Factors Distinguishing Proximal and Distal Internal Carotid Artery Occlusions in Patients with Acute Ischemic Stroke

Acute internal carotid artery (ICA) occlusions cause extensive brain ischemia. Accurate determination of the occlusion site facilitates rapid revascularization interventions and improves prognosis. However, proximal ICA occlusions, as determined with computed tomography (CT) angiography, often are located more distally. Therefore, we assessed clinical and imaging factors associated with the accurate determination of occlusion sites. In this observational study, we evaluated 102 patients who presented acute ischemic stroke symptoms and had a CT angiography within 6 h, showing proximal ICA occlusion. The participants were divided into two groups, depending on whether there was correspondence between digital subtraction angiography and CT angiography regarding the occlusion location. Proximal occlusions were, accordingly, categorized as “true” (correspondence) or “false” (no correspondence; distal). Demographic, clinical, and imaging features were analyzed. Multivariate regression analysis was performed to identify factors predicting the correspondence between actual ICA occlusion sites and those detected by CT angiography. The shape (Odds ratios, OR = 646.584; Confidence interval, CI = 21.703–19263.187; p < 0.001) and the length (OR = 0.696; CI = 0.535–0.904; p = 0.007) of the ICA occlusion and atrial fibrillation (OR = 0.024; CI = 0.002–0.340; p = 0.006) were significant factors. The cut-off length of ICA stump at 6.2 mm, the sensitivity was 71%, and the specificity was 70% (area under the ROC curve = 0.767).

Response prediction of vestibular schwannoma after gamma-knife radiosurgery using pretreatment dynamic contrast-enhanced MRI: a prospective study

OBJECTIVES

There are few known predictive factors for response to gamma-knife radiosurgery (GKRS) in vestibular schwannoma (VS). We investigated the predictive role of pretreatment dynamic contrast-enhanced (DCE)-MRI parameters regarding the tumor response after GKRS in sporadic VS.

METHODS

This single-center prospective study enrolled participants between April 2017 and February 2019. We performed a volumetric measurement of DCE-MRI-derived parameters before GKRS. The tumor volume was measured in a follow-up MRI. The pharmacokinetic parameters were compared between responders and nonresponders according to 20% or more tumor volume reduction. Stepwise multivariable logistic regression analyses were performed, and the diagnostic performance of DCE-MRI parameters for the prediction of tumor response was evaluated by receiver operating characteristic curve analysis.

RESULTS

Ultimately, 35 participants (21 women, 52 ± 12 years) were included. There were 22 (62.9%) responders with a mean follow-up interval of 30.2 ± 5.7 months. K^trans (0.036 min^-1 vs. 0.057 min^-1, p = .008) and initial area under the time-concentration curve within 90 s (IAUC90) (84.4 vs. 143.6, p = .003) showed significant differences between responders and nonresponders. K^trans (OR = 0.96, p = .021) and IAUC90 (OR = 0.97, p = .004) were significant differentiating variables in each multivariable model with clinical variables for tumor response prediction. K^trans showed a sensitivity of 81.8% and a specificity of 69.2%, and IAUC90 showed a sensitivity of 100% and a specificity of 53.8% for tumor response prediction.

CONCLUSION

DCE-MRI (particularly K^trans and IAUC90) has the potential to be a predictive factor for tumor response in VS after GKRS.

KEY POINTS

•Pretreatment prediction of gamma-knife radiosurgery response in vestibular schwannoma is still challenging. •Dynamic contrast-enhanced MRI could have predictive value for the response of vestibular schwannoma after gamma-knife radiosurgery.

Computed tomography complements ultrasound for the differential diagnosis of traumatic neuroma from recurrent tumor in patients with postoperative thyroid cancer

OBJECTIVES

Traumatic neuromas (TNs) mimic recurrent tumors in US after total thyroidectomy (TT) and lateral neck dissection (LND) for thyroid cancer. We aimed to evaluate whether CT could complement US in the differential diagnosis of TNs from recurrent thyroid cancer in the dissected neck.

