From the Guidelines
For imaging ribs, a standard MRI with dedicated chest protocols is recommended, as it provides superior detection of bone marrow pathologies, stress fractures, and soft tissue involvement, although CT may be preferred for acute traumatic rib fractures where better bony detail is needed. This typically involves T1-weighted and STIR (Short Tau Inversion Recovery) sequences, which are particularly useful for detecting bone marrow edema, fractures, and soft tissue abnormalities around the ribs 1. The MRI should be performed with surface coils positioned over the area of interest to maximize signal quality. Contrast enhancement with gadolinium may be added if there's suspicion of infection, inflammation, or tumor. Patients will need to hold their breath during certain sequences to minimize respiratory motion artifacts that can blur rib details.
Key Considerations
- MRI is superior to CT or X-ray for detecting bone marrow pathologies, stress fractures, and soft tissue involvement, though it may not be the first-line imaging choice for acute traumatic rib fractures where CT typically offers better bony detail 1.
- The examination usually takes 30-45 minutes, and patients should remove all metal objects before entering the scanner to ensure safety and image quality.
- For cases where respiratory motion can be an issue, such as imaging the ribs, MRI may not be the most suitable initial imaging modality, suggesting that CT could be considered in such scenarios 1.
Imaging Protocols
- T1-weighted and STIR sequences are essential for detecting bone marrow edema, fractures, and soft tissue abnormalities around the ribs.
- Contrast enhancement with gadolinium can be useful in cases of suspected infection, inflammation, or tumor.
- Surface coils should be positioned over the area of interest to maximize signal quality.
Clinical Context
- The choice between MRI and CT for rib imaging depends on the clinical context, including the suspicion of acute traumatic injury, bone marrow pathology, or soft tissue involvement.
- In cases of suspected rib fractures from minor blunt trauma, a radiograph of the chest is usually appropriate for the initial imaging, with CT or MRI considered for further evaluation based on clinical findings and suspicion of complications 1.
From the Research
MRI Sequences for Rib Imaging
The following MRI sequences can be used for rib imaging:
- T1-weighted spin-echo images 2
- Fat-suppressed T2-weighted images 2
- STIR (short-TI inversion recovery) images 2, 3
- T2 Dixon sequence 4
- Diffusion-weighted imaging (DWI) sequences 4, 5
Diagnostic Accuracy of MRI Sequences
The diagnostic accuracy of different MRI sequences for detecting rib fractures and other bone marrow lesions is as follows:
- Fat-suppressed T2-weighted images and STIR images have higher lesion contrast and are more conspicuous than T1-weighted images 2
- T2 Dixon sequence with fat+water reconstructions offers similar reproducibility and diagnostic accuracy as the combination of T1+STIR sequences 4
- The "sandwich" sign on T2-weighted fat-suppressed sequences is a characteristic finding of type I rib fractures 6
Advantages and Disadvantages of MRI Sequences
The advantages and disadvantages of different MRI sequences are:
- Fat-suppressed T2-weighted images and STIR images have higher lesion contrast, but may have lower image quality and more motion artifacts than T1-weighted images 2
- T2 Dixon sequence with fat+water reconstructions can shorten examination time without loss of diagnostic accuracy, but may have marginal differences in accuracy compared to the standard T1+STIR protocol 4