Biomedical subjects

James M Provenzale

Publications and source records attributed to James M Provenzale.

80 records · Page 5Linked to original sources

PubMed2002

Comparison of permeability in high-grade and low-grade brain tumors using dynamic susceptibility contrast MR imaging.

OBJECTIVE: The purpose of this study was to compare permeability measurements in high-grade and low-grade glial neoplasms using a T2(*)-weighted method. Our hypothesis was that permeability measurements using a T2(*)-weighted technique would show permeability in high-grade neoplasms to be higher than that in low-grade neoplasms. MATERIALS AND METHODS: Twelve patients with biopsy-proven high-grade neoplasms and 10 patients with biopsy-proven low-grade neoplasms underwent dynamic susceptibility contrast MR perfusion imaging (TR/TE, 1500/80) after bolus infusion of 0.2 mmol/kg of MR contrast material. Color-coded permeability-weighted maps were created using a model that weights relative contributions to signal intensity from intravascular T2(*) effects and extravascular T1 effects from blood-brain barrier permeability. Two measures of permeability were performed: mean value of highest permeability found on three images through the tumor (mean regional value) and highest value found at any region of interest in the tumor (single area of maximum permeability). Depending on the normality of the data sets, we used the Wilcoxon's rank sum test or the two-tailed Student's t test for statistical analysis. RESULTS: For low-grade tumors, the range was 0.006-0.041, and the median of the mean regional value for each image was 0.017. For high-grade tumors, the range was 0.005-0.092, and the median of the mean regional value was 0.035 (p = 0.025). For low-grade tumors, the range was 0.008-0.045, and the mean of the single area of maximum values was 0.02. For high-grade tumors, the range was 0.007-0.136, and the mean of the single area of maximum values was 0.054 (p = 0.018). CONCLUSION: Permeability values for high-grade tumors obtained using a T2(*)-weighted method were significantly greater than those for low-grade tumors and are consistent with previous studies reporting results using T1-weighted methods.

Adult↗

PubMed2002

Evaluation of software for registration of contrast-enhanced brain MR images in patients with glioblastoma multiforme.

OBJECTIVE: We evaluated commercially available software that rapidly and automatically registers brain MR images on a clinical workstation, and we studied the accuracy of these registrations. SUBJECTS AND METHODS: Ten patients with a diagnosis of glioblastoma multiforme underwent contrast-enhanced inversion recovery prepared three-dimensional (3D) volumetric spoiled gradient-recalled acquisition in the steady state (SPGR) MR imaging (contiguous 1.5-mm slice thickness, 96-104 slices). After this imaging sequence, each patient was brought out of the head coil into a sitting position and then repositioned in the coil. The inversion recovery prepared 3D SPGR sequence was then repeated. A commercially available software program operating on a clinical workstation was used to automatically register the second inversion recovery prepared SPGR series to the first. The speed of registration was recorded. The accuracy of each registration was estimated by recording the coordinates of eight anatomic landmarks on the registered and reference series and by calculating the mean error among matching landmarks. RESULTS: In nine of 10 patients, the registration software produced a visually satisfactory registration. In one patient, a second registration was necessary to produce a satisfactory registration. The processing time for each iteration was 48.3 +/- 3.8 sec (mean +/- SD). The mean error in aligning matching anatomic landmarks ranged from 0.67 to 1.41 mm, with an overall mean of 1.18 mm. The largest error among matching landmarks was 2.3 mm. CONCLUSION: Commercially available registration software can automatically register 3D imaging volumes in less than 1 min. The mean error in registration was approximately equivalent to the dimensions of a single voxel.

Adult↗

PubMed2002

Evaluation of normal age-related changes in anisotropy during infancy and childhood as shown by diffusion tensor imaging.

OBJECTIVE: The first purpose of this study was to compare the degree of anisotropy in compact white matter and noncompact white matter in each of three pediatric age groups using diffusion tensor imaging. We hypothesized that anisotropy would be higher in compact white matter than in noncompact white matter in each age group. The second purpose of our study was to compare the increase in anisotropy over time in compact versus noncompact white matter during early childhood. We hypothesized that increases in anisotropy would be higher in noncompact white matter. MATERIALS AND METHODS: We retrospectively analyzed anisotropy maps derived from diffusion tensor imaging studies performed in 66 pediatric patients (age range, 4 days-71 months; mean age, 18.6 months) who underwent clinical MR imaging and were found to have no abnormalities on conventional MR images. Anisotropy was measured in three compact white matter structures (corpus callosum, internal capsule, cerebral peduncle) and two regions of noncompact white matter (corona radiata and peripheral white matter). Patients were assigned to one of the three following groups on the basis of age: group 1, younger than 12 months (n = 40); group 2, 12-35 months (n = 11); and group 3, 36-71 months (n = 15). First, we compared anisotropy values of noncompact white matter with those of compact white matter for each age group. Second, we compared the increase over time in anisotropy of noncompact white matter regions with that seen in compact white matter structures. RESULTS: Among all three age groups, anisotropy measurements in compact white matter structures were higher than those in noncompact white matter (p < 0.01). The mean anisotropy values in noncompact white matter for groups 1, 2, and 3, respectively, were 0.349, 0.480, and 0.531. The mean anisotropy values in compact white matter for groups 1, 2, and 3, respectively, were 0.494, 0.646, and 0.697. When age groups were compared, a statistically significant increase in anisotropy was seen in both compact white matter and noncompact white matter (p < 0.01). However, the increase in anisotropy was significantly greater in non-compact white matter regions than in compact white matter structures when comparing group 1 with group 3 (p < 0.01) as well as group 1 with group 2 (p < 0.01). CONCLUSION: Although anisotropy measurements were higher in compact than non-compact white matter in all three age groups, the increase in anisotropy was greater in non-compact white matter across each of the three groups. These data suggest that although myelination is initially greater in compact white matter, the change in myelination may be greater in noncompact white matter during the first few years after infancy.

