the ceiling of DeltaBOLD during continuous auditory activation. According to the known predominantly contralateral auditory processing, monaural auditory stimulation reduced predominantly contralateral (0.41 +/- 0.13%; P < 0.00001) and significantly less (P < 0.0001) ipsilateral DeltaBOLD (0.33 +/- 0.17%; P < 0.00001). The non-auditory area was not affected. Second, this BOLD ceiling was exploited to generate an initial activation map of continuous auditory activation (ON period). In contrast to standard fMRI, an OFF period without neuronal activation was not required. BOLD ceiling fMRI is proposed as a complement to standard fMRI for those conditions where ON-OFF paradigms are impossible.

Acoustic Stimulation↗

PubMed2005

Optimizing brain MRI protocols in the follow-up of patients with multiple sclerosis T2-weighted MRI of the brain after the administration of gadopentetate dimeglumine.

The aim of our study was to determine whether T2-weighted (T2w) MRI of the brain could be performed immediately after the administration of gadopentetate dimeglumine (gadolinium DTPA) in patients with multiple sclerosis (MS) without a loss in image quality or diagnostic reliability. Sixteen patients with clinically diagnosed MS were included in the study. Twenty-four patients with various cerebral pathologies (14 patients with multiple lacunar lesions) were examined in order to exclude masking of T2 hyperintense lesions other than MS lesions. Images of 10 patients without pathological changes served as a control condition for the qualitative analysis. In these 50 patients, T1w and T2w MRI was performed before and after the administration of gadolinium DTPA. Signal intensities were measured within T2 hyperintense cerebral lesions, in T1-enhancing lesions and in normal appearing brain tissue on T2w turbo spin-echo (TSE) sequences. Both quantitative and qualitative analysis did not show significant differences between T2w pre- and postcontrast series. T2w MRI performed prior to and after the administration of gadolinium DTPA provides similar information in patients with MS. With a TR of 3.2 s, not a single lesion was obscured on T2w postcontrast series. Acquisition of T2w MR images immediately after the administration of gadolinium DTPA allows for shorter examination time and assures sufficient time for contrast enhancement in cerebral lesions with a disrupted blood-brain barrier.

Adolescent↗

PubMed2005

Characteristics of ultrasmall superparamagnetic iron oxides in patients with brain tumors.

OBJECTIVE: The aim of this study was to evaluate the characteristics of an ultrasmall superparamagnetic iron oxides (USPIO) agent in patients with brain tumors and to correlate changes on MRI with histopathologic data collected systematically in all patients. SUBJECTS AND METHODS: Nine patients with brain tumors were imaged before and 24 hr after administration of a USPIO at a dose of 2.6 mg Fe/kg. Analysis of MR images included qualitative and quantitative comparison of the USPIO and gadolinium enhancement of brain tumors. Brain surgery was performed 25-112 hr after administration of the USPIO. The histopathologic workup included iron histochemistry with diaminobenzidine (DAB)-enhanced Perls stain. RESULTS: In seven of nine patients, USPIO-related changes of signal intensity were observed in gadolinium-enhancing brain tumors on T1- and T2*-weighted sequences. The difference in signal intensity on T1-weighted USPIO series was 40.1% +/- 26.7% (mean +/- SD). On T2*-weighted USPIO series, the difference in signal intensity was -33.1% +/- 18.4% in solid tumor parts. Areas of suspected radiation necrosis did not enhance in three patients with prior radiation therapy. Iron histochemistry revealed the presence of iron deposits in macrophages in two patients. CONCLUSION: USPIO agents will not replace gadolinium in the workup of patients with brain tumors. Our findings suggest that USPIO agents seem to offer complementary information and may help to differentiate between brain tumors and areas of radiation necrosis. Signal intensity changes on T2*-weighted images might be related to the blood pool properties of the agent, possibly reflecting steady-state susceptibility effects.

Adult↗

PubMed2005

Arterialization of cerebral veins on dynamic MDCT angiography: a possible sign of a dural arteriovenous fistula.