MATERIAL AND METHODS

We retrospectively included a total of 97 consecutive US-detected lesions (28 TNs and 69 recurrent tumors) in patients with a previous history of TT and LND for thyroid cancer. The lesions were classified as benign, indeterminate, or suspicious according to the presence of benign or suspicious features on US and CT. Imaging features and categories on US and CT were compared between TNs and recurrent tumors. The diagnostic performances of US and CT for differentiating between TNs and recurrent tumors were calculated.

RESULTS

On US, most TNs and recurrent tumors showed internal hyperechogenicity without hilar echogenicity or hilar vascularity and were categorized as suspicious lesions (23/28, 82.1% vs. 53/69, 76.8%). On CT, all TNs lacked strong enhancement without hilar fat or hilar vessel enhancement and were categorized as indeterminate lesions (28/28, 100%). In contrast, most recurrent tumors showed strong enhancement and were categorized as suspicious lesions (63/69, 91.3%). The addition of CT to US corrected 23 false-positive diagnoses in 28 TNs and 10 false-negative diagnoses in 69 recurrent tumors.

CONCLUSIONS

CT complements US for the correct differentiation of TNs from recurrent tumors in postoperative thyroid cancer patients. The addition of CT to US may prevent unnecessary painful biopsy or surgery.

KEY POINTS

• In the dissected neck, traumatic neuromas could mimic US suspicious LNs owing to its internal hyperechogenicity. • CT effectively differentiated traumatic neuromas from recurrent thyroid cancers by demonstrating significantly different enhancement patterns. • CT could complement US and may prevent unnecessary painful biopsy or surgery for US-detected lesions after thyroidectomy and neck dissection.

Midterm Outcomes After Low-Profile Visualization Endoluminal Support or Atlas Stent-Assisted Coiling of Intracranial Aneurysms: A Propensity Score Matching Analysis

BACKGROUND

The interplay of various commercially available stents during coil embolization of intracranial aneurysms and their ultimate impact are subject to debate.

OBJECTIVE

To compare midterm outcomes of Low-Profile Visualization Endoluminal Support (LVIS) (MicroVention Inc) and Atlas (Stryker) stent-assisted coiling procedures.

METHODS

A total of 459 intracranial aneurysms subjected to coil embolization using LVIS (n = 318) or Atlas stents (n = 141) between April 2015 and December 2019 were eligible for study. To assess occlusive status postembolization, magnetic resonance angiography and/or conventional angiography were used. The Raymond classification was applied to categorize recanalization. Our analysis was propensity score matched according to probability of stent type deployed.

RESULTS

Eventually, 41 aneurysms (8.9%) displayed recanalization (minor, 28; major, 13) 6 mo after coiling. Patient age (P = .018), sex (P = .015), aneurysmal location (P < .001), and type of aneurysm (P < .001) differed significantly by group. Overall and major recanalization rates at midterm were similar in both groups (9.1% and 8.5% vs 3.1% and 2.1%, respectively), and there was no significant difference even after 1:1 propensity score matching (odds ratio [OR] = 0.75 [P = .514] and OR = 0.75 [P = .706], respectively).

CONCLUSION

In stent-assisted coil embolization of intracranial aneurysms, midterm outcomes of LVIS and Atlas device groups were similar, despite theoretic LVIS superiority. Further randomized comparative studies are needed to confirm our findings.

Prediction of brain age from routine T2-weighted spin-echo brain magnetic resonance images with a deep convolutional neural network

Our study investigated the feasibility and clinical relevance of brain age prediction using axial T2-weighted images (T2-WIs) with a deep convolutional neural network (CNN) algorithm. The CNN model was trained by 1,530 scans in our institution. The performance was evaluated by the mean absolute error (MAE) between the predicted brain age and the chronological age based on an internal test set (n=270) and an external test set (n=560). The ensemble CNN model showed an MAE of 4.22 years in the internal test set and 9.96 years in the external test set. Participants with grade 2-3 white matter hyperintensity (WMH) showed a higher corrected predicted age difference (PAD) than grade 0 WMH (posthoc p<0.001). Participants diagnosed with diabetes mellitus also had a higher corrected PAD than those without diabetes (adjusted p=0.048), although it showed no significant differences according to the diagnosis of hypertension or dyslipidemia. We suggest that routine clinical T2-WIs are feasible to predict brain age, and it might be clinically relevant according to the WMH grade and the presence of diabetes mellitus.

