Factors contributing to blood-brain barrier disruption following intracarotid injection of nonionic iodinated contrast medium for cerebral angiography: experimental study in rabbits

Quantification of ischemic brain edema after mechanical thrombectomy using dual-energy computed tomography in patients with ischemic stroke

Net water uptake (NWU) is a quantitative imaging biomarker used to assess cerebral edema resulting from ischemia via Computed Tomography (CT)-densitometry. It serves as a strong predictor of clinical outcome. Nevertheless, NWU measurements on follow-up CT scans after mechanical thrombectomy (MT) can be affected by contrast staining. To improve the accuracy of edema estimation, virtual non-contrast images (VNC-I) from dual-energy CT scans (DECT) were compared to conventional polychromatic CT images (CP-I) in this study. We examined NWU measurements derived from VNC-I and CP-I to assess their agreement and predictive value in clinical outcome. 88 consecutive patients who received DECT as follow-up after MT were included. NWU was quantified on CP-I (cNWU) and VNC-I (vNWU). The clinical endpoint was functional independence at discharge. cNWU and vNWU were highly correlated (r = 0.71, p < 0.0001). The median difference between cNWU and vNWU was 8.7% (IQR: 4.5-14.1%), associated with successful vessel recanalization (mTICI2b-3) (ß: 11.6%, 95% CI 2.9-23.0%, p = 0.04), and age (ß: 4.2%, 95% CI 1.3-7.0%, p = 0.005). The diagnostic accuracy to classify outcome between cNWU and vNWU was similar (AUC:0.78 versus 0.77). Although there was an 8.7% median difference, indicating potential edema underestimation on CP-I, it did not have short-term clinical implications.

Relationship between Transient Cortical Blindness and Contrast Medium Leakage That Occurs after Endovascular Treatment of Posterior Circulation Aneurysms

Objective

The mechanism of transient cortical blindness after endovascular treatment-a rare phenomenon-has not been elucidated; however, it is assumed to be related to contrast medium leakage (CML). We investigated the relationship between postoperative CML and cortical blindness in patients who underwent endovascular treatment for vascular lesions of posterior circulation.

Methods

This retrospective cohort study included 28 patients who underwent endovascular treatment for posterior circulation aneurysms at our hospital between January 2014 and December 2018. Cerebral CT was performed immediately after endovascular treatment and 24 h later. CT images were retrospectively evaluated with special interest in the presence and distribution of leakage of the contrast medium (CM). Patients were classified into the following three groups based on CT findings: Group A, no CML (11 patients); Group B, unilateral CML (5 patients); and Group C, bilateral CML (9 patients).

Results

The posterior circulation aneurysms were located in the basilar artery in 13 (52.0%) cases, in the posterior cerebral artery in 1 (4.0%) case, and in the vertebral artery in 11 (44.0%) cases. There was no difference regarding the adjunctive technique used for endovascular treatment between the groups. Patients in Group C used a significantly larger amount of CM than those in the other two groups. A longer operation time was associated with a larger amount of CM used during treatment. VerifyNow assay revealed that the P2Y12 reaction unit was significantly lower in Groups B and C. Cortical blindness was transiently observed in 2 of 9 patients (22.2%) in Group C, both of which showed CML surrounding the bilateral parieto-occipital sulcus.

Conclusion

Both patients with cortical blindness showed bilateral CML, both of which showed CML surrounding the bilateral parieto-occipital sulcus. The CM-induced blood-brain barrier disruption may be the cause of cortical blindness.

Hyperattenuations on flat-panel computed tomography after successful recanalization of mechanical thrombectomy for anterior circulation occlusion

Background

To evaluate intraparenchymal hyperattenuation (IPH) on flat-panel computed tomography (FPCT) findings and their clinical usefulness for predicting prognosis after successful mechanical thrombectomy (MT) for acute occlusion of anterior circulation.

Methods

A retrospective review was conducted for 158 consecutive patients undergoing mechanical thrombectomy during the last six years. After excluding those with posterior circulation occlusion or incomplete recanalization and those without FPCT, 82 patients were finally included. Immediate post-procedural IPH on FPCT was categorized into four patterns (none, striatal, cortical, or combined pattern). Follow-up magnetic resonance images or CT scans after 48 hours from MT were analyzed according to FPCT findings. The existence of hemorrhagic transformation, intracerebral hemorrhage, and brain swelling was evaluated. Functional clinical outcomes were accessed with post-procedural 3-month modified Rankin scales (mRS).