OBJECTIVE: MDCT angiography allows fast imaging of the cerebral vessels, and its potential as a noninvasive technique to detect vascular abnormalities on the basis of morphologic changes is well established. We analyzed vascular enhancement patterns of cerebral venous structures on MDCT angiography, which enabled us to diagnose dural arteriovenous fistula. CONCLUSION: MDCT angiography performed during an early arterial phase showed asymmetrically higher contrast intensity in the transverse or sigmoid sinus, or both, in five patients. In all patients, digital subtraction angiography confirmed the presence of a dural arteriovenous fistula on the side on which the higher contrast intensity appeared. Radiologists should actively look for this sign in the imaging workup of patients presenting with nonspecific symptoms that might be related to a dural arteriovenous fistula.

Aged↗

PubMed2004

Measuring blood volume and vascular transfer constant from dynamic, T(2)*-weighted contrast-enhanced MRI.

Dynamic, contrast-enhanced MRI (deMRI) is increasingly being used to evaluate cerebral microcirculation. There are two different approaches for analyzing deMRI data. Intravascular indicator dilution theory has been used to estimate blood volume (and perfusion), usually from T(2)- or T(2) (*)-weighted images of the first pass of the bolus. However, the theory assumes that the tracer (i.e., contrast agent) remains intravascular, which is often not the case when the blood-brain barrier (BBB) is damaged. Furthermore, the method provides no information on the vascular transfer constant. Pharmacokinetic modeling analyses of T(1)-weighted images after first pass do give values of the vascular transfer constant and the volume of the extravascular, extracellular space (EES), but they generally are unable to give estimates of blood volume. In this study we apply pharmacokinetic modeling to dynamic T(2) (*)-weighted imaging of the first pass of a tracer bolus. This method, which we call first-pass pharmacokinetic modeling (FPPM), gives an estimate of the blood volume, vascular transfer constant, and EES volume. The method was applied to a group of 26 patients with surgically proven tumors (10 glioblastomas multiforme (GBMs), six lymphomas, and 10 meningiomas). The measurements of the blood volume and transfer constant were consistent with the known physiology of these tumors.

Blood Volume↗

PubMed2004

Conventional MR imaging with simultaneous measurements of cerebral blood volume and vascular permeability in ganglioglioma.

The conventional MR imaging appearance of gangliogliomas is often variable and nonspecific. Conventional MR images, relative cerebral blood volume (rCBV) and vascular permeability (K(trans)) measurements were reviewed in 20 patients with pathologically proven grade 1 and 2 gangliogliomas (n = 20) and compared to a group of grade 2 low-grade gliomas (n = 30). The conventional MRI findings demonstrated an average lesion size of 4.1 cm, contrast enhancement (n = 19), variable degree of edema, variable mass effect, necrosis/cystic areas (n = 8), well defined (n = 12), signal heterogeneity (n = 9), calcification (n = 4). The mean rCBV was 3.66 +/- 2.20 (mean +/- std) for grade 1 and 2 gangliogliomas. The mean rCBV in a comparative group of low-grade gliomas (n = 30), was 2.14 +/- 1.67. p Value < 0.05 compared with grade 1 and 2 ganglioglioma. The mean K(trans) was 0.0018 +/- 0.0035. The mean K(trans) in a comparative group of low-grade gliomas (n = 30), was 0.0005 +/- 0.001. p Value = 0.14 compared with grade 1 and 2 ganglioglioma. The rCBV measurements of grade 1 and 2 gangliogliomas are elevated compared with other low-grade gliomas. The K(trans), however, did not demonstrate a significant difference. Gangliogliomas demonstrate higher cerebral blood volume compared with other low-grade gliomas, but the degree of vascular permeability in gangliogliomas is similar to other low-grade gliomas. Higher cerebral blood volume measurements can help differentiate gangliogliomas from other low-grade gliomas.

Adolescent↗

PubMed2003

Radicular pain after vertebroplasty: compression or irritation of the nerve root? Initial experience with the "cooling system".

