title: Chemical Shift MR Imaging of the Adrenal Gland: Principles, Pitfalls, and Applications.
abstract: Adrenal lesions are a common imaging finding. The vast majority of adrenal lesions are adenomas, which contain intracytoplasmic (microscopic) fat. It is important to distinguish between adenomas and malignant tumors, and chemical shift magnetic resonance (MR) imaging can be used to accomplish this distinction by depicting the fat in adenomas. Chemical shift imaging is based on the difference in precession frequencies of water and fat molecules, which causes them to be in different relative phases during the acquisition sequence and allows in-phase and opposed-phase images to be obtained. It is important to acquire these images by using the earliest possible echo times, with the opposed-phase echo before the in-phase echo, and by using a single breath hold to preserve diagnostic accuracy. Intracytoplasmic fat is depicted as signal drop on opposed-phase images when compared with in-phase images. Both qualitative and quantitative methods for assessing signal drop are detailed. The appearances of adrenal adenomas and other adrenal tumors on chemical shift MR images are described, and discriminatory ability at chemical shift MR imaging compared with that at adrenal computed tomography (CT) is explained. Other adrenal-related conditions in which chemical shift MR imaging is helpful are also discussed. Chemical shift MR imaging is a robust tool for evaluating adrenal lesions that are indeterminate at nonenhanced CT. However, it is important to know the advantages and disadvantages, including several potential imaging pitfalls. The characterization of adrenal lesions by using chemical shift MR imaging and adrenal CT should always occur in the appropriate clinical setting.
authors: From the Department of Radiology, Northwestern Memorial Hospital, Northwestern University Feinberg School of Medicine, 676 N Saint Clair St, Suite 800, Chicago, IL 60611.
authors: Sharon Z
authors: SZ
authors: Adam
authors: From the Department of Radiology, Northwestern Memorial Hospital, Northwestern University Feinberg School of Medicine, 676 N Saint Clair St, Suite 800, Chicago, IL 60611.
authors: Paul
authors: P
authors: Nikolaidis
authors: From the Department of Radiology, Northwestern Memorial Hospital, Northwestern University Feinberg School of Medicine, 676 N Saint Clair St, Suite 800, Chicago, IL 60611.
authors: Jeanne M
authors: JM
authors: Horowitz
authors: From the Department of Radiology, Northwestern Memorial Hospital, Northwestern University Feinberg School of Medicine, 676 N Saint Clair St, Suite 800, Chicago, IL 60611.
authors: Helena
authors: H
authors: Gabriel
authors: From the Department of Radiology, Northwestern Memorial Hospital, Northwestern University Feinberg School of Medicine, 676 N Saint Clair St, Suite 800, Chicago, IL 60611.
authors: Nancy A
authors: NA
authors: Hammond
authors: From the Department of Radiology, Northwestern Memorial Hospital, Northwestern University Feinberg School of Medicine, 676 N Saint Clair St, Suite 800, Chicago, IL 60611.
authors: Tanvi
authors: T
authors: Patel
authors: From the Department of Radiology, Northwestern Memorial Hospital, Northwestern University Feinberg School of Medicine, 676 N Saint Clair St, Suite 800, Chicago, IL 60611.
authors: Vahid
authors: V
authors: Yaghmai
authors: From the Department of Radiology, Northwestern Memorial Hospital, Northwestern University Feinberg School of Medicine, 676 N Saint Clair St, Suite 800, Chicago, IL 60611.
authors: Frank H
authors: FH
authors: Miller
mesh_terms: D000236:Adenoma / Q000000981:diagnostic imaging*; D000273:Adipose Tissue / Q000000981:diagnostic imaging; D000310:Adrenal Gland Neoplasms / Q000000981:diagnostic imaging* / Q000556:secondary; D000311:Adrenal Glands / Q000000981:diagnostic imaging*; D000314:Adrenal Rest Tumor / Q000000981:diagnostic imaging; D016477:Artifacts; D001834:Body Water; D002277:Carcinoma / Q000000981:diagnostic imaging; D006486:Hemosiderosis / Q000000981:diagnostic imaging; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D033162:Incidental Findings; D008067:Lipoma / Q000000981:diagnostic imaging; D008113:Liver Neoplasms / Q000000981:diagnostic imaging; D008279:Magnetic Resonance Imaging / Q000379:methods*; D009378:Neoplasms, Multiple Primary / Q000000981:diagnostic imaging; D010673:Pheochromocytoma / Q000000981:diagnostic imaging; D011522:Protons; D014057:Tomography, X-Ray Computed
chemical_list: D011522:Protons