Clinical Correlation of a New MR Imaging Method for Assessing Lumbar Foraminal Stenosis • H.-J. Park, S.S. Kim, S.-Y. Lee, N.-H. Park, M.-H. Rho, H.-P. Hong, H.-J. Kwag, S.-H. Kook, and S.-H. Choi
Two different systems for grading foraminal stenosis, the Wildermuth (degree of fat obliteration) and the Lee system (type of stenosis, degree of fat obliteration, and nerve root compression) were assessed and correlated with clinical findings. Interobserver agreement was greater with the Lee system. Both systems had good correlation with clinical symptoms, especially for older patients, but the Lee system was better for younger subjects. Although both systems performed well, the Lee system was slightly better.
Detection of Microhemorrhage in Posterior Reversible Encephalopathy Syndrome Using Susceptibility-Weighted Imaging • A.M. McKinney, B. Sarikaya, C. Gustafson, and C.L. Truwit
Hemorrhage in posterior reversible encephalopathy syndrome occurs in 15-17% of patients but can be underestimated by using conventional MRI. Thus, these authors used SWI to study 31 patients with PRES and found that microbleeds were present in nearly 65% and subarachnoid hemorrhage in 10%. In some patients, microhemorrhages persisted after PRES resolved and in others these developed after its onset. Although the clinical significance of these small bleeds is not known, they could be caused by endothelial cell damage.
Susceptibility-Weighted Imaging in Patients with Pyogenic Brain Abscesses at 1.5T: Characteristics of the Abscess Capsule • P.H. Lai, H.C. Chang, T.C. Chuang, H.W. Chung, J.Y. Li, M.J. Weng, J.H. Fu, P.C. Wang, S.C. Li, and H.B. Pan
The rim of cerebral abscesses is dark on T2 presumably due to the accumulation of oxygen radicals in inflammatory cells. Because DWI is more sensitive to susceptibility effects than other MRI sequences, these authors used it to evaluate 14 abscesses. DWI agreed with previous observations detecting mild hypointensity in most abscess rims, compatible with the presence of paramagnetic substances due to oxygen free radicals from phagocytosis. SWI provides another means of establishing the diagnosis and helping us to understand the pathophysiology of abscesses.
Fellows’ Journal Club
Practice Patterns and Opening Pressure Measurements Using Fluoroscopically Guided Lumbar Puncture • A.S. Abel, J.R. Brace, A.M. Mckinney, A.R. Harrison, and M.S. Lee
Here is an article that offers evidence-based information regarding different protocols used for fluoroscopically guided lumbar punctures. The data were obtained via Web-based anonymous questionnaires sent to neuroradiologists. From 577 responses the following information can be gleaned: most neuroradiologists place the patient prone, use a 22-gauge needle, and access the L2-3 or L3-4 spaces. The techniques for measuring pressure vary widely and only a minority of neuroradiologists rotate their patients for this purpose. The authors recommend developing a uniform protocol for opening pressure measurement.
Differentiation of Tumefactive Demyelinating Lesions from High-Grade Gliomas with the Use of Diffusion Tensor Imaging • C.H Toh, K.-C. Wei, S.-H. Ng, Y.-L. Wan, M. Castillo, and C.-P. Lin
Although perfusion and MRS have been used to differentiate tumefactive demyelinating lesions from gliomas, this article explores the use of DTI for this purpose. The authors measured fractional anisotropy inside the lesions, at their periphery, and in the perilesional zone in 8 TDLs and 13 gliomas. Fractional anisotropy in the peripheral enhancing portions of the lesions was higher in TDLs than in gliomas, whereas in the perilesional zones fractional anisotropy was higher in gliomas. Thus, DTI was helpful in differentiating between these 2 lesions.
Acute Effects of Alcohol on the Human Brain: Diffusion Tensor Imaging Study • L.M. Kong, W.B. Zheng, G.P. Lian, and H.D. Zhang
Is DTI helpful in assessing the effects of acute alcohol ingestion on the brain? Sixteen healthy volunteers were given either low or high doses of alcohol in the form of wine and DTI measurements were obtained at 0.5, 1, 2, and 3 hours after its initiation. No abnormalities were seen by conventional MRI but low ADC values were found in the frontal lobe, thalamus, and middle cerebellar peduncle especially at 1 and 2 hours. Breath alcohol measurements reached their peak at 30 minutes. DTI is thus better than breath measurements for detection of acute alcohol-induced changes.