Abstract
The CT appearance of the anterior skull base has been investigated but with limited attention directed to the olfactory recess. As defined by opacity abutting the undersurface of the cribriform plate, the prevalence of olfactory recess opacity (ORO) on sinus CT was examined to clarify whether this should raise suspicion for an unsuspected pathologic process. Outpatient sinus CTs were evaluated for ORO in 500 consecutive patients (mean age, 46.9 years; 52.6% women). On a per-side basis (n = 1000), the presence of surgical changes, inflammatory sinus disease, and concha bullosa was determined by 2 neuroradiologists. Logistic regression was used to examine the association of ORO with these variables. ORO was identified in 59 (11.8%) patients, bilateral in 27 (5.4%), and unilateral in 32 (6.4%). There were 343 of 1000 ethmoid sides that were diseased, and 66 (27.2%) showed ipsilateral ORO. In contrast, only 20 (3.0%) of 657 clear ethmoid sides showed ORO (P < .0001). ORO was significantly (P = .013) more common with previous surgery (18/75; 24.0%) than without (68/925; 7.4%). Ipsilateral concha bullosa was not associated with ORO. Of 32 patients with unilateral ORO, 5 (15.6%) had no ethmoid opacification or previous surgery, and 1 of these patients had an encephalocele causing the ORO. Finally, unilateral ORO was present in only 1 of 122 patients with completely clear sinuses (the encephalocele that was just mentioned). ORO is distinctly uncommon without sinonasal inflammation or previous surgery. Isolated unilateral ORO raises suspicion for an underlying neoplasm or cephalocele and warrants further evaluation.
Highlights
AND PURPOSE: The CT appearance of the anterior skull base has been investigated but with limited attention directed to the olfactory recess
There is a limited body of CT literature dedicated to the anatomy of the olfactory recess, with more extensive studies addressing the variations of adjacent structures such as the cribriform plate and fovea ethmoidalis
These studies have focused primarily on the effect of olfactory recess anatomy on the sense of smell[1,2] and how anatomic variations might pertain to preoperative planning.[3,4,5,6,7,8,9]
Summary
Outpatient sinus CTs were evaluated for ORO in 500 consecutive patients (mean age, 46.9 years; 52.6% women). On a per-side basis (n ϭ 1000), the presence of surgical changes, inflammatory sinus disease, and concha bullosa was determined by 2 neuroradiologists. The radiology information system was used to identify 500 consecutive outpatients age 18 years or older who had undergone routine sinus CT between January 1, 2000, and February 1, 2001, on the same CT scanner (Lightspeed; GE Healthcare; Milwaukee, Wis). The paranasal sinuses were evaluated on a per-side basis (n ϭ 1000) for the presence of the following features: concha bullosa (pneumatization extending into the bulbous portion of the middle turbinate), infectious or inflammatory changes (polyps, mucosal or mucoperiosteal thickening, air fluid levels, mucus retention cysts), cribriform plate integrity, and postsurgical anatomy (ethmoidectomy or middle turbinectomy, or both). A normally pneumatized sinus lacking such features was considered to be clear
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
