MR diagnosis of paraganglioma of the head and neck: value of contrast enhancement.

Abstract

OBJECTIVE.Contrast

MR Findings of the Spinal Paraganglioma: Report of Three Cases

“…This hypervascularity results in punctate areas of flow void interspersed in a matrix of increased signal intensity caused by slow flow and tumor cell; this produces a "salt-and-pepper"appearance on T2-weighted images. However, small tumors tend not to show the flowvoid phenomenon (16). In our cases, all three cases showed tubular and dot-like signal void structures around and within the tumors that represent high velocity flow.…”

Magnetic resonance imaging or metaiodobenzylguanidine scintigraphy for the demonstration of paragangliomas?

“…We use intravenous contrast agents such as gadopentetate dimeglumine (Magnevist) only in selected cases. Because of the natural contrast between vascular structures and surrounding tissues in MR imaging, opacification of vessels with intravenous contrast agents as in CT is not necessary for delineation [89]. Moreover, intravenous contrast enhancement in MR imaging may result in the reduction of contrast between both normal and abnormal adrenal glands and surrounding retroperitoneal fat.…”

MRI Sequences in Head & Neck Radiology – State of the Art

“…cysts, sinus tracts, fistulae or cartilaginous remnants based on location and clinical symptoms [4] sinonasal inverted papilloma convoluted cerebriform pattern on T2w and T1wC+ [6] paraganglioma "salt and pepper" appearance (30 -40 %) [7] cancer intermediate to high signal in T2w, high signal in T1wC+, mass, infiltration, inhomogeneity, necrosis perineural invasion T2w and T1w thickening and T1wC+ contrast enhancement along the cranial nerve [8] dural invasion nodular dural enhancement on T1wC+ and width of enhancement of more than 5 mm [9] mandibular bone invasion replacement of peripheral hypointense signal (cortical bone) through either tumor signal intensity on both T1w and T2w, or central hyperintense signal (medullary bone) is replaced by intermediate tumor signal [11] neoplastic invasion of laryngeal cartilages low T1w signal, similar to that of tumor T2w signal and similar to tumor T1wC+ signal [12] residual cancer after chemoradiation therapy intermediate T2 signal intensity similar to that of the untreated tumor with areas formed a focal expansible mass > = 1 cm [14] dissection high T1w signal in the vessel wall [15] TIRM/STIR, Dixon, spectral fat sat edema, swelling, tumor high signal in TIRM/STIR necrosis, cystic lesions high signal in TIRM/STIR adipose tissue (lipoma, cholesterol granuloma) suppressed signal lymph node metastasis nodal size (minimum axial diameter of 8 -9 mm in level II and 7 -8 mm for the rest of the neck), loss of hilar structure and necrosis (varying level of low-to-high signal intensity on T2w fat sat depending on keratinization, and coagulation and liquefaction necrosis) [18]; lower signal than regular or reactive lymph nodes on inverted TIRM/ STIR [16] extranodal tumor spread nodal size, shaggy margin and flare sign on T2w fat sat [19] SSFP (CISS, FIESTA), SPACE, VISTA, 3D-FLAIR cerebellopontine angles and inner ear (facial and vestibulocochlear nerves, schwannomas)…”

“…The convoluted cerebriform pattern on T2w and T1wC+images is a reliable feature of sinonasal inverted papilloma, with focal loss of the cerebriform pattern to be a clue to the diagnosis of focal malignancy [6]. Paraganglioma may show the typical "salt and pepper" appearance in about 30 -40 % of cases [7]. Skull base pathologies including various complications from sinonasal and mastoid infections such as orbital cellulitis, orbital abscess, meningitis, epidural and intracranial abscess or thrombosis of venous sinuses are typical MRI indications.…”