STUDY DESIGN: During vertebroplasty (VP), polymethylmethacrylate (PMMA) may leak into the posterior epidural venus plexus, provoking symptoms ranging from radicular pain to medullar compression. OBJECTIVES: To propose and test the feasibility of a procedure (cooling system) to prevent radicular irritation caused by foraminal PMMA leakage. SUMMARY OF BACKGROUND DATA: Foraminal leak of PMMA, as observed during VP, may lead to radiculalgia. Several mechanisms of nerve root irritation have been proposed. Considering heat or local chemical irritation has led us to treat immediately by local periradicular irrigation with a cooling liquid. METHODS: Four consecutive patients with observed foraminal leakage were treated by local fluid injection. Immediately after observation of a foraminal leak, a 20-gauge Chiba needle was positioned to reach the foramen. Ten cubic centimeters of lidocaine (0.2%) was followed by 100-200 cc of pressurized saline perfusion within 10-20 minutes (cooling system). RESULTS: In all patients with foraminal leakage, no radicular pain existed after application of the cooling system. No complications were observed with its use. CONCLUSION: In presence of a foraminal leakage, the immediate application of a cooling irrigation may protect the root from injury, which is explained by the hypothesis that the main mechanism of injury may be more related to heat or chemical irritation of the nerve than compression.

Adult↗

PubMed2003

Percutaneous vertebroplasty in metastatic disease: transpedicular access and treatment of lysed pedicles--initial experience.

For the treatment of lytic disease involving the pedicles of vertebrae in patients with metastatic disease, the authors performed percutaneous vertebroplasty by using an access route via the lysed pedicle. Fifty-one pedicles were treated in 32 consecutive patients. In all cases, a radiologically satisfactory filling of both the affected pedicle and the vertebral body was achieved. Clinically effective pain relief was obtained in 24 (75%) of 32 patients, and no clinical complications were observed.

Adult↗

PubMed2002

Painful osteolytic metastasis of the atlas: treatment with percutaneous vertebroplasty.

STUDY DESIGN: Technical note. OBJECTIVE: To describe a technique for performing percutaneous vertebroplasty of C1 for treatment of osteolytic metastatic disease involving the lateral portions of the atlas in which precautions are taken to protect the vertebrobasilar arterial supply and a posterior access route is used for cement delivery. SUMMARY OF BACKGROUND DATA: Percutaneous vertebroplasty (PVP) has proved to be efficient for the treatment of painful osteolytic vertebral disease. Good clinical experience with this technique suggested its extension to stabilize a painful osteolytic lesion of the atlas. METHODS: A patient with known parotid cancer presented with neck pain refractory to conservative treatment. On computed tomography, osteolytic destruction of the atlas that mainly involved the right lateral mass and surrounded the vertebral artery was found. On digital subtraction angiography, the lesion was shown to be highly vascularized and supplied mainly by direct branches of the ipsilateral vertebral artery. To avoid the risk of cement reflux from the tumor vascular bed to the involved vertebral artery, coil occlusion of the involved V3 segment was performed before vertebroplasty. Percutaneous vertebroplasty was then carried out using a percutaneous posteroanterior direction access route. RESULTS: Satisfactory filling of the osteolytic lesion with cement was achieved radiologically. Three days after the intervention and at a 9-month follow-up examination, the patient was free of pain. CONCLUSIONS: Vertebroplasty used to treat an osteolytic lesion of the atlas involving the lateral mass was performed by a posterior percutaneous approach. To prevent vertebrobasilar embolism, the involved vertebral artery was occluded before polymer injection.

Aged↗

PubMed2002

Imaging of the intracranial venous system with a contrast-enhanced volumetric interpolated examination.

