Objectives <p>Venous distention may occur in the early stages of spontaneous intracranial hypotension (SIH) as a compensatory mechanism. We hypothesized that analysis of superior sagittal sinus distention (SSSD) on T2-weighted axial images, in combination with other imaging findings, could enhance diagnostic accuracy for SIH.</p> Methods <p>This retrospective study analyzed data from patients diagnosed with SIH across three institutions. Data from one institution served as the training set, while data from the remaining two institutions constituted the validation set. Patients with non-spontaneous hypotensive headaches from the same institution during the study period were selected as controls. Two senior neuroradiologists and one junior neuroradiologist evaluated SSSD along with four other imaging findings.</p> Results <p>In the training set, senior neuroradiologists demonstrated 84.48% sensitivity in identifying SSSD, significantly higher than other findings, with 89.66% specificity, slightly lower than alternative findings. In the validation set, both sensitivity and specificity for SSSD reached 100%, indicating high diagnostic accuracy. When assessing differences in interpretation among radiologists of varying experience, the junior neuroradiologist showed lower sensitivity (67.24%) for SSSD compared to pachymeningeal thickening. However, their sensitivity improved substantially in the validation set relative to other findings, reaching 60%.</p> Conclusion <p>SSSD demonstrates higher sensitivity compared to other imaging findings and exhibits consistent reliability across different institutions and varying levels of neuroradiologist expertise. When integrated with additional imaging findings, it can substantially improve SIH diagnosis.</p>