Fulminant Course of Acute Necrotizing Encephalopathy Followed by Serial MRI: A Case Report

Acute necrotizing encephalopathy (ANE) is a rare but distinctive type of influenza-associated encephalopathy characterized by symmetric multiple lesions with an invariable thalamic involvement. Although the exact pathogenesis of ANE remains unclear, the most prevalent hypothesis is the “cytokine storm,” which results in blood-brain-barrier breakdown. We present the case of a 10-year-old boy with fulminant ANE confirmed with serial MRI studies, including diffusion-weighted imaging and susceptibility-weighted imaging. A comparison of these serial images demonstrated detailed and longitudinal changes in MRI findings during the clinical course corresponding to pathophysiological changes. Our case clarifies the pathogenesis of ANE brain lesions using serial imaging studies and suggests that early immunomodulatory therapy reduces brain damage.

Cerebrovascular Reservoir and Arterial Transit Time Changes Assessed by Acetazolamide-Challenged Multi-Phase Arterial Spin Labeling Perfusion MRI in Chronic Cerebrovascular Steno-Occlusive Disease

Purpose

To explore cerebrovascular reservoir (CVR) and arterial transit time (ATT) changes using acetazolamide-challenged multi-phase arterial spin labeling (MP-ASL) perfusion-weighted MRI in chronic cerebrovascular steno-occlusive disease.

Materials and Methods

This retrospective study enrolled patients with chronic steno-occlusion who underwent acetazolamide-challenged MP-ASL between June 2019 and October 2020. Cerebral blood flow, CVR, basal ATT, and ATT changes associated with severe stenosis, total occlusion, and chronic infarction lesions were compared.

Results

There were 32 patients (5 with bilateral steno-occlusion) in our study sample. The CVR was significantly reduced during total occlusion compared with severe stenosis (26.2% ± 28.8% vs. 41.4% ± 34.1%, respectively, p = 0.004). The ATT changes were not significantly different (p = 0.717). The CVR was marginally lower in patients with chronic infarction (29.6% ± 39.1% vs. 38.9% ± 28.7%, respectively, p = 0.076). However, the ATT was less shortened in patients with chronic infarction (−54 ± 135 vs. −117 ± 128 ms, respectively, p = 0.013).

Conclusion

Acetazolamide-challenged MP-ASL provides an MRI-based CVR evaluation tool for chronic steno-occlusive disease.

De Novo Intracranial Aneurysms Detected on Imaging Follow-Up of Coiled Aneurysms in a Korean Population

Objective

Coiled aneurysms are known to recanalize over time, making follow-up evaluations mandatory. Although de novo intracranial aneurysms (DNIAs) are occasionally detected during routine patient monitoring, such events have not been thoroughly investigated to date. Herein, we generated estimates of DNIA development during long-term observation of coiled cerebral aneurysms, focusing on incidence and the risk factors involved.

Materials and Methods

In total, 773 patients undergoing coil embolization of intracranial aneurysms between 2008 and 2010 were reviewed retrospectively. Their medical records and radiologic data accrued over the extended period (mean, 52.7 ± 29.7 months) were analyzed. For the detection of DNIA, follow-up magnetic resonance angiography and/or conventional angiography were used. The incidence of DNIAs and related risk factors were analyzed using Cox proportional hazards regression and Kaplan-Meier product-limit estimator.

Results

In 19 (2.5%) of the 773 patients with coiled aneurysms, DNIAs (0.56% per patient-year) developed during continued long-term monitoring (3395.3 patient-years). Of these, 9 DNIAs (47.4%) were detected within 60 months, with 10 (52.6%) emerging thereafter. The most common site involved was the posterior communicating artery (n = 6), followed by the middle cerebral artery (n = 5) and the basilar top (n = 4). Multivariate analysis indicated that younger age (< 50 years) (hazard ratio [HR] = 1.045; p = 0.010) and recanalization of coiled aneurysms (HR = 2.560; p = 0.047) were significant factors in DNIA formation, whereas female sex, smoking, and hypertension fell short of statistical significance. Cumulative survival rates without DNIA were significantly higher in older subjects (> 60 years; p < 0.001) and in the absence of post-coiling aneurysm recurrence (p = 0.006).

