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Cortical Venous Thrombosis


KEY FACTS

Terminology

  • Cortical/cerebral venous thrombosis (CVT)

  • Dural sinus thrombosis (DST)

  • CVT with DST > isolated CVT without DST

Imaging

  • NECT

    • Cord sign (hyperdense vein)

    • Involved veins usually enlarged (distended with clot), irregular

    • ± petechial parenchymal hemorrhage, edema

  • CECT

    • If DST, empty-delta sign (25-30% of cases)

    • CTV: Thrombi may be seen as filling defects

  • MR

    • Acute thrombus isointense on T1WI

    • Hypointense on T2WI (can mimic flow void)

    • T2* GRE best (clot usually blooms)

  • 2D time of flight MRV

    • Thrombus seen as sinus discontinuity, loss of vascular flow signal

    • Subacute thrombus T1 hyperintense (mimics patent flow on maximum intensity projection)

  • Imaging recommendations

    • NECT, CECT scans ± CTV

    • If CT negative → MR/MRV with T1WI C+, GRE

    • If MR is equivocal → DSA (gold standard)

Top Differential Diagnoses

  • Normal (circulating blood slightly hyperdense)

  • Anatomic variant (hypoplastic segment can mimic DST)

Clinical Issues

  • Most common symptom is headache

  • Seizure

Diagnostic Checklist

  • If “convexal” subarachnoid hemorrhage is seen, consider CVT

Autopsy case shows thrombus in several cortical veins
, the pathologic basis for the cord sign.

(Courtesy E.T. Hedley-Whyte, MD.)

Axial NECT scan in a patient with thrombosis of the superior sagittal sinus shows dense clot
filling and expanding of the superior sagittal sinus. Thrombus is seen in a vein
over the cerebral convexity. Most (but not all) cortical vein thrombi occur as extension from clot in an adjacent dural venous sinus.

Autopsy case of transverse sinus thrombosis
that occluded the vein of Labbé shows extensive hemorrhagic venous infarction of the temporal, parietal, and occipital lobes
.

(Courtesy R. Hewlett, MD.)

This 23-year-old woman presented in the ER with “migraine headache.” Initial NECT scan (L) was called normal. Note the hyperdense thrombus in left TS
. CT 1 day later (right) shows vein of Labbé thrombosis
and a large left temporal lobe hemorrhagic venous infarct
.

TERMINOLOGY

Abbreviations

  • Cortical/cerebral venous thrombosis (CVT)

  • Dural sinus thrombosis (DST)

Definitions

  • Superficial cerebral venous thrombosis

    • Usually with DST but isolated CVT without DST can occur

IMAGING

General Features

  • Best diagnostic clue

    • “Cord” sign on NECT, T2* GRE

  • Location

    • Cortical veins (unnamed)

      • –

        Anastomotic vein of Labbé

      • –

        Anastomotic vein of Trolard

    • Can be solitary, multiple

  • Morphology

    • Veins usually enlarged (distended with clot), irregular

    • Linear, cigar-shaped thrombus

CT Findings

  • NECT

    • Hyperdense cortical vein (“cord” sign) ± DST

    • Parenchymal abnormalities common

      • –

        Petechial hemorrhage, edema

      • –

        Hypodensity in affected vascular distribution

    • Need NECT to exclude false-negative CTV

      • –

        Thrombus dense, can mimic enhancement

  • CECT

    • If DST present

      • –

        “Empty delta” sign (25-30% of cases)

    • “Shaggy,” irregular enhancing veins (collateral channels)

  • CTV

    • Thrombus seen as filling defect in cortical veins

    • Abnormal collateral channels (e.g., enlarged medullary veins)

    • Negative CTV does not exclude CVT

      • –

        Limited value for chronic CVT

        • □

          Organizing thrombosis also enhances

      • –

        Limited value for nonocclusive thrombus

      • –

        Optimize technique using thin slice (0.6 mm) MDCT with venous phase enhancement and dedicated sagittal and coronal MPR (1-2 mm)

      • –

        Thick slice (3-5 mm) sliding or overlapping MIPs in sagittal and coronal planes

      • –

        Concurrent NECT important to exclude false-negative CTV due to intrinsically dense thrombus

      • –

        Subacute and chronic thromboses can enhance: Potential false-negative

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