Diffusion tensor magnetic resonance imaging may show abnormalities in the normal-appearing cervical spinal cord from patients with multiple sclerosis

Objective This study aims to evaluate “in vivo” the integrity of the normal-appearing spinal cord (NASC) in patients with multiple sclerosis (MS) compared to controls, using diffusion tensor MR imaging. Methods We studied 32 patients with MS and 17 without any neurologic disorder. Fractional anisotropy (FA), axial diffusivity (AD), radial diffusivity (RD) and mean diffusivity (MD) were calculated within regions of interest at C2 and C7 levels in the four columns of the spinal cord. Results At C2, FA value was decreased in MS patients. Besides, RD value was higher in MS than in controls. At C7, MD values were increased in MS. Conclusion The NASC in the right column of the cervical spinal cord showed abnormal FA, RD and MD values, which is possibly related to demyelination, since the FA abnormality was related to the RD and not to the AD

Increased posterior cingulate cortex efficiency may predict cognitive impairment in asymptomatic HIV patients

Purpose: Despite antiretroviral therapy, approximately half of individuals with human immunodeficiency virus (HIV) will develop HIV-associated neurocognitive disorder (HAND). Efficiency of brain networks is of great importance for cognitive functioning, since functional networks may reorganize or compensate to preserve normal cognition. This study aims to compare efficiency of the posterior cingulate cortex (PCC) between patients with and without HAND and controls. We hypothesize HAND negative (HAND–) patients will show higher PCC efficiency than HAND positive (HAND+) patients. Methods: A total of 10 HAND + patients were compared with 9 HAND– patients and 17 gender-, age-, and education-matched controls. Resting-state functional MRI was acquired with a 3 Tesla scanner. Local efficiency, a measure of network functioning, was investigated for PCC. Network differences among HAND +, HAND– patients and controls were tested as well as correlations between network parameters and cognitive test performance in different domains. Results: HAND– patients showed significantly increased PCC efficiency compared with healthy controls (p = 0.015). No differences were observed between HAND + patients and either controls (p = 0.327) or HAND– patients (p = 0.152). In HAND– patients, PCC efficiency was positively related with cognitive performance in the attention/working memory domain (p = 0.003). Conversely, in HAND + patients, PCC efficiency was negatively correlated with performance in the abstraction/executive domain (p = 0.002). Conclusion: HAND– patients showed a higher level of PCC efficiency compared with healthy subjects, and PCC efficiency was positively related to cognitive performance. These results support the functional reorganization hypothesis, that increased PCC efficiency is a compensation technique to maintain cognitive functioning

"Million dollar nerve” magnetic resonance neurography: first normal and pathological findings

Objectives: To evaluate prospectively the feasibility of magnetic resonance neurography (MRN) in identifying the anatomical characteristics of thenar muscular branch (TMB) of the median nerve, also known as the “million dollar nerve”, in patients and controls. Methods: Thirteen patients affected by carpal tunnel syndrome (CTS) and four healthy controls had their hands scanned on a 3T MR imaging scanner for TMB visualization. Median nerve anatomical variations were classified into four groups according to the Poisel’s classification system modified by Lanz. TMB signal intensity and diameter were assessed for the diagnosis of neuropathy. Results: TMB was successfully identified in all patients and subjects by using MRN. The most suitable pulse sequences to identify and measure nerve diameter were 3D DW-PSIF and T2-FS-TSE. The axial oblique and sagittal oblique planes are complementary in demonstrating its entire course. TMB had mostly an extraligamentous course with radial side origin (93.8%, each). All patients experienced increased T2 signal intensity (P < 0.001) and thickened nerves. Mean TMB diameters were 1.27 ± 0.21 mm (range, 1.02–1.74 mm) and 0.87 ± 0.16 mm (0.73–1.08 mm) (P = 0.008) in the patient and control groups, respectively. Conclusion: MRN is a reliable imaging technique for identification and anatomical characterization of TMB in patients affected by CTS. This innovative imaging workup may therefore be included in the preoperative evaluation of patients scheduled for carpal tunnel release, especially in CTS with TMB involvement or even in isolated TMB neuropathySimObjectives: To evaluate prospectively the feasibility of magnetic resonance neurography (MRN) in identifying the anatomical characteristics of thenar muscular branch (TMB) of the median nerve, also known as the “million dollar nerve”, in patients and controls. Methods: Thirteen patients affected by carpal tunnel syndrome (CTS) and four healthy controls had their hands scanned on a 3T MR imaging scanner for TMB visualization. Median nerve anatomical variations were classified into four groups according to the Poisel’s classification system modified by Lanz. TMB signal intensity and diameter were assessed for the diagnosis of neuropathy. Results: TMB was successfully identified in all patients and subjects by using MRN. The most suitable pulse sequences to identify and measure nerve diameter were 3D DW-PSIF and T2-FS-TSE. The axial oblique and sagittal oblique planes are complementary in demonstrating its entire course. TMB had mostly an extraligamentous course with radial side origin (93.8%, each). All patients experienced increased T2 signal intensity (P < 0.001) and thickened nerves. Mean TMB diameters were 1.27 ± 0.21 mm (range, 1.02–1.74 mm) and 0.87 ± 0.16 mm (0.73–1.08 mm) (P = 0.008) in the patient and control groups, respectively. Conclusion: MRN is a reliable imaging technique for identification and anatomical characterization of TMB in patients affected by CTS. This innovative imaging workup may therefore be included in the preoperative evaluation of patients scheduled for carpal tunnel release, especially in CTS with TMB involvement or even in isolated TMB neuropathy