FLEX February 2024

Stern et al

236

Fig. 15. Infantile hemangioma. Coronal fat-suppressed T2 ( A ) and axial fat-suppressed post contrast T1 ( B ) magnetic resonance images show a bulky mass in the right face subcutaneous tissues that invades the masticator and parotid spaces and contains prominent flow voids ( arrows ).

lymph nodes with peripheral rim enhancement and central hypodense necrosis, adja cent inflammatory change, and occasionally calcifications. Furthermore, diffusion weighted imaging can be useful for differentiating malignant from benign lymph nodes in adults and some older children 26 ; however, this correlation has not yet been well established in young children. Abscess Although head and neck infections are generally not difficult to diagnose clinically, im aging plays an important role in the precise localization of the involved space for timely incision and drainage if necessary. 27,28 CT is helpful in identifying abscess formation, which presents as a hypodense collection with a complete peripheral rim of enhance ment ( Fig. 18 ). A focal collection without enhancement or with an incomplete rim of enhancement is indicative of phlegmon. In particular, multiplanar MRI sequences are useful for depicting the extent of head and neck abscesses, which appear as peripherally enhancing fluid collections ( Fig. 19 ).

Fig. 16. Mycobacterial adenitis. Axial ( A ) and reconstructed reformatted ( B ) contrast enhanced CT images demonstrate multiple enlarged lymph nodes in the left neck with het erogeneous enhancement. Areas of central low density ( white arrowheads ) represent nodal necrosis.

Downloaded for Anonymous User (n/a) at STANFORD UNIVERSITY from ClinicalKey.com by Elsevier on January 02, 2024. For personal use only. No other uses without permission. Copyright ©2024. Elsevier Inc. All rights reserved.