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Advances in clinical application of spectral CT iodine quantification in the assessment of Crohn's disease activity
Jun-Yi Zhou, Yi-Hong Fan, Si-Si Zheng
Jun-Yi Zhou, Si-Si Zheng, Department of Radiology, The First Affiliated Hospital of Zhejiang Chinese Medical University, Zhejiang Provincial Hospital of Chinese Medicine, Hangzhou 310000, Zhejiang Province, China
Yi-Hong Fan, Department of Gastroenterology, The First Affiliated Hospital of Zhejiang Chinese Medical University, Zhejiang Provincial Hospital of Chinese Medicine, Hangzhou 310000, Zhejiang Province, China
Corresponding author: Si-Si Zheng, Attending Physician, Department of Radiology, The First Affiliated Hospital of Zhejiang Chinese Medical University, Zhejiang Provincial Hospital of Chinese Medicine, No. 54 Youdian Road, Shangcheng District, Hangzhou 310000, Zhejiang Province, China. zhengsisi@zcmu.edu.cn
Received: June 25, 2026 Revised: August 2, 2026 Accepted: September 1, 2026 Published online: October 28, 2026
Crohn's disease (CD) is a chronic inflammatory bowel disease characterized by transmural inflammation and a relapsing-remitting course. Objective and reproducible assessment of disease activity remains central to clinical management. Spectral computed tomography (CT) can simultaneously provide virtual monoenergetic images, iodine maps, and spectral parameters, thereby improving visualization of the inflamed bowel wall and enabling quantitative assessment of perfusion and iodine uptake. Previous studies have shown that iodine concentration, normalized iodine concentration, and related spectral parameters correlate with the Crohn's Disease Activity Index, endoscopic activity scores, histopathology, and mucosal healing. In recent years, machine learning and deep learning have further expanded its applications in activity detection, lesion segmentation, and treatment-response prediction. This review summarizes the technical basis, key parameters, clinical evidence, artificial intelligence-integrated applications, and current challenges of spectral CT iodine quantification in CD activity assessment, with the aim of supporting standardization and clinical translation.
Citation: Zhou JY, Fan YH, Zheng SS. Advances in clinical application of spectral CT iodine quantification in the assessment of Crohn's disease activity. Shijie Huaren Xiaohua Zazhi 2026; 34(10): 835-841
Turner D, Ricciuto A, Lewis A, D'Amico F, Dhaliwal J, Griffiths AM, Bettenworth D, Sandborn WJ, Sands BE, Reinisch W, Schölmerich J, Bemelman W, Danese S, Mary JY, Rubin D, Colombel JF, Peyrin-Biroulet L, Dotan I, Abreu MT, Dignass A, International Organization for the Study of IBD. STRIDE-II: An Update on the Selecting Therapeutic Targets in Inflammatory Bowel Disease (STRIDE) Initiative of the International Organization for the Study of IBD (IOIBD): Determining Therapeutic Goals for Treat-to-Target strategies in IBD.Gastroenterology. 2021;160:1570-1583.
[PubMed] [DOI]
Rimola J, Ordás I, Rodriguez S, García-Bosch O, Aceituno M, Llach J, Ayuso C, Ricart E, Panés J. Magnetic resonance imaging for evaluation of Crohn's disease: validation of parameters of severity and quantitative index of activity.Inflamm Bowel Dis. 2011;17:1759-1768.
[PubMed] [DOI]
Gao Y, Zhang B, Zhao D, Li S, Rong C, Sun M, Wu X. Automatic Segmentation and Radiomics for Identification and Activity Assessment of CTE Lesions in Crohn's Disease.Inflamm Bowel Dis. 2024;30:1957-1964.
[PubMed] [DOI]
Kucharzik T, Taylor S, Allocca M, Burisch J, Ellul P, Iacucci M, Maaser C, Baldin P, Bhatnagar G, Ben-Horin S, Bettenworth D, Chavannes M, Driessen A, Flanagan E, Furfaro F, Maconi G, Karmiris K, Kellar A, De Kock I, Katsanos K, Kopylov U, Lu C, Nardone OM, Noor NM, Novak K, Borralho Nunes P, van Rheenen P, Rimola J, Rosini F, Rubin D, Scharitzer M, Stoker J, Uzzan M, Vavricka S, Verstockt B, Wilkens R, Zidar N, Zilli A, Yanai H, Feakins R. ECCO-ESGAR-ESP-IBUS Guideline on Diagnostics and Monitoring of Patients with Inflammatory Bowel Disease: Part 1.J Crohns Colitis. 2025;19:jjaf106.
[PubMed] [DOI]
Ananthakrishnan AN, Adler J, Chachu KA, Nguyen NH, Siddique SM, Weiss JM, Sultan S, Velayos FS, Cohen BL, Singh S; AGA Clinical Guidelines Committee. AGA Clinical Practice Guideline on the Role of Biomarkers for the Management of Crohn's Disease.Gastroenterology. 2023;165:1367-1399.