Results

Of 82 patients, 34 patients were found to have IPH (16 with a striatal pattern, 8 with a cortical pattern, and 10 with a combined pattern). Hemorrhagic complication (P<0.001), brain swelling (P<0.001), and poor mRS scores (P=0.042) showed significant differences according to IPH patterns. Multivariate logistic regression analysis revealed that the presence of a striatal pattern (OR: 13.26, P<0.001), cortical pattern (OR: 11.61, P=0.009), and combined pattern (OR: 45.34, P<0.001) independently predicted hemorrhagic complications. The location of the occlusion (OR: 4.13, P=0.034), cortical pattern (OR: 5.94, P=0.039), and combined pattern (OR: 39.85, P=0.001) predicted brain swelling. Age (OR: 1.07, P=0.006) and the presence of a combined pattern (OR: 10.58, P=0.046) predicted poor clinical outcomes.

Conclusions

FPCT is a rapid and effective tool for a prompt follow-up just after MT to predict prognosis. Those with striatal patterns showed relatively good clinical outcomes despite significant hemorrhage. Cortical IPH patterns independently predicted a high rate of post-procedural hemorrhage or brain swelling. Combined pattern is a strong predictor for both radiologic and poor clinical outcomes.

Fatal contrast medium-induced adverse response to iohexol in carotid artery angioplasty: A case report

RATIONALE

Adverse drug reactions (ADRs) to iohexol occur infrequently and generally result in good outcomes. This report describes a 51-year-old man suffering from an ADR to iohexol (Omnipaque 300), which proved fatal.

PATIENT CONCERNS

The patient was admitted to hospital due to intermittent dizziness over 2 years and transient numbness and weakness of the right limbs for 1 week. The patient was investigated using carotid artery angioplasty (CAA), during which the patient suffered a sudden disorder of consciousness and a tonic-clonic seizure leading to status epilepticus. After the CAA, the patient suffered from increasing cerebral edema volume.

DIAGNOSES

Results of digital subtraction angiography and computed tomography angiography performed at another hospital before the CAA suggested severe stenosis of the left internal carotid artery at the spinal C1 level. In the processes of intraoperative and postoperative CAA, the patient developed severe allergic reactions to the contrast agent including epilepsy, brain tissue edema, and renal failure, which were typical according to the 10th edition of the American College of Radiology Manual on Contrast Media (ACR Manual on Contrast Media, Version 10.3, 2017).

INTERVENTIONS

The patient was treated with antiepileptic, antianaphylactic therapy, and control of blood pressure. Due to rapid and severe brain edema, a decompressive craniectomy was performed on the left side, but it was unsuccessful in reducing brain edema. Subsequently, the patient was started on continuous renal replacement therapy for progressive renal dysfunction.

OUTCOMES

Despite the use of a variety of medical and surgical interventions, it was not possible to control the patient's condition, which gradually declined leading to death, 7 days post-CAA.

LESSONS

To the authors' knowledge, this represents the 1st case of fatal contrast-induced ADR to iohexol during CAA. Although a variety of preoperative tests for iohexol allergy were performed according to recommendations from the ACR Manual on Contrast Media (Version 10.3, 2017), severe complications related to iodized contrast agent still occurred. If the ADR had been recognized sooner and decompressive craniectomy and continuous renal replacement therapy were applied earlier, it would have improved the patients' prognosis.

Contrast-induced Encephalopathy Following Embolization of Intracranial Aneurysms in Hemodialysis Patients

Contrast-induced encephalopathy is a very rare complication associated with endovascular treatment of intracranial aneurysms. Patients with renal dysfunction may be prone to developing contrast medium neurotoxicity as a result of delayed elimination of the contrast medium in renal metabolism. This article focuses on our experience with contrast-induced encephalopathy in patients with end-stage renal disease requiring hemodialysis. The authors retrospectively reviewed five patients diagnosed with contrast-induced encephalopathy who underwent aneurysm coil embolization at their institution from January 2006 to December 2015. During the 10-year period, embolization was performed in 755 cases, among which contrast-induced encephalopathy occurred in five patients (0.66%). Three of the five patients were undergoing dialysis for chronic renal failure (one male and two female; mean age 66.7). Embolization for hemodialysis patients was performed in eight during the same period and the incidence of contrast-induced encephalopathy in hemodialysis patients is quite high in our series (3 of 8; 38%). Procedures were performed in one for recurrence of unruptured anterior-communicating artery aneurysm and in two for unruptured basilar-tip aneurysm. Mean approximately 220 ml of contrast media was used among three hemodialysis patients. All three patients showed an improvement or a control in symptoms soon after hemodialysis. Recovery of neurological symptoms was complete in two and almost normal in one within 1 week after intervention. Contrast-induced encephalopathy should be kept in mind as an expected complication of aneurysm embolization in hemodialysis patients. In hemodialysis patients with contrast-induced encephalopathy, performing hemodialysis is an effective treatment to improve symptoms early.

