Anatomy of Neck Muscles, Spaces, and Lymph Nodes.

The following article details the muscular anatomy of the head and neck, including insertion, origin, action and innervation, organized by anatomic subunit and/or major action. This article also describes the spaces of the head and neck, including boundaties and contents. Finally, cervical lymph nodes are addressed according to anatomic location and lymphatic drainage.

Intravoxel incoherent motion MR imaging analysis for diagnosis of placenta accrete spectrum disorders: A pilot feasibility study.

BACKGROUND: Placenta accreta spectrum (PAS) disorders occur when the placenta adheres abnormally to the uterine myometrium and can have devastating effects on maternal health due to risks of massive postpartum hemorrhage and possible need for emergency hysterectomy. PAS can be difficult to diagnose using routine clinical imaging with ultrasound and structural MRI. OBJECTIVE: To determine feasibility of using intravoxel incoherent motion (IVIM) magnetic resonance imaging (MRI) analysis in the diagnosis of the placenta accreta spectrum disorders in pregnant women. METHODS: A total of 49 pregnant women were recruited including 14 with pathologically confirmed cases of PAS and 35 health controls without prior cesarean delivery and no suspected PAS by ultrasound. All women underwent diffusion-weighted imaging with an 8 b-value scanning sequence. A semi-automated method for image processing was used, creating a 3D object map, which was then fit to a biexponential signal decay curve for IVIM modeling to determine slow diffusion (Ds), fast diffusion (Df), and perfusion fraction (Pf). RESULTS: Our results demonstrated a high degree of model fitting (R2 ≥ 0.98), with Pf significantly higher in those with PAS compared to healthy controls (0.451 ± 0.019 versus 0.341 ± 0.022, p = 0.002). By contrast, no statistical difference in the Df (1.70 × 10-2 ± 0.38 × 10-2 versus 1.48 × 10-2 ± 0.08 × 10-2 mm2/s, p = 0.211) or Ds (1.34 × 10-3 ± 0.10 × 10-3 versus 1.45 × 10-3 ± 0.007 × 10-3 mm2/s, p = 0.215) was found between subjects with PAS and healthy controls. CONCLUSIONS: The use of MRI, and IVIM modeling in particular, may have potential in aiding in the diagnosis of PAS when other imaging modalities are equivocal. However, the widespread use of these techniques will require generation of large normative data sets, consistent sequencing protocols, and streamlined analysis techniques.

Diffusion MR Imaging in the Head and Neck: Principles and Applications.

Diffusion imaging is a functional MR imaging tool that creates tissue contrast representative of the random, microscopic translational motion of water molecules within human body tissues. Long considered a cornerstone MR imaging sequence for brain imaging, diffusion-weighted imaging (DWI) increasingly is used for head and neck imaging. This review reports the current state of diffusion techniques for head and neck imaging, including conventional DWI, DWI trace with apparent diffusion coefficient map, diffusion tensor imaging, intravoxel incoherent motion, and diffusion kurtosis imaging. This article describes background physics, reports supportive evidence and potential pitfalls, highlights technical advances, and details practical clinical applications.