Accuracy of detecting enlargement of aneurysms using different MRI modalities and measurement protocols

Abstract

OBJECTIVE Aneurysm growth is considered predictive of future rupture of intracranial aneurysms. However, how accurately neuroradiologists can reliably detect incremental aneurysm growth using clinical MRI is still unknown. The purpose of this study was to assess the agreement rate of detecting aneurysm enlargement employing generally used MRI modalities. METHODS Three silicone flow phantom models, each with 8 aneurysms of various sizes at different sites, were used in this study. The aneurysm models were identical except for an incremental increase in the sizes of the 8 aneurysms, which ranged from 0.4 mm to 2 mm. The phantoms were imaged on 1.5-T and 3-T MRI units with both time-of-flight (TOF) and contrast-enhanced MR angiography. Three independent expert neuroradiologists measured the aneurysms in a blinded manner using different measurement approaches. The individual and agreement detection rates of aneurysm enlargement among the 3 experts were calculated. RESULTS The mean detection rate of any increase in any aneurysmal dimension was 95.7%. The detection rates of the 3 observers (observers A, B, and C) were 98.0%, 96.6%, and 92.7%, respectively (p = 0.22). The detection rates of each MRI modality were 91.3% using 1.5-T TOF, 97.2% using 1.5-T with Gd, 95.8% using 3.0-T TOF, and 97.2% using 3.0-T with Gd (p = 0.31). On the other hand, the mean detection rate for aneurysm enlargement was 54.8%. Specifically, the detection rates of observers A, B, and C were 49.0%, 46.1%, and 66.7%, respectively (p = 0.009). As the incremental enlargement value increased, the detection rate for aneurysm enlargement increased. The use of 1.5-T Gd improved the detection rate for small incremental enlargement (e.g., 0.4-1 mm) of the aneurysm (p = 0.04). The location of the aneurysm also affected the detection rate for aneurysm enlargement (p< 0.0001). CONCLUSIONS The detection rate and interobserver agreement were very high for aneurysm enlargement of 0.4-2 mm. The detection rate for at least 1 increase in any aneurysm dimension did not depend on the choice of MRI modality or measurement protocol. Use of Gd improved the accuracy of measurement. Aneurysm location may influence the accuracy of detecting enlargement.

Intracranial aneurysm growth: consistency of morphological changes

“…The resolution (both in plane and in the slice direction) was around 0.5 mm, which was our detection limit for aneurysm growth. Previous studies showed that the detection rate for aneurysm growth was high for growth > 0.4 mm, 26 but smaller enlargement might be missed. Nevertheless, these smaller enlargements are also difficult to detect on other modalities and might have limited clinical relevance.…”

Surveillance of Unruptured Intracranial Aneurysms

“…Although, according to a phantom study on silicone models, the mean detection rates of MRA for an increase in aneurysmal dimensions were 95.7%, the mean detection rate for aneurysmal growth was only 54.8%. 31 As this would increase the incidence of inefficient scanning, the cost-effectiveness of frequent follow-up would be even lower. In addition, false positives would cause unnecessary stress for patients and may unnecessarily expose patients to treatment complications.…”

A Transparent Vessel-on-a-Chip Device for Hemodynamic Analysis and Early Diagnosis of Intracranial Aneurysms by CFD and PC-MRI

“…In particular, the intracranial aneurysm (IA), also known as the brain aneurysm, is a high-lethality-rate disease and high in proportion in the population. The growth and rupture of IAs are the result of multiple factors, such as the external environment, smoking, and so on. , The presence of IAs can accelerate growth and rupture of other surrounding IAs . Normally, stroke and neurological disease caused by IAs can give rise to 50% of patients dying before treatment .…”

“…The growth and rupture of IAs are the result of multiple factors, such as the external environment, smoking, and so on. 1,2 The presence of IAs can accelerate growth and rupture of other surrounding IAs. 3 Normally, stroke and neurological disease caused by IAs can give rise to 50% of patients dying before treatment.…”