Outcome Differences between Intra-Arterial Iso- and Low-Osmolality Iodinated Radiographic Contrast Media in the Interventional Management of Stroke III Trial

BACKGROUND AND PURPOSE

Intracarotid arterial infusion of nonionic, low-osmolal iohexol contrast medium has been associated with increased intracranial hemorrhage in a rat middle cerebral artery occlusion model compared with saline infusion. Iso-osmolal iodixanol (290 mOsm/kg H2O) infusion demonstrated smaller infarcts and less intracranial hemorrhage compared with low-osmolal iopamidol and saline. No studies comparing iodinated radiographic contrast media in human stroke have been performed, to our knowledge. We hypothesized that low-osmolal contrast media may be associated with worse outcomes compared with iodixanol in the Interventional Management of Stroke III Trial (IMS III).

MATERIALS AND METHODS

We reviewed prospective iodinated radiographic contrast media data for 133 M1 occlusions treated with endovascular therapy. We compared 5 prespecified efficacy and safety end points (mRS 0-2 outcome, modified TICI 2b-3 reperfusion, asymptomatic and symptomatic intracranial hemorrhage, and mortality) between those receiving iodixanol (n = 31) or low-osmolal contrast media (n = 102). Variables imbalanced between iodinated radiographic contrast media types or associated with outcome were considered potential covariates for the adjusted models. In addition to the iodinated radiographic contrast media type, final covariates were those selected by using the stepwise method in a logistic regression model. Adjusted relative risks were then estimated by using a log-link regression model.

RESULTS

Of baseline or endovascular therapy variables potentially linked to outcome, prior antiplatelet agent use was more common and microcatheter iodinated radiographic contrast media injections were fewer with iodixanol. Relative risk point estimates are in favor of iodixanol for the 5 prespecified end points with M1 occlusion. The percentage of risk differences are numerically greater for microcatheter injections with iodixanol.

CONCLUSIONS

While data favoring the use of iso-osmolal iodixanol for reperfusion of M1 occlusion following IV rtPA are inconclusive, potential pathophysiologic mechanisms suggesting clinical benefit warrant further investigation.

Flat detector angio-CT following intra-arterial therapy of acute ischemic stroke: identification of hemorrhage and distinction from contrast accumulation due to blood-brain barrier disruption

BACKGROUND AND PURPOSE

Flat panel detector CT in the angiography suite may be valuable for the detection of intracranial hematomas; however, abnormal contrast enhancement frequently mimics hemorrhage. We aimed to assess the accuracy of flat panel detector CT in detecting/excluding intracranial bleeding after endovascular stroke therapy and whether it was able to reliably differentiate hemorrhage from early blood-brain barrier disruption.

MATERIALS AND METHODS

Seventy-three patients were included for retrospective evaluation following endovascular stroke therapy: 32 after stent-assisted thrombectomy, 14 after intra-arterial thrombolysis, and 27 after a combination of both. Flat panel CT images were assessed for image quality and the presence and type of intracranial hemorrhage and BBB disruption by 2 readers separately and in consensus. Follow-up by multisection head CT, serving as the reference standard, was evaluated by a single reader.

RESULTS

Conventional head CT revealed intracranial hematomas in 12 patients (8 subarachnoid hemorrhages, 7 cases of intracerebral bleeding, 3 SAHs plus intracerebral bleeding). Image quality of flat panel detector CT was considered sufficient in all cases supratentorially and in 92% in the posterior fossa. Regarding detection or exclusion of intracranial hemorrhage, flat panel detector CT reached a sensitivity, specificity, positive and negative predictive values, and accuracy of 58%, 85%, 44%, 91%, and 81%, respectively. Maximum attenuation measurements were not valuable for the differentiation of hemorrhage and BBB disruption.

