Morphological Characteristics of Supertubual Recess Measured by Multiplanar Reconstruction from Multi-Slice Spiral CT Scans

LIU Tingting; CAO Hetao; HUANG Hong; SU Hai; YU Qin

doi:10.3969/j.issn.1672-2922.2014.02.29

Abstract：Objective To study morphological characteristics of supertubual recess (STR) and develop an accurate meth-od to measure its sizes on MSCT. Methods MSCT volume data of 40 non-pathologic temporal bones from 20 patients were post-processed by two experienced radiologists. Collins planar was reconstructed along the OML(method A), 30° to the base-line (method B), along the horizontal line (method C) or the otosteon planes (method D). The surrounding bony walls of STR were reconstructed and examined in real time along planes parallel or perpendicular to the incudomalleolar joint long axes. General morphological characteristics of STR was examined using VR. The deepest anterior-to-posterior diameter (AP) and longest transverse diameter (T) were measured. Average values were analyzed and their coefficient of variation(CV)were calcu-lated, Comparison among the four methods were done using paired t test. Results The antero-medial, antero-lateral and an-tero-superior walls of STR presented with arcs of various degrees corresponding to the degree of mastoid pneumatization. Both the posteromedial and posterolateral walls were relatively flat, in a generally funnel-shape. Mean AP diameter was 4.07±1.18 mm, 4.38±1.10 mm, 4.02±1.09 mm and 4.31±0.88 mm for Methods A, B, C and D, respectively. The AP diameters from Meth-ods B and D were greater than those from A and C. CV analysis among methods showed: A>C>B>D. Mean T was 4.16 ± 1.07mm, 3.68±0.98 mm, 4.11±1.02 mm and 3.67±0.79 mm for Methods A, B, C and D, respectively, with those from Methods A and C greater than those from B and D. Analysis of CV for transverse diameter also showed:B>A>C>D. Conclusion Recon-struction along otosteon planes can be used as a reliable method to measure the size of STR, providing clear anatomical land-marks, simple operation and reliable data.