Uncommon Anatomical Variants of the Dural Venous Sinuses: A Case Series Highlighting Diagnostic Pitfalls in MR Venography

Background: Recognizing normal variants of the dural venous sinuses is essential to avoid misdiagnosing them as pa-thology, particularly venous sinus thrombosis. Aim of Study: To present a series of uncommon anatom-ical variations of the dural venous sinuses observed on MR venography that were initially suspected to represent vascular pathology. Patients and Methods: From a larger cohort of patients undergoing MR venography, we present seven selected cases that demonstrated rare anatomical variants mimicking vascu-lar pathology. Imaging was performed using a 1.5 Tesla MRI scanner with 3D MRV and conventional MRI sequences. Results: - Case 1: Hypoplastic left transverse and sigmoid sinuses mim-icking left-sided thrombosis. - Case 2: Aplasia of the anterior one-third of the superior sagit-tal sinus with compensatory bilateral cortical drainage. - Case 3: Bifurcated superior sagittal sinus simulating venous duplication or thrombus. - Case 4: Bilateral persistent occipital sinuses associated with transverse sinus aplasia. - Case 5: Persistent anterior falcine sinus mimicking an en-hancing interhemispheric mass. - Case 6: Persistent falcine sinus associated with aplastic straight sinus. - Case 7: Aneurysmal dilatation of the torcular herophili mim-icking vein of Galen malformation. Conclusion: Understanding and identifying anatomical variants of the dural venous sinuses on MR venography is criti-cal to prevent misinterpretation and unnecessary interventions. MRV readers should be aware of these patterns to distinguish them from true vascular pathologies.