Editor’s Choices

Longitudinal Whole-Brain N-Acetylaspartate Concentration in Healthy Adults • D.J. Rigotti, I.I. Kirov, B. Djavadi, N. Perry, J.S. Babb, and O. Gonen
This article addresses the issue of neuronal changes over time. N-acetylaspartate is surrogate marker of neuronal viability and integrity as seen on hydrogen MR spectroscopy. Here, the authors utilized their own method of measuring whole-brain NAA in a small cohort of healthy adults with each receiving 4 scans (baseline and annual) during a 3-year period. The data were converted to absolute millimole concentrations of this metabolite. They found that whole-brain NAA was stable over a 3-year period in healthy adults. It qualifies therefore as a biomarker for global neuronal loss and dysfunction in diffuse neurologic disorders that may be well worth considering as a secondary outcome measure candidate for clinical trials.

Thalamic Damage Predicts the Evolution of Primary-Progressive Multiple Sclerosis at 5 Years • S. Mesaros, M.A. Rocca, E. Pagani, M.P. Sormani, M. Petrolini, G. Comi, and M. Filippi
The importance of gray matter lesions in multiple sclerosis cannot be underestimated. These authors used diffusion tensor imaging from the thalami of patients with primary-progressive MS to assess its ability in predicting long-term disability accumulation. They examined conventional MR and DTI studies of 54 patients (and 8 controls) at baseline, 15 months, and 5 years. Patients were reassessed clinically at 5 years. At baseline and follow-up, measures of lesion load, brain atrophy, and normalized thalamic volume were obtained. Mean diffusivity and fractional anisotropy histograms of the normal-appearing white matter, the whole gray matter without the thalami, and, last, the thalami were obtained. A multivariate analysis was used to evaluate the predictors of long-term neurologic deterioration. They concluded that short-term accrual of thalamic damage and the severity of involvement in the normal-appearing white matter predict long-term accumulation of disability in PPMS as measured by the Expanded Disability Status Scale.

Apparent Diffusion Coefficient Mapping for Sinonasal Diseases: Differentiation of Benign and Malignant Lesions • M. Sasaki, S. Eida, M. Sumi, and T. Nakamura
Because CT and conventional MR imaging findings of sinonasal lesions overlap considerably, these authors decided to evaluate the utility of diffusion-weighted imaging in differentiating these lesions. They obtained apparent diffusion coefficient values in 61 proved lesions (19 benign, 28 malignant, and 14 inflammatory). As expected, ADC values of malignant lesions were much lower than those of the other 2 types. Additionally, the higher the percentage area of the tumor that had low ADC, the greater was the chance of it being malignant. If 78% of lesion area had low ADC, the ability to differentiate between malignant and benign reached a 94% specificity. ADCs could also differentiate lymphoma from other malignant tumors. Conclusions: ADC mapping may be an effective MR imaging tool for the differentiation of benign/inflammatory lesions from malignant tumors in the sinonasal area.

Fellows’ Journal Club

Safety of High Doses of Urokinase and Reteplase for Acute Ischemic Stroke • V. Misra, R. El Khoury, R. Arora, P.R. Chen, S. Suzuki, N. Harun, N.R. Gonzales, A.D. Barreto, J.C. Grotta, and S.I. Savitz
If a patient has previously received tissue plasminogen activator for cerebral ischemia, is it safe to give him or her urokinase or reteplase intra-arterially for persistent arterial occlusion? If yes, how much can be given? Here, the authors addressed those questions. During a 10-year period they collected data from 197 such patients (72 had received UK and the others RT). Demographics, baseline National Institutes of Health Stroke Scale scores, recanalization rates, rates of attempted mechanical thrombectomy, mortality, symptomatic hemorrhage, and discharge modified Rankin Scale scores were collected. Mechanical thrombolysis was attempted in 60-72% of patients in both groups. The authors found no correlation between symptomatic intracranial hemorrhages and administration of either UK or RT. There was no correlation between mortality and doses of either drug. They concluded that high intra-arterial doses of UK and RT may be safe when given with or without mechanical thrombectomy in patients with acute ischemic stroke, despite already having received a full dose of intravenous rtPA.

Influence of Nomenclature in the Interpretation of Lumbar Disk Contour on MR Imaging: A Comparison of the Agreement Using the Combined Task Force and the Nordic Nomenclatures • E. Arana, F.M. Kovacs, A. Royuela, A. Estremera, H. Sarasíbar, G. Amengual, I. Galarraga, C. Martínez, A. Muriel, V. Abraira, J. Zamora, and C. Campillo
There is little agreement between observers when reporting disk abnormalities. These authors evaluated the influence of using criteria set by the Combined Task Force (of which ASNR is a member) and the Nordic Modic Consensus Group Classification in the interpretation of lumbar disk contour. Among the variables assessed on the Nordic form, those analyzed for this study were Schmorl nodes (yes/no) and disk contour (normal, bulging, protrusion [focal or broad-based], and hernia [extrusion or sequestration]). With the CTF form, the recorded variables were intravertebral herniation (yes/no) and disk contour (normal, symmetric bulging disk, focal-based herniation, broad-based herniation, and extrusion). The categorization of intra- and interobserver agreement proved the same across nomenclatures. Intraobserver reliability was substantial for intravertebral herniations and disk contour abnormalities. Interobserver reliability was moderate for intravertebral herniations and fair-to-moderate for disk contour. Conclusions: in clinical practice, regardless of the specific nomenclature used, a standardized nomenclature supports only moderate interobserver agreement. The Nordic nomenclature increases self-confidence in an individual observer’s report, but is less clear regarding the classification of disks as normal versus bulging.

Transient Hyperintensity in the Subthalamic Nucleus and Globus Pallidus of Newborns on T1-Weighted Images • T. Taoka, N. Aida, T. Ochi, Y. Takahashi, T. Akashi, T. Miyasaka, A. Iwamura, M. Sakamoto, and K. Kichikawa
In newborns, high signal intensity in the subthalamic nuclei may be indicative of cerebral ischemia, particularly in combination with high signal in the posterior putamen. This article describes transient and normal high signal intensity in the subthalamic nuclei and globi pallidus. Seventy-nine neonates who had normal examinations 2 years later were included in the study. The authors performed qualitative and quantitative evaluations of these 2 regions on T1- and T2-weighted images and correlated their results with postnatal and gestational ages. With increasing postnatal age at examination, the high signal intensity on the T1-weighted images for both subthalamic and globi pallidus diminished. Although the disappearance of this hyperintensity was well correlated with the postnatal age at examination for both the qualitative and quantitative studies, there was no correlation with gestational age at examination. For the T2 images, there was no correlation with either the postnatal age or gestational age at examination.