1	Central and Precentral Sulci Display of Reproducible Patterns on MR imaging B Kim, SL Jung, KJ Ahn, YJ Kim, JY Byun The Catholic University of Korea, Seoul, KOREA
2	"The central sulcus (CS" The central sulcus (CS) is important for localization of motor and sensory cortices Locating the CS plays an essential role in planning the neurosurgical approach and avoiding injury to the primary motor cortex during neurosurgical resections MR usually allows identification of the CS on a vertex axial, sagittal midline or parasagittal lateral sections Identification of landmarks around the CS minimizes pitfalls created by local variation, although anatomical distortion by the a mass lesion makes it difficult to localize CS using these anatomic methods Functional MR improves detection of the CS
3	"to demonstrate reproducible patterns of..." to demonstrate reproducible patterns of CS and precentral sulcus (PS) on brain MR imaging (with 5 mm slice thickness / 2 mm gap) to enable physicians to recognize these patterns on imaging studies
4	"80 healthy persons" 80 healthy persons (male: 40, female: 40, age : 20-49, median: 40) T1, T2 weighted and FLAIR MR images on axial and sagittal images with 5 mm slice thickness / 2 mm gap Determination of patterns pattern of gray-white difference in CS and PS relationship to the sylvian fissure, superior and inferior frontal sulci presence and type of knob/hook on precentral gyrus
5	Cortical signal intensity Precentral versus Central sulci
6	"Gray-white distinction" Gray-white distinction less distinct at the CS more distinct at the PS T1 WI N=138/160 (86.3%) FLAIR image N=144/160 (90%)
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8	"Superior Frontal Sulcus forms angle..." Superior Frontal Sulcus forms angle with PS anterior to the CS n=150/160 (93.8%)
9	"A constant relationship between the..." A constant relationship between the posterior ends of the SFS and PS facilitated accurate identification of the anterior border of the precentral gyrus Kido et al. (Radiology 135:373-377, 1980) On the evaluation of interobserver comparison, axial image yielded the most consistent results (76% for control subjects and patients) Sobel et al. (AJNR 14:915-925, 1993) Sulcal connectivity between the SFS and PS: 92% on the right hemisphere, 100% on the left hemisphere Naidich et al. (Neurosurgery 36:517-532, 1995) Ono et al. (Atlas of the cerebral sulci, Stuttgart, Georg Thieme Verlag, 1990)
10	Axial Image: Knob on the Precentral Gyrus Knob N=155/160 (96.9%)
11	"Knob on the Precentral Gyrus" Knob on the Precentral Gyrus Functional MR revealed neural elements involved in motor hand function are located in a characteristic ‘precentral knob’ Located just posterior to the junction of SFS and PS Faces and forms the ‘middle knee’ of the CS Detected in 100% of normal hemisphere and 95% of affected hemisphere on axial plane, and was of inverted omega shape (90%) and horizontal epsilon shape (10%) Yousry et al. (Brain 120:141-157, 1997)
12	Sagittal image: Inferior Frontal Sulcus PS intersects inferior frontal sulcus (98.1%) as well as sylvian fissure (93.1%)
13	Sagittal image: Sylvian Fissure CS does not directly intersect the sylvian fissure but to the subcentral gyrus N=140/160 (87.5%)
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18	"47 year-old woman with meningioma" 47 year-old woman with meningioma
19	"Widening of CS by the..." Widening of CS by the mass White matter edema outlines anteroinferiorly displaced knob
20	"Left hand motor fMR" Left hand motor fMR Activation anterior to the mass
21	"Postoperative MR" Postoperative MR Edema and postoperative change in postcentral gyrus
22	"17 year-old woman" 17 year-old woman Intractable seizure with seizure focus originating from left frontal region on EEG Right hand motor functional MR showed activation at the left cortical region
23	Summary Axial Gray-white distinction less distinct at the CS than that at the PS on T1 weighted (86.3%) and FLAIR images (90%) PS intersecting the superior frontal sulcus (93.8%) anterior to the CS Motor hook region was identified (96.9%) as single (68.1%) or multiple (28.8%) hump CS intersects interhmispheric fissure (81.3%) Sagittal images CS does not directly intersect the sylvian fissure but to the subcentral gyrus (87.5%) PS intersecting the inferior frontal sulcus (98.1%) inferiorly intersects sylvian fissure (93.1%) fMR enables to localize CS in patients with brain lesion
24	Conclusion The precentral and central sulci show reproducible patterns on routine clinical MR images obtained at 1.5 T. Recognizing these patterns enables the physician to localize and manage the lesion adjacent to the central sulcus.
25	References Kido DK, Le May M, Levinson Aw, Benson WE. Computed tomographic localization of the precentral gyrus. Radiology 1980;135:373-377 Sobel DF, Gallen CC, Schwartz BJ et al. Locating the central sulcus: comparison of MR anatomic and magnetoencephalographic functional methods. AJNR 1993;14:915-925 Naidich TP, Valavanis AG, Kubik S. Anatomic relationship along the low-middle convexity: Part I-Normal specimens and magnetic resonance imaging. Neurosurgery 1995;36:517-532 Ono et al. Atlas of the cerebral sulci, Stuttgart, Georg Thieme Verlag, 1990 Yousry TA, Alkadhi SH, Schmidt D et al. Localization of the motor hand area to a knob on the precentral gyrus. A new landmark. Brain 1997;120:141-157