Normal and Variant Abdominal Anatomy on Magnetic Resonance Imaging




The diagnostic usefulness of abdominal magnetic resonance (MR) imaging lies in the improved contrast resolution and ability to qualify several tissue characteristics of a specific organ or lesion. Our institution uses organ-specific protocols to facilitate technical reproducibility and optimize scan duration. These protocols are discussed individually in this article when applicable, noting that many build on a basic protocol with slight variations. Because most abdominal MR imaging studies are targeted toward an organ or area of interest, this article discusses the protocol strategies and relevant anatomy in a segmented/organ-specific manner.


Abdominal magnetic resonance (MR) imaging has traditionally been used as a problem-solving method after a previous indeterminate imaging investigation such as computed tomography (CT) or ultrasound, frequently using organ-specific protocols to highlight the condition in question. Increasingly, abdominal MR imaging is being used as a primary imaging investigation with expansion of clinical indications and increased awareness of cumulative ionizing radiation dose in medical imaging. Therefore, it is important to understand the normal abdominal anatomy on MR imaging, particularly the visceral organ appearances, as well as commonly encountered variants and disease mimics. Because most abdominal MR imaging studies are targeted toward an organ or area of interest, this article discusses the protocol strategies and relevant anatomy in a segmented/organ-specific manner.


In general, abdominal MR imaging benefits substantially from the use of a high field strength magnet (1.5 Tesla or greater) and local phased-array surface coils around the anatomy of interest. Most commonly, breath-held sequences with high temporal resolution and moderate spatial resolution are frequently used in abdominal MR imaging to mitigate the effects of respiratory and bowel motion. However, when high spatial resolution and improved image signal are required, motion compensation techniques such as respiratory triggering or diaphragm-navigation can be used to facilitate longer acquisition times. The diagnostic usefulness of abdominal MR imaging lies in the improved contrast resolution and ability to qualify several tissue characteristics of a specific organ or lesion. Generally, abdominal MR imaging protocols include precontrast T1-weighted images, T2-weighted images, and dynamic postcontrast T1-weighted images with sufficient imaging redundancy of the organ system in question. Our institution uses organ-specific protocols to facilitate technical reproducibility and optimize scan duration. These protocols are discussed individually in this article when applicable, noting that many build on a basic protocol with slight variations ( Table 1 ).



Table 1

Example protocols




























































































































































































































































Abdominal/Liver Protocol
Coronal T2 Axial T2 Axial In/Opposed T1 Axial Fat- Suppressed T2 Axial Diffusion Axial Pre/Post T1 Axial Dynamic Pre/Post T1
Pulse sequence SSFSE SSFSE SPGR FSE SE EPI SPGR 3D SPGR
Repetition time (ms) Minimum Minimum 150 4000 6000 150 Minimum
Echo time (ms) 180 180 2.3/4.6 90 Minimum Minimum Minimum
FOV (cm) 40 36 To fit To fit 40 To fit To fit
Slice thickness (mm) 8 6 6 6 6 6 4
Matrix 256 × 128 256 × 128 256 × 160 256–320 × 192 128 × 128 512 × 160 320 × 160
Signal averages 0.5 NEX 0.5 NEX 1 NEX 4 NEX 8 NEX 1 NEX 0.5 NEX
MRCP Sequences Kidney Sequences Adrenal Sequences
Axial MRCP 3D MRCP Axial Water Suppressed T1 Coronal Dynamic Pre/Post T1 Coronal In/Opposed T1
Pulse sequence SSFSE FRFSE SPGR 3D SPGR SPGR
Repetition true (ms) Minimum Minimum 170 Minimum Minimum
Echo time (ms) 180 650 Minimum Minimum 2.3/4.6
FOV (cm) 40 36 To fit To fit To fit
Slice thickness (mm) 5 1.4 6 3 5
Matrix 256 × 160 256 × 256 256 × 160 320 × 160 256 × 160
Signal averages 0.5 NEX 2 NEX 1 NEX 0.5 NEX 1 NEX
MR Enterography Sequences MRA Sequences
Axial Steady-state Coronal Steady-state Coronal Dynamic Pre/Post T1 3D Phase Contrast
Pulse sequence FIESTA FIESTA 3D SPGR 3D PC
Repetition time (ms) Minimum Minimum Minimum Minimum
Echo time (ms) Minimum Minimum Minimum Minimum
FOV (cm) 32–40 38–40 28–40 (prefer 30) 28
Slice thickness (mm) 6 3 2.4 2.5
Matrix 256 × 256 256 × 256 288 × 160 256 × 192
Signal averages 1 1 0.5–1 NEX 1 NEX

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Sep 18, 2017 | Posted by in MAGNETIC RESONANCE IMAGING | Comments Off on Normal and Variant Abdominal Anatomy on Magnetic Resonance Imaging
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