Volume Determination of Intracranial Aneurysms Using 16-Row Multislice Computed Tomography Angiography

Can early computed tomography angiography after endovascular aortic aneurysm repair predict the need for reintervention in patients with type II endoleak?

PURPOSE

This study was designed to identify parameters on CT angiography (CTA) of type II endoleaks following endovascular aortic aneurysm repair (EVAR) for abdominal aortic aneurysm (AAA), which can be used to predict the subsequent need for reinterventions.

METHODS

We retrospectively identified 62 patients with type II endoleak who underwent early CTA in mean 3.7 ± 1.9 days after EVAR. On the basis of follow-up examinations (mean follow-up period 911 days; range, 373-1,987 days), patients were stratified into two groups: those who did (n = 18) and those who did not (n = 44) require reintervention. CTA characteristics, such as AAA, endoleak, as well as nidus dimensions, patency of the inferior mesenteric artery, number of aortic branch vessels, and the pattern of endoleak appearance, were recorded and correlated with the clinical outcome.

RESULTS

Univariate and receiver operating characteristic curve regression analyses revealed significant differences between the two groups for the endoleak volume (surveillance group: 1391.6 ± 1427.9 mm(3); reintervention group: 3227.7 ± 2693.8 mm(3); cutoff value of 2,386 mm(3); p = 0.002), the endoleak diameter (13.6 ± 4.3 mm compared with 25.9 ± 9.6 mm; cutoff value of 19 mm; p < 0.0001), the number of aortic branch vessels (2.9 ± 1.2 compared with 4.2 ± 1.4 vessels; p = 0.001), as well as a "complex type" endoleak pattern (13.6 %, n = 6 compared with 44.4 %, n = 8; p = 0.02).

CONCLUSIONS

Early CTA can predict the future need for reintervention in patients with type II endoleak. Therefore, treatment decision should be based not only on aneurysm enlargement alone but also on other imaging characteristics.

Typical coronary appearance of dilated cardiomyopathy versus left ventricular concentric hypertrophy: coronary volumes measured by multislice computed tomography

Several coronary angiographic studies have reported that enlarged and tortuous epicardial coronary arteries are characteristic of patients with left ventricular concentric hypertrophy (LVCH). Recently, we showed that small volumes opacified by contrast medium can be accurately measured by 64-multislice computed tomography (MSCT) and that there is a direct relationship between the coronary artery volume and left ventricular (LV) mass. However, the relationship of coronary artery volume with LV mass in patients with dilated cardiomyopathy (DCM) is unknown. The present study was designed to investigate this issue. Thirteen patients with DCM and 18 patients with LVCH who underwent MSCT angiography were included in this analysis. The coronary arteries were segmented on a workstation, and the appropriate window settings obtained from the results of the phantom experiments were applied to the volume-rendered images to calculate the total coronary artery volume (right and left coronary arteries). The absolute coronary lengths and volumes in patients with LVCH and DCM were greater than those in controls. The coronary artery volumes adjusted for LV mass in patients with DCM were found to be smaller than those in patients with LVCH or in controls, and these values did not differ between patients with LVCH and controls (DCM 4.1 ± 0.9, LVCH 5.4 ± 1.4, controls 5.5 ± 2.3 ml/100 g of LV mass, P < 0.005; DCM vs LVCH, P < 0.01; and DCM vs control, P < 0.0005). This study showed that the increase in the coronary artery volume in patients with LVCH matched the increase in LV mass, but a decreased coronary volume with regard to LV mass was characteristic of patients with DCM.

Application of multislice computed tomographic angiography in diagnosis and treatment of intracranial aneurysms

OBJECTIVES

The aim of the study is to assess the clinical value of 16-row multislice computed tomographic angiography (CTA) for detection and treatment of intracranial aneurysms.

PATIENTS AND METHODS

Between January 2005 and October 2008, 388 patients were included and successively underwent 16-slice CTA for suspected intracranial aneurysms. Three neuroradiologists independently reviewed CTA and DSA images. The combined interpretations of digital subtraction angiography (DSA) and surgical findings were considered as the ultimate reference standard against which the diagnostic accuracy of CTA and DSA were compared.

RESULTS

The reference standard revealed 287 aneurysms in 256 patients. There was no statistically significant difference in accuracy between 16-slice CTA and conventional DSA. The sensitivity, specificity, and accuracy of 16-slice CTA in detecting all aneurysms were 98.3, 97.0, and 97.9%, respectively, on a per-aneurysm basis. The sensitivity of 16-slice CTA was 90.0% for reader 1 and 93.3% for reader 2 for less than 3mm aneurysms. One hundred eighty-nine aneurysms were deemed amenable to endovascular therapy on the basis of CTA images, 98% of whom (185) were successfully treated with this method. Forty-eight aneurysms were considered candidates for surgical treatment, and all aneurysms were deemed completely occluded during surgical clipping. Sixteen-slice CTA images provided important preoperative information, which could assist the endovascular and surgical therapy of aneurysms.

CONCLUSIONS

Sixteen-slice CTA is a highly accurate imaging examination of the first line imaging technique for the detection of intracranial aneurysms, and it can provide sufficient diagnostic information in guiding the surgical and endovascular therapy of aneurysms.

