The MR scanner in a nutshell

In the magnetic resonance (MR) scanner, a well-controlled interplay of a static main magnetic field, time-varying gradient magnetic fields, and radiofrequency fields is used to generate images. Here these three different types of magnetic or electromagnetic fields are summarized in relation to hardware components of the MR system. The sequential activation of gradient magnetic and radiofrequency fields, along with the data collection process, is accomplished using MR pulse sequences, of which the overall concept is outlined.

MRI of Lateral Skull Base Lesions

ABSTRACT This article reviews the role of magnetic resonance imaging (MRI) in the evaluation of lateral skull base lesions. Due to superior soft tissue resolution and multiplanar capability, MRI provides accurate information and exquisite anatomical detail. Thus, it guides the surgeon in proper preoperative planning regarding the approach of a lesion. MRI is also useful in post-treatment follow-up to assess the therapeutic response and to identify potential complications. We discuss the relevant anatomy, indications of MRI and MR pulse sequences used in the diagnosis of lesions of lateral skull base. Characteristic MRI findings of various lesions which help to arrive at a specific diagnosis as well as pitfalls of MRI which may confound the diagnosis are described. Newer MR pulse sequences enable image-guided surgery, which assist the surgeon intraoperatively, are briefly discussed. In summary, this article emphasizes the role of MRI in providing a specific answer to a clinical problem and its ability to guide the clinician for better management of patients.