Asymmetric pneumatization of the petrous apex PETER S. ROLAND, MD. WILLIAM L. MEYERHOFF, MD, PhD, LINDA O. JUDGE, MD, and BRUCE E. MICKEY, MD, Dallas, Texas
Three patients with high-Intensity MR signals from one petrous apex, but nonpathologlc fine-cut computed tomography are reported. In two of the three patients, normal bone marrow within the petrous apex on one side Is believed to have generated the highIntensity signal. In one of the three patients, the etiology of the MR image remains obscure, but may represent the earliest stages of petrous cholesterol granuloma or mucocele. We have reviewed 500 head CT scans performed for non-otologlc reasons, In an attempt to establish the frequency of this finding. The literature on MR and CT Imaging of the petrous apex and asymmetric pneumatization of the petrous apex Is reviewed. (OTOLARYNGOL HEAD NECK SURG 1990;103:80.)
H a y e s and Amy' recently reported a case of a 44-yearold woman with right facial pain in which MR imaging demonstrated a high-intensity signal on T,- and T 2 weighted images in one petrous apex. An axial CT scan demonstrated an extensively pneumatized petrous apex on the contralateral side. They concluded that the ab normal signal on MR was caused by bone marrow filling the nonpneumatized petrous apex. We have recently seen three similar patients at the University of Texas Southwestern Medical Center at Dallas. Two of the three were specifically referred to us for surgery. The other patient was already scheduled for surgery at an other institution and came seeking a second opinion. We have recommended observation for all of these pa tients based on findings from high-resolution computed tomography. In the case of two of the patients, the bright signal seen within one petrous apex probably represents asymmetric petrous apex pneumatization. In the third case, the pathologic process underlying the radiologie findings and their clinical significance remain obscure.
From the Departments of Otorhinolaryngology (Drs. Roland and Meyerhoff), Radiology (Dr. Judge), and Neurosurgery (Dr. Mickey), University of Texas Southwestern Medical Center. Presented at the Combined Otorhinolaryngology-Head and Neck Sur gery Spring Meeting of the American Neurotologic Society, San Francisco, Calif., March 31, 1989. Submitted for publication March 31, 1989; accepted Aug. 30, 1989. Reprint requests: Peter S. Roland, MD, University of Texas South western Medical Center, Department of OtorhinolaryngologyHead and Neck Surgery, 5323 Harry Hines Blvd., Dallas, TX 75235-9035. 23/1/16392
CASE REPORTS Case 1. A 44-year-old woman with symmetric neurosen sory hearing loss was referred by a neurosurgeon for operative removal of a petrous apex lesion demonstrated on MR im aging. Several weeks before referral, she had been treated with systemic steroids for a subjective left sudden neurosen sory hearing loss from which she thought she had recovered completely. Comparison of several audiograms performed be fore and after treatment, however, revealed no significant threshold difference. The patient also reported daily bitemporal headaches responsive to nonsteroidal anti-inflammatory agents. Physical examination was entirely normal, except for moderate obesity. Cranial nerves II through XII were intact bilaterally (except for her neurosensory hearing loss), as was the remainder of her neurologic examination. Complete audiologic evaluation revealed a gradually sloping, symmetric, and moderate neurosensory loss. Speech reception threshold (SRT) was 55 dB on the right and 50 dB on the left. Speech discrimination scores were 84% bilaterally. Examination of the MR1 revealed an area of bright signal intensity in the left petrous apex on Τ,-weighted images (TR 700 ms, TE 35 ms) (Fig. 1). Asymmetry was apparent on a short echo T2weighted image (TR 2000 ms, TE 45 ms), but was perhaps less intense (Fig. 2). CT scanning demonstrated a highly pneumatized contralateral petrous apex with relative opacification or nonaeration of the left petrous apex. There was no evidence of expansion or erosion, although some slight sclerosis of the posterior bony margin was noted (Fig. 3). The septate structure of the petrous apex, however, was pre served (Fig. 4). Because the CT examination did not dem onstrate findings consistent with an erosive or destructive lesion, operation was deferred in favor of observation. She has been followed for 29 months, with no change in her symptoms, and two subsequent CT examinations have failed to reveal any changes. Case 2. A 32-year-old woman with a 1-year history of left-sided, deep, boring otalgia was referred for surgical re-
80 Downloaded from oto.sagepub.com at CAMBRIDGE UNIV LIBRARY on June 5, 2016
Volume 103 Number 1 July 1990
Asymmetric pneumatizatlon of the petrous apex
Fig. 1. Case 1. T,-weighted Image of left petrous apex demonstrates area of increased signal intensity.
