Assessment of paediatric craniopharyngioma progression: a comparison of contrast-enhanced and non-contrast MRI

Purpose Standard assessment of treatment response in craniopharyngioma (CP) includes volumetric measurement of solid and cystic tumour components on contrast-enhanced MRI. This study compared the detection of tumour progression using MRI with and without contrast administration. Methods Progressive disease (PD) was assessed based on the measurement of tumour volume change using MRI without contrast. Contrast-enhanced MRI served as the reference standard. Results In most patients, non-contrast T1- and T2-weighted sequences were sufficient to assess PD. Non-contrast MRI showed a sensitivity of 89.9%, specificity of 91.4%, positive predictive value of 0.90 (unadjusted; model-derived: 0.99), and negative predictive value of 0.90 (unadjusted; model-derived: 0.99). No improvement in the detection of PD based on CP metastatic implants along the surgical/interventional pathway was seen after contrast in our cohort. There were limitations in the detection of subtle tumour progression on non-contrast MRIs. In cases of a volume increase above the 25% threshold, particularly in the > 25–40% range, false-negative results may occur. Tumour progression with small initial volumes (≤ 0.8 cm³) may also be overlooked. Conclusions For CPs without volume increase or no detectable or measurable tumour residue, contrast administration may be omitted. Non-contrast MRI demonstrated high diagnostic accuracy. However, performance decreased in cases with 25–40% volume increase (grey zone), where contrast-enhanced MRI is recommended, as well as for CPs with a small tumour volume (≤ 0.8 cm³). The entire skull must be evaluated to rule out CP metastatic implants; high diagnostic image quality is required.