No quantitative computed tomography (CT) biomarker is actually sufficiently accurate to assess Crohn’s disease (CD) lesion activity, with adequate precision to guide clinical decisions.
Purpose
To assess the available literature on the use of iodine concentration (IC), from multi-spectral CT acquisition, as a quantitative parameter able to distinguish healthy from affected bowel and assess CD bowel activity and heterogeneity of activity along the involved segments.
Material and Methods
A literature search was conducted to identify original research studies published up to February 2022. The inclusion criteria were original research papers (>10 human participants), English language publications, focus on dual-energy CT (DECT) of CD with iodine quantification (IQ) as an outcome measure. The exclusion criteria were animal-only studies, languages other than English, review articles, case reports, correspondence, and study populations <10 patients.
Results
Nine studies were included in this review; all of which showed a strong correlation between IC measurements and CD activity markers, such as CD activity index (CDAI), endoscopy findings and simple endoscopic score for Crohn's disease (SES-CD), and routine CT enterography (CTE) signs and histopathologic score. Statistically significant differences in IC were reported between affected bowel segments and healthy ones (higher P value was P < 0.001), normal segments and those with active inflammation (P < 0.0001) as well as between patients with active disease and those in remission (P < 0.001).
Conclusion
The mean normalized IC at DECTE could be a reliable tool in assisting radiologists in the diagnosis, classification and grading of CD activity.
TorresJMehandruSColombelJ-F, et al.Crohn’s disease. Lancet2017;389:1741–1755.
2.
BruiningDHZimmermannEMLoftusEV, et al.Consensus recommendations for evaluation, interpretation, and utilization of computed tomography and magnetic resonance enterography in patients with small bowel Crohn’s disease. Radiology2018;286:776–799.
3.
AdamSZRabinowichAKessnerR, et al.Spectral CT of the abdomen: where are we now?Insights Imaging2021;12:138.
4.
WichmannJLHardieADSchoepfUJ, et al.Single- and dual-energy CT of the abdomen: comparison of radiation dose and image quality of 2nd and 3rd generation dual-source CT. Eur Radiol2017;27:642–650.
5.
GandhiNSBakerMEGoenkaAH, et al.Diagnostic accuracy of CT enterography for active inflammatory terminal ileal Crohn disease: comparison of full-dose and half-dose images reconstructed with FBP and half-dose images with SAFIRE. Radiology2016;280:436–445.
6.
UhrigMSimonsDKachelrießM, et al.Advanced abdominal imaging with dual energy CT is feasible without increasing radiation dose. Cancer Imaging2016;16:15.
7.
XinLYangXHuangN, et al.The initial experience of the upper abdominal CT angiography using low-concentration contrast medium on dual energy spectral CT. Abdom Imaging2015;40:2894–2899.
8.
MegibowAJKambadakoneAAnanthakrishnanL. Dual-energy computed tomography: image acquisition, processing, and workflow. Radiol Clin North Am2018;56:507–520.
9.
KraussB. Dual-Energy computed tomography: technology and Challenges. Radiol Clin North Am2018;56:497–506.
10.
PatinoMProchowskiAAgrawalMD, et al.Material separation using dual-energy CT: current and emerging applications. Radiographics2016;36:1087–1105.
11.
FulwadhvaUPWortmanJRSodicksonAD. Use of dual-energy CT and iodine maps in evaluation of bowel disease. Radiographics2016;36:393–406.
12.
Große HokampNGilkesonRJordanMK, et al.Virtual monoenergetic images from spectral detector CT as a surrogate for conventional CT images: unaltered attenuation characteristics with reduced image noise. Eur J Radiol2019;117:49–55.
13.
AtwiNESmithDLFloresCD, et al.Dual-energy CT in the obese: a preliminary retrospective review to evaluate quality and feasibility of the single-source dual-detector implementation. Abdom Radiol (NY)2019;44:783–789.
14.
ParakhAMacriFSahaniD. Dual-energy computed tomography: dose reduction, series reduction, and contrast load reduction in dual-energy computed tomography. Radiol Clin North Am2018;56:601–624.
15.
MichalakGGrimesJFletcherJ, et al.Technical note: improved CT number stability across patient size using dual-energy CT virtual monoenergetic imaging. Med Phys2016;43:513.
