Ossification of the petrosphenoidal ligament: multidetector computed tomography findings of an unusual variation with a potential role in abducens nerve palsy.
OBJECTIVE
The petrosphenoidal ligament (PSL) forms the roof of Dorello's canal in which the abducens nerve courses. An ossified PSL may play a role in abducens nerve palsy although it is controversial. Therefore, we aimed to investigate the incidence and the imaging features of PSL ossification using multidetector computed tomography (MDCT).


METHODS
Consecutive head CT scans, performed between January 2014 and May 2014, were retrospectively evaluated by two radiologists to look for a partial or complete ossification at the expected site of the PSL using axial, reformatted coronal and sagittal images.


RESULTS
We found 46 patients (32 men, 14 women) with ossification of the PSL out of 523 head CT scans (46/523, 8.8%). A total of 61 PSL ossifications (31 unilateral; 15 bilateral) were found in 1,046 petroclival regions (61/1,046, 5.8%). Of these 61 ossifications, 34 (34/523, 6.5%) were on the right and 27 (27/523, 5.1%) were on the left; 38 (38/1,046, 3.6%) were classified as partial and 23 (23/1,046, 2.2%) were classified as complete.


CONCLUSIONS
Ossification of the PSL is not a rare finding on MDCT. This imaging technique can reliably demonstrate the imaging features of an ossified PSL.
Department of Radiology, Faculty of Medicine, Mersin University, 34. Cadde, Çiftlikköy Kampüsü, 33343, Mersin, Turkey, anilozgur@yahoo.com.
Anıl
A
Özgür
Kaan
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Esen
D000010:Abducens Nerve / Q000000981:diagnostic imaging*; D020434:Abducens Nerve Diseases / Q000000981:diagnostic imaging*; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D008022:Ligaments / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D061330:Multidetector Computed Tomography; D009999:Ossification, Heterotopic / Q000000981:diagnostic imaging*; D010579:Petrous Bone / Q000033:anatomy & histology; D012189:Retrospective Studies; D013100:Sphenoid Bone / Q000033:anatomy & histology; D055815:Young Adult