Correlation between Intravoxel Incoherent Motion Magnetic Resonance Imaging Derived Metrics and Serum Soluble CD40 Ligand Level in an Embolic Canine Stroke Model

OBJECTIVE: To determine the relationship between intravoxel incoherent motion (IVIM) imaging derived quantitative metrics and serum soluble CD40 ligand (sCD40L) level in an embolic canine stroke model. MATERIALS AND METHODS: A middle cerebral artery occlusion model was established in 24 beagle dogs. Experimental dogs were divided into low- and high-sCD40L group according to serum sCD40L level at 4.5 hours after establishing the model. IVIM imaging was scanned at 4.5 hours after model establishment using 10 b values ranging from 0 to 900 s/mm². Quantitative metrics diffusion coefficient (D), pseudodiffusion coefficient (D*), and perfusion fraction (f) of ischemic lesions were calculated. Quantitative metrics of ischemic lesions were normalized by contralateral hemisphere using the following formula: normalized D = D(stroke) / D(contralateral). Differences in IVIM metrics between the low- and high-sCD40L groups were compared using t test. Pearson's correlation analyses were performed to determine the relationship between IVIM metrics and serum sCD40L level. RESULTS: The high-sCD40L group showed significantly lower f and normalized f values than the low-sCD40L group (f, p 0.05). Both f and normalized f values were negatively correlated with serum sCD40L level (f, r = −0.789, p 0.05). CONCLUSION: The f value derived from IVIM imaging was negatively correlated with serum sCD40L level. f value might serve as a potential imaging biomarker to assess the formation of microvascular thrombosis in hyperacute period of ischemic stroke.

Multimodal magnetic resonance imaging for assessing lacunar infarction after proximal middle cerebral artery occlusion in a canine model / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>A new lacunar infarction model was recently established in beagle dogs through proximal middle cerebral artery (MCA) occlusion by thrombus. This study aimed to characterize the model by multimodal magnetic resonance imaging (MRI) and to investigate its potential role for the future stroke research.</p><p><b>METHODS</b>The left proximal MCA was embolized with an autologous thrombus in six beagles. Diffusion-weighted imaging (DWI) and T2-weighted imaging (T2WI) were performed every half hour during the first six hours after occlusion, followed by three time points at 12 hours, 24 hours, and one week. Perfusion-weighted imaging (PWI) and magnetic resonance angiography (MRA) were carried out at six hours, 24 hours and one week. The PWI-DWI mismatch ratio was defined as (PWI-DWI)/DWI ischemic volume.</p><p><b>RESULTS</b>Lacunar infarcts induced by MCA occlusion were located in the left caudate nucleus and internal capsule. All the lesions could be detected within two hours by DWI. Lesion volume on DWI increased in a time dependent manner, from (87.19 ± 67.16) mm(3) at one hour up to (368.98 ± 217.05) mm(3) at 24 hours (P = 0.009), while that on PWI gradually decreased from (7315.00 ± 2054.38) mm(3) at six hours to (4900.33 ± 1319.71) mm(3) at 24 hours and (3334.33 ± 1195.11) mm(3) at one week (P = 0.002). The mismatch ratio was 41.93 ± 22.75 at six hours after ischemia, showing "extensive mismatch", and decreased to 18.10 ± 13.74 at 24 hours (P = 0.002). No MCA recanalization was observed within 24 hours after MCA occlusion.</p><p><b>CONCLUSIONS</b>Lacunar infarction induced by proximal MCA occlusion could be detected early by DWI and was characterized by extensive PWI-DWI mismatch. Multimodal MRI is useful to demonstrate the natural evolution of PWI-DWI mismatch. This ischemic model could be further used for investigating early thrombolysis in lacunar stroke showing extensive mismatch.</p>

Follow-Up of 58 Traumatic Carotid-Cavernous Fistulas after Endovascular Detachable-Balloon Embolization at a Single Center

BACKGROUND AND PURPOSE: This study evaluated the clinical value of detachable-balloon embolization for traumatic carotid-cavernous fistula (TCCF), focusing on the frequency, risk factors, and retreatment of recurrence. METHODS: Fifty-eight patients with TCCF underwent transarterial detachable-balloon embolization between October 2004 and March 2011. The clinical follow-up was performed every 3 months until up to 3 years postprocedure. Each patient was placed in either the recurrence group or the nonrecurrence group according to whether a recurrence developed after the first procedure. The relevant factors including gender, fistula location, interval between trauma and the interventional procedure, blood flow in the carotid-cavernous fistula, number of balloons, and whether the internal carotid artery (ICA) was sacrificed were evaluated. RESULTS: All 58 TCCFs were successfully treated with transarterial balloon embolization, including 7 patients with ICA sacrifice. Recurrent fistulas occurred in seven patients during the follow-up period. Univariate analysis indicated that the interval between trauma and the interventional procedure (p=0.006) might be the main factor related to the recurrence of TCCF. The second treatments involved ICA sacrifice in two patients, fistula embolization with balloons in four patients, and placement of a covered stent in one patient. CONCLUSIONS: Detachable balloons can still serve as the first-line treatment for TCCFs and recurrent TCCFs despite having a nonnegligible recurrence rate. Shortening the interval between trauma and the interventional procedure may reduce the risk of recurrence.