Thrombus Length Estimation on Delayed Gadolinium–Enhanced T1

Abstract

Background and Purpose Previous studies revealed a close relationship between thrombus length and recanalization rate after intravenous thrombolysis (IVT). As a novel approach, we prospectively adjusted the order of sequence acquisition to obtain delayed gadolinium-enhanced T1 (dGE-T1) and thereby assess thrombus length on dGE-T1 to evaluate its predictive value for recanalization after IVT. Methods We reviewed prospectively collected clinical and imaging data from acute ischemic stroke patients with middle cerebral artery (MCA) occlusion who underwent multimodal MRI before and 24 hours after IVT. Perfusion-weighted imaging (PWI) was performed followed by conventional T1. We measured thrombus length on dGE-T1 and examined its association with MCA recanalization. Results Of the included 74 patients, the median age was 66 years and 28 (37.8%) were women. Thrombus length was 8.18 ± 4.56 mm on dGE-T1, which was an acceptable predictor for no recanalization (odds ratio 1.196; 95% CI: 1.015 to 1.409; p=0.033), with a receiver-operator characteristic of 0.732 (95% CI: 0.619 to 0.845; p=0.001). The optimal cut-off point was identified at 6.77 mm, which yielded a sensitivity of 77.8%, a specificity of 57.9%, and odds ratio 4.81 (95% CI: 1.742 to 13.292; p=0.002). Moreover, no one achieved recanalization after IVT when length of thrombus exceeded 14 mm on dGE-T1. Conclusions The dGE-T1, obtained by simply adjusting scanning order in multimodal MRI protocol, is a useful tool for thrombus length estimation and MCA recanalization prediction after IVT.

Assessment of thrombus length in acute ischemic stroke by post-contrast magnetic resonance angiography

“…Recently Yan et al presented evidence that thrombus lengths can be assessed on delayed gadolinium-enhanced T1 images in patients with MCA occlusion 23. This supports our assumption that depicting the distal terminus of the thrombus by means of contrast agent is beneficial in thrombus length assessment.…”

“…However, the method of thrombus length assessment differed remarkably in both studies (native thin slice CT versus contrast-enhanced MRA). Methodological differences may also explain substantial differences to results from Yan et al , using a slice thickness of 5 mm in delayed gadolinium-enhanced 2D T1-sequence to estimate thrombus lengths 23. Patients with poor outcome had thrombi with an optimal cut-off value of 7.7 mm.…”

Association of clot burden score with radiographic and clinical outcomes following Solitaire stent retriever thrombectomy: analysis of the SWIFT PRIME trial

“…Multiple studies have shown that a longer thrombus length, greater thrombus volume, and higher clot burden are predictive of IV t-PA failure in achieving successful recanalization, as well as of poor neurological outcome 1 2 4 8. The prognostic value of such clot characteristics on recanalization achieved with mechanical thrombectomy approaches has not been well studied.…”

Slow Collateral Flow Is Associated with Thrombus Extension in Patients with Acute Large-Artery Occlusion

“…P revious studies have demonstrated that characteristics of thrombus, especially thrombus length, were closely related to the rate of recanalization, clinical outcome after intravenous thrombolysis (IVT), 1 and even stroke etiology in patients with acute ischemic stroke with large-artery occlusion (LAO). 2,3 However, the dynamic changes of the thrombus after IVT and how the remaining thrombus affects clinical outcome in human stroke are still poorly understood.…”

“…Delayed gadolinium-enhanced T1 (dGE-T1), which can delineate the distal end of the thrombus and avoid blooming artifacts of the susceptibility vessel sign, was proved a useful tool for accurate measurement of thrombus length when combined with time-of-flight MR angiography. 1 Similarly, 4D CT angiography, derived from CT perfusion, can not only outline intracranial thrombi better than conventional single-phase CTA 6 but also evaluate collateral flow with increased sensitivity. 7 Therefore, we designed this study with the following objec-tives: 1) to assess the change of thrombus length in patients with LAO without recanalization at 24 hours after IVT detected on dGE-T1 and 4D-CTA derived from CTP, 2) to evaluate the relationship between the changing of thrombus length and collaterals, and 3) to find the influencing factors of different changing patterns of thrombus length.…”