Conclusion

In most patients with coiled aneurysms, development of DNIAs during long-term monitoring is rare. However, younger patients (< 50 years) or patients with recurring aneurysms appear to be predisposed to DNIAs.

Diagnostic Performance of a Combination of Shear Wave Elastography and B-Mode Ultrasonography in Differentiating Benign From Malignant Thyroid Nodules

Objectives

This study was conducted to compare clinicopathologic and radiologic factors between benign and malignant thyroid nodules and to evaluate the diagnostic performance of shear wave elastography (SWE) combined with B-mode ultrasonography (US) in differentiating malignant from benign thyroid nodules.

Methods

This retrospective study included 92 consecutive patients with 95 thyroid nodules examined on B-mode US and SWE before US-guided fine-needle aspiration biopsy or surgical excision. B-mode US findings (composition, echogenicity, margin, shape, and calcification) and SWE elasticity parameters (maximum [E_max], mean, minimum, and nodule-to-normal parenchymal ratio of elasticity) were reviewed and compared between benign and malignant thyroid nodules. The diagnostic performance of B-mode US and SWE for predicting malignant thyroid nodules was analyzed. The optimal cutoff values of elasticity parameters for identifying malignancy were determined. Diagnostic performance was compared between B-mode US only, SWE only, and the combination of B-mode US with SWE.

Results

On multivariate logistic regression analysis, age (odds ratio [OR], 0.90; P=0.028), a taller-than-wide shape (OR, 11.3; P=0.040), the presence of calcifications (OR, 15.0; P=0.021), and E_max (OR, 1.22; P=0.021) were independent predictors of malignancy in thyroid nodules. The combined use of B-mode US findings and SWE yielded improvements in sensitivity, the positive predictive value, the negative predictive value, and accuracy compared with the use of B-mode US findings only, but with no statistical significance.

Conclusion

When SWE was combined with B-mode US, the diagnostic performance was better than when only B-mode US was used, although the difference was not statistically significant.

Abstract WP131: Is 3 Years Adequate for Tracking Completely Occluded Coiled Aneurysms?

Objective: To ascertain the long-term durability of coiled aneurysms completely occluded at 36 months during follow-up given the potential for delayed recanalization.

Methods: As a retrospective review, we examined 299 patients with 339 aneurysms, all completely occluded at 36 months in follow-up images obtained between 2011 and 2013. Medical records and radiologic data acquired during extended monitoring (mean, 74.3±22.5 months) were retrieved, analyzing incidence (including average annual risk) and risk factors of delayed recanalization.

Results: A total of five coiled aneurysms (1.5%) occluded completely at 36 months showed recanalization (0.46 % per aneurysm-year) during continued long-term surveillance (1081.9 aneurysm-years), two surfacing within 60 months and three developing thereafter. Four showed minor recanalization, with only one instance of major recanalization. The latter involved posterior communicating artery as an apparent de novo lesion, arising at the neck of a firmly coiled sac, and was unrelated to coil compaction or growth. Additional embolization was undertaken. In multivariate analysis, second embolization for recurred aneurysm (HR=22.088, p=0.003) independently correlated with delayed recanalization.

Conclusion: Almost all coiled aneurysms (98.5%) showing complete occlusion at 36 months post-embolization proved to be stable in extended observation. Therefore, it is reasonable to suspend imaging surveillance of coiled aneurysms after 3 years in the absence of demonstrable recanalization. However, recurrent aneurysms were predisposed to delayed recanalization.

Clinicoradiological Features of Recurrent Meningioma With High Grade Transformation

BACKGROUND/AIM

A minority of grade I meningiomas (MG1s) recur after surgical resection and their progression is associated with high grade transformation (HGT). This study aimed to characterize the clinicoradiological features of recurrent MGs (RMG) with HGT.

PATIENTS AND METHODS

We identified 17 patients diagnosed with MG1 who then underwent surgery for RMG. Patients were categorized into HGT group vs. non-HGT (nHGT) group based on RMG histological grade and clinicoradiological features were comparatively analyzed.

RESULTS

HGT was observed in 41.4% of RMGs. Original tumor size was larger in the HGT group and recurrence time interval was shorter. Following recurrence, 57.1% in the HGT group experienced further disease progression, compared to 22.2% in the nHGT group.

