Kiyofumi Yamada

Optical Frequency Domain Imaging Evaluation of Progressive Carotid Plaque and In-Stent Restenosis Lesion with Multiple Neovascularizations

BACKGROUND Neovascularization (NV) plays an important role in plaque progression and plaque vulnerability. However, visualization of NV is difficult using standard imaging tools. Recently, optical frequency domain imaging (OFDI) has provided images of intraplaque microstructure that could not be visualized by previous imaging modalities. Here we report a rare case of NV in the carotid plaque detected both before carotid artery stenting (CAS) and in an in-stent restenotic lesion using OFDI. CASE DESCRIPTION A 71-year-old man with asymptomatic severe left carotid artery stenosis was scheduled for CAS. The degree of stenosis had progressed during short-term follow-up. Preoperative magnetic resonance imaging suggested vulnerable plaque. We performed OFDI to evaluate plaque morphology before and after the CAS procedure. Before CAS, OFDI revealed multiple NVs in the carotid plaque, localized around the most stenotic lesion. After CAS, OFDI showed good apposition of the stent to the vascular wall. At 5 months after CAS, in-stent restenosis was detected, which was treated by CAS. Before CAS of the restenotic lesion, OFDI revealed multiple NVs in the restenotic lesion inside the stent struts. After stenting, no ischemic lesions were detected, and restenosis did not occur again over the 1-year follow-up period. CONCLUSIONS In carotid artery plaque, NV might correlate with plaque progression and in-stent restenosis. OFDI enables advanced evaluation of NVs in the carotid artery plaque.

High intensity signal in the plaque on routine 3D-TOF MRA is associated with ischemic stroke in the patients with low-grade carotid stenosis

BACKGROUND AND PURPOSE Carotid artery stenosis is one of the major causes of ischemic strokes. However, degree of stenosis is not always correlated with frequency of ischemic strokes. The aim of this study was to evaluate relationships between high intensity signal (HIS) in the carotid plaques on maximum intensity projection (MIP) images detected by routine three-dimensional time-of-flight magnetic resonance angiography (3D-TOF MRA) and ischemic strokes in the patients with low-grade stenosis. METHODS One hundred fifty two patients with low-grade carotid artery stenosis (30%-49%) were included. The presence of HIS located in the plaque but having no connection to the lumen in all projections on MIP images of 3D-TOF MRA was defined as HIS-positive using the previously reported criteria. We analyzed the relationship between the presence of HIS and prior ischemic strokes. RESULTS Prior ipsilateral ischemic strokes were observed more frequently in HIS-positive group (12 of 56, 21.4%) than HIS-negative group (1 of 96: 1%) (p<0.001). In multivariate logistic regression analysis, the presence of HIS (odds ratio: 31.8, 95% confidential interval (CI): 3.81-264, p=0.001) and hyperlipidemia (odds ratio: 10.45, 95% CI: 1.01-13.4, p=0.048) were independent determinants of prior ischemic strokes after adjustment for age. CONCLUSIONS HIS in plaques on MIP images of 3D-TOF MRA was an independent determinant of prior ischemic strokes.

Relationship between Hemorrhagic Complications and Target Vessels in Acute Thrombectomy

PURPOSE Intracranial hemorrhage after thrombectomy using a catheter to treat acute major cerebral artery occlusion is known to exacerbate patient outcomes. This study was performed to determine the relationship between middle cerebral artery (MCA) tortuosity and postoperative hemorrhage. METHODS We examined 111 consecutive patients who underwent acute thrombectomy for major intracranial artery occlusion in the anterior circulation at our hospital between September 2013 and June 2016. Patients in whom intracranial hemorrhage or subarachnoid hemorrhage was seen on head computed tomography 12-24 hours after surgery were assigned to the hemorrhagic group, whereas all the other patients were assigned to the nonhemorrhagic group. The groups were compared for tortuosity of the MCA, which was evaluated by finding the top-to-bottom (TB) distance of the M1 segment on anterior-posterior view angiograms. A modified Rankin scale score of 0-2 at 3 months after onset was considered a favorable prognosis. RESULTS The hemorrhagic group comprised 28 patients (25.2%) and the nonhemorrhagic group comprised 83 patients (74.8%). No significant difference in patient characteristics was seen between the groups. The hemorrhagic group displayed significantly fewer patients with a favorable prognosis (17.9% versus 43.4%, P = .016). The TB distance was significantly greater in the hemorrhagic group (hemorrhagic group, 9.7 mm; nonhemorrhagic group, 7.6 mm; P = .002); multivariate analysis also identified a TB distance over 8.8 mm as a factor independently associated with postoperative intracranial hemorrhage (P = .001). CONCLUSIONS Post-thrombectomy hemorrhage was significantly correlated with TB distance. A solution is needed for selecting and combining devices used in patients with a TB distance over 8.8 mm.