Usefulness of additional diffusion MRI acquisition prior to mechanical thrombectomy for acute large vessel occlusion in the early time period at a CT-based stroke center.

OBJECTIVE: This study aimed to investigate whether evaluating the infarction core using additionally acquired diffusion magnetic resonance imaging (MRI) could help improve the assessment of prognosis including complication rates and modify the strategy for mechanical thrombectomy in endovascular procedures at a computed tomography (CT)-based stroke center. METHODS: Single-center data from patients with acute large-vessel occlusion in the anterior circulation who underwent mechanical thrombectomy between May 2018 and January 2021 were analyzed. Diffusion MRI sequences were performed during the preparation period for mechanical thrombectomy after CT angiography. We set the infarction core reference volume on diffusion MRI to 60 cc and divided the patients into two groups: a small infarction core group (less than 60 cc) and a large infarction core group (more than 60 cc). The baseline characteristics, radiological and clinical outcomes of the patients were investigated and compared between the two groups. RESULTS: The difference in numbers between the two groups was not significant in the Alberta Stroke Program Early Computed Tomography (ASPECT) score; however, the ASPECT score on diffusion MRI showed a remarkable difference between the two groups. The large infarction core volume group on diffusion MRI had a poor prognosis, with the modified Rankin score at 90 days showing a statistically significant difference (p = 0.011). Complications after the procedure, such as hemorrhagic transformation, that can occur after reperfusion, symptomatic intracerebral hemorrhage, decompressive craniectomy for increased intracranial pressure, and mortality, were significantly more frequent in the large infarction core volume group. CONCLUSION: At a CT-based stroke center, additionally acquired diffusion MRI without a time delay for reperfusion would improve the assessment of prognosis including complication rate, and could help neurointerventionists determine the extent of recanalization of occluded vessels during mechanical thrombectomy.

Comparison of Coronary Computed Tomography Angiography Image Quality With High-concentration and Low-concentration Contrast Agents: The Randomized CONCENTRATE Trial.

PURPOSE: To confirm that the image quality of coronary computed tomography (CT) angiography with a low tube voltage (80 to 100 kVp), iterative reconstruction, and low-concentration contrast agents (iodixanol 270 to 320 mgI/mL) was not inferior to that with conventional high tube voltage (120 kVp) and high-concentration contrast agent (iopamidol 370 mgI/mL). MATERIALS AND METHODS: This prospective, multicenter, noninferiority, randomized trial enrolled a total of 318 patients from 8 clinical sites. All patients were randomly assigned 1: 1: 1 for each contrast medium of 270, 320, and 370 mgI/mL. CT scans were taken with a standard protocol in the high-concentration group (370 mgI/mL) and with 20 kVp lower protocol in the low-concentration group (270 or 320 mgI/mL). Image quality and radiation dose were compared between the groups. Image quality was evaluated with a score of 1 to 4 as subject image quality. RESULTS: The mean HU, signal-to-noise ratio, and contrast-to-noise ratio of the 3 groups were significantly different (all P<0.0001). The signal-to-noise ratio and contrast-to-noise ratio of the low-concentration groups were significantly lower than those of the high-concentration group (P<0.05). However, the image quality scores were not significantly different among the 3 groups (P=0.745). The dose length product and effective dose of the high-concentration group were significantly higher than those of the low-concentration group (P<0.0001 and 0.003, respectively). CONCLUSIONS: The CT protocol with iterative reconstruction and lower tube voltage for low-concentration contrast agents significantly reduced the effective radiation dose (mean: 3.7±2.7 to 4.1±3.1 mSv) while keeping the subjective image quality as good as the standard protocol (mean: 5.7±3.4 mSv).

Clinical outcomes of rescue stenting for failed endovascular thrombectomy: a multicenter prospective registry.

