What imaging study should be ordered for further evaluation of a peri-vascular mass in the putamen shown on a computed tomography (CT) head?

MRI with Contrast is the Best Imaging Study for Evaluating a Perivascular Mass in the Putamen

MRI of the head without and with IV contrast is the most appropriate next imaging study for further evaluation of a perivascular mass in the putamen shown on CT head. 1

Rationale for MRI with Contrast

• MRI is preferred over CT for further evaluation due to its superior soft-tissue contrast and anatomic detail, which is essential for characterizing a perivascular mass in the putamen 1
• MRI with contrast provides optimal visualization of both the mass and its relationship to surrounding vascular structures, which is critical for determining the nature of a perivascular lesion 1
• According to the ACR Appropriateness Criteria for proven parenchymal abnormalities, MRI head without and with IV contrast receives the highest rating (9/9) for evaluation of lesions like those in the basal ganglia 1
• Contrast administration is particularly useful to evaluate for underlying enhancing mass or vascular malformation that may be associated with the perivascular abnormality 1

Additional Vascular Imaging Considerations

• MR angiography (MRA) of the head without and with IV contrast should be obtained in conjunction with the MRI to evaluate for underlying vascular malformation 1
• MRA has a high rating (8/9) in the ACR guidelines for evaluation of vascular abnormalities associated with parenchymal lesions 1
• MR venography (MRV) should also be considered if there is concern for venous thrombosis or vascular malformation, with a rating of 7/9 in the ACR guidelines 1
• These studies can be performed during the same imaging session as the MRI, providing comprehensive evaluation without additional patient visits 1

Why MRI is Superior to Other Modalities for This Clinical Scenario

• While CT without contrast is excellent for initial detection of hemorrhage (rating 9/9), it is limited in characterizing soft tissue abnormalities in the basal ganglia 1
• CT angiography (CTA) is useful but provides less detailed information about the parenchymal components of the mass compared to MRI 1
• MRI can better differentiate between various pathologies that can present as perivascular masses in the putamen, including:
  • Vascular malformations 1
  • Perivascular spaces (which may be dilated in certain conditions) 2
  • Perivascular epithelioid cell tumors 3
  • Other putaminal lesions that may have vascular components 4

Special Considerations for Perivascular Lesions

• Ultra-high-field MRI techniques can transform standard sequences into angiographic methods that simultaneously image small vessels and associated parenchyma, which is particularly valuable for perivascular lesions in deep brain structures like the putamen 5
• Specialized MR sequences such as susceptibility-weighted imaging (SWI) are highly sensitive for detecting vascular abnormalities and should be included in the protocol 1
• If the perivascular mass proves to be a vascular malformation, follow-up imaging with MR angiography will be more sensitive than standard MRI in detecting residual or recurrent flow 6

Clinical Implications

• Accurate characterization of a perivascular mass in the putamen is essential as lesions in this location can be associated with movement disorders and other neurological symptoms 4
• The putamen is particularly vulnerable to vascular pathology, and dilated perivascular spaces in this region have been associated with certain neurodegenerative conditions 2
• Comprehensive vascular imaging is crucial as treatment approaches will differ significantly depending on whether the mass represents a true vascular malformation, tumor with vascular components, or another entity 1