Anisotropy↗

PubMed2002

Dynamic CT perfusion imaging with acetazolamide challenge for the preprocedural evaluation of a patient with symptomatic middle cerebral artery occlusive disease.

We describe the use of a CT-based method of cerebral perfusion imaging, dynamic CT perfusion imaging, for the pre- and postprocedural assessment of cerebral blood flow in a patient with symptomatic middle cerebral artery occlusive disease who underwent balloon angioplasty with stent placement in the affected artery. Dynamic CT perfusion imaging represents a widely available and minimally invasive alternative to other available methods of cerebral perfusion imaging.

Acetazolamide↗

PubMed2002

Diffusion-weighted imaging in a patient with vertebral and epidural abscesses.

In this report, we describe the appearance of the spinal vertebral body and epidural abscesses in a patient who underwent diffusion-weighted imaging of the spine and CT-guided aspiration of one of the abscesses. The abscesses were hyperintense relative to the surrounding tissues on diffusion-weighted images, and they appeared dark on apparent diffusion coefficient maps; these findings were consistent with those of published reports of the brain and liver.

Aged↗

PubMedDate not supplied

Tensor diffusion imaging in B12 leukoencephalopathy.

Anisotropy measurements were obtained from periventricular foci of T2 prolongation and adjacent normal-appearing white matter in a case of B12 leukoencephalopathy. Measurements were compared with mean values from two age-matched control subjects. Anisotropy was greatly reduced in the lesions evident on T2-weighted images and in the normal-appearing adjacent white matter (WM), indicating that the extent of WM tract disruption was greater than could be identified on routine MR sequences.

Cerebral Cortex↗

PubMedDate not supplied

MRI lesion severity and mortality in geriatric depression.

OBJECTIVE: The authors correlated magnetic resonance imaging (MRI) lesion severity and mortality among depressed elderly patients. METHOD: They examined the association of mortality and deep white-matter hyperintensity (DWMH), periventricular hyperintensity (PVH), and subcortical gray-matter hyperintensity (SGH) ratings in 259 subjects. RESULTS: DWMH and PVH were significantly associated with mortality initially, and, in final modeling, DWMH remained significant. CONCLUSION: These findings suggest that there is a relationship between cerebrovascular disease severity and mortality among depressed patients. More studies, with larger sample sizes, comparing depressed patients and control subjects are needed to further elucidate this relationship.

Aged↗

PubMedDate not supplied

Normal structures in the intracranial dural sinuses: delineation with 3D contrast-enhanced magnetization prepared rapid acquisition gradient-echo imaging sequence.

BACKGROUND AND PURPOSE: The potential pitfalls in the diagnosis of dural sinus thrombosis include the presence of arachnoid granulations, intrasinus fibrotic bands (so-called septa), and hypoplasia or aplasia of the dural sinuses. The purpose of this study was to assess the appearance, distribution, and prevalence of arachnoid granulations and septa in the dural sinuses by using a high resolution 3D contrast-enhanced magnetization prepared rapid acquisition gradient-echo (MPRAGE) imaging sequence. METHODS: Conventional MR images and contrast-enhanced MPRAGE images of 100 consecutive patients who had no abnormalities of the dural sinuses were retrospectively reviewed. The incidence, site, number, size, signal intensity, and shape of arachnoid granulations and septa within the sinuses and their relationship with adjacent veins were recorded. RESULTS: With 3D contrast-enhanced MPRAGE imaging, 433 round, oval, or lobulated focal filling defects were found in a total of 90 patients. Curvilinear septa were observed in 92 patients. Sixty-nine patients had round, oval, or lobulated defects in the transverse sinus, 59 had such defects in the superior sagittal sinus, and 47 had such defects in the straight sinus. All except two of the above defects were isointense relative to CSF on all images. These structures were presumed to be arachnoid granulations. Of 431 arachnoid granulations, 233 (53.8%) were located in the superior sagittal sinus, 122 (28.1%) in the transverse sinus, and 76 (17.6%) in the straight sinus. One or more veins were seen to enter arachnoid granulations in 414 (96%) instances. CONCLUSION: The contrast-enhanced 3D MPRAGE imaging sequence showed a much higher prevalence and a different distribution of arachnoid granulations and septa within dural sinuses than have been observed in previous radiologic studies. Arachnoid granulations were closely related spatially to veins.

Adolescent↗