Usefulness of spectral computed tomography for evaluation of intestinal activity and severity in ileocolonic Crohn’s disease

Abstract

Background:Assessment of intestinal activity and severity of Crohn’s disease (CD) is crucial to guide treatment. In this study, we aimed to investigate the accuracy of spectral computed tomography (CT) in this assessment and make a comparison with conventional CT.Methods:A total of 50 patients with ileocolonic CD underwent spectral CT scanning. Conventional CT and spectral CT images were reconstructed. Endoscopic lesions were classified as absent, mild lesions and severe lesions. Qualitative and quantitative findings in CT images were compared in these segments. Logistic regressions were established, based on conventional and spectral CT parameters, to predict intestinal activity and severity. Comparisons were made by receiver operating characteristic (ROC) curve.Results:The results showed that bowel wall hyperenhancement, ulcers on CT images, comb sign, bowel wall thickness, normalized iodine concentration (NIC) and slope of HU curve (λHU) increased significantly (p < 0.01) with endoscopic severity. In predicting intestinal activity, spectral CT demonstrated higher accuracy (99.6% versus 94.7%), sensitivity (99.1% versus 93.4%) and specificity (99.9% versus 94.4%) than conventional CT. In predicting intestinal severity, spectral CT also had higher accuracy (96.5% versus 91.9%), sensitivity (96.5% versus 92.1%) and specificity (95.8% versus 89.8%) than conventional CT. Besides, both NIC and λHU correlated significantly with Simple Endoscopic Score for CD (r = 0.833 and r = 0.771; both p < 0.001), but their correlations with C-reactive protein (r = 0.578 and r = 0.513; both p < 0.01) and Harvey–Bradshaw Index (r = 0.545 and r = 0.522; both p < 0.01) were moderate.Conclusions:Compared with conventional CT, spectral CT had higher accuracy in detecting intestinal activity and severity of CD, which could be an alternative choice in evaluation of CD.

Creeping fat in patients with ileo‐colonic Crohn's disease correlates with disease activity and severity of inflammation: A preliminary study using energy spectral computed tomography

“…Our previous study found that energy spectral CT was better than conventional CT for assessing disease activity and severity in CD, and the results were in good agreement with those from endoscopy . However, to our knowledge, a quantitative analysis of creeping fat in CD using similar methods has not been reported yet.…”

“…The thickness was 1.25 mm. The slope of the HU curve (λ HU ) was obtained, which represented an X‐ray attenuation coefficient at different energy levels ranging from 40 keV to 140 keV and could be calculated using the following formula:…”

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.…”

“…Similarly, IQ may also aid in the monitoring of disease activity in the relatively homogenous group of Crohn’s disease patients. Three studies [ 30 , 56 , 57 ], with a relatively low risk of bias ( Figure S1 ), found significant correlation between IC measurements and various validated methods of evaluating disease activity such as CDAI, endoscopy and biochemistry as shown in Table 3 .…”

“…These measurements can be applied in the different scan phases, e.g., arterial (IC-A), venous (IC-V) or delayed phase (IC-D). Multiple studies investigating IQ have included normalized IC (nIC) as an outcome measure [ 30 , 31 , 32 ], which is calculated based on the equation nIC = IC lesion /IC reference (the reference most commonly being the aorta). The main point of including nIC is to reduce technical or physiological variabilities in iodine load within the tissue of interest due to varying cardiac output and phase times.…”