On MRI, a malignant bone tumor shows low T1 signal and high T2 signal with heterogeneous post-contrast enhancement and cortical destruction. Which sequence is MOST useful for determining the intramedullary extent of tumor for surgical planning?
- A T1-weighted sequence without fat suppression ✓
- B T2-weighted fat-suppressed sequence
- C Short tau inversion recovery (STIR)
- D Gradient-echo sequence
Correct answer: A. T1-weighted sequence without fat suppression
Explanation
T1-weighted images without fat suppression are the gold standard for assessing the intramedullary extent of bone marrow involvement by tumor, because normal marrow appears bright (fatty marrow) and tumor appears dark (low T1 signal), providing excellent contrast. STIR and T2-fat-sat are more sensitive for edema and perilesional reaction but do not delineate the tumor-marrow interface as sharply as T1. Gradient-echo is used for susceptibility effects and not ideal for margin delineation.
Reference: Grainger & Allison's Diagnostic Radiology, 7th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.