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Three patients with high-Intensity MR signals from one petrous apex, but nonpathologlc fine-cut computed tomography are reported. In two of the three patients, normal bone marrow within the petrous apex on one side Is believed to have generated the highIntensity signal. In one of the three patients, the etiology of the MR image remains obscure, but may represent the earliest stages of petrous cholesterol granuloma or mucocele. We have reviewed 500 head CT scans performed for non-otologlc reasons, In an attempt to establish the frequency of this finding. The literature on MR and CT Imaging of the petrous apex and asymmetric pneumatization of the petrous apex Is reviewed. (OTOLARYNGOL HEAD NECK SURG 1990;103:80.)
H a y e s and Amy' recently reported a case of a 44-yearold woman with right facial pain in which MR imaging demonstrated a high-intensity signal on T,- and T 2 weighted images in one petrous apex. An axial CT scan demonstrated an extensively pneumatized petrous apex on the contralateral side. They concluded that the ab normal signal on MR was caused by bone marrow filling the nonpneumatized petrous apex. We have recently seen three similar patients at the University of Texas Southwestern Medical Center at Dallas. Two of the three were specifically referred to us for surgery. The other patient was already scheduled for surgery at an other institution and came seeking a second opinion. We have recommended observation for all of these pa tients based on findings from high-resolution computed tomography. In the case of two of the patients, the bright signal seen within one petrous apex probably represents asymmetric petrous apex pneumatization. In the third case, the pathologic process underlying the radiologie findings and their clinical significance remain obscure.
From the Departments of Otorhinolaryngology (Drs. Roland and Meyerhoff), Radiology (Dr. Judge), and Neurosurgery (Dr. Mickey), University of Texas Southwestern Medical Center. Presented at the Combined Otorhinolaryngology-Head and Neck Sur gery Spring Meeting of the American Neurotologic Society, San Francisco, Calif., March 31, 1989. Submitted for publication March 31, 1989; accepted Aug. 30, 1989. Reprint requests: Peter S. Roland, MD, University of Texas South western Medical Center, Department of OtorhinolaryngologyHead and Neck Surgery, 5323 Harry Hines Blvd., Dallas, TX 75235-9035. 23/1/16392
CASE REPORTS Case 1. A 44-year-old woman with symmetric neurosen sory hearing loss was referred by a neurosurgeon for operative removal of a petrous apex lesion demonstrated on MR im aging. Several weeks before referral, she had been treated with systemic steroids for a subjective left sudden neurosen sory hearing loss from which she thought she had recovered completely. Comparison of several audiograms performed be fore and after treatment, however, revealed no significant threshold difference. The patient also reported daily bitemporal headaches responsive to nonsteroidal anti-inflammatory agents. Physical examination was entirely normal, except for moderate obesity. Cranial nerves II through XII were intact bilaterally (except for her neurosensory hearing loss), as was the remainder of her neurologic examination. Complete audiologic evaluation revealed a gradually sloping, symmetric, and moderate neurosensory loss. Speech reception threshold (SRT) was 55 dB on the right and 50 dB on the left. Speech discrimination scores were 84% bilaterally. Examination of the MR1 revealed an area of bright signal intensity in the left petrous apex on Τ,-weighted images (TR 700 ms, TE 35 ms) (Fig. 1). Asymmetry was apparent on a short echo T2weighted image (TR 2000 ms, TE 45 ms), but was perhaps less intense (Fig. 2). CT scanning demonstrated a highly pneumatized contralateral petrous apex with relative opacification or nonaeration of the left petrous apex. There was no evidence of expansion or erosion, although some slight sclerosis of the posterior bony margin was noted (Fig. 3). The septate structure of the petrous apex, however, was pre served (Fig. 4). Because the CT examination did not dem onstrate findings consistent with an erosive or destructive lesion, operation was deferred in favor of observation. She has been followed for 29 months, with no change in her symptoms, and two subsequent CT examinations have failed to reveal any changes. Case 2. A 32-year-old woman with a 1-year history of left-sided, deep, boring otalgia was referred for surgical re-
80 Downloaded from oto.sagepub.com at CAMBRIDGE UNIV LIBRARY on June 5, 2016
Volume 103 Number 1 July 1990
Asymmetric pneumatizatlon of the petrous apex
Fig. 1. Case 1. T,-weighted Image of left petrous apex demonstrates area of increased signal intensity.
29:
NSO·SM·« M
