Introduction: Empty sella in MRI is an important finding associated with idiopathic intracranial hypertension (IIH). This study assesses the sensitivity and reproducibility of several morphological measures of the sella and pituitary gland to indentify the measure that best differentiates IIH from controls. Additionally, the study assesses reversal in gland compression following treatment.
Methods: Sagittal 3D-T1W sequence with 1 mm isotropic resolution was obtained from ten newly diagnosed IIH patients and 11 matched healthy controls. Follow-up MRI scans were obtained from eight patients at 1-week post-lumbar puncture and acetazolamide treatment. 1D and 2D measures of absolute and normalized heights and cross-sectional areas of the gland and sella were obtained to identify the measure that best differentiates IIH patients and controls.
Results: Overall area-based measurements had higher sensitivity than length with p < 0.0001 for sella area compared with p = 0.004 for normalized gland height. The gland cross-sectional areas were similar in both cohorts (p = 0.557), while the sella area was significantly larger in IIH, 200 ± 24 versus 124 ± 25 mm(2), with the highest sensitivity and specificity, 100% and 90.9%, respectively. Absolute gland area was the most sensitive measure for assessing post treatment changes, with 100% sensitivity and 50 % specificity. Average post-treatment gland area was 18% larger (p = 0.016). Yet, all eight patients remained within the empty sella range based on a normalized gland area threshold of 0.41.
Conclusions: Sellar area is larger in IIH, and it demonstrated highest sensitivity for differentiating IIH from control subjects, while absolute gland area was more sensitive for detecting post treatment changes.