Vascular lesions:
It's important to distinguish the real masses from vascular pseudo masses to avoid an unnecessary biopsy.[5]
Jugular bulb pseudolesion:
CT: Homogeneous mass contiguous to the jugular vein (pseudomass) or enlargement of the pars vascularis.
MR: Slow or turbulent flow can induce loss of the flow void,
mimicking a real mass ( Fig. 2 ).
[3]
Dehiscent jugular bulb:
CT: Essential for diagnosis.
A deficient sigmoid plate can lead the jugular vein to penetrate the middle ear.
MR: Turbulent flow can be confusing.
The bone structures are poorly evaluated ( Fig. 3 ). [6,
7]
Infectious lesions:
The surrounding structures (such as mastoid cells in Fig. 4 and parotid gland in Fig. 5 ) can get infected and affect the jugular foramen causing thrombosis.
[5]
Jugular thrombosis as a complication of infection:
CT: Spontaneously hyperdense occupation of the jugular vein and with contrast we confirm the thrombosis.
MR: Absence of flow void and no enhancement.
( Fig. 4 and Fig. 5 )
Tumoral lesions:
Considering anatomic relationships,
tumoral pathologies can be distinguished in intrinsic and extrinsic.
[2,
4]
Intrinsic:
Paraganglioma:
CT: Homogeneous and expansive lesion with a permeative bone pattern.
MR: It has a typical “salt and pepper” appearance in T2,
with flow voids (pepper) within the hyperintense mass and haemorrhage areas (salt).
Intense contrast enhancement ( Fig. 6 ).
[3,
4,
5,
8]
Neurinoma:
CT: Homogeneous mass with bone remodelling with foramen widening.
MR: Hyperintense mass in T2,
intermediate in T1 and contrast enhancement ( Fig. 7 ).
[2,
3,
9,
10]
Meningioma:
CT: Extra-axial isodense mass and bone hyperostosis and calcifications.
MR: Intermediate signal in T1 and T2,
with intense contrast enhancement.
Pathognomonic sign: dural tail (Fig. 8 ).
[2,
3,
10,
11]
Extrinsic:
Chordoma:
It affects the clivus and can compromise the jugular foramen.
CT:Bone destruction and intralesional calcifications.
MR: Hypointense in T1,
hyperintense in T2 and peripheral enhancement ( Fig. 9 ).
[2]
Parapharyngeal Sarcoma:
CT: infiltrative,
heterogeneous tumour with areas of necrosis,
haemorrhage and bone destruction.
MR: hyperintense in T2,
isointense in T1,
and heterogeneous enhancement ( Fig. 10 ).[3,
4]
Tumour of the endolymphatic sac:
The features of this diagnose are similar to cholesterol granuloma,
the difference is the location.
The endolymphatic sac tumour is posterior to the petrous pyramid and the cholesterol granuloma is frequently in the petrous apex.
CT: extensive bone erosion with spicules,
similar to paraganglioma.
MR: cystic,
hyperintense in T1 and T2,
heterogeneous due to the presence of calcium.
It has peripheral contrast enhancement ( Fig. 11 ).
[12]