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Hemangiomas are typically found in the pediatric age group. The majority are of the cavernous type and less likely the capillary type. They are best demonstrated by MRI and show marked enhancement. They are also very bright on T2 MRI. Foci of signal void may be vascular channels or phleboliths (Figures 2.49–2.51). They are typically slow flow lesions and may not be angiographically evident. US can vary from hypoechoic to heterogenous (Wong et al. 2004).

Other rare vascular lesions within salivary glands, most commonly the parotid gland, include aneurysms, pseudoaneurysms, and arteriovenous fistulae (AVFs). The aneurysms or pseudoaneurysms are most commonly associated with trauma or infection (mycotic). MRI in high flow lesions demonstrates “flow voids” or an absence of signal but slow flow lesions or turbulent flow can demonstrate heterogenous signal mimicking a mass. Contrast enhancement and MRA can help delineate vascular lesions from masses. CT without contrast however demonstrates a mass or masses isodense to skeletal muscle or normal blood vessels. With contrast, large vascular channels become more obvious, although smaller lesions may still mimic a mass. US (especially Doppler US) can reveal characteristic flow patterns of arterial waveforms in the venous channels for AVFs. US can also delineate aneurysms with their turbulent flow patterns. Angiography is typically reserved for endovascular treatment. CTA or MRA is useful for noninvasive assessment of arterial feeders and venous anatomy in AVFs and in defining aneurysms (Wong et al. 2004).

Figure 2.49. Direct coronal CT displayed in bone window demonstrating smooth erosion of the hard palate on the right lateral aspect, along with a dense calcification consistent with a phlebolith (arrow). A hemangioma is presumed based on this CT scan.

Figure 2.50. Coronal fat suppressed contrast‐enhanced T1 MRI image corresponding to the same level as Figure 2.49, demonstrating a sharply marginated homogenously enhancing mass (arrow).

Figure 2.51. Coronal fat saturated T2 MRI image demonstrating a well‐demarcated hyperintense mass with a focal signal void centrally. A hemangioma containing a phlebolith (arrow) was presumed based on this MRI.