Deep Learning-Based Reconstruction Improves the Image Quality of Low-Dose CT Colonography.

RATIONALE AND OBJECTIVES: To evaluate the image quality of low-dose CT colonography (CTC) using deep learning-based reconstruction (DLR) compared to iterative reconstruction (IR). MATERIALS AND METHODS: Adults included in the study were divided into four groups according to body mass index (BMI). Routine-dose (RD: 120 kVp) CTC images were reconstructed with IR (RD-IR); low-dose (LD: 100kVp) images were reconstructed with IR (LD-IR) and DLR (LD-DLR). The subjective image quality was rated on a 5-point scale by two radiologists independently. The parameters for objective image quality included noise, signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR). The Friedman test was used to compare the image quality among RD-IR, LD-IR and LD-DLR. The KruskalWallis test was used to compare the results among different BMI groups. RESULTS: A total of 270 volunteers (mean age: 47.94 years ± 11.57; 115 men) were included. The effective dose of low-dose CTC was decreased by approximately 83.18% (5.18mSv ± 0.86 vs. 0.86mSv ± 0.05, P < 0.001). The subjective image quality score of LD-DLR was superior to that of LD-IR (3.61 ± 0.56 vs. 2.70 ± 0.51, P < 0.001) and on par with the RD- IR's (3.61 ± 0.56 vs. 3.74 ± 0.52, P = 0.486). LD-DLR exhibited the lowest noise, and the maximum SNR and CNR compared to RD-IR and LD-IR (all P < 0.001). No statistical difference was found in the noise of LD-DLR images between different BMI groups (all P > 0.05). CONCLUSION: Compared to IR, DLR provided low-dose CTC with superior image quality at an average radiation dose of 0.86mSv, which may be promising in future colorectal cancer screening.

Mesenteric creeping fat index defined by CT enterography is associated with early postoperative recurrence in patients with Crohn's disease.

OBJECTIVES: To investigate the value of mesenteric creeping fat index (MCFI) defined by computed-tomography enterography (CTE) in patients with Crohn's Disease (CD) for predicting early postoperative recurrence. METHODS: A total of 110 patients with CD who underwent CTE and I-stage intestinal resection surgery from December 2013 to December 2018 were enrolled. Two radiologists independently assessed CTE parameters, including MCFI, with scores ranging from 1 to 8; bowel-wall thickening, with a scale of 1 to 3; mural hyperenhancement, mural stratification, submucosal fat deposition, mesenteric fibrofatty proliferation, mesenteric hypervascularity, mesenteric fat stranding, with a scale of 0 to 2; abscess/fistula, enlarged mesenteric lymph node, abdominal and pelvic effusion, with a scale of 0 to 1. Imaging findings associated with early recurrence were assessed using logistic regression analysis. RESULTS: Within one year follow-up, early postoperative recurrence occurred in 56.4 % (62/110) patients with CD. In univariate analysis, MCFI, bowel-wall thickening, mesenteric hypervascularity, mesenteric fat stranding, abscess/fistula and mesenteric lymphadenopathy were associated with early postoperative recurrence. Among all variables, MCFI (score ≥ 4) contributes the optimal AUC (0.838 [0.758-0.919]), specificity (89.6 %), positive predictive value (90.7 %), accuracy (83.6 %), and risk ratio (OR = 32.42 [10.69-98.33], p < 0.001). In multivariate analysis, only MCFI was an independent predictor of early postoperative recurrence (OR = 25.71 [7.65-86.35], p < 0.001). CONCLUSION: CTE features are useful in predicting early postoperative recurrence in patients with CD, MCFI may be a valuable tool for clinical monitoring and follow-up.

Anatomical variations of the branches from left colic artery and middle colic artery at splenic flexure.

BACKGROUND: Variations of the vasculature at splenic flexure by left colic artery (LCA) and middle colic artery (MCA) remain ambiguous. OBJECTIVES: This study aim to investigate the anatomical variations of the branches from LCA and MCA at splenic flexure area. METHODS: Using ultra-thin CT images (0.5-mm thickness), we traced LCA and MCA till their merging site with paracolic marginal arteries through maximum intensity projection (MIP) reconstruction and computed tomography angiography (3D-CTA). RESULTS: A total of 229 cases were retrospectively enrolled. LCA ascending branch approached upwards till the distal third of the transverse colon in 37.6%, reached the splenic flexure in 37.6%, and reached the lower descending colon in 23.1%, and absent in 1.7% of the cases. Areas supplied by MCA left branch and aMCA were 33.2%, 44.5% and 22.3% in the proximal, middle and distal third of transverse colon of the cases, respectively. The accessory MCA separately originated from the superior mesenteric artery was found in 17.9% of the cases. Mutual correlation was found that, when the LCA ascending branch supplied the distal transverse colon, MCA left branch tended to feed the proximal transverse colon; when the LCA ascending branch supplied the lower part of descending colon, MCA left branch was more likely to feed the distal third of transverse colon. CONCLUSIONS: Vasculature at splenic flexure by LCA and MCA varied at specific pattern. This study could add more anatomical details for vessel management in surgeries for left-sided colon cancer.

[Evaluation of three-dimensional CT reconstruction on the anatomic variation of inferior mesenteric artery and left colic artery].

OBJECTIVE: To demonstrate the clinical applicability of three-dimensional CT angiography by evaluating the anatomic features and variation of inferior mesenteric artery(IMA) and left colic artery(LCA) in order to provide reference to vessel ligation strategy in laparoscopic rectal cancer surgery. METHODS: Clinical and image data of 123 patients receiving abdominal multislice CT at The Sixth Affiliated Hospital from 2014 to 2015 were retrospectively analyzed. The images were 3D-reconstructed with computer 3D CT angiography and arterial enhancement phase images were chosen for analysis. Linear distances from IMA root to abdominal aortic bifurcation and from LCA at IMA root level to IMA root were measured. Branch types of IMA, coursing pattern of LCA, and association between LCA and inferior mesenteric vein (IMV) site were summarized. RESULTS: Of 123 cases, 80 were males and 43 were females, mean age was (46.8±16.6) years, body weight was (57.7±10.4) kg, and BMI was (21.3±3.6) kg/m2. The average distance from IMA root to abdominal aortic bifurcation was (42.5±7.9) mm, and this distance was closely associated with body weight (OR=4.771, 95%CI: 1.398 to 16.283, P=0.013). Longer distance tended to appear in the heavier patients. LCA and sigmoid artery (SA) originating from same single IMA was found in 61(49.6%) cases; LCA and SA forking at same point in 35(28.5%) cases; LCA and SA coursing together and forking afterwards in 24(19.5%) cases, and LCA disappearing in 3(2.4%) cases. In 71(57.7%) patients, LCA ascended medial to the lateral border of left kidney, while in 16(13.0%) patients, LCA arranged below the inferior border of left kidney. When the LCA site was higher and the distance from LCA to IMA root was closer [distance from LCA to IMA root level was (24.2±9.9) mm, (30.0±15.2) mm and (66.6±12.3) mm, F=83.2, P<0.001]. At the level of IMA root, LCA located medial to IMV in 21(17.1%) cases, located just lateral to IMV in 54(43.9%) cases, and located lateral and ascended far away from IMV in 48(39.0%) cases. CONCLUSION: 3D-CT angiography is non-invasive, efficient and accurate in evaluating coursing features and variation of IMA and its branches, which can provide important reference to the surgeons, promising laparoscopic surgery smooth and safe.