Moloney Fiachra, James Karl, Twomey Maria, Ryan David, Grey Tyler M, Downes Amber, Kavanagh Richard G, Moore Niamh, Murphy Mary Jane, Bye Jackie, Carey Brian W, McSweeney Sean E, Deasy Conor, Andrews Emmett, Shanahan Fergus, Maher Michael M, O'Connor Owen J
Department of Radiology, Cork University Hospital, University College Cork, Cork, Ireland.
School of Medicine, University College Cork, Cork, Ireland.
Emerg Radiol. 2019 Apr;26(2):169-177. doi: 10.1007/s10140-018-1658-z. Epub 2018 Nov 17.
Performance of a modified abdominopelvic CT protocol reconstructed using full iterative reconstruction (IR) was assessed for imaging patients presenting with acute abdominal symptoms.
Fifty-seven patients (17 male, 40 female; mean age of 56.5 ± 8 years) were prospectively studied. Low-dose (LD) and conventional-dose (CD) CTs were contemporaneously acquired between November 2015 and March 2016. The LD and CD protocols imparted radiation exposures approximating 10-20% and 80-90% those of routine abdominopelvic CT, respectively. The LD images were reconstructed with model-based iterative reconstruction (MBIR), and CD images with hybrid IR (40% adaptive statistical iterative reconstruction (ASIR)). Image quality was assessed quantitatively and qualitatively. Independent clinical interpretations were performed with a 6-week delay between reviews.
A 74.7% mean radiation dose reduction was achieved: LD effective dose (ED) 2.38 ± 1.78 mSv (size-specific dose estimate (SSDE) 3.77 ± 1.97 mGy); CD ED 7.04 ± 4.89 mSv (SSDE 10.74 ± 5.5 mGy). LD-MBIR images had significantly lower objective and subjective image noise compared with CD-ASIR (p < 0.0001). Noise reduction for LD-MBIR studies was greater for patients with BMI < 25 kg/m than those with BMI ≥ 25 kg/m (5.36 ± 3.2 Hounsfield units (HU) vs. 4.05 ± 3.1 HU, p < 0.0001). CD-ASIR studies had significantly better contrast resolution, and diagnostic acceptability (p < 0.0001 for all). LD-MBIR studies had significantly lower streak artifact (p < 0.0001). There was no difference in sensitivity for primary findings between the low-dose and conventional protocols with the exception of one case of enteritis.
Low-dose abdominopelvic CT performed with MBIR is a feasible radiation dose reduction strategy for imaging patients presenting with acute abdominal pain.
评估采用全迭代重建（IR）重建的改良腹部盆腔CT方案对出现急性腹部症状患者的成像效果。
前瞻性研究了57例患者（17例男性，40例女性；平均年龄56.5±8岁）。在2015年11月至2016年3月期间同时采集低剂量（LD）和常规剂量（CD）CT图像。LD和CD方案的辐射剂量分别约为常规腹部盆腔CT的10 - 20%和80 - 90%。LD图像采用基于模型的迭代重建（MBIR）进行重建，CD图像采用混合IR（40%自适应统计迭代重建（ASIR））进行重建。对图像质量进行了定量和定性评估。独立的临床解读在两次评估之间延迟6周进行。
平均辐射剂量降低了74.7%：LD有效剂量（ED）2.38±1.78 mSv（尺寸特异性剂量估计（SSDE）3.77±1.97 mGy）；CD ED 7.04±4.89 mSv（SSDE 10.74±5.5 mGy）。与CD - ASIR相比，LD - MBIR图像的客观和主观图像噪声显著更低（p < 0.0001）。BMI < 25 kg/m²的患者LD - MBIR研究的降噪效果比BMI≥25 kg/m²的患者更好（5.36±3.2亨氏单位（HU）对4.05±3.1 HU，p < 0.0001）。CD - ASIR研究的对比分辨率和诊断可接受性显著更好（所有p < 0.0001）。LD - MBIR研究的条纹伪影显著更低（p < 0.0001）。除1例肠炎外，低剂量和常规方案对主要发现的敏感性无差异。
采用MBIR的低剂量腹部盆腔CT是对出现急性腹痛患者进行成像的一种可行的辐射剂量降低策略。
