Seizures (successfully treated with antiepileptic medications)


Persistent drainage pathways that connect the confluence of sinuses with the sigmoid sinus/internal jugular vein bilaterally. Atretic left transverse/sigmoid sinus segments (incidental).


Persistent occipital sinuses


• Aside from understanding the various limitations/pitfalls of MR venography, recognizing anatomic variants of major venous drainage is critical and surgically relevant.

• “Flow gaps” can be seen in up to 30% of normal MR scans typically within the hypoplastic transverse sinus, principally as a function of slow intravascular flow, in-plane flow, and/or complex flow patterns. Hypoplasia of the transverse or sigmoid sinus may be associated with alternative drainage pathways (eg, persistent occipital sinus).

• Occipital sinuses usually communicate cranially at the torcular Herophili and caudally at the foramen magnum, where a multitude of variations may exist.

• Occipital sinuses have been reported in up to 10% of normal subjects and may be associated with atretic transverse/sigmoid sinus segments and internal jugular vein. Correlation with CT may bolster confident diagnosis by demonstrating a smaller caliber sigmoid sinus groove and/or jugular foramen.

• Occipital venous network is believed to regress once most of the venous flow passes through the major dural sinuses when children assume the upright position.

• Relevance: (Accidental) discovery of a persistent occipital sinus during posterior fossa surgery can result in catastrophic hemorrhage and/or occlusion of the occipital sinus that may lead to venous thrombosis/infarction.

— Rahul V. Pawar, MD, DABR, is a radiologist at Saint Barnabas Medical Center in Livingston, New Jersey.
— David Dunaway, DO, is a radiology resident at Saint Barnabas.
— Lyle R. Gesner, MD, is the neuroradiology section head at Saint Barnabas.



  1. Provenzale JM, Kranz PG. Dural sinus thrombosis: sources of error in image interpretation. AJR Am J Roentgenol. 2011;196(1):23-31.
  2. Kobayashi K, Suzuki M, Ueda F, Matsui O. Anatomical study of the occipital sinus using contrast-enhanced magnetic resonance venography. Neuroradiology. 2006;48(6):373-379.
  3. Ayanzen RH, Bird CR, Keller PJ, McCully FJ, Theobald MR, Heiserman JE. Cerebral MR venography: normal anatomy and potential diagnostic pitfalls. AJNR Am J Neuroradiol. 2000;21(1):74-78.

Submission Instructions

Submit cases directly to Rahul V. Pawar, MD, DABR (section editor for “On the Case”) at rvp325@yahoo.com. Cases submitted should be relevant and interesting. All modalities and subspecialties within radiology are equally considered.

Case submission entails two PowerPoint slides:

a. History (one-line phrase)
b. Two to five high-quality images in JPEG format without annotations
c. Name(s) of the author(s) (three maximum) and respective institutions

a. Diagnosis
b. Concise bulleted discussion (one to two lines each), including the following: pertinent clinical history, diagnostic imaging findings, differential diagnoses, treatment (if applicable)
c. Two to three relevant and current references, preferably citing peer-reviewed radiology literature

Section Editor: Rahul V. Pawar, MD, DABR
Department of Radiology, Division of Neuroradiology
Saint Barnabas Medical Center/Barnabas Ambulatory Care Center