CONCLUSION

A considerable HGT rate in RMGs developed after MG1 was observed. Although HGT was not distinguished from nHGT by radiological features, HGT in RMG was associated with larger initial tumor size and shorter recurrence time interval.

Does Systemic Hypertension Impact Recanalization of Coiled Aneurysms?

PURPOSE

It is well known that hypertension is a significant factor in the formation, growth, and rupture of aneurysms and recanalization of coiled aneurysms is affected by hemodynamic stress. At present, however, the impact of hypertension on recanalization of coiled aneurysms has not been adequately investigated. This study examined the relation between hypertension and subsequent outcomes of coiled aneurysms, using a matched patient analysis.

METHODS

A total of 715 subjects undergoing coil embolization of intracranial aneurysms between 2011 and 2013 were selected for study. Time-of-flight magnetic resonance or conventional angiography was used (singly or together) to gauge degrees of occlusion after coiling, applying the Raymond classification in grading recanalization. Patients with hypertension were grouped as controlled or uncontrolled, based on blood pressure readings at outpatient clinics. Hypertensive and non-hypertensive subjects were matched (1:1) for several relevant variables.

RESULTS

Overall, 484 patients (67.7%) were hypertensive (controlled 338; uncontrolled 146). During the follow-up period (28.6 ± 9.7 months), 129 aneurysms (18.0%) displayed recanalization (minor 58; major 71). Patient age, concomitant diabetes, hyperlipidemia, aneurysm size, neck size, depth-to-neck ratio, and aneurysm type differed significantly in hypertensive and non-hypertensive groups; however, group incidences of cumulative recanalization were similar (p = 0.297). After 1:1 matching the cumulative recanalization rate (13.5%) in hypertensive and non-hypertensive counterparts (14.3%) again proved similar (p = 0.578). In the hypertensive group, in addition, recanalization showed no relation to controlled and uncontrolled subgroup (odds ratio, OR = 1.000, p > 0.999).

CONCLUSION

Unlike other aspects of evolving aneurysms (e.g. formation, growth, or rupture), recanalization of coiled aneurysms seems to be unaffected by systemic hypertension.

Determination of Aneurysm Volume Critical for Stability After Coil Embolization: A Retrospective Study of 3530 Aneurysms

BACKGROUND

Recurrence is one of the concerns even after successful endovascular treatment of intracranial aneurysms. We sought to determine the critical aneurysm volume and risk factors related to aneurysmal stability in patients undergoing coil embolization of intracranial aneurysms.

METHODS

Aneurysm volume and follow-up imaging data were retrieved in 3042 patients with 3530 aneurysms who were treated with endovascular coil embolization from January 2006 to October 2016. We analyzed the anatomic outcome in relation to aneurysm volume and determined the critical aneurysm volume favoring coil embolization.

RESULTS

Recanalization rates were 2.8%, 6.3%, 19.4%, and 67.4% in each group with aneurysm volume of <10, 10-100, 100-1000, and >1000 mm³, respectively. When we investigated the 100-1000 mm³ group, the recanalization rate remarkably increased at 500 mm³ (16.4% vs. 57.5%, P < 0.0001; odds ratio [OR], 6.968; 95% confidence interval [CI], 3.562-13.631). In the entire cohort, recanalization rates were significantly different between aneurysm volume of <500 and >500 mm³ (7.2% vs. 62.9%, respectively; P < 0.0001; OR, 21.848; 95% CI, 13.944-34.235). In aneurysm volumes of >500 mm³, the location was a significant prognostic factor for long-term stability (posterior circulation vs. anterior circulation; OR, 4.737; 95% CI, 1.275-17.602; P = 0.020).

CONCLUSIONS

In our series of cerebral aneurysms treated with coil embolization, 500 mm³ was found to be the critical volume determining stability after coil embolization. Large volume aneurysms in the posterior circulation were especially prone to recanalization after coiling.

Is 3 years adequate for tracking completely occluded coiled aneurysms?

OBJECTIVE

The authors conducted a study to ascertain the long-term durability of coiled aneurysms completely occluded at 36 months' follow-up given the potential for delayed recanalization.

