Abstract
Prospective baseline MRI was obtained on 31 patients who had “total” removal of acoustic schwannoma 6 months to 9 years previously. Follow-up MRI was performed after 1–2 years on patients with questionable abnormalities. We found four patterns (1) internal auditory canals (IAC) with nonenhancing soft-tissue strands, possibly scars or distorted residual nerves (8); (2) IAC with marginal enhancement-reactive dura mater (16); (3) IAC with contrast-enhancing globular tissues suggesting residual or recurrent tumour (5); (4) high-signal intensity in the IAC before contrast medium administration, probably related to graft with fat/fascia/muscle (2). Prospective 1-to 2-year follow-up studies were available in 8, 5, and 1 patients in groups 2, 3, and 4 respectively. In group 2, dural enhancement remained unchanged in 5 patients and decreased in 3. In group 3 follow-up showed 1 tumor recurrence (surgically confirmed) and 4 stable abnormalities. In group 4, follow-up in 1 of the 2 patients was stable. In groups 1 and 2, the MRI features correlate well with complete tumor removal. Whether follow-up in these groups is indicated needs to be determined. In group 3 residual or recurrent tumor cannot be excluded. In group 4, grafts may prevent adequate visualization of the IAC.
Similar content being viewed by others
References
Mueller DP, Gantz BJ, Dolan KD (1992) Gadolinium-enhanced MR of the postoperative internal auditory canal following acoustic neuroma resection via the middle fossa approach. AJNR 13: 197–200
Glasscock ME, Kveton JF, Jackson SC, McKennan KX (1986) A systematic approach to the surgical management of acoustic neuroma. Laryngoscope 96: 1088–1094
Glasscock ME, Shambaugh GE, Johnson GD (1990) Surgery of the ear. Saunders, Philadelphia, pp 535–565
Lanzieri CF, Larkins M, Mancall A, Lorig R, Duchesneau PM, Rosenbloom SA, Weinstein MA (1988) Cranial postoperative site: MR imaging appearance. AJNR 9: 27–34
Elster AD, DiPersio DA (1990) Cranial postoperative site: assessment with contrast-enhanced MR imaging. Radiology 174: 93–98
Burke JW, Podrasky AE, Bradley WG (1990) Meninges: benign postoperative enhancement on MR images. Radiology 174: 99–102
Valvassori GE, Guzman M (1989) Growth rate of acoustic neuromas. Am J Otol 10: 174–176
Cohen NL, Ransohoff J (1984) Hearing preservation — posterior fossa approach. Otolaryngol Head Neck Surg. 92: 176–183
Glasscock ME III, Hayes JW, Jackson CG, Steenerson RL (1978) A one-staged combined approach for the management of large cerebellopontine angle tumors. Laryngoscope 88: 1563–1576
Gardner G, Robertson JH (1985) Facial nerve function in cerebellopontine angle tumor surgery. J Otol [Suppl]: 74–79
Millen SJ, Daniels D, Meyer G (1990) Gadolinium-enhanced magnetic resonance imaging in facial nerve lesions. Otolaryngol Head Neck Surg 102: 26–33
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Smith, M., Castillo, M., Campbell, J. et al. Baseline and follow-up MRI of the internal auditory canal after suboccipital resection of acoustic schwannoma: appearances and clinical correlations. Neuroradiology 37, 317–320 (1995). https://doi.org/10.1007/BF00588345
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF00588345