[PubMed] [DOI]
Li J, Xu M, Qian W, Ling F, Chen Y, Li S, Cheng Y, Zhu L. Clinical value of fecal calprotectin for evaluating disease activity in patients with Crohn's disease.Front Physiol. 2023;14:1186665.
[PubMed] [DOI]
Kim KO. Endoscopic activity in inflammatory bowel disease: clinical significance and application in practice.Clin Endosc. 2022;55:480-488.
[PubMed] [DOI]
Taylor SA, Mallett S, Bhatnagar G, Baldwin-Cleland R, Bloom S, Gupta A, Hamlin PJ, Hart AL, Higginson A, Jacobs I, McCartney S, Miles A, Murray CD, Plumb AA, Pollok RC, Punwani S, Quinn L, Rodriguez-Justo M, Shabir Z, Slater A, Tolan D, Travis S, Windsor A, Wylie P, Zealley I, Halligan S; METRIC study investigators. Diagnostic accuracy of magnetic resonance enterography and small bowel ultrasound for the extent and activity of newly diagnosed and relapsed Crohn's disease (METRIC): a multicentre trial.Lancet Gastroenterol Hepatol. 2018;3:548-558.
[PubMed] [DOI]
Bruining DH, Zimmermann EM, Loftus EV, Sandborn WJ, Sauer CG, Strong SA; Society of Abdominal Radiology Crohn's Disease-Focused Panel. Consensus Recommendations for Evaluation, Interpretation, and Utilization of Computed Tomography and Magnetic Resonance Enterography in Patients With Small Bowel Crohn's Disease.Radiology. 2018;286:776-799.
[PubMed] [DOI]
Mao Y, Mao Y, Xu Z, Li J, Xu M, Fan Y, Zheng S. Optimizing computed tomography enterography with virtual monoenergetic imaging of second-generation dual-layer spectral CT in inflammatory bowel disease.Quant Imaging Med Surg. 2025;15:12812-12822.
[PubMed] [DOI]
Chen Y, Liu X, Zeng H, Zhang J, Li Z, Wu B, Huang Z, Song B. The clinical applications of dual-layer spectral detector CT in digestive system diseases.Eur Radiol. 2025;35:3547-3557.
[PubMed] [DOI]
Albrecht MH, Vogl TJ, Martin SS, Nance JW, Duguay TM, Wichmann JL, De Cecco CN, Varga-Szemes A, van Assen M, Tesche C, Schoepf UJ. Review of Clinical Applications for Virtual Monoenergetic Dual-Energy CT.Radiology. 2019;293:260-271.
[PubMed] [DOI]
Nehnahi M, Simon G, Moinet R, Piton G, Camelin C, Ronot M, Delabrousse É, Calame P. Quantifying iodine concentration in the normal bowel wall using dual-energy CT: influence of patient and contrast characteristics.Sci Rep. 2023;13:22714.
[PubMed] [DOI]
De Kock I, Delrue L, Lecluyse C, Hindryckx P, De Vos M, Villeirs G. Feasibility study using iodine quantification on dual-energy CT enterography to distinguish normal small bowel from active inflammatory Crohn's disease.Acta Radiol. 2019;60:679-686.
[PubMed] [DOI]
Dane B, Sarkar S, Nazarian M, Galitzer H, O'Donnell T, Remzi F, Chang S, Megibow A. Crohn Disease Active Inflammation Assessment with Iodine Density from Dual-Energy CT Enterography: Comparison with Histopathologic Analysis.Radiology. 2021;301:144-151.
[PubMed] [DOI]
Dane B, Kernizan A, O'Donnell T, Petrocelli R, Rabbenou W, Bhattacharya S, Chang S, Megibow A. Crohn's disease active inflammation assessment with iodine density from dual-energy CT enterography: comparison with endoscopy and conventional interpretation.Abdom Radiol (NY). 2022;47:3406-3413.
[PubMed] [DOI]
Zhu C, Hu J, Rong C, Zhou J, Zhang B, Gao Y, Li C, Li J, Wu X. Mucosal healing assessment in Crohn's disease with normalized iodine concentration from dual-energy CT enterography: comparison with endoscopy.Insights Imaging. 2023;14:63.
[PubMed] [DOI]
Zhou HF, Chen W, Li JQ, Bai GJ, Guo LL. Prediction of pathological activity in Crohn's disease based on dual-energy CT enterography.Abdom Radiol (NY). 2024;49:1829-1838.
[PubMed] [DOI]
Lin Z, Hong M, Zhong H, Zheng X, Lin Y, Yang D, Zhong S, Yue X. Measurements on slope parameter mapping based on dual-energy CT enterography for improving Crohn's disease diagnosis and inflammatory activity evaluation.Sci Rep. 2025;15:429.
[PubMed] [DOI]
Zhong J, Wang L, Yan C, Xing Y, Hu Y, Ding D, Ge X, Li J, Lu W, Shi X, Yuan F, Yao W, Zhang H. Deep learning image reconstruction generates thinner slice iodine maps with improved image quality to increase diagnostic acceptance and lesion conspicuity: a prospective study on abdominal dual-energy CT.BMC Med Imaging. 2024;24:159.
