Fiber tracking of the white matter using diffusion tensor imaging is a new imaging technique to visualize the integrity of the white matter. This study investigated the capability of this technique to localize the lacunar infarctions, particularly with respect to the body parts affected, by correlating the location of the lesion with the clinical symptoms topographically. Twenty-seven patients with capsular and pericapsular small acute infarctions underwent diffusion tensor imaging and subsequent fiber tracking of the corticospinal tract (CST). According to the lesion topography with regard to the CST, the infarctions were classified into four types: (1) the anterior type (n = 9) involving the anterior part of the CST, (2) the central type (n = 9) involving the middle or whole part of the CST, (3) the posterior type (n = 5) involving the posterior part of the CST and (4) the intact type (n = 4) not involving the CST. Motor weakness of the face, upper extremities and lower extremities was found at 100%, 67% and 44%, respectively in the anterior type, at 89%, 100% and 89%, respectively in the central type and at 20%, 80% and 100%, respectively in the posterior type. The intact type was not associated with motor weakness. In conclusion, the fiber tracking technique of the CST enables the specific localization of capsular and pericapsular infarctions with regard to the body parts affected. These results also confirm the topographical accuracy of the fiber tracking of the CST.