BACKGROUND: Mechanical thrombectomy (MT) is a primary endovascular modality for acute intracranial large vessel occlusion. However, further treatment, such as rescue stenting, is occasionally necessary for refractory cases. We aimed to investigate the efficacy and safety of rescue stenting in first-line MT failure and to identify the clinical factors affecting its clinical outcome. METHODS: A multicenter prospective registry was designed for this study. We enrolled consecutive patients who underwent rescue stenting for first-line MT failure. Endovascular details and outcomes, follow-up patency of the stented artery, and clinical outcomes were summarized and compared between the favorable and unfavorable outcome groups. RESULTS: A total of 78 patients were included. Intracranial atherosclerotic stenosis was the most common etiology for rescue stenting (97.4%). Seventy-seven patients (98.7%) were successfully recanalized by rescue stenting. A favorable outcome was observed in 66.7% of patients. Symptomatic intracranial hemorrhage and mortality were observed in 5.1% and 4.0% of patients, respectively. The stented artery was patent in 82.1% of patients on follow-up angiography. In a multivariable analysis, a patent stent on follow-up angiography was an independent factor for a favorable outcome (OR 87.6; 95% CI 4.77 to 1608.9; p=0.003). Postprocedural intravenous maintenance of glycoprotein IIb/IIIa inhibitor was significantly associated with the follow-up patency of the stented artery (OR 5.72; 95% CI 1.45 to 22.6; p=0.013). CONCLUSIONS: In this multicenter prospective registry, rescue stenting for first-line MT failure was effective and safe. For a favorable outcome, follow-up patency of the stented artery was important, which was significantly associated with postprocedural maintenance of glycoprotein IIb/IIIa inhibitors.

Direct aspiration thrombectomy as a first-pass approach for very elderly patients with ischemic stroke.

OBJECTIVE: This study aimed to determine whether an age of ≥ 80 years would affect the radiological and clinical outcomes of the direct aspiration first pass strategy for large vessel occlusion. METHODS: This study analyzed single-center data of patients with stroke who were treated with mechanical thrombectomy between May 2018 and October 2020. Baseline characteristics, as well as radiological and clinical outcomes of patients were recorded, analyzed, and compared between the very elderly (≥80 years) and elderly patients (<80 years). RESULTS: Sixty patients underwent mechanical thrombectomy using the Sofia aspiration catheter for mainstem occlusion of the middle cerebral artery. The direct aspiration first pass strategy was effective in 56.3% (n = 9) and 54.4% (n = 24) in the very elderly and elderly groups, respectively (p = 0.907). The final successful recanalization rates (thrombolysis in cerebral infarction ≥2b) were 75.0% (n = 12) and 70.5% (n = 31) in the very elderly group and elderly groups, respectively (p = 0.999). There was no significant between-group difference in the good 90-day clinical outcome (modified Rankin Scale ≤2) (50.0% and 56.8% in the very elderly and elderly groups, respectively, p = 0.639). Further, there were no significant between-group differences in complication rates. CONCLUSION: There was no difference in the recanalization rates and clinical outcomes of the direct aspiration first-pass strategy for patients aged ≥ 80 and < 80 years with occlusive lesions in large vessels.

Comparison of coronary computed tomography angiography image quality with high- and low-concentration contrast agents (CONCENTRATE): study protocol for a randomized controlled trial.

BACKGROUND: With the development of computed tomography (CT) technology, coronary CT angiography can be acquired with low doses of radiation and contrast agent without a loss of diagnostic performance. The primary objective of the CONCENTRATE study is to prove the noninferiority of the enhancement effect of low-concentration contrast agents compared to a high-concentration contrast agent of the coronary artery and myocardium with coronary CT angiography. METHODS/DESIGN: The CONCENTRATE study is a prospective, multicenter, noninferiority, randomized trial evaluating the enhancement effect of low-concentration contrast agents (270 and 320 mg iodine/ml) compared with a high-concentration contrast agent (370 mg iodine/ml) in the coronary artery and myocardium of coronary artery CT angiography. The primary efficacy measurement is the enhancement of coronary arteries as measured in Hounsfield units. The target population comprises 318 patients with suspected coronary artery disease who have been referred for clinically indicated nonemergent coronary CT angiography. Eligible participants are randomized for three different concentrations of the contrast agent in a 1:1:1 allocation ratio to one of three arms. The CONCENTRATE trial is a double-blind study, where the subjects and the outcome assessor are blinded to the concentration of the contrast agent used for coronary the CT angiography. Eight clinical sites in Korea are participating in this trial. DISCUSSION: The CONCENTRATE study will determine whether low-concentration contrast agents are able to provide diagnostic image quality in coronary CT angiography. TRIAL REGISTRATION: NCT02549794 . Registered on 14 September 2015.

Spontaneous aortic pseudoaneurysm rupture into the sigmoid colon in Behçet's disease patient.

Behçet's disease (BD) is a multisystem autoimmune disorder characterized by recurrent orogenital ulcers, uveitis, and skin lesions. The vascular manifestations include thrombophlebitis, stenosis, occlusion, and pseudoaneurysm. BD infrequently precipitates aortic pseudoaneurysm rupture into the sigmoid mesocolon and lumen of the adjacent colon. Here we report an extremely rare case of spontaneous abdominal aortic pseudoaneurysm rupture via the sigmoid mesocolon into the lumen of the sigmoid colon in a 37-year-old patient with BD.

