Three-dimensional rotational angiography for craniotomy planning and postintervention evaluation of intracranial aneurysms

Risk of intracranial aneurysm recurrence after microsurgical clipping based on 3D digital subtraction angiography

OBJECTIVE

Current knowledge of recurrence rates after intracranial aneurysm (IA) surgery relies on 2D digital subtraction angiography (DSA), which fails to detect more than 75% of small aneurysm remnants. Accordingly, the discrimination between recurrence and growth of a remnant remains challenging, and actual assessment of recurrence risk of clipped IAs could be inaccurate. The authors report, for the first time, 3D-DSA-based long-term durability and risk factor data of IA recurrence and remnant growth after microsurgical clipping.

METHODS

Prospectively collected data for 305 patients, with a total of 329 clipped IAs that underwent baseline 3D-DSA, were evaluated. The incidence of recurrent IA was described by Kaplan-Meier curves. Risk factors for IA recurrence were analyzed by multivariable Cox proportional hazards and logistic regression models.

RESULTS

The overall observed proportion of IA recurrence after clipping was 2.7% (9 of 329 IAs) at a mean follow-up of 46 months (0.7% per year). While completely obliterated IAs did not recur during follow-up, incompletely clipped aneurysms (76 of 329) demonstrated remnant growth in 11.8% (3.4% per year). Young age and large initial IA size significantly increased the risk of IA recurrence.

CONCLUSIONS

The findings support those in previous studies that hypothesized that completely clipped IAs have an extremely low risk of recurrence. Conversely, the results highlight the significant risk posed by incompletely clipped IAs. Young patients with initial large IAs and incomplete obliteration have an especially high risk for IA recurrence and therefore should be monitored more closely.

Interrater and intrarater agreement superior for three-dimensional digital subtraction angiography (3D-DSA) over 2D-DSA classification for detecting remnants after intracranial aneurysm clipping, a GRRAS Reliability and Agreement Study

BACKGROUND

Growing evidence suggests that three-dimensional digital subtraction angiography (3D-DSA) is superior to 2D-DSA in detection of intracranial aneurysm (IA) remnants after clipping. With a simple, practical quantitative scale proposed to measure maximal remnant dimension on 3D-DSA, this study provides a rigorous interrater and intrarater reliability and agreement study comparing this newly established scale with a commonly used (Sindou) 2D-DSA scale.

METHOD

Records of 43 patients with clipped IAs harboring various sized remnants who underwent 2D- and 3D-DSA between 2012 and 2018 were evaluated. Using the 2D and 3D scales, six raters scored these remnants and repeated the scoring task 8 weeks later. Interrater and intrarater agreement for both grading schemes were calculated using kappa (κ) statistics.

RESULTS

Interrater agreement was highly significant, yielding κ-values at 95% CI (p = 0.000) of 0.225 for the first [0.185; 0.265] and 0.368 s [0.328; 0.408] time points for 2D-DSA and values of 0.700 for the first [0.654; 0.745] and 0.776 s [0.729; 0.822] time points for 3D-DSA. Intrarater agreement demonstrated κ-values between 0.139 and 0.512 for 2D-DSA and between 0.487 and 0.813 for 3D-DSA scores.

CONCLUSION

Interrater and intrarater agreement was minimal or weak for 2D-DSA scores, but strong for 3D-DSA scores. We propose that baseline 3D-DSA characterization may prove more reliable when categorizing clipped IA remnants for purposes of risk stratification and lifelong follow-up.

Value of 3-Dimensional Digital Subtraction Angiography for Detection and Classification of Intracranial Aneurysm Remnants After Clipping

BACKGROUND

The current gold standard for evaluation of the surgical result after intracranial aneurysm (IA) clipping is two-dimensional (2D) digital subtraction angiography (DSA). While there is growing evidence that postoperative 3D-DSA is superior to 2D-DSA, there is a lack of data on intraoperative comparison.

OBJECTIVE

To compare the diagnostic yield of detection of IA remnants in intra- and postoperative 3D-DSA, categorize the remnants based on 3D-DSA findings, and examine associations between missed 2D-DSA remnants and IA characteristics.

METHODS

We evaluated 232 clipped IAs that were examined with intraoperative or postoperative 3D-DSA. Variables analyzed included patient demographics, IA and remnant distinguishing characteristics, and 2D- and 3D-DSA findings. Maximal IA remnant size detected by 3D-DSA was measured using a 3-point scale of 2-mm increments.

RESULTS

Although 3D-DSA detected all clipped IA remnants, 2D-DSA missed 30.4% (7 of 23) and 38.9% (14 of 36) clipped IA remnants in intraoperative and postoperative imaging, respectively (95% CI: 30 [ 12, 49] %; P-value .023 and 39 [23, 55] %; P-value = <.001), and more often missed grade 1 (< 2 mm) clipped remnants (odds ratio [95% CI]: 4.3 [1.6, 12.7], P-value .005).

CONCLUSION

Compared with 2D-DSA, 3D-DSA achieves a better diagnostic yield in the evaluation of clipped IA. Our proposed method to grade 3D-DSA remnants proved to be simple and practical. Especially small IA remnants have a high risk to be missed in 2D-DSA. We advocate routine use of either intraoperative or postoperative 3D-DSA as a baseline for lifelong follow-up of clipped IA.

Intra- and inter-observer variability in intracranial aneurysm segmentation: comparison between CT angiography (semi-automated segmentation software stroke VCAR) and digital subtraction angiography (3D rotational angiography)

PURPOSE

To compare size and morphologic features of three-dimensional aneurysm models, obtained with a semi-automated segmentation software (Stroke VCAR, GE, USA) from cerebral CT angiography (CTA) data, to three-dimensional aneurysm models obtained with digital subtraction angiography (DSA, with 3D rotational angiography acquisition-3DRA), considered as the reference standard.

