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Background and Purpose: Differentiation of enhancing malignant lesions on conventional MR imaging can be difficult and various newer imaging techniques have been suggested. Our aim was to evaluate the role of PSR obtained from DSC perfusion measurements in differentiating lymphoma, GBM, and metastases. The effectiveness of PSR was compared with that of rCBV. We hypothesized that the newly defined parameter of PSR is more sensitive and specific in differentiating these lesions., Materials and Methods: This retrospective study included 66 patients (39 men and 27 women; age range: 27-82 years) with a pathologically proved diagnosis of primary CNS lymphoma, GBM, or metastases (22 patients in each group). Mean PSR, min PSR, max PSR, and rCBV were calculated. The classification accuracy of these parameters was investigated by using ROC., Results: Mean PSR was high (113.15 ± 41.59) in lymphoma, intermediate in GBM (78.22 ± 14.27), and low in metastases (53.46 ± 12.87) with a P value < .000. F values obtained from 1-way ANOVA analysis for mean, min, and max PSR ratios were 29.9, 39.4, and 23.4, respectively, which were better than those of rCBV (11.1) in differentiating the 3 groups. Max PSR yielded the best ROC characteristics with an A(z) of 0.934 (95% CI, 0.877-0.99) in differentiating lymphoma from metastases and GBM. The A(z) for mean and min PSR of 0.938 (95% CI, 0.0.884-0.990) and 0.938 (95% CI, 0.884-0.991), respectively, was better than rCBV (A(z), 0.534; 95% CI, 0.391-0.676) in the differentiation of metastases from GBM and lymphoma (P ≤ .0001)., Conclusions: PSR appears to be a parameter that helps in differentiating intracerebral malignant lesions such as GBM, metastases, and lymphoma.

Background and Purpose: The effects of a number of diffusion-encoding gradient directions (NDGD) on diffusion tensor imaging (DTI) indices have been studied previously with theoretic analysis and numeric simulations. In this study, we made in vivo measurements in the human brain to compare different clinical scan protocols and to evaluate their effects on the calculated DTI indices., Methods: Fifteen healthy volunteers were scanned with a 1.5T MR scanner. Single-shot DTI images were acquired using 3 protocols different in NDGD and number of excitations (NEX) for each direction (NDGD/NEX = 6/10, 21/3, 31/2). Means and standard error of mean (SEM) were calculated and compared in 6 regions of interest (ROIs) for mean diffusivity (D), fractional anisotropy (FA), diffusion tensor eigenvalues (lambda(1), lambda(2), and lambda(3)), and correlation coefficients (r) of these indices among the 3 DTI protocols., Results: At the ROI level, no significant differences were found for the mean and SEM of D and FA among protocols (P > .05). The 6-NDGD protocol, however, yielded higher values for lambda(1) and lambda(2) and lower values for lambda(3) in most ROIs (P < .05) compared with the other protocols. At the voxel level, the correlation between the protocols r(21-31) were higher than r(6-21) and r(6-31) in most ROIs. The correlation of FA among 3 protocols also increased with increasing anisotropy., Conclusion: For ROI analyses, different NDGDs lead to similar values of FA and D but different eigenvalues. However, different NDGDs at the voxel level provide varying values. The selection of the NDGD, therefore, should depend on the focus of different DTI applications.

Background and Purpose: Patients successfully treated with vertebroplasty often return with new pain caused by a new vertebral body fracture. The new fractures often are adjacent to the vertebral bodies that were initially treated. In our clinical work, we have observed that cement leakage into the disk increases the risk of new fracture of the adjacent vertebral body. This study analyzed the risk of new fractures of adjacent vertebral bodies in relationship to cement leakage into the disk., Methods: This study was based on 38 patients with painful compression fractures treated with vertebroplasty. Patients who returned with new pain after initial successful vertebroplasty were evaluated by repeat MR imaging. We analyzed the incidence of new fractures of adjacent vertebral bodies in relationship to cement leakage into the disk that had occurred during the initial vertebroplasty., Results: Fourteen patients developed new fractures during the follow-up period. In 10 patients, the new fractures were associated with cement leakage into the disk, whereas four patients had new fractures that were not associated with cement leakage into the disk. This difference was statistically significant (P =.018). A detailed analysis showed that 58% of vertebral bodies adjacent to a disk with cement leakage fractured during the follow-up period compared with 12% of vertebral bodies adjacent to a disk without cement leakage (P <.0005)., Conclusion: Leakage of cement into the disk during vertebroplasty increases the risk of a new fracture of adjacent vertebral bodies.

