Feasibility study using iodine quantification on dual-energy CT enterography to distinguish normal small bowel from active inflammatory Crohn’s disease

Abstract

Background Assessment of Crohn's disease (CD) activity is important to identify patients with active inflammation for therapy management. Quantitative analysis can provide objective measurement of disease presence. Purpose To evaluate the feasibility of quantitative analysis of contrast-enhanced dual-energy computed tomography (DECT) data in detection of small bowel inflammation in patients with CD with an emphasis on iodine quantification. Material and Methods DECT enterography was prospectively performed in 20 patients with active CD and in 20 healthy individuals, as the control group. Iodine overlay images were created. Wall thickness, attenuation, absolute iodine density, relative iodine density, and fat fraction were measured in the terminal ileum of all patients by two radiologists. Intraclass correlation coefficients were calculated to assess inter-rater agreement. Parameters were compared between patient groups using mixed model analysis. Receiver operating characteristic (ROC) analysis was performed. Results Both absolute and relative iodine density were significantly higher in active disease than in normal small bowel (all P < 0.001). In contrast, measurement of fat fraction was not significantly different in affected terminal ileal loops compared to normal terminal ileum ( P = 0.075). ROC analysis demonstrated a similar excellent diagnostic accuracy of wall thickness, attenuation, and absolute and relative iodine density with area under the ROC curve (AUC) values in the range of 0.96 for attenuation to 1 for relative iodine density. Conclusion DECT with iodine quantification can be used in distinguishing normal small bowel from active inflammatory CD. Further research should investigate the value of iodine quantification in grading CD activity and in monitoring therapeutic response.

A Preliminary Study on the Feasibility of the Quantitative Parameters of Dual-Energy Computed Tomography Enterography in the Assessment of the Activity of Intestinal Crohn’s Disease

“…In recent years, many studies have looked at the separation function of DECTE substances, mostly focusing on analysis and differentiation using quantitative parameters, such as iodine value and energy-spectrum profile. [2][3][4][5][6][7][8][9][10][11][12] DECTE scanning technology offers evaluation with the adoption of morphological results and improved diagnostic accuracy with the virtual monoenergetic spectrum CT values, energy-spectrum curve slope, and iodine content of organ and tissues as well as other quantitative parameters obtained by post-processing. The increased contrast in low keV images may help with lesion identification, and the increased signal-to-noise ratio in high keV images may assist with detailed observation.…”

“…The data of 29 patients (Table 1) diagnosed with CD between July 1, 2016, and December 31, 2019, in the Department of Gastroenterology, Fujian Provincial Hospital, were retrospectively collected and subjected to double-phase DECTE enhancement scans. In each patient, the diseased intestinal segments (mucosal hyperenhancement, wall thickening (small intestine ≥3mm, large intestine ≥5mm), mural stratification with a prominent vasa recta (comb sign), mesenteric fat stranding, and Extra-intestinal complications (fistulas, peri-intestinal abscesses) [1][2][3][4][5] )was selected for the observation group (when there was more than one diseased segment, up to four segments were selected at the same time), and the normal intestinal segments (with an intestinal lumen diameter of <2.5 cm and intestinal wall thickness of <3 mm without morphological signs of CD) were selected for the control group, resulting in a total of 56 segments being included.…”

Gastrointestinal Applications of Iodine Quantification Using Dual-Energy CT: A Systematic Review

“…Two of four DECT enterography studies concerning Crohn’s disease used Crohn’s disease activity index (CDAI) as reference [ 56 , 57 ], and two studies used endoscopy, biochemistry and clinical symptoms as reference [ 30 , 58 ]. The outcome measure included nIC-V for all studies except one study by Kim et al [ 56 ], which only included IC-V. ROI placements were set on either iodine maps or conventional images covering the most enhanced areas.…”

Stepwise analysis of potential accuracy-influencing factors of iodine quantification on a fast kVp-switching second-generation dual-energy CT: from 3D-printed phantom to a simple solution in clinical routine use

“…Nevertheless, positioning does have an influence on the absolute measurement error. Since absolute IC values are used as diagnostic markers, these differences are relevant when interpreting findings in patients with different indications for CT such as lesion detection/characterization, differentiation, tumor grading, and therapy monitoring (8–11,16–21). Therefore, to avoid this error, a standardized, anterior, median position of the vial was chosen for the following measurements in the patient cohort.…”