A contrast-enhanced interpolated, three-dimensional (3D) gradient-echo MR sequence with asymmetric k-space sampling, which we refer to as volumetric interpolated brain examination (VIBE), was evaluated for its depiction of the normal intracranial venous system and compared with two-dimensional (2D) time-of-flight (TOF) MR venography (MRV). Fifteen subjects underwent contrast-enhanced VIBE imaging (TR/TE 8 ms/4.4 ms, flip angle 18 degrees, acquisition time, 2 min 20 s, voxel size approximately 1.5 mm(3)) and standard 2D TOF MRV (TR/TE 27 ms/9 ms, flip angle 35 degrees ). The presence of 19 venous structures per subject was assessed on maximum intensity projections (MIP) of the whole data set (whole-brain MIP) and on MIP images reconstructed spontaneously from source images (interactive MIP/source images). Results from a consensus reading where all imaging techniques and display modalities were available were taken as the standard of reference for the presence of venous structures. In addition, 10 subjects underwent both unenhanced and enhanced VIBE imaging. The value of subtracted data sets (unenhanced VIBE subtracted from enhanced VIBE) was then evaluated. Overall, VIBE provided a superior visualization of the cerebral veins than 2D TOF MRV (VIBE, sensitivity (reader 1/reader 2): 98%/99%, negative predictive value 64%/71%; TOF sensitivity: 85%/84%, negative predictive value 15%/15%; Wilcoxon signed-rank test VIBE vs TOF, p<0.001 for both readers). The VIBE interactive MIP/source images were superior to whole-brain MIP reconstructions. Image subtraction was not necessary for delineation of venous structures but improved small vein conspicuity. Contrast-enhanced VIBE acquisitions are faster and enable a visualization of the normal intracranial venous system superior to that of 2D TOF MRV.

Adolescent↗

PubMed2002

Intracranial mass lesions: dynamic contrast-enhanced susceptibility-weighted echo-planar perfusion MR imaging.

Dynamic contrast agent-enhanced perfusion magnetic resonance (MR) imaging provides physiologic information that complements the anatomic information available with conventional MR imaging. Analysis of dynamic data from perfusion MR imaging, based on tracer kinetic theory, yields quantitative estimates of cerebral blood volume that reflect the underlying microvasculature and angiogenesis. Perfusion MR imaging is a fast and robust imaging technique that is increasingly used as a research tool to help evaluate and understand intracranial disease processes and as a clinical tool to help diagnose, manage, and understand intracranial mass lesions. With the increasing number of applications of perfusion MR imaging, it is important to understand the principles underlying the technique. In this review, the essential underlying physics and methods of dynamic contrast-enhanced susceptibility-weighted echo-planar perfusion MR imaging are described. The clinical applications of cerebral blood volume maps obtained with perfusion MR imaging in the differential diagnosis of intracranial mass lesions, as well as the pitfalls and limitations of the technique, are discussed. Emphasis is on the clinical role of perfusion MR imaging in providing insight into the underlying pathophysiology of cerebral microcirculation.

Brain Diseases↗

PubMed2002

Relative cerebral blood volume measurements in intracranial mass lesions: interobserver and intraobserver reproducibility study.

PURPOSE: To assess inter- and intraobserver reproducibility for different techniques of measuring relative cerebral blood volume (rCBV) in patients with intracranial mass lesions. MATERIALS AND METHODS: Three independent observers (neuroradiology fellows) who were blinded to the histopathologic diagnosis performed rCBV measurements in 50 patients with various intracranial mass lesions. Three different methods were compared. With method 1, placement of a single region of interest was guided by a color overlay map. With methods 2 and 3, the highest rCBV value and the mean of repeated rCBV measurements, respectively, were recorded. Calculations of the intraclass correlation coefficient, coefficient of variation (CV), and descriptive statistics were used to determine the levels of reproducibility. A multiple linear regression model was used to evaluate for possible explanatory factors for interobserver variance. RESULTS: Method 2 had, overall, the best reproducibility of all techniques, with an intraclass interobserver correlation coefficient of 0.71 (indicating good agreement), interobserver CV of 30%, and intraobserver CV in the range of 32%-41%. Measurement variations between observers correlated significantly (P <.001) with increasing rCBV values. CONCLUSION: In this study, interobserver and intraobserver reproducibility of rCBV measurements were clinically acceptable.

Adolescent↗

PubMedDate not supplied

Rheological changes after stenting of a cerebral aneurysm: a finite element modeling approach.