CONCLUSIONS

Flat panel CT after endovascular stroke treatment was able to exclude the rare event of an intracranial hemorrhage with a high negative predictive value. Future studies should evaluate the predictive value of BBB disruptions in flat panel detector CT for the development of relevant hematomas.

Serious Blood-Brain Barrier Disruption after Coil Embolization of Unruptured Intracranial Aneurysm : Report of Two Cases and Role of Immediate Postembolization CT Scan

Abnormal contrast enhancement on brain computed tomography (CT) scan after diagnostic or interventional angiography is not rare, and has known to be induced by temporary blood-brain barrier (BBB) disruption from contrast media. Furthermore, it has been regarded as clinically subtle, but reported to have no symptom or mild transient symptoms. However, we recently experienced two cases of serious BBB disruption during the acute period after coiling of an unruptured intracranial aneurysm. One patient presented with an unruptured paraclinoid internal carotid artery (ICA) aneurysm on the right and the other with an unruptured right supraclinoid ICA aneurysm. Both patients showed similar findings on immediate postembolization CT scan and clinical courses after coiling. Typical radiological, clinical characteristics of BBB disruption were described. In addition, the role of immediate postembolization CT scan are also discussed.

Transient global aphasia with hemiparesis following cerebral angiography : relationship to blood brain barrier disruption

Temporary disruption of the blood-brain barrier (BBB) after cerebral angiography is presumably caused by nonionic radiographic contrast medium (CM). We hereby report a case of 58-year-old woman who developed decreased mentality, global aphasia and aggravated right hemiparesis after cerebral angiography. Brain CT examination demonstrated gyriform enhancement throughout the left cerebral cortex and thalamus. MR diffusion did not reveal acute infarction. MR angiography did not show any stenosis, spasm or occlusion at the major cerebral vessels. Follow-up CT scan after 1 day did not show any gyriform enhancement. Worsened neurologic signs and symptoms were improved completely after 7 days. In the present study, disruption of the BBB with contrast medium after angiography seems to be the causative factor of transient neurologic deterioration.

Cerebral injury from intracarotid injection in an alpaca (Vicugna pacos)

A mixture of ketamine, xylazine, and butorphanol was inadvertently injected into the right carotid artery of a 1-year-old alpaca. Injection was followed by a brief period of recumbency and seizure activity. The alpaca recovered, but was euthanatized 72 hr later because of development of progressive neurologic deficits. Pathologic findings were confined to the right cerebrum, meninges, thalamus, and hippocampus. Cerebrocortical edema with astrocytic reaction, perivascular hemorrhage and neutrophilic infiltration, and fibrinoid necrosis of vasculature within the meninges and thalamus were the most prominent lesions. Neuronal necrosis was mild. Astrocytic reaction within the right cerebral cortex was confirmed with immunohistochemistry for glial fibrillary acidic protein.

Immediate CT findings following embolization of cerebral aneurysms: suggestion of blood-brain barrier or vascular permeability change

INTRODUCTION

Although endovascular techniques are widely used for the treatment of cerebral aneurysms, the immediate postprocedural brain CT findings have not been reported. Therefore, in the present study we assessed the immediate postprocedural brain CT findings following the uneventful coil embolization of cerebral aneurysms.

METHODS

Included in the study were 59 patients with 61 cerebral aneurysms after uncomplicated coil embolization. Acute subarachnoid hemorrhage was present with 32 of the 61 aneurysms. All patients underwent a brain CT scan just before and within 2 h after the endovascular treatment. If the postprocedural CT scan revealed any new findings, a follow-up CT scan and/or MRI were performed within 24 h. The variables related to the abnormal CT findings were also evaluated.

RESULTS

Among the 61 immediate brain CT scans, 26 (43%) showed abnormal findings, including cortical contrast enhancement (n=21, 34%), subarachnoid contrast enhancement (n=8, 13%), intraventricular contrast enhancement (n=5, 8%), and striatal contrast enhancement (n=2, 3%). Single or mixed CT findings were also seen. None of the 61 aneurysms was associated with new neurological symptoms after endovascular treatment, and all patients made an uneventful recovery. Abnormal findings were more likely to be found with lower body weight and with increased corrected amounts of contrast material and heparin (P<0.05).

CONCLUSION

After uneventful endovascular treatment of cerebral aneurysms, the immediate brain CT findings can reveal various patterns of abnormal contrast enhancement. Recognizing the immediate brain CT findings is important, as they can mimic various diseases.