标准剂量 CT 肠造影与 50%降低剂量 CT 肠造影前瞻性比较，评估克罗恩病时分别采用和不采用降噪技术。

A prospective comparison of standard-dose CT enterography and 50% reduced-dose CT enterography with and without noise reduction for evaluating Crohn disease.

机构信息

Department of Radiology and Research Institute of Radiology, University of Ulsan College of Medicine, Asan Medical Center, Songpa-gu, Seoul, Korea.

出版信息

AJR Am J Roentgenol. 2011 Jul;197(1):50-7. doi: 10.2214/AJR.11.6582.

DOI:10.2214/AJR.11.6582

PMID:21701010

Abstract

OBJECTIVE

The purpose of this study was to prospectively compare standard-dose CT enterography (CTE) and 50% reduced-dose CTE, obtained with and without an image noise reduction method, in the evaluation of Crohn disease.

SUBJECTS AND METHODS

Ninety-two patients (69 men and 23 women; mean age [± SD], 31.2 ± 9.5 years) with Crohn disease underwent CTE. Using a dual-source scanner equipped with a proprietary noise reduction method (iterative reconstruction in image space [IRIS]), three sets of CTE images were obtained: standard-dose filtered back projection (FBP) (i.e., weighted FBP), low-dose (i.e., 50% reduction) FBP, and low-dose IRIS CTE. Image noise was measured. Two independent radiologists evaluated subjective image quality (1 [worst] to 4 [best]) and findings of active Crohn disease in the terminal small-bowel segment, including mural hyperenhancement, thickening and stratification, comb sign, and increased perienteric fat attenuation (1 [definitely absent] to 5 [definitely present]).

RESULTS

The mean (± SD) volume CT dose index (CTDI(vol)) was 7.0 ± 0.9 mGy and 3.5 ± 0.5 mGy for standard-dose and low-dose CTE examinations, respectively. The mean (± SD) image noise for standard-dose FBP, low-dose FBP, and low-dose IRIS CTE was 10.6 ± 1.7 HU, 13.9 ± 2.1 HU, and 9.7 ± 1.7 HU, respectively (p < 0.001 for all comparisons). Both assessors found that image quality was poorer with low-dose (mean grade (± SD), 2.3 ± 0.4-2.7 ± 0.5) than in standard-dose (3 ± 0) CTE (p < 0.01), and one found that image quality was poorer with low-dose IRIS (2.3 ± 0.4) than with low-dose FBP (2.7 ± 0.5) CTE (p < 0.01). Low-dose (with or without IRIS) and standard-dose CTE showed ≥ 85% agreement (one-sided 95% CI ≥ 77%) in interpretation of bowel findings.

CONCLUSION

Low-dose CTE using 50% reduced-dose performed similarly to standard-dose CTE in identifying findings of enteric inflammation of Crohn disease. Although a noise reduction method markedly reduced image noise in half-dose examinations, its effect on image quality was not as great and was reader dependent.

摘要

目的

本研究旨在前瞻性比较标准剂量 CT 肠造影（CTE）和 50%降低剂量 CTE，包括和不包括图像降噪方法，用于评估克罗恩病。

对象和方法

92 例（69 名男性和 23 名女性；平均年龄[±标准差]，31.2±9.5 岁）克罗恩病患者行 CTE 检查。使用配备专有降噪方法（迭代重建图像空间[IRIS]）的双源扫描仪，获得三组 CTE 图像：标准剂量滤波反投影（FBP）（即加权 FBP）、低剂量（即 50%降低）FBP 和低剂量 IRIS CTE。测量图像噪声。两名独立的放射科医生评估主观图像质量（1[最差]至 4[最佳]）和终端小肠段活动性克罗恩病的发现，包括壁层强化、增厚和分层、梳状征和增加的肠周脂肪衰减（1[肯定不存在]至 5[肯定存在]）。

结果

标准剂量和低剂量 CTE 检查的平均（±标准差）容积 CT 剂量指数（CTDI(vol)）分别为 7.0±0.9 mGy 和 3.5±0.5 mGy。标准剂量 FBP、低剂量 FBP 和低剂量 IRIS CTE 的平均（±标准差）图像噪声分别为 10.6±1.7 HU、13.9±2.1 HU 和 9.7±1.7 HU（所有比较均 p<0.001）。两位评估者均发现低剂量（平均等级（±标准差），2.3±0.4-2.7±0.5）比标准剂量（3±0）CTE 的图像质量更差（p<0.01），一位评估者发现低剂量 IRIS（2.3±0.4）比低剂量 FBP（2.7±0.5）CTE 的图像质量更差（p<0.01）。低剂量（带或不带 IRIS）和标准剂量 CTE 在解释肠腔发现方面具有≥85%的一致性（单侧 95%CI≥77%）。