METHODS

In this retrospective study, we reviewed 132 patients, with a total number of 137 intracranial aneurysm, who underwent CTA and subsequent DSA examination, supplemented with 3DRA. We compared neck length, short axis and long axis measured on 3DRA model to the same variables measured on 3D-CTA model by two blinded readers and to the automatic software dimensions. Therefore, statistics analysis assessed intra-observer and inter-observer variability and differences between patients with or without subarachnoid hemorrhage (SAH).

RESULTS

There were no significant differences in short-axis and long-axis measurements between 3D angiographic and 3D-CTA models, while comparison of neck lengths revealed a statistically significant difference, which tended to be greater for smaller neck lengths (partial volume effect and "kissing vessels" artifact). There were significant differences between manual and automatic data measured for the same three variables, and the presence of SAH did not affect aneurysm 3D reconstruction. Inter-observer agreement resulted moderate for neck length and substantial for short axis and long axis.

CONCLUSION

The examined 3D-CTA segmentation system is a reproducible procedure for aneurysm morphologic characterization and, in particular, for assessment of aneurysm sac dimensions, but considerable carefulness is required in neck length interpretation.

Interrater Agreement in the Radiologic Characterization of Ruptured Intracranial Aneurysms Based on Computed Tomography Angiography

OBJECTIVE

To determine interrater agreement in the initial radiologic characterization of ruptured intracranial aneurysms based on computed tomography angiography (CTA) with special emphasis on the rater's level of experience.

METHODS

One junior and one senior rater of 5 high-volume neurovascular tertiary centers evaluated anonymized CTA images of 30 consecutive patients with aneurysmal subarachnoid hemorrhage. Each rater described location, side, size, and morphology in a standardized manner. Interrater variability was analyzed using intraclass correlation and Fleiss' kappa analysis.

RESULTS

There was a high level of agreement for location (κ = 0.76, 95% confidence interval [CI] 0.74-0.79), side (κ = 0.95, CI 0.91-0.99), maximum diameter (intraclass correlation coefficient [ICC] 0.81, CI 0.70-0.90), and dome (ICC 0.78, CI 0.66-0.88) of intracranial aneurysms. In contrast, a lower level of agreement was observed for aneurysms' neck diameter (ICC 0.39, CI 0.28-0.58), the presence of multiple aneurysms (κ = 0.35, CI 0.30-0.40), and aneurysm morphology (blister κ = 0.11, CI -0.05 to 0.07; fusiform κ = 0.54, CI 0.48-0.60; multilobular, κ = 0.39 CI 0.33-0.45). The interrater agreement in the senior rater group was greater than in the junior rater group.

CONCLUSIONS

Interrater agreement confirms the benefit of CTA as initial diagnostic imaging in ruptured intracranial aneurysms but not for aneurysm morphology and presence of multiple aneurysms. A trend towards greater interrater agreement between more experienced raters was noticed.

Reliability of dual- vs single-volume reconstruction of three-dimensional digital subtraction angiography for follow-up evaluation of endovascularly treated intracranial aneurysms

INTRODUCTION

Single-volume reconstruction of three-dimensional (3D) digital subtraction angiography (DSA) can be effectively used for aneurysm assessment and planning of endovascular embolization. Unfortunately, post-embolization follow-up angiographic images can be obscured by artifact. The dual-volume reconstruction technique was developed in order to reduce artifact and enhance the visualization of the aneurysm, the parent vessel and side branches, and endovascular devices. The purpose of this study was to compare the reliability of dual- vs single-volume reconstruction of 3D DSA in evaluation of follow-up images after endovascular embolization of intracranial aneurysms.

METHOD

Four cerebrovascular neurosurgeons independently and blindly reviewed 20 randomly selected dual-and single-volume reconstructions of 3D DSAs demonstrating cerebral aneurysms treated with primary coil embolization, stent-assisted coil embolization, or Pipeline embolization. Five images were repeated for each modality (single and dual volume) in order to assess intra-rater reliability. The intraclass correlation coefficient was calculated as a measure of the overall inter-rater agreement. Cohen's kappa value was used to assess repeat measurement consistency for each rater.

RESULTS

Overall inter-rater agreement using dual- and single-volume reconstruction was 0.81 and 0.75, respectively. Dual-volume reconstruction resulted in superior agreement in assessing location, occlusion status, position of aneurysm recanalization or residual, status of nearby branches, presence of coil migration and presence of intravascular devices (stent or Pipeline).

CONCLUSION

Three-dimensional reconstruction is an important complementary imaging technique in evaluating the angioarchitecture of aneurysms and recanalization after endovascular embolization. Dual-volume reconstruction imaging was associated with superior inter- and intra-rater reliability.

3D-holoscopic imaging: a new dimension to enhance imaging in minimally invasive therapy in urologic oncology

BACKGROUND AND PURPOSE

Existing imaging modalities of urologic pathology are limited by three-dimensional (3D) representation on a two-dimensional screen. We present 3D-holoscopic imaging as a novel method of representing Digital Imaging and Communications in Medicine data images taken from CT and MRI to produce 3D-holographic representations of anatomy without special eyewear in natural light. 3D-holoscopic technology produces images that are true optical models. This technology is based on physical principles with duplication of light fields. The 3D content is captured in real time with the content viewed by multiple viewers independently of their position, without 3D eyewear.

METHODS

We display 3D-holoscopic anatomy relevant to minimally invasive urologic surgery without the need for 3D eyewear.

RESULTS

The results have demonstrated that medical 3D-holoscopic content can be displayed on commercially available multiview auto-stereoscopic display.

CONCLUSION

The next step is validation studies comparing 3D-Holoscopic imaging with conventional imaging.