Background and Purpose: White matter changes such as periventricular hyperintensity (PVH) and deep white matter hyperintensity (DWMH) are associated with both periventricular edema and ischemic white matter degeneration. Their diagnostic and predictive value in normal pressure hydrocephalus (NPH) is unclear. To identify prognostically important changes, we classified PVH and DWMH at MR imaging in a large series of patients with NPH, before and after ventriculoperitoneal shunt surgery., Methods: Axial proton density- and T2-weighted turbo spin-echo sequences and coronal T1-weighted sequences were performed on a 0.5-T imager in 34 patients with NPH, before and 3 months after shunt surgery. PVH at the anterior, central, and posterior thirds of the lateral ventricles was assessed on transaxial images with a semiquantitative five-step scale describing the extension (in mm) and shape of the PVH. DWMH was quantified with a four-step scale. The number of cortical and subcortical lacunar infarctions, the flow void sign, and the width of the third and lateral ventricles were registered. Gait ability, need for sleep, urinary incontinence, living conditions, and psychometric test performance were assessed pre- and postoperatively., Results: After shunt surgery, 25 patients improved and nine did not. PVH, DWMH, and other MR imaging variables before shunting did not differ between groups, and no MR imaging variable could predict the clinical effect of shunt surgery. Postoperatively, the width of PVH was reduced in the improved patients, and clinical improvement correlated with reduction in PVH. Only the irregular type of PVH located at the frontal horns was reduced postoperatively. The presence of risk factors or MR imaging changes normally associated with cerebrovascular disease had no negative influence on the outcome of shunt surgery., Conclusion: The presence of DWMH or subcortical lacunar infarctions in NPH did not predict a poor outcome from shunt surgery and should not be used as exclusion criteria for shunting. No MR imaging findings could predict outcome of shunt surgery in patients with NPH. Clinical improvement after surgery is associated with reduction in the irregular type of PVH located around the frontal horns.

CT was used to document temporal lobe atrophy in 39 patients who were diagnosed clinically as having Alzheimer disease; the results were compared with those from 29 healthy elderly control subjects who were matched for age and education. The diagnosis of Alzheimer disease was made according to clinical criteria consistent with those specified by an NINCDS workshop. These included detailed medical and neuropsychological assessments. Temporal lobe atrophy was assessed by evaluating the temporal horns and sylvian cisterns. Temporal horn measurements greater than 3 mm occurred only in patients with Alzheimer disease while measurements less than or equal to this occurred in both Alzheimer patients and control subjects. Subjective evaluation of the sylvian cistern indicated that 24/29 controls had normal-appearing cisterns while only 5/39 Alzheimer patients had similar findings. In contrast to temporal horns, sylvian cisterns were more sensitive but less specific as discriminators between Alzheimer patients and normal controls.

The effect of fat suppression on orbital MR imaging was tested by using a derivative of the Dixon method called chopper fat suppression in eight normal volunteers and eight patients with normal conventional orbital MR studies. Chopper fat suppression requires no postacquisition image processing or increased scan time and can be applied through a wide range of T1 to T2 weighting. In normal orbits, fat suppression was found to be advantageous for imaging the lacrimal gland and the optic nerve. Using fat-suppressed T1- or intermediate-weighted sequences, 2000/30 (TR/TE), the optic nerve was recognized by its high signal intensity relative to adjacent CSF, dural sheath, and surrounding fat. The technique minimized loss of anatomic detail by reducing chemical shift misregistration artifact. Disadvantages included an overall lower orbital signal/noise ratio. When used in conjunction with a TR/TE combination carefully selected for both anatomic region of interest and suspected pathology, the fat-suppression technique has the potential for improving the visualization of orbital lesions.