Abstract
Objective: To evaluate the comparative accuracy of non-contrast CT and MRI for the diagnosis of pituitary microadenoma.
Methodology: This cross-sectional study was conducted at Doctors Hospital Lahore in the radiology department from September 2024 and January 2025. It included 121 patients clinical suspicion of pituitary microadenomas. Participants were scanned using CT followed by non-contrast MRI, and confirmation of diagnosis was done by histopathology as the reference standard. Sensitivity, specificity, positive predictive value, negative predictive value, and overall diagnostic accuracy were determined.
Results: Out of 121 patients, 70 (57.9%) were females. Mean age was 40.74±10.35 years. The sensitivity of non-contrast MRI was 37.25% (38/102), while its specificity reached 89.47% (17/19). The diagnostic method demonstrated strong capabilities at excluding false positives, but its poor ability to detect true positives contributed to its low sensitivity. The technique demonstrated a total accuracy of 45.5% (55 of 121 patients).
Conclusion: While non-contrast MRI surpassed the CT scan in specificity and safety (avoiding radiation/contrast), its low sensitivity highlighted the need for more careful interpretation in negative cases. The absence of contrast agents and ionizing radiation in non-contrast MRI made it a suitable first-line diagnostic tool for screening pituitary microadenomas, providing prospective safety for patient monitoring.

Key words: Pituitary microadenoma, non-contrast MRI, histopathology, endocrine tumors.