Clinical effect of double coaxial self-expandable metallic stent in management of malignant colon obstruction.

PURPOSE: We aimed to evaluate the clinical effectiveness and safety of double coaxial self-expandable metallic stent (DCSEMS) in management of malignant colonic obstruction as a bridge to surgery or palliation for inoperable patients. METHODS: Between April 2006 and December 2012, 49 patients (27 males and 22 females; median age, 68 years; age range, 38-91 years) were selected to receive decompressive therapy for malignant colonic obstruction by implanting a DCSEMS. Application of DCSEMS was attempted in 49 patients under fluoroscopic guidance. The obstruction was located in the transverse colon (n=2), descending colon (n=7), sigmoid colon (n=24), rectosigmoid junction (n=6), and the rectum (n=10). The intended use of DCSEMS was as a bridge to elective surgery in 23 patients and palliation in 26 patients. RESULTS: Clinical success, defined as >50% dilatation of the stent with subsequent symptomatic improvement, was achieved in 48 of 49 patients (98%). The stent was properly inserted in all patients. No immediate major procedure-related complications occurred. One patient in the bridge-to-surgery group had colon perforation three days after DCSEMS application. Four patients had late migrations of the double stent. CONCLUSION: Application of DCSEMS is safe and effective in management of malignant colonic obstruction; it prevents stent migration and tumor ingrowth and lowers perforation rate during the stent application.

Clinical results of intraarterial thrombolysis according to tPA administration and perfusion/diffusion mismatching.

BACKGROUND: IA-Tx and advanced dynamic imaging studies have been adopted for ischemic stroke patient treatment. Many patients are treated with IV-tPA, but this treatment is not always feasible. In this study, IA-Tx was used for patients for whom IV-tPA was not indicated or when IV-tPA did not result in recanalization. METHODS: A total of 156 patients treated with IA-Tx were retrospectively reviewed. Of these, 72 patients were treated with a full dose of IV-tPA before receiving the IA-Tx; the remaining 84 patients only received IA-Tx. An initial imaging study using CTA and acute stroke MRI followed. Patients' demographics and clinical results were recorded and compared according to P/D mismatching and IV-tPA. RESULTS: Among P/D-mismatched patients, the recanalization rate was 80 % and the symptomatic intracranial hemorrhage rate was 14.5 %, while among P/D-matched patients, the rates were 63 % and 41.3 % respectively (p < 0.05). A favorable clinical outcome occurred in 49.1 % of P/D-mismatched, but only in 21.7 % of P/D-matched patients (p < 0.05). Among patients who were treated with IV-tPA before undergoing IA-Tx, the recanalization rate was 79.2 % and the sICH rate was 27.8 %, while it was 71.4 % and 17.9 % in patients who did not receive IV-tPA (p < 0.05). CONCLUSIONS: Patients who have P/D mismatching and are treated with IA-Tx have higher recanalization rates and a greater probability of a favorable outcome than patients who have P/D matching and receive IA-Tx. For patients who do not undergo successful recanalization after IV-tPA or who are not indicated for IV-tPA, the authors recommend IA-Tx after undergoing appropriate imaging evaluation.

Transcatheter N-butyl cyanoacrylate embolization of pseudoaneurysms.

PURPOSE: To report clinical experience with N-butyl cyanoacrylate (NBCA) for embolization of pseudoaneurysms at various locations. MATERIALS AND METHODS: Retrospective study of patients with pseudoaneurysms treated with NBCA over a 4-year period was conducted. Seventeen consecutive patients were evaluated, including three women and 14 men ranging in age from 25 to 77 years (mean, 60.6 y). NBCA was the only embolic agent used in 15 patients; in two patients, a liquid coil and a microcoil were placed before administration of NBCA. NBCA was mixed with iodized oil in a 1:3 ratio to control its polymerization time and to make it radiopaque. Diagnostic angiography and embolization were performed at the same session. Embolized sites included gastrointestinal tract (n = 6), spleen (n = 5), liver (n = 2), kidney (n = 1), chest (n = 1), oral cavity (n = 1), and buttock (n = 1). RESULTS: NBCA embolization was successful in 16 of 17 patients (94%), with complete occlusion of pseudoaneurysms. In one patient with a gastroduodenal artery stump pseudoaneurysm, NBCA embolization failed, and a stent-graft (8 mm/40 mm) was placed in the hepatic artery, excluding the pseudoaneurysm and preserving the hepatic artery. No major complications occurred, and there were no recurrences of pseudoaneurysms. CONCLUSIONS: NBCA embolization was an effective method for the treatment of pseudoaneurysms.