16.
HigashigaitoKEulerAEberhardM, et al.Contrast-enhanced abdominal CT with clinical photon-counting detector CT: assessment of image quality and comparison with energy-integrating detector CT. Acad Radiol2022;29:689–697.
17.
DeckerJABetteSLubinaN, et al.Low-dose CT of the abdomen: initial experience on a novel photon-counting detector CT and comparison with energy-integrating detector CT. Eur J Radiol2022;148:110181.
18.
YehBMObmannMMWestphalenAC, et al.Dual energy computed tomography scans of the bowel: benefits, pitfalls, and future directions. Radiol Clin North Am2018;56:805–819.
19.
NodaYGoshimaSNakashimaY, et al.Iodine dose optimization in portal venous phase virtual monochromatic images of the abdomen: prospective study on rapid kVp switching dual energy CT. Eur J Radiol2020;122:108746.
20.
LuXLuZYinJ, et al.Effects of radiation dose levels and spectral iterative reconstruction levels on the accuracy of iodine quantification and virtual monochromatic CT numbers in dual-layer spectral detector CT: an iodine phantom study. Quant Imaging Med Surg2019;9:188–200.
21.
StillerWSkornitzkeSFritzF, et al.Correlation of quantitative dual-energy computed tomography iodine maps and abdominal computed tomography perfusion measurements: are single-acquisition dual-energy computed tomography iodine maps more than a reduced-dose surrogate of conventional computed tomography perfusion?Invest Radiol2015;50:703–708.
22.
PageMJMcKenzieJEBossuytPM, et al.The PRISMA 2020 statement: an updated guideline for reporting systematic reviews. BMJ2021;372:71.
23.
EriksenMBFrandsenTF. The impact of patient, intervention, comparison, outcome (PICO) as a search strategy tool on literature search quality: a systematic review. J Med Libr Assoc2018;106:420–431.
24.
WhitingPFRutjesAWSWestwoodME, et al.QUADAS-2: a revised tool for the quality assessment of diagnostic accuracy studies. Ann Intern Med2011;155:529–536.
25.
KimYSKimSHRyuHS, et al.Iodine quantification on spectral detector-based dual-energy CT enterography: correlation with Crohn’s disease activity index and external validation. Korean J Radiol2018;19:1077–1088.
26.
DaneBDuenasSHanJ, et al.Crohn’s disease activity quantified by iodine density obtained from dual-energy computed tomography enterography. J Comput Assist Tomogr2020;44:242–247.
27.
XiaoW-XZhuY-TZhangZ-C, et al.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. Int J Gen Med2021;14:7051–7058.
28.
PengJCFengQZhuJ, et al.Usefulness of spectral computed tomography for evaluation of intestinal activity and severity in ileocolonic Crohn’s disease. Therap Adv Gastroenterol2016;9:795–805.
29.
De KockIDelrueLLecluyseC, et al.Feasibility study using iodine quantification on dual-energy CT enterography to distinguish normal small bowel from active inflammatory Crohn’s disease. Acta Radiol2019;60:679–686.
30.
Villanueva CamposAMTardáguila de la FuenteGUtrera PérezE, et al.Value of dual-energy CT enterography in the analysis of pathological bowel segments in patients with Crohn’s disease. Radiologia (Engl Ed)2018;60:223–229.
31.
ChenJZhouJYangJ, et al.Efficiency of dual-energy computed tomography enterography in the diagnosis of Crohn’s disease. BMC Med Imaging2021;21:185.
32.
DaneBSarkarSNazarianM, et al.Crohn disease active inflammation assessment with iodine density from dual-energy CT enterography: comparison with histopathologic analysis. Radiology2021;301:144–151.
33.
DaneBO’DonnellTReamJ, et al.Novel dual-energy computed tomography enterography iodine density maps provide unique depiction of Crohn disease activity. J Comput Assist Tomogr2020;44:772–779.
34.
GiaslakiotisKBairdAWarrenBF. Submucosal fat deposition in a patient with Crohn’s disease: the fat halo sign. Histopathology2008;53:611–612.
35.
SymonsRKraussBSahbaeeP, et al.Photon-counting CT for simultaneous imaging of multiple contrast agents in the abdomen: An in vivo study. Med Phys2017;44:5120–5127.
