Petrous apex lesions are rare, and they are often noted incidentally, unrelated to the presenting clinical manifestation (Leonetti et al. 2001). However, in the presence of petrous apex lesions, a variety of clinical symptoms is noted, such as hearing loss, dizziness, headaches, and tinnitus (Muckle et al. 1998). Usually, these lesions can be precisely defined using imaging techniques such as CT and MR. Although MR-guided biopsies through a transsphenoidal access have been attempted in the petrous apex region (Bootz et al. 2001), such procedures are usually unnecessary if an experienced radiologist studies the lesion. MR specifically plays an important role in the differentiation of petrous apex lesions, that can often be easily detected with CT, but where CT does not always permit to correctly differentiate the imaging finding (Pisanischi and Langer 2000). The importance of MR on this matter has been emphasized since the late 1980s and early 1990s (Griffin et al. 1987; Greenberg et al. 1988; Jackler and Parker 1992; Arriaga and Brackmann 1991). The study of the spontaneous signal intensities of these lesions on T1- and T2-weighted images and of the enhancement pattern of the internal matrix of the lesions often allows to provide a correct diagnosis with a very high degree of confidence (Curtin and Som 1995). Consequently, the radiologist plays an important role in the process of decision making, whether the area in question needs surgical therapy, and influences the process of deciding on the exact type of surgery that should be performed (Chang et al. 1998; Profant and Steno 2000; Brackmann and Toh 2002). MR scanning is helpful to evaluate for complete removal, complication, recurrence, or formation of complicating granulation tissue (Pisanischi and Langer 2000).