Hemodynamic changes in intracranial aneurysms after stent placement include the appearance of areas with stagnant flow and low shear rates. We investigated the influence of stent placement on blood flow velocity and wall shear stress of an intracranial aneurysm using a finite element modeling approach. To assess viscosity changes induced by stent placement, the rheology of blood as non-Newtonian fluid was taken into account in this model. A two-dimensional model with a parent artery, a smaller branching artery, and an aneurysm located at the bifurcation, before and after stent placement, was used for simulation. Flow velocity plots and wall shear stress before and after stent placement was calculated over the entire cardiac circle. Values for dynamic viscosity were calculated with a constitutive equation that was based on experimental studies and yielded a viscosity, which decreases as the shear rate increases. Stent placement lowered peak velocities in the main vortex of the aneurysm by a factor of at least 4 compared to peak velocities in the main artery, and it considerably decreased the wall shear stress of the aneurysm. Dynamic viscosity increases after stent placement persisted over a major part of the cardiac cycle, with a factor of up to 10, most pronounced near the dome of the aneurysm. Finite element modeling can offer insight into rheological changes induced by stent treatment of aneurysms and allows visualizing dynamic viscosity changes induced by stent placement.

Blood Flow Velocity↗

PubMedDate not supplied

Three-dimensional, T1-weighted gradient-echo imaging of the brain with a volumetric interpolated examination.

BACKGROUND AND PURPOSE: T1-weighted, 3D gradient-echo MR sequences can be optimized for rapid acquisition and improved resolution through asymmetric k-space sampling and interpolation. We compared a volumetric interpolated brain examination (VIBE) sequence with a magnetization-prepared rapid acquisition gradient echo (MP RAGE) sequence and a 2D T1-weighted spin-echo (SE) sequence. METHODS: Thirty consecutive patients known or suspected to have focal brain lesions underwent postcontrast studies (20 mL of gadopentetate dimeglumine) with VIBE, MP RAGE, and 2D T1-weighted SE imaging. Source and 5-mm VIBE and MP RAGE reformations, and 5-mm T1-weighted SE images were compared qualitatively and by using signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR). SNRs in a gadolinium-doped water phantom were also measured for all three sequences. RESULTS: On the source images, SNRs for gray matter (GM) and white matter (WM), and CNRs for WM-to-GM and contrast-enhancing lesion-to-GM were slightly, but significantly higher for the VIBE sequence than for the MP RAGE sequence (P <.05). On 5-mm reformations, WM-to-GM CNR was significantly higher on VIBE and MP RAGE images than on T1-weighted SE images (P <.001), but contrast-enhancing lesion-to-GM CNRs were higher on SE images compared with both gradient-echo sequences (P <.001). Qualitatively, VIBE images showed fewer flow artifacts than did SE and MP RAGE images (P <.05). In the phantom, VIBE SNR was higher than MP RAGE SNR for short T1 relaxation times. CONCLUSION: VIBE provides an effective, alternative approach to MP RAGE for fast 3D T1-weighted imaging of the brain.

Adult↗

PubMedDate not supplied

Preoperative assessment of intracranial tumors with perfusion MR and a volumetric interpolated examination: a comparative study with DSA.

BACKGROUND AND PURPOSE: In evaluating intracranial tumors, a safe low-cost alternative that provides information similar to that of digital subtraction angiography (DSA) may be of interest. Our purpose was to determine the utility and limitations of a combined MR protocol in assessing (neo-) vascularity in intracranial tumors and their relation to adjacent vessels and to compare the results with those of DSA. METHODS: Twenty-two consecutive patients with an intracranial tumor who underwent preoperative stereoscopic DSA were examined with contrast-enhanced dynamic T2*-weighted perfusion MR imaging followed by a T1-weighted three-dimensional (3D) MR study (volumetric interpolated brain examination [VIBE]). The maximum relative cerebral blood volume (rCBV) of the tumor was compared with tumor vascularity at DSA. Critical vessel structures were defined in each patient, and VIBE images of these structures were compared with DSA findings. For full exploitation of the 3D data sets, maximum-intensity projection algorithms reconstructed in real time with any desired volume and orientation were used. RESULTS: Tumor blush scores at DSA were significantly correlated with the rCBV measurements (r = 0.75; P <.01, Spearman rank correlation coefficient). In 17 (77%) patients, VIBE provided all relevant information about the venous system, whereas information about critical arteries were partial in 50% of the cases and not relevant in the other 50%. CONCLUSION: A fast imaging protocol consisting of perfusion MR imaging and a volumetric MR acquisition provides some of the information about tumor (neo-) vascularity and adjacent vascular anatomy that can be obtained with conventional angiography. However, the MR protocol provides insufficient visualization of distal cerebral arteries.

Adult↗