Carotid artery stenting and follow-up: Value of 64-MSCT angiography as complementary imaging method to color-coded duplex sonography

[Evaluation of Noise Properties at Nonuniformity Area and Resolution Properties of CT Image Using Iterative Reconstruction Method]

PURPOSE

The purpose of this study was to investigate the resolution property and the noise properties at the nonuniformity area in the slice plane of iterative reconstruction (IR)-CT image.

METHODS

CT images of a phantom with nonuniformity areas including multiple contrast (medium, high, and ultra-high contrast) signals were acquired at various scan dose conditions and reconstructed with different iterative intensity levels. The noise properties at the nonuniformity and the uniformity areas were evaluated by measuring normalized noise power spectra (nNPSs) using subtracted images from sequential scanning data under the same scan conditions. We investigated the relationship between the noise properties and the resolution properties evaluated by measuring task transfer function (TTF) using multiple contrast signals before the subtraction.

RESULTS

There was a correlation between the nNPS at the nonuniformity area and the TTF because the nNPS values at high spatial frequency were increased with superior TTF (higher dose, mild iterative intensity, and higher contrast level). The differences in the high spatial frequency component of the nNPSs among each task were decreased with the inferior TTF tasks.

CONCLUSION

We conclude that the noise properties in the slice plane at the nonuniformity area and resolution properties of the IR-CT image were correlated similar to image quality properties of the linear imaging system due to the dependence of the nNPSs curve on the TTF value under each task.

Carotid computed tomography angiography after cobalt-based alloy carotid artery stenting using ultra-high-resolution computed tomography with model-based iterative reconstruction

In conventional carotid computed tomographic angiography, the artifacts of the stent vary depending on the structure and characteristics of the alloy type. Cobalt-based alloy stents have been reported to exhibit high artifacts, and accurate evaluation of the internal lumen can be difficult. Recently, ultra-high-resolution computed tomography scanner systems have become available for clinical practice. The primary features of this computed tomography scanner are a 0.25-mm detector row width and a 1024 × 1024 matrix. We report a case-series of carotid artery stenting using a cobalt-based alloy stent scanned by an ultra-high-resolution computed tomography scanner system and model-based iterative reconstruction. We also report that the combination of the ultra-high-resolution computed tomography scanner system with model-based iterative reconstruction would be useful to evaluate vessel patency after placement of a cobalt-based alloy stent.

A meta-analysis of the effect of stent design on clinical and radiologic outcomes of carotid artery stenting

OBJECTIVE

Procedural characteristics, including stent design, may influence the outcome of carotid artery stenting (CAS). A thorough comparison of the effect of stent design on outcome of CAS is thus warranted to allow for optimal evidence-based clinical decision making. This study sought to evaluate the effect of stent design on clinical and radiologic outcomes of CAS.

METHODS

A systematic search was conducted in MEDLINE, Embase, and Cochrane databases in May 2018. Included were articles reporting on the occurrence of clinical short- and intermediate-term major adverse events (MAEs; any stroke or death) or radiologic adverse events (new ischemic lesions on postprocedural magnetic resonance diffusion-weighted imaging [MR-DWI], restenosis, or stent fracture) in different stent designs used to treat carotid artery stenosis. Random effects models were used to calculate combined overall effect sizes. Metaregression was performed to identify the effect of specific stents on MAE rates.

RESULTS

From 2654 unique identified articles, two randomized, controlled trials and 66 cohort studies were eligible for analysis (including 46,728 procedures). Short-term clinical MAE rates were similar for patients treated with open cell vs closed cell or hybrid stents. Use of an Acculink stent was associated with a higher risk of short-term MAE compared with a Wallstent (risk ratio [RR], 1.51; P = .03), as was true for use of Precise stent vs Xact stent (RR, 1.55; P < .001). Intermediate-term clinical MAE rates were similar for open vs closed cell stents. Use of open cell stents predisposed to a 25% higher chance (RR, 1.25; P = .03) of developing postprocedural new ischemic lesions on MR-DWI. No differences were observed in the incidence of restenosis, stent fracture, or intraprocedural hemodynamic depression with respect to different stent design.

CONCLUSIONS

Stent design is not associated with short- or intermediate-term clinical MAE rates in patients undergoing CAS. Furthermore, the division in open and closed cell stent design might conceal true differences in single stent efficacy. Nevertheless, open cell stenting resulted in a significantly higher number of subclinical postprocedural new ischemic lesions detected on MR-DWI compared with closed cell stenting. An individualized patient data meta-analysis, including future studies with prospective homogenous study design, is required to adequately correct for known risk factors and to provide definite conclusions with respect to carotid stent design for specific subgroups.

Diagnostic value of ultrasound score, color Doppler ultrasound RI and spiral CT for ovarian tumors

Diagnostic value of ultrasound score, color Doppler ultrasound resistance index (RI) and spiral computed tomography (CT) for ovarian tumors was investigated. In total 224 patients pathologically diagnosed with ovarian tumor after operation in Cangzhou Central Hospital were selected, including 120 patients with benign ovarian tumor and 104 patients with malignant ovarian tumor. Patients with benign and malignant tumors were scored according to the ultrasound scoring criteria. The color Doppler ultrasound examination was performed and the corresponding RI was recorded. At the same time, 64-slice spiral CT was performed, and results were compared with the postoperative pathological diagnosis. Also, the sensitivity, specificity and accuracy of the combined application of the three methods were detected. The RI value of benign ovarian tumor was higher than that of malignant ovarian tumor, displaying statistically significant difference (P<0.05). The sensitivity, specificity and accuracy of the combined application of the three methods were 96.49, 90.91 and 93.75%, respectively. Ultrasound scoring, color Doppler ultrasound RI and 64-slice spiral CT have good diagnostic value for ovarian tumor, and the diagnostic accuracy rate of the combined application is higher. Therefore, different examination methods can be selected in clinic according to the different situations.

The Effect of Stent Cell Geometry on Carotid Stenting Outcomes

PURPOSE

The aim of this study was to investigate the effect of stent cell geometry on midterm results of carotid artery stenting (CAS).

MATERIALS AND METHOD

One hundred fifty-five patients underwent CAS between February 2010 and December 2012. Ninety-one open- and 84 closed-cell stents were used in this non-randomized, retrospective study. Periprocedural complications were defined as the ones happened during the procedure or within 30 days afterwards. Starting from the 6th month after the procedure, in-stent restenosis was detected with multidetector computed tomography angiography and classified into four groups from focal restenosis to occlusion.

RESULTS

Eleven complications were encountered in the periprocedural period (four on the open- and seven on the closed-cell group). Total complication rate was 6.3% (11/175). No significant difference was detected in terms of periprocedural complications between two groups (p = 0.643). There was statistically significant difference between stent design groups in regard to radiological findings (p = 0.002). Sixteen of open-cell stents and three of closed-cell stents had focal restenosis. One closed-cell stent had diffuse proliferative restenosis and one open-cell stent had total occlusion.

CONCLUSION

In-stent restenosis was more common in open-cell stent group, which have larger free cell area than closed-cell stents. Although our radiologic findings promote us to use closed-cell design if 'possible', no difference was detected in terms of clinical outcomes.