PT - JOURNAL ARTICLE AU - M. Caulo AU - C. Briganti AU - P.A. Mattei AU - B. Perfetti AU - A. Ferretti AU - G.L. Romani AU - A. Tartaro AU - C. Colosimo TI - New Morphologic Variants of the Hand Motor Cortex as Seen with MR Imaging in a Large Study Population AID - 10.3174/ajnr.A0597 DP - 2007 Sep 01 TA - American Journal of Neuroradiology PG - 1480--1485 VI - 28 IP - 8 4099 - http://www.ajnr.org/content/28/8/1480.short 4100 - http://www.ajnr.org/content/28/8/1480.full SO - Am. J. Neuroradiol.2007 Sep 01; 28 AB - BACKGROUND AND PURPOSE: The hand motor cortex (HMC) has been classically described as having an omega or epsilon shape in axial-plane images obtained with CT and MR imaging. The aim of this study was to use MR imaging and Talairach normalization in a large sample population that was homogeneous for age and handedness to evaluate in a sex model a new classification with 5 morphologic variants of the HMC in the axial plane (omega, medially asymmetric epsilon, epsilon, laterally asymmetric epsilon, and null).MATERIALS AND METHODS: Structural brain MR images were obtained from 257 right-handed healthy subjects (143 men and 114 women; mean age, 23.1 ± 1.1 years) via a Talairach space transformed 3D magnetization-prepared rapid acquisition of gradient echo sequence. The frequencies of the different HMC variants were reported for hemisphere and sex.RESULTS: The new variants of the HMC (medially asymmetric epsilon, laterally asymmetric epsilon, and null) were observed in 2.9%, 7.0%, and 1.8% of the hemispheres, respectively. Statistically significant sex differences were observed: The epsilon variant was twice as frequent in men, and an interhemispheric concordance for morphologic variants was observed only for women.CONCLUSION: The large study population permitted the description of a new morphologic classification that included 3 new variants of the HMC. This new morphologic classification should facilitate the identification of the precentral gyrus in subsequent studies and in everyday practice.