From the Guidelines
Yes, brain masses can often be detected on MRI scans without contrast, as standard MRI sequences like T1-weighted, T2-weighted, and FLAIR imaging can reveal many types of brain abnormalities based on their natural tissue characteristics. According to the most recent study 1, non-contrast-enhancing diffuse glioma parts with high cellularity might appear less hyperintense on T2-weighted and FLAIR sequences than oedema and might destroy the anatomical structure of the infiltrated tissue, causing focal mass effect.
Some key points to consider:
- Non-contrast-enhancing tumour is often located in closer proximity to contrast-enhancing tumour than are areas of oedema with only low tumour cell density 1.
- Diffuse gliomas present as mostly hyperintense lesions on non-contrast-enhanced T2-weighted and T2-weighted fluid-attenuated inversion recovery (FLAIR) sequences, with variable signal on contrast-enhanced T1-weighted sequences 1.
- Minimum preoperative MRI datasets include T2-weighted sequences and contrast-enhanced T1-weighted sequences 1.
- Contrast enhancement with gadolinium-based agents significantly improves detection and characterization of many brain lesions by highlighting areas where the blood-brain barrier is disrupted.
However, the use of contrast agents can significantly improve the detection and characterization of brain masses, especially in cases where the blood-brain barrier is disrupted. As noted in 1, contrast agents can help distinguish between active tumor and treatment effects like radiation necrosis, and can also help identify smaller lesions that may be missed on non-contrast images.
In terms of imaging protocols, MRI head without and with IV contrast is highly recommended, with a rating of 9, as it provides parenchymal imaging and CT or MR vascular brain imaging, and contrast is useful to evaluate for underlying enhancing mass or vascular malformation 1.
Overall, while brain masses can be detected on MRI scans without contrast, the use of contrast agents is highly recommended to maximize diagnostic accuracy, especially in cases where the blood-brain barrier is disrupted or where smaller lesions need to be identified.
From the Research
Brain Mass Visibility on MRI without Contrast
- Brain mass can be visible on Magnetic Resonance Imaging (MRI) without contrast, as certain MRI sequences can provide sufficient information for diagnosis and monitoring 2, 3.
- Steady-state free-precession (SSFP) MR imaging has been shown to be effective in characterizing complex cystic masses of the brain, including distinguishing edema from tumor and detecting the contents of hemorrhagic cysts 3.
- Non-contrast-enhanced sequences, such as arterial spin labeling, have also shown promise in reducing the need for contrast agents in brain tumor imaging 2.
- Dynamic-susceptibility contrast MRI can estimate relative cerebral blood volume in gliomas without the need for contrast agents, although acquisition strategies and leakage-correction algorithms can affect the fidelity of these estimates 4.
- Perfusion MR imaging can provide quantitative cellular and hemodynamic information about brain tumors, which can be useful in diagnosis and monitoring, even without contrast agents 5.
- Advanced MRI techniques, such as diffusion and perfusion imaging, MR spectroscopy, and positron emission tomography (PET) tracers, can provide additional information about brain metastases and other brain masses, potentially supplementing standard MR evaluation 6.