Early Detection and Quantification of Cerebral Venous Thrombosis by Magnetic Resonance Black-Blood Thrombus Imaging

Abstract

Background and purpose: Early diagnosis of cerebral venous thrombosis (CVT) is currently a major clinical challenge. We proposed a novel magnetic resonance black-blood thrombus imaging technique (MRBTI) for detection and quantification of CVT.

Methods: MRBTI was performed on 23 patients with proven CVT and 24 patients with negative CVT confirmed by conventional imaging techniques. Patients were divided into 2 groups based on the duration of clinical onset: ≤7 days (group 1) and between 7 and 30 days (group 2). Signal/noise ratio was calculated for the detected thrombus, and contrast/noise ratio was measured between thrombus and lumen and also between thrombus and brain tissue. The feasibility of using MRBTI for thrombus volume measurement was explored, and total thrombus volume was calculated for each patient.

Results: In 23 patients with proven CVT, MRBTI correctly identified 113 of 116 segments with a sensitivity of 97.4%. Thrombus signal/noise ratio was 153±57 and 261±95 for group 1 (n=10) and group 2 (n=13), respectively (P<0.01). Thrombus to lumen contrast/noise ratio was 149±57 and 256±94 for group 1 and group 2, respectively. Thrombus to brain tissue contrast/noise ratio was 41±36 and 120±63 (P<0.01), respectively. Quantification of thrombus volume was successfully conducted in all patients with CVT, and mean volume of thrombus was 10.5±6.9 mL.

Conclusions: The current findings support that with effectively suppressed blood signal, MRBTI allows selective visualization of thrombus as opposed to indirect detection of venous flow perturbation and can be used as a promising first-line diagnostic imaging tool.

Keywords: magnetic resonance imaging; sinus thrombosis, intracranial; venous thrombosis.

Figure 1

MRBTI images of a 48-year-old male with sub-acute CVT. On TOF images, normal venous sinuses were depicted with bright venous flow signals (arrowheads in A and B) and minor flow defects (black arrowhead in A) observed in the superior sagittal sinus was not considered as thrombus by radiologists. With blood signal adequately suppressed on MRBTI, normal venous sinus were depicted as black area (arrowheads in C and D) and hyper-intense signal was found in the right transverse sinus suggesting a fresh thrombus (arrow in D). The thrombus was also confirmed on TOF (arrow in B).

Figure 2

High thrombus SNR, thrombus-to-lumen CNR, and thrombus-to-gray matter CNR were obtained with MRBTI in both thrombus groups. They were all significantly different between the two groups.

Figure 3

MRBTI of a 27-year-old male patient with sub-acute CVT. A: MRBTI demonstrated hyper-intense signal intensity in the superior sagittal sinus (arrowheads), the right transverse and sigmoid sinuses (arrowheads), and the cortical veins (arrows) suggesting intraluminal thrombus formation. B: All thrombi semi-automatically outlined by software based on their high signal contrast were rendered with red color and volume was 21.5 cc. C: sagittal, coronal and axial sections of maximum intensity projection (MIP) reformations of MRBTI better depicted the thrombosed segments with hyper-intense signals.

Figure 4

MRBTI of a 23-year-old female patient who was imaged on Day 7 (A and B) and Day 14 (C and D) after symptomatic onset. MRBTI demonstrated hyper-intense signal intensity in left transverse sinus suggesting intraluminal thrombus formation. The thrombus on Day 7 (arrowheads) and Day 14 (arrows) exhibited different hyper-intense signal patterns. CVT volume was 22.4cc and 12.5cc on day 7 and day 14, respectively. Notice the right transverse sinus with suppressed lumen signals became larger in size in response to the gradual occlusion of the left transverse sinus.