What initial imaging studies and management should be ordered for a patient presenting with an intracranial mass, considering factors such as age, history of cancer, and immunocompromised status?

Initial Imaging and Management for Intracranial Mass

Order a non-contrast CT head immediately as the first-line imaging study, followed by MRI brain with and without contrast for definitive characterization of the mass. 1

First-Line Imaging: Non-Contrast CT Head

CT head without contrast is the initial imaging test of choice for suspected intracranial mass, as it can be performed rapidly and safely in all patients, particularly in emergent settings where mass effect, hemorrhage, or hydrocephalus need immediate assessment. 1

When to Add Contrast-Enhanced CT

• Consider contrast-enhanced CT if intracranial infection, tumor, or inflammatory pathologies are suspected, though this typically follows the non-contrast screening study rather than serving as first-line imaging. 1
• Contrast-enhanced CT is particularly useful when MRI is contraindicated or unavailable and there is clinical concern for progression of intracranial infection (abscess, empyema), tumor, or inflammatory conditions. 1

Definitive Imaging: MRI Brain with and without Contrast

MRI should be used in preference to CT scanning for definitive characterization of intracranial masses and is the standard imaging modality for preoperative evaluation. 1

Essential MRI Sequences

• T1-weighted images with and without contrast medium (standard protocol) 1
• T2-weighted images and/or FLAIR imaging to assess edema and tumor extent 1
• Three-dimensional scans using the same technique for surgical planning 1

Advanced MRI Techniques (Optional)

• Functional MRI, diffusion-weighted imaging, perfusion studies, and/or proton MR spectroscopy can be combined with standard sequences to better characterize the mass. 1
• MRI has superior sensitivity for detecting subtle lesions, ischemia, and enhancement compared to CT, making it complementary for evaluating suspected intracranial mass lesions. 1, 2

Clinical Context Modifying Imaging Approach

History of Cancer

• Obtain contrast-enhanced imaging early (either CT with contrast or proceed directly to MRI with contrast) when metastatic disease is suspected, as history of malignancy is a risk factor for intracranial findings. 1
• Consider staging imaging of the primary cancer site if not already performed.

Immunocompromised Status

• Prioritize contrast-enhanced studies to evaluate for opportunistic infections (fungal granulomas, toxoplasmosis, lymphoma). 3
• High index of suspicion for intracranial fungal granuloma should exist in immunocompromised patients with intracranial lesions, requiring early diagnosis and surgical decompression. 3
• Blood and urine cultures should be obtained as microbiological analysis aids diagnosis. 3

Age Considerations

• Older age is a risk factor for intracranial findings on imaging and should lower the threshold for obtaining studies. 1
• In elderly patients with deep-seated lesions and very poor systemic or neurological condition, the risk from biopsy may outweigh the risk from misdiagnosis, though this should remain exceptional. 1

Histological Confirmation

Histological confirmation of the diagnosis should be obtained, because neuroimaging is not sufficiently specific. 1

• Biopsy or surgical resection is standard, as imaging alone cannot definitively distinguish between tumor types, infections, or inflammatory lesions. 1
• The sample should be representative of the lesion, particularly any area of contrast enhancement. 1

Common Pitfalls to Avoid

• Do not rely on imaging alone for diagnosis - even characteristic-appearing lesions require histological confirmation, as primary intracranial smooth muscle tumors can mimic meningiomas on imaging. 4
• Do not skip contrast administration when tumor, infection, or inflammatory pathology is suspected, as non-contrast studies have limited sensitivity for these conditions. 1
• Do not delay MRI when CT is unrevealing - 70% of patients with missed ischemic stroke diagnoses presented with altered mental status, and MRI detected the pathology. 2
• Thoroughly investigate intracranial hemorrhage that appears out of proportion to any known causative event, as underlying masses (including meningiomas) can present as acute hemorrhage. 5