Arteriovenous fistula of the superior gluteal artery as a complication of posterior iliac crest bone graft harvesting: 3D-CT angiography and arterial embolization.

Superior gluteal artery injuries are rare, but potentially serious complications that occur during posterior iliac crest bone graft harvesting. The authors reported an arteriovenous fistula of the superior gluteal artery, which occurred as a complication during posterior iliac crest bone graft harvesting and was diagnosed with 3D-CT angiography, then treated with arterial embolization.

A multi-center, randomized, clinical study to compare the effect and safety of autologous cultured osteoblast(Ossron) injection to treat fractures.

BACKGROUND: We performed a multicenter, open, randomized, clinical study of autologous cultured osteoblast injection for long-bone fracture, to evaluate the fracture healing acceleration effect and the safety of autologous cultured osteoblasts. METHODS: Sixty-four patients with long-bone fractures were randomly divided into two groups, i.e. those who received autologous cultured osteoblast injection and those who received no treatment. The sum of the difference in the callus formation scores after four and eight weeks, was used as the first efficacy variable. RESULTS: The autologous cultured osteoblast injection group showed fracture healing acceleration of statistical significance, and there were no specific patient complications when using this treatment. CONCLUSION: Autologous cultured osteoblast injection should therefore be considered as a successful treatment option for treating long-bone fracture.

The endovascular management of saccular posterior inferior cerebellar artery aneurysms.

OBJECTIVE: The purpose of this retrospective study was to report the outcome of the endovascular treatment of eight patients with eight saccular posterior inferior cerebellar artery (PICA) aneurysms. MATERIALS AND METHODS: Over the last seven years (1999-2006), eight consecutive patients with saccular PICA aneurysms were treated by endovascular methods. Five of the aneurysms were presented with subarachnoid hemorrhaging, whereas three were discovered incidentally. Four of the aneurysms (3 ruptured and 1 incidental) were treated by intrasaccular coiling, whereas the remaining four (1 ruptured and 3 incidental) were treated by vertebral artery (VA) occlusion. RESULTS: Of the four aneurysms treated by intrasaccular coiling, three were completely packed with coils and one was partially packed. In three of four patients who underwent vertebral artery occlusions, follow-up digital subtraction angiographies demonstrated thrombosed aneurysms and PICA. No procedure-related morbidity occurred and no re-bleed was encountered during a follow-up examination (mean; 31 months). CONCLUSION: As a result of this study, we found that the endovascular management of saccular PICA aneurysms should be considered as safe and effective.

Cranioplasty effect on the cerebral hemodynamics and cardiac function.

BACKGROUND: Cranioplasty is usually performed for aesthetic, protective and patient comfort reasons. The objective of this study is to examine the effects of cranioplasty on the cerebral hemodynamics and cardiovascular system. METHODS: Twenty-seven patients who had undergone cranioplasty after extensive skull bone removal to prevent uncontrollable intracranial hypertension were included in this study. Arterial blood flow velocities in the middle cerebral artery (MCA) and internal carotid artery (ICA) were assessed by transcranial doppler (TCD). The cardiac functions were evaluated using the echocardiogram. And cerebral blood flow were measured by perfusion CT. FINDINGS: The blood flow velocity at the MCA ipsilateral to the cranioplasty was decreased from 50.5 +/- 15.4 cm/s preoperative to 38.1 +/- 13.9 cm/s following cranioplasty (p < 0.001) and from 33.1 +/- 8.3 cm/s to 26.4 +/- 6.6 cm/s at the ICA (p < 0.001). The stroke volume was increased from 64.7 +/- 18.3 ml/beat, to 73.3 +/- 20.4 ml/beat (p < 0.001), while the cardiac output and mean arterial blood pressure were unchanged. The cerebral blood flow was increased from 39.1 +/- 7.2 ml/100g/min to 44.7 +/- 8.9 ml/100g/min on the cranioplasty side (P = 0.05). CONCLUSIONS: Cranioplasty can get rid of the atmospheric pressure on the brain and increase the cerebral blood flow as well as improve the cardiovascular functions. A skull defect should be corrected, because cranioplasty has not only aesthetic or protective effects but also improves the cardiovascular functions.