Prognostic significance of hyoid bone invasion in advanced base of tongue carcinoma treated by chemoradiation.

OBJECTIVES: To examine the prognostic influence of hyoid bone invasion in advanced base of tongue squamous cell carcinoma treated with chemoradiation. METHODS: We retrospectively reviewed pre-treatment imaging (CT/MRI) for the presence or absence of hyoid bone invasion in patients with advanced (clinical T3 or T4a stage) base of tongue squamous cell carcinoma treated with chemoradiation from January 2001 to January 2011. We compared patients with hyoid bone invasion to those without based on the following metrics: 1-, 2- and 5-year locoregional recurrence-free survival, disease-free survival, disease-specific survival and overall survival. RESULTS: Eleven of thirty-seven patients had hyoid invasion present on pre-treatment imaging. Average follow-up was 45 months. Patients with hyoid bone invasion were found to have lower percentages in all survival metrics measured compared to patients without, respectively, with statistical significance achieved in the following: 2-year locoregional recurrence-free survival: 36.4% versus 86.4% (P = 0.006), 5-year locoregional recurrence-free survival: 12.5% versus 63.6% (P = 0.05), 2-year disease-free survival: 36.4% versus 77.3% (P = 0.05), 5-year disease-free survival: 12.5% versus 63.3% (P = 0.05) and the Kaplan-Meier curve for locoregional recurrence-free survival (P = 0.0075). CONCLUSIONS: Hyoid bone invasion by base of tongue squamous cell carcinoma may indicate a poorer prognosis despite treatment. Hyoid bone invasion may be a possible indication for intensification of treatment and/or may indicate a necessity for increasing the degree of post-treatment surveillance monitoring and imaging.

Magnocellular and parvocellular visual pathways have different blood oxygen level-dependent signal time courses in human primary visual cortex.

PURPOSE: The magnocellular and parvocellular pathways (M and P pathways) are the major pathways of the visual system, with distinct histologic and physiologic properties that may also have different metabolic characteristics. We hypothesize that the differences of the 2 visual pathways would also manifest as differences in the signal time course of blood oxygen level-dependent functional MR imaging (BOLD fMRI). The differences in BOLD signal time course may provide insight into the metabolic requirements of the 2 pathways. METHODS: Eleven fMRI sessions on 6 subjects were performed using stimuli that preferentially activated the 2 pathways. Regions commonly activated by both the M and P stimuli in the primary visual cortex (V1) were determined, and the contrast elicited by the stimulus, time-to-peak (TTP), and the full width at half maximum (FWHM) of the BOLD signal time course were measured. RESULTS: The functional stimuli activated cortical regions described previously in the literature, such as V1, V4, and V5. Within V1, the TTP of the signal time course of the 2 stimuli were statistically different, with the P stimulus generating TTPs that were on average 12% faster than the M stimulus (P = .0037). CONCLUSION: We have demonstrated the ability to functionally differentiate the M and P stimuli in a commonly activated anatomic region. Because the BOLD response is dependent on the ratio of oxyhemoglobin and deoxyhemoglobin in the blood, the difference in the BOLD time course between the 2 stimuli suggests that the oxygen demand of the 2 pathways may be different.

Diffusion tensor imaging of the pediatric spinal cord at 1.5T: preliminary results.

BACKGROUND AND PURPOSE: Recent studies suggest that pediatric subjects as old as 8-years-of-age may have difficulty with the ISNCSCI examinations. Our aim was to investigate DTI parameters of healthy spinal cord in children with noncervical IS for comparison with children with SCI and to prospectively evaluate reliability measures of DTI and to correlate the measures obtained in children with SCI with the ISNCSCI. MATERIALS AND METHODS: Five controls with thoracic and lumbar IS and 5 children with cervical SCI were imaged twice by using a single-shot echo-planar diffusion-weighted sequence. Axial imaging was performed to cover the entire cervical spinal cord in controls. For the SCI subjects, 2 vertebral bodies above and below the injury were imaged. FA and D values were obtained at different levels of the cervical spinal cord. All subjects with SCI had undergone ISNCSCI clinical examinations. Statistical analysis was performed to access differences of the DTI indices between the controls and SCI subjects, reproducibility measurements, and correlations between DTI and ISNCSCI. RESULTS: Subjects with SCI showed reduced FA and increased D values compared with controls. Test-retest reproducibility showed good ICC coefficients in all the DTI index values among controls (≥0.9), while the SCI group showed moderate ICC (≥0.77). There were statistically significant correlations between the various DTI indices and ISNCSCI scores. CONCLUSIONS: Preliminary DTI indices in children were determined and showed good reproducibility. Reduced FA and increased D values were seen in children with SCI in comparison with controls and showed good clinical correlation with ISNCSCI examinations.