METHODS

In this retrospective review, the authors examined 299 patients with 339 aneurysms, all shown to be completely occluded at 36 months on follow-up images obtained between 2011 and 2013. Medical records and radiological data acquired during the extended monitoring period (mean 74.3 ± 22.5 months) were retrieved, and the authors analyzed the incidence of (including mean annual risk) and risk factors for delayed recanalization.

RESULTS

A total of 5 coiled aneurysms (1.5%) occluded completely at 36 months showed recanalization (0.46% per aneurysm-year) during the long-term surveillance period (1081.9 aneurysm-years), 2 surfacing within 60 months and 3 developing thereafter. Four showed minor recanalization, with only one instance of major recanalization. The latter involved the posterior communicating artery as an apparent de novo lesion, arising at the neck of a firmly coiled sac, and was unrelated to coil compaction or growth. Additional embolization was undertaken. In a multivariate analysis, a second embolization for a recurrent aneurysm (HR = 22.088, p = 0.003) independently correlated with delayed recanalization.

CONCLUSIONS

Almost all coiled aneurysms (98.5%) showing complete occlusion at 36 months postembolization proved to be stable during extended observation. However, recurrent aneurysms were predisposed to delayed recanalization. Given the low probability yet seriousness of delayed recanalization and the possibility of de novo aneurysm formation, careful monitoring may be still considered in this setting but at less frequent intervals beyond 36 months.

Isolated Trochlear Nerve Palsy in a Patient with Superior Cerebellar Rete Mirabile

BACKGROUND

Rete mirabile is a very rare vascular malformation and superior cerebellar artery (SCA) rete mirabile is not reported previously. We report a new case of rete mirabile of SCA initially detected by magnetic resonance imaging and transfemoral cerebral angiography.

CASE DESCRIPTION

This report illustrates the case of a 58-year-old man who presented with vertical diplopia. Brain magnetic resonance angiography and transfemoral cerebral angiography revealed a rete mirabile of SCA and 3-dimensional volume isotropic turbo spin echo acquisition, brain magnetic resonance imaging sequence, demonstrated that the cisternal segment of the ipsilateral trochlear nerve was compressed by this vascular malformation. We assumed that his cranial nerve palsy was caused by the rete mirabile of the right SCA. During the 8 weeks presence of diplopia, the patient was observed and the symptom was relieved spontaneously.

CONCLUSIONS

We provide a first report in the literature of rete mirabile involving the SCA and suggest a descriptive knowledge of rete mirabile for clinicians during decision-making of treatment.

Safety and efficacy of anterior communicating artery compromise during endovascular coil embolization of adjoining aneurysms

OBJECTIVE

In the presence of symmetric A1 flow, the safety and efficacy of compromising the anterior communicating artery (ACoA) during coil embolization of ACoA aneurysms has yet to be evaluated. Herein, the authors describe their experience, focusing on procedural safety.

METHODS

Between October 2012 and July 2017, 285 ACoA aneurysms with symmetric A1 flows were treated at the authors' institution by endovascular coil embolization. Clinical and angiographic outcome data were subjected to binary logistic regression analysis.

RESULTS

ACoA compromise was chosen in the treatment of 71 aneurysms (24.9%), which were completely (n = 15) or incompletely (n = 56) compromised. In the remaining 214 lesions, the ACoA was preserved. Although 9 patients (3.2%) experienced procedure-related thromboembolisms (compromised, 4; preserved, 5), all but 1 patient (with ACoA compromise) were asymptomatic. In multivariate analysis, subarachnoid hemorrhage at presentation was the sole independent risk factor for thromboembolism (OR 15.98, p < 0.01), with ACoA compromise being statistically unrelated. In 276 aneurysms (96.8%) with follow-up of > 6 months (mean 20.9 ± 13.1 months, range 6-54 months), recanalization was confirmed in 21 (minor, 15; major, 6). A narrow (≤ 4 mm) saccular neck (p < 0.01) and ACoA compromise (p = 0.04) were independently linked to prevention of recanalization.

CONCLUSIONS

During coil embolization of ACoA aneurysms, the ACoA may be compromised without serious complications if A1 flows are symmetric. This approach may also confer some long-term protection from recanalization, serving as a valid treatment option for such lesions.

