The overcrowding of osteal posterior cranial fossa in adults: multi-slice CT measurements and clinical significance

Objective: To assess the clinical value of MSCT in diagnosing the overcrowding of osteal posterior cranial fossa (PCF) in adults. Methods: MSCT images of a cohort of 52 adult patients with foramen magnum osteal malformation confirmed by surgery (diseased group), and 100 healthy adults (control group) were retrospectively reviewed. Images post-processing techniques included multi-planer reformation (MPR) and volume rendering (VR). The posterior cranial fossa volume (PCFV), posterior cranial fossa height (PCFH), clivus length (CL), clivus gradient (CG), supraocciput length (SL), and 100 normal adults. Independent-sample student's t test was used to compare the differences between patients and normal adults. Results: The results of PCFV, PCFH, CL, SL, FMD and CG, male of control group were (168.2 ± 12.3) cm3, (38.2 ± 1.2), (47.1 ± 2.8), (41.1 ± 1.8), (36.6 ± 4.9)mm, (51.5 ± 3.6)degree, female of control group were (157.5 ± 10.2) cm3, (36.5 ± 1.4), (46.2 ± 2.2), (39.7 ± 1.3), (35.2 ± 3.8), (49.6 ± 3.1)degree; diseased group were (128.7 ± 11.7) cm3, (30.6 ± 1.9), (36.2 ± 1.4), (37.3 ± 0.9), (33.9 ± 3.5)mm, (44.5 ± 2.8)degree. There was significant sex difference in PCFV, PCFH, CL, SL and CG in control group (t=4.70, 6.44, 4.84, 4.43 and 2.81 respectively, P<0.01), but FMD was not significant (t=1.97, P<0.05); the results of PCFV, PCFH, CL, CG and SL were significant different between diseased group and male of control group (t=16.62, 24.04, 25.01, 14.17 and 10.99 respectively, P<0.01); the results of PCFV, PCFH, CL, CG and SL were significant different between diseased group and female of control group (t=13.23, 17.80, 27.50, 11.67 and 8.73 respectively, P<0.01); but there were no significant differences of FMD between diseased group and control group, both male and female (t=2.96, 2.07, P<0.05). Conclusions: The overcrowding of PCF can be accurately measured by MCST. As a routine preoperative examination, MSCT is helpful in the therapeutic selection and the anatomic and pathologic study of PCF. (authors)