[PubMed] [DOI]
You Y, Liang Y, Chen L, Li Z, Gao B, Wang X, Yuan M, Xue Y, Liu Y, Gao J. Radiomics analysis of dual-energy CT-derived iodine maps for differentiating between T1/2 and T3/4a in gastric cancer: A multicenter study.Eur J Radiol. 2025;186:112054.
[PubMed] [DOI]
Kim TM, Lee JM, Yoon JH, Joo I, Park SJ, Jeon SK, Schmidt B, Martin S. Prediction of microvascular invasion of hepatocellular carcinoma: value of volumetric iodine quantification using preoperative dual-energy computed tomography.Cancer Imaging. 2020;20:60.
[PubMed] [DOI]
Liu ZG, Xie SS. Expanding the role of radiomics and artificial intelligence in the management of inflammatory bowel disease: Insights, opportunities, and challenges.World J Gastroenterol. 2025;31:112107.
[PubMed] [DOI]
Li J, Xie G, Tang W, Zhang L, Zhang Y, Zhang L, Wang D, Li K. Establishing a machine learning model based on dual-energy CT enterography to evaluate Crohn's disease activity.Insights Imaging. 2024;15:115.
[PubMed] [DOI]
Guez I, Focht G, Greer MC, Cytter-Kuint R, Pratt LT, Castro DA, Turner D, Griffiths AM, Freiman M. Development of a multimodal machine-learning fusion model to non-invasively assess ileal Crohn's disease endoscopic activity.Comput Methods Programs Biomed. 2022;227:107207.
[PubMed] [DOI]
Cai W, Wu X, Guo K, Chen Y, Shi Y, Lin X. Deep-Learning, Radiomics and Clinic Based Fusion Models for Predicting Response to Infliximab in Crohn's Disease Patients: A Multicentre, Retrospective Study.J Inflamm Res. 2024;17:7639-7651.
[PubMed] [DOI]
Zhang W, Xie H, Ying S, Zeng X, Liao X, Hu S, Zeng H, Zou Q, Zeng D, Meng F. Crohn's disease: research progress in decoding pathogenic multi-network and precision management of artificial intelligence radiomics.Front Immunol. 2026;17:1774889.
[PubMed] [DOI]
Jacobsen MC, Thrower SL, Ger RB, Leng S, Court LE, Brock KK, Tamm EP, Cressman ENK, Cody DD, Layman RR. Multi-energy computed tomography and material quantification: Current barriers and opportunities for advancement.Med Phys. 2020;47:3752-3771.
[PubMed] [DOI]
Lennartz S, Cao J, Pisuchpen N, Srinivas-Rao S, Locascio JJ, Parakh A, Hahn PF, Mileto A, Sahani D, Kambadakone A. Intra-patient variability of iodine quantification across different dual-energy CT platforms: assessment of normalization techniques.Eur Radiol. 2024;34:5131-5141.
[PubMed] [DOI]
Kim YS, Kim SH, Ryu HS, Han JK. Iodine Quantification on Spectral Detector-Based Dual-Energy CT Enterography: Correlation with Crohn's Disease Activity Index and External Validation.Korean J Radiol. 2018;19:1077-1088.
[PubMed] [DOI]
Silverman AL, Shung D, Stidham RW, Kochhar GS, Iacucci M. How Artificial Intelligence Will Transform Clinical Care, Research, and Trials for Inflammatory Bowel Disease.Clin Gastroenterol Hepatol. 2025;23:428-439.e4.
[PubMed] [DOI]
Zhao W, Lv T, Lee R, Chen Y, Xing L. Obtaining dual-energy computed tomography (CT) information from a single-energy CT image for quantitative imaging analysis of living subjects by using deep learning.Pac Symp Biocomput. 2020;25:139-148.
[PubMed] [DOI]
Zeng R, Lin CY, Li Q, Jiang L, Skopec M, Fessler JA, Myers KJ. Performance of a deep learning-based CT image denoising method: Generalizability over dose, reconstruction kernel, and slice thickness.Med Phys. 2022;49:836-853.
[PubMed] [DOI]
Bousse A, Kandarpa VSS, Rit S, Perelli A, Li M, Wang G, Zhou J, Wang G. Systematic Review on Learning-based Spectral CT.IEEE Trans Radiat Plasma Med Sci. 2024;8:113-137.
[PubMed] [DOI]
Jensen LJ, Kim D, Elgeti T, Steffen IG, Hamm B, Nagel SN. Stability of Radiomic Features across Different Region of Interest Sizes-A CT and MR Phantom Study.Tomography. 2021;7:238-252.
[PubMed] [DOI]
Huang L, Li H, Wang S, Ren Y. Prediction of early mucosal healing of Crohn's disease after treatment with biologics- a novel nomogram based on radiomics and clinical risk factors.Front Pharmacol. 2025;16:1586300.
[PubMed] [DOI]