18F‐FDG PET/CT and MRI in the follow‐up of head and neck squamous cell carcinoma

We evaluated the diagnostic performance of ¹⁸F‐FDG PET/CT and MRI for the assessment of head and neck squamous cell carcinoma (HNSCC) relapse. Since early treatment might prevent inoperable relapse, we also evaluated THE performance of early unenhanced ¹⁸F‐FDG PET/CT in residual tumor detection. The study was prospectively performed on 32 patients who underwent ¹⁸F‐FDG PET/CT and MRI before treatment and at 4 and 12 months after treatment. ¹⁸F‐FDG PET/CT was also performed 2 weeks after the end of radiotherapy. Histopathology or a minimum of 18 months follow‐up were used as gold standard. Before treatment ¹⁸F‐FDG PET/CT and MRI detected all primary tumors except for two limited vocal fold lesions (sensitivity 94%). MRI was more sensitive than ¹⁸F‐FDG PET/CT for the detection of local extension sites (sensitivity 75 vs 58%), but at the cost of a higher rate of false positive results (positive predictive value 74 vs 86%). For relapse detection at 4 months, sensitivity was significantly higher for ¹⁸F‐FDG PET/CT (92%) than for MRI (70%), but the diagnostic performances were not significantly different at 12 months. For the detection of residual malignant tissue 2 weeks post‐radiotherapy, sensitivity and specificity of ¹⁸F‐FDG PET/CT were respectively 86 and 85% (SUV cut‐off value 5.8). ¹⁸F‐FDG PET/CT is effective in the differentiation between residual tumor and radiation‐induced changes, as early as 2 weeks after treatment of a primary HNSCC. For follow‐up, performance of ¹⁸F‐FDG PET/CT and MRI are similar except for a higher sensitivity of ¹⁸F‐FDG PET/CT at 4 months. Copyright © 2011 John Wiley & Sons, Ltd.     

Sensorimotor and cognitive functions in a SOD1(G37R) transgenic mouse model of amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis (ALS) is a neurological disorder involving degeneration of motor neurons in brain and spinal cord, leading to progressive atrophy of skeletal muscles and, ultimately, paralysis and death. Copper-mediated oxidative damage is proposed to play a critical role in the pathogenesis of Cu/Zn superoxide dismutase (SOD1) - linked hereditary amyotrophic lateral sclerosis. To understand more clearly the pathogenesis of sensorimotor dysfunction and to find the most appropriate methods for early detection of symptoms and for monitoring them across time, a murine model was assessed at three time points (5, 8, and 11 months). Transgenic mice with the G37R mutation of human SOD1 exhibited earliest signs of dysfunction at 8 months in terms of a pathological hindpaw clasping reflex, as well as slowed movement time on a suspended bar, anomalies in footprint patterns, weaker grip strength, raised somatosensory thresholds, and deficits in passive avoidance learning, yielding a margin of 3-4 months before death to test experimental therapies.     

External globus pallidus stimulation modulates brain connectivity in Huntington's disease

Positron emission tomography with O-15-labeled water was used to study at rest the neurophysiological effects of bilateral external globus pallidus (GPe) deep brain stimulation in patients with Huntington''s disease (HD). Five patients were compared with a control group in the on and off states of the stimulator. External globus pallidus stimulation decreased neuronal activity and modulated cerebral connectivity within the basal ganglia-thalamocortical circuitry, the sensorimotor, and the default-mode networks. These data indicate that GPe stimulation modulates functional integration in HD patients in accordance with the basal ganglia-thalamocortical circuit model.