ARRS Case of the Week


Case Author: Brian D. Petersen, MD, University of Colorado


58-year-old woman with 1 year of numbness, burning pain described as 8 of 10, and tingling involving both feet and radiating to mid calf bilaterally; examination showed hyperreflexia, bilateral upgoing Babinski sign, and sustained clonus of the right ankle.

Imaging Findings

Sagittal T2-weighted MR image (A) of the lumbar spine shows a low-lying conus (arrow) at L4–L5 and hypoplastic L4 and L5 vertebral bodies. Sagittal T1-weighted MR image (B) shows tissue of linear high T1 signal intensity (arrows) in the sacral canal and fusion of the spinous processes (star). Representative axial T2-weighted MR images from superior to inferior show a small syrinx (arrow, C), focal short-segment splitting of the spinal cord (arrows, D) with distal rejoining (not pictured). Inferior most image (E) shows a small focus of chemical shift artifact (arrow) corresponding to the thin high-signal-intensity structure in B.


Diastematomyelia, Pang type 2 with tethered cord related to fatty filum

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Teaching Points

Diastematomyelia is sagittal division of the spinal cord into two distinct hemicords. Cords can be divided by a fibrous or bony septum. CT can supplement MRI, and the findings define or exclude a bony septum.

Pang type 1 diastematomyelia has separate dural sacs with an osseous or fibrous spur. Pang type 2 has a single dural sac. Diastematomyelia is asymptomatic unless the cord is tethered; 75% of diastematomyelia cases have a tethered cord.

In 91% of cases of diastematomyelia, the hemicords reunite distally into a single filum terminale; 50% of cases of diastematomyelia have an associated syrinx (as in this case).

In 85% of cases, diastematomyelia is associated with spinal anomalies at the level of the cord division.

Intersegmental laminar fusion is pathognomonic of diastematomyelia.

Suggested Readings

Barkovich AJ. Pediatric neuroimaging, 4th ed. Philadelphia, PA: Lippincott, 2005

Ross JS, Brant-Zawadski M, Moore KR, Crim J, Chen MZ, Katzman GL. Diagnostic imaging: spine. Salt Lake City, UT: Amirsys, 2007:1–56

This page is updated with new content weekly. It was last updated on March 19, 2019.