Comparative analysis of coil embolization in posterior and anterior communicating artery aneurysms

Background

Recanalization rates after coil embolization are known to be higher in cerebral aneurysms of the posterior (vs anterior) circulation. Although often grouped with anterior lesions, aneurysms of the posterior communicating artery (PcoA) may nevertheless behave differently.

Objective

We performed a comparative analysis to explore differences in recanalization rates of PcoA and anterior communicating artery (AcoA) aneurysms, both integral to the circle of Willis.

Methods

Between October 2012 and July 2017, 699 AcoA (n=427) and PcoA (n=272) aneurysms were treated by endovascular coil embolization, monitoring 667 (95.4%) via radiologic imaging for ≥ 6 months. Cumulative recordings of medical and imaging data were retrospectively reviewed, conducting propensity score matching and binary logistic regression analysis.

Results

In the 667 aneurysms followed longer term, recanalization occurred in 111 (16.6%; minor 72; major 39) and was significantly more frequent in PcoA (25.5%) than in AcoA (11.0%; P<0.01) aneurysms during similar follow-up periods. After 1:1 propensity score matching, an even greater proclivity for recanalization was evident at PcoA sites (PcoA 23.0%; AcoA 12.2%; P<0.01). Although A1 segment dominance was linked to recanalization in AcoA aneurysms (18.2% vs 7.6%; P=0.01), the PcoA counterpart had no bearing on recanalization (27.7% vs 24.1%; P=0.51).

Conclusions

Despite a clear preponderance of AcoA aneurysms, recanalization of PcoA aneurysms proved significantly greater, attesting to posterior circulation behavior.

Selective compromise of hypoplastic posterior communicating artery variants with aneurysms treatable by coil embolization: clinical and radiologic outcomes

Background

Posterior communicating artery (PcoA) compromise may serve as adjunctive treatment in patients with hypoplastic variants of PcoA who undergo coil embolization of PcoA aneurysms. However, procedural safety and the propensity for later recanalization are still unclear.

Objective

To evaluate clinical and radiologic outcomes of coil embolization in this setting, focusing on compromise of PcoA.

Methods

As a retrospective review, we examined 250 patients harboring 291 aneurysms of hypoplastic PcoAs, all consecutively treated by coil embolization between January 2004 and June 2016. PcoA compromise was undertaken in conjunction with 81 of the treated aneurysms (27.8%; incomplete 53; complete 28). Medical records and radiologic data were assessed during extended monitoring.

Results

During the mean follow-up of 33.9±24.6 months (median 36 months), a total of 107 (36.8%) coiled aneurysms showed recanalization (minor 50; major 57). Recanalization rates were as follows: PcoA preservation 40.5% (85/210); incomplete PcoA occlusion 34.0% (18/53); complete PcoA occlusion 14.3% (4/28). Aneurysms >7 mm (HR 3.40; P<0.01), retreatment for recanalization (HR 3.23; P<0.01), and compromise of PcoA (P<0.01) emerged from multivariate analysis as significant risk factors for recanalization. Compared with PcoA preservation, complete PcoA compromise conferred more favorable outcomes (HR 0.160), whereas incomplete compromise of PcoA fell short of statistical significance. Thromboembolic infarction related to PcoA compromise did not occur in any patient.

Conclusion

PcoA compromise in conjunction with coil embolization of PcoA aneurysms appears safe in hypoplastic variants of PcoA, helping to prevent recanalization if complete occlusion is achieved.

Growth pattern change of a benign clear cell 'sugar' tumor of the lung: Serial imaging surveillance over seven years

Clear cell tumor of the lung is a rare benign mesenchymal tumor and only sporadic cases have been previously reported. The present study reports the case of a 58-year-old man who presented with an incidentally detected solitary pulmonary nodule. Based on comparisons with serial previous chest and spine radiographs, a growth pattern change in the nodule (initial gradual growth over 4.5 years, then recent no growth over 2.5 years) was identified. The nodule was diagnosed as a benign clear cell tumor of the lung (CCTL) following surgical resection. Few studies have previously reported interval growth of CCTLs and the growth pattern of CCTL is not yet well known. To the best of our knowledge, this is the first reported case in which the growth pattern change of CCTL was identified via serial imaging over 7 years of follow-up.