Sixteen-row multislice computed tomography angiography in the diagnosis and characterization of intracranial aneurysms: comparison with conventional angiography and intraoperative findings

Object

The goal of this study was to prospectively compare the effectiveness of 16-slice computed tomography (CT) angiography with that of conventional digital subtraction (DS) angiography and the surgical findings used to detect and characterize intracranial aneurysms.

Methods

Two hundred forty-four consecutive patients underwent both CT angiography and DS angiography no more than 3 days apart. Computed tomography angiography was performed with a 16-row multislice CT scanner in which a collimation of 0.75 mm was used. Two observers independently reviewed the CT images, and 1 of the 3 attending neuroradiologists reviewed the DS angiograms. They determined the presence, location, quantitation, and characterization of the intracranial aneurysms. Statistical results were calculated independently for the image interpretation performed by the 2 CT scan readers and the DS angiogram reader by using the combination of DS angiography or intraoperative findings or both as a reference standard.

Results

One hundred thirty-six patients harboring 153 intracranial aneurysms were included in this series. There was no statistically significant difference in sensitivity between 16-slice CT angiography and conventional DS angiography (p > 0.05). The sensitivities of 16-slice CT angiography for aneurysms < 5 mm, 5–10 mm, and > 10 mm were 94.8, 100, and 100%, respectively, on a per-aneurysm basis. The overall sensitivity and specificity of CT angiography for aneurysms were 98.0 and 99.1%, respectively. Sixteen-slice CT angiograms were clearer and more accurate in depicting the relationship of aneurysms to bone structures and adjacent branch vessels.

Conclusions

Computed tomography angiography using a 16-slice scanner is an accurate tool for detecting and characterizing intracranial aneurysms, including small aneurysms. Noninvasive 16-slice CT angiography will become a viable replacement for conventional DS angiography in the diagnosis and characterization of aneurysms.

Accuracy of 16-row multislice computed tomographic angiography for assessment of small cerebral aneurysms

OBJECTIVE

Many cases of subarachnoid hemorrhage are the result of rupture of small cerebral aneurysms. The aim of the study was to assess the diagnostic accuracy of 16-row multislice computed tomographic angiography (CTA) in detecting small cerebral aneurysms (<or=5 mm) compared with digital subtraction angiography (DSA), surgical findings, or both.

METHODS

One hundred ninety-two consecutive patients underwent CTA for suspected cerebral aneurysms. All aneurysms prospectively detected by CTA were confirmed by DSA or surgery. This was performed with a 16-detector row machine, with a detector slice of 0.75 mm, reconstruction interval of 0.40 mm, and timing determined by bolus trigger. CTA and DSA images were reviewed by two independent, blinded neuroradiologists who performed aneurysm detection, quantitation, and characterization using maximum-intensity projections, shaded-surface display, and volume-rendering techniques reconstructions.

RESULTS

Combining CTA, DSA, and intraoperative findings, 64 small cerebral aneurysms (<or=5 mm) were identified in 54 (28%) of the 192 patients. Three small cerebral aneurysms identified on CTA were not clearly depicted at DSA but were confirmed at surgery. The sensitivity, specificity, and accuracy of 16-slice CTA for small aneurysms were all 100% on a per aneurysm basis. The positive predictive value and negative predictive value of 16-slice CTA for small aneurysms were both 100%, respectively, on a per aneurysm basis. There was no statistically significant difference in sensitivity between 16-slice CTA and DSA (P > 0.05). Sixteen-slice CTA images show more clarity and accuracy in the relationship of aneurysms to bone structures and adjacent branch vessels.

CONCLUSION

Noninvasive 16-slice CTA is sensitive enough to replace conventional DSA in the triage, diagnosis, and treatment planning in patients with small cerebral aneurysms.

Volume changes of experimental carotid sidewall aneurysms due to embolization with liquid embolic agents: a multidetector CT angiography study

Iodine-containing polyvinyl alcohol polymer (I-PVAL) is a novel precipitating liquid embolic that allows for artifact-free evaluation of CT angiography (CTA). As accurate aneurysm volumetry can be performed with multidetector CTA, we determined volumes of experimental aneurysms before, immediately after, and 4 weeks after embolization of 14 porcine experimental carotid sidewall aneurysms with this liquid embolic. An automated three-dimensional software measurement tool was used for volumetric analysis of volume-rendering CTA data. Furthermore, intra-aneurysmal pressure changes during liquid embolization were measured in four silicone aneurysms and potential polymer volume changes within 4 weeks were assessed in vitro. Liquid embolic injection was performed during temporary balloon occlusion of the aneurysm neck, resulting in a mean occlusion rate of 98.3%. Aneurysms enlarged significantly during embolization by 61.1 +/- 28.9%, whereas a significant shrinkage of 5.6 +/- 2.7% was observed within the follow-up period. Histologic analysis revealed an inflammatory foreign body reaction with partial polymer degradation. In silicone aneurysm models, intra-aneurysmal pressure remained unchanged during liquid embolic injection, whereas balloon inflation resulted in a mean pressure increase of 31.2 +/- 0.7%. No polymer shrinkage was observed in vitro. The aneurysm enlargement noted was presumably due to pressure elevation after balloon inflation, which resulted in dilatation of the weak venous wall of the newly constructed aneurysm--another shortcoming of this experimental aneurysm model. The volume decrease after 4 weeks expressed partial polymer degradation.