A Volumetric Metric for Monitoring Intracranial Aneurysms: Repeatability and Growth Criteria in a Longitudinal MR Imaging Study

Abstract

BACKGROUND AND PURPOSE:The reliability of contrast-enhanced MRA in monitoring serial volumetric changes of unruptured intracranial aneurysms has not been established. We aimed to determine the coefficient of variance of contrast-enhanced MRA in measuring aneurysm volumes, thus establishing criteria for aneurysm growth and permitting identification of variables predictive of growth.MATERIALS AND METHODS: Aneurysm volumes were measured from serial contrast-enhanced MRA studies of patients with untreated intracranial aneurysms who underwent .2 sequential MR imaging evaluations. After coregistering all sequential studies in 3D space for each aneurysm and signal intensity normalization, aneurysm volume was determined across all time points. A linear mixed effects model was built to estimate the coefficient of variance of the measurement as well as to determine predictive variables. Growth was defined as relative growth exceeding 2 times the measurement coefficient of variance (sudden growth, as 4 times the coefficient of variance).RESULTS: A total of 95 patients with 112 aneurysms were included (5.9 scans during 4.0 years on average, 616 scan measurements in total). The coefficient of variance was 5.5% of the aneurysm volume, and the relative growth rate was dependent on the location: anterior cerebral artery, 4.52% per year; vertebral artery, 2.46% per year; middle cerebral artery, 2.74% per year; basilar artery, 2.36% per year; internal carotid artery, 1.14% per year. Thirty-six of 112 (32%) aneurysms were characterized as growing, and 11/36 of them had an episode of sudden growth. CONCLUSIONS:Volume measurement of unruptured intracranial aneurysms by contrast-enhanced MRA seems a reliable metric for tracking the growth trajectory of aneurysms. Furthermore, the aneurysm growth rate differs among different locations.

Risk Factors for Pericallosal Artery Aneurysm Rupture Based on Morphological Computer-Assisted Semiautomated Measurement and Hemodynamic Analysis

“…The methods for image reconstruction and computational fluid dynamics simulation (CFD) simulation of hemodynamic studies were detailed in our previous publications ( Hu et al, 2015a , b ; Qin et al, 2017 ). Firstly, 3D models were generated with Raw DICOM format images and processed using Mimics medical software (Version 19.0, Materialise, Leuven, Belgium) and Geomagic Studio version 12.0 (Geomagic Inc., Cary, NC, United States), saved as standard tessellation language format as the input for the next step ( Qin et al, 2017 ; Liu et al, 2021 ).…”

Incidental intracranial saccular aneurysm in a patient with post-Covid-19 headache: What to do with the incidentaloma?

“…15 In Table 1 are listed meta-analysis studies that evaluated different conditions that may modify the risk of rupture of a still unruptured intracranial aneurysm. Age >70-years-old Brinjikji et al 28 Arterial hypertension Backes et al 26 ; Wermer et al 27 Woman Jin et al 25 ; Backes et al 24 ; Brinjikji et al 28 ; Wermer et al 27 Aneurysm size >7 mm Brinjikji et al 28 ; Wermer et al 27 Middle cerebral artery aneurysm Brinjikji et al 28 ; Wermer et al 27 Using longitudinal analysis of the aneurysm volume, Liu and coworkers 29 demonstrated in a series of 112 aneurysms in 95 patients (the mean follow-up time was 4.0 years.) with UIA that there was evident growth at one year of follow-up in 8% of cases.…”

“…36/112 (32%) of the aneurysms exhibited noticeable growth during the study, and 11/36 (31%) aneurysms with noticeable change had an episode of abrupt growth (only 11 of the 112 aneurysms (9.8%) presented an episode of sudden growth). 29 The relative growth rate was dependent on age and the location of the aneurysm, with aneurysms of the anterior cerebral artery showing the fastest growth rate of 4.07% per year. In this study, aneurysms of the middle cerebral artery presented an annual growth rate of 1.41%.…”

“…In this study, aneurysms of the middle cerebral artery presented an annual growth rate of 1.41%. 29 A recent study 11 evaluated the role of statins in unruptured intracranial aneurysm growth and rupture, observing whether atorvastatin (20 mg daily) was associated with aneurysm growth or rupture in patients with less than 7 mm aneurysms. Among the 1.087 enrolled patients, 489 (45%) took atorvastatin (mean follow-up duration of 33.0 ± 12.5 months).…”

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“…The methods for image reconstruction and computational fluid dynamics simulation (CFD) simulation of hemodynamic studies were detailed in our previous publications (Hu et al, 2015a,b;Qin et al, 2017). Firstly, 3D models were generated with Raw DICOM format images and processed using Mimics medical software (Version 19.0, Materialise, Leuven, Belgium) and Geomagic Studio version 12.0 (Geomagic Inc., Cary, NC, United States), saved as standard tessellation language format as the input for the next step (Qin et al, 2017;Liu et al, 2021).…”