Classic signs in head and neck imaging.

Radiologists have long relied upon the use of metaphoric imaging signs to attribute meaning to disease or anatomy-specific imaging patterns encountered in clinical imaging. Teachers of radiology often employ the use of such signs to help learners rapidly identify the typical appearance of various pathologies. Head and neck (H&N) imaging is no exception, and as a specialty that deals with uncommon pathologies and complex anatomy, learners and practising radiologists alike may benefit from this simplistic, pattern-based approach. In this review, we present a compendium of classic imaging signs of H&N lesions, including signs related to traumatic, infectious, neoplastic, congenital, and inflammatory aetiologies found throughout the spectrum of H&N sites (temporal bones, orbits, paranasal sinuses, larynx, salivary glands, and neck soft tissues). Additionally, we identify potential pitfalls and detail critical clinical ramifications related to the rapid and accurate diagnosis of these pathologies.

Diffusion imaging for tumor grading of supratentorial brain tumors in the first year of life.

BACKGROUND AND PURPOSE: Supratentorial tumors in the first year of life are typically large and heterogeneous at presentation, making differentiation of these CNS neoplasms on pre-operative imaging difficult. We hypothesize that the ADC value can reliably differentiate high- versus low-grade supratentorial tumors in this patient population. MATERIALS AND METHODS: A blinded review of ADC maps was performed on 19 patients with histologically proved supratentorial brain tumors diagnosed within the first year of life. Minimum ADC values obtained by region of interest from 2 neuroradiologists were averaged and compared with World Health Organization tumor grade. ADC values for the entire tumor were also obtained by use of a semi-automated histogram method and compared with World Health Organization tumor grade. Data were analyzed by use of Spearman ρ and Student t test, with a value of P < .05 considered statistically significant. RESULTS: For the manual ADC values, a significant negative correlation was found between the mean minimum ADC and tumor grade (P = .0016). A significant difference was found between the mean minimum ADC of the low-grade (1.14 × 10(-3) mm(2)/s ± 0.30) and high-grade tumors (0.64 × 10(-3) mm(2)/s ± 0.28) (P = .0018). Likewise, the semi-automated method demonstrated a significant negative correlation between the lowest 5th (P = .0002) and 10th (P = .0009) percentile individual tumor ADC values and tumor grade, a significant difference between the mean 5th and 10th percentile ADC values of the low-grade and high-grade groups (P = .0028), and a significant positive correlation with values obtained by manual region-of-interest placement (P < .000001). CONCLUSIONS: ADC maps can differentiate high- versus low-grade neoplasms for supratentorial tumors presenting in the first year of life, given the significant negative correlation between ADC values and tumor grade.