Magnetic resonance imaging of the adrenal gland

Sajal S. Pokharel, Ihab R Kamel

Research output: Chapter in Book/Report/Conference proceedingChapter

Abstract

Introduction Magnetic resonance imaging (MRI) is an extremely powerful tool for evaluating the adrenal glands. MRI has the unique ability to characterize soft tissues. Th is ability allows for specific pathologic diagnoses to be made in a large number of adrenal lesions. Th is is accomplished without the use of ionizing radiation and, oft entimes, without the need for intravenous contrast material. However, certain lesions may remain indeterminate on MRI findings alone. In these cases, correlation with the overall clinical picture will aid in diagnosis. Rarely, biopsy may be required for definitive diagnosis. MRI utilizes the property of proton nuclear magnetic resonance coupled with robust spatial localization techniques to generate images. Various pulse sequences can be performed in the course of an MRI study. A pulse sequence is a series of radiofrequency electromagnetic wave excitations, magnetic gradients, and resulting radio frequency signals (echoes), which can be arranged in a variety of ways. The arrangement determines which tissue property is emphasized. Pulse sequences can be formulated to highlight certain aspects of the tissues being imaged. For example, the sequence can highlight tissue water content (e.g., T2-weighted) or fat content (e.g., Dixon fat-only images). Lipid detection techniques In fact, fat or lipid detection turns out to be very important in imaging of the adrenal glands. Several lipid-sensitive sequences exist. The two major categories that are utilized in adrenal imaging are chemical shift selective suppression (CHESS) and chemical shift imaging (CSI). Both of these techniques harness the property that water protons and fat protons resonate (precess, spin) at slightly different frequencies (rates) when placed in a strong external magnetic field. This difference in rate of precession is also called the chemical shift. The way these two sequences utilize this property differs such that the resulting images give complementary information. Chemical shift imaging Since there is a precessional (resonance, spin) frequency difference between water and fat protons, only at specific interval periods during nuclear spin precession will a lipid proton and a water proton be in sync, i.e., “in phase.”

Original languageEnglish (US)
Title of host publicationAndrogens in Gynecological Practice
PublisherCambridge University Press
Pages191-199
Number of pages9
ISBN (Electronic)9781139649520
ISBN (Print)9781107041318
DOIs
StatePublished - Jan 1 2015
Externally publishedYes

ASJC Scopus subject areas

  • Medicine(all)

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