Pilocytic astrocytoma: correlation between the initial imaging features and clinical aggressiveness

Area of Science:

• Neuro-oncology
• Radiology
• Pathology

Background:

• Astrocytomas are histologically classified as fibrillary or pilocytic.
• Imaging features of fibrillary astrocytomas correlate with aggressiveness, aiding prognosis.
• The correlation between pilocytic astrocytoma imaging and clinical aggressiveness is not well-established.

Purpose of the Study:

• To compare initial MR and CT imaging features of pilocytic astrocytoma with clinical tumor aggressiveness.
• To determine if imaging features can predict the clinical behavior and prognosis of pilocytic astrocytoma.

Main Methods:

• Retrospective evaluation of initial MR or CT scans from 32 patients with pilocytic astrocytoma.
• Analysis of lesion characteristics: location, size, calcification, morphology, and contrast enhancement.
• Correlation of imaging findings with clinical tumor aggressiveness (aggressive vs. nonaggressive based on clinical course).

Main Results:

• No significant differences in lesion size or location between aggressive and nonaggressive pilocytic astrocytomas.
• Similar presence or absence of calcification in both aggressive and nonaggressive groups.
• Most pilocytic astrocytomas exhibited moderate to marked enhancement and multilobular morphology, irrespective of clinical aggressiveness.

Conclusions:

• Initial CT and MR imaging features of pilocytic astrocytoma are unreliable predictors of clinical behavior.
• Imaging findings do not accurately forecast which pilocytic astrocytomas will be aggressive or have a poor prognosis.