The accuracy of preoperative imaging in measuring the length of the ileocolic segment affected by Crohn's disease: a prospective cohort study

AIM

The study aimed to evaluate the accuracy of imaging for measurement of the length of the ileocolic segment affected by Crohn's disease.

METHOD

Fifty-four consecutive patients who underwent resection between 2011 and 2014 for ileocolic Crohn's disease were prospectively studied. All had preoperative MR or CT enterography. Two independent radiologists measured the length of the diseased intestinal segment. The measurements were compared with the length of disease assessed on pathology of the non-fixed surgical specimen.

RESULTS

The median preoperative length of the Crohn's disease segment on imaging was 20.5 (2-73) cm and 20 (3-90) cm, as measured by the two radiologists. Interobserver agreement was substantial (κ = 0.69) with a correlation coefficient (r) of 0.82 (P < 0.001). The median length of the Crohn's disease segment on pathological examination was 16.5 (2-75) cm and was closely correlated with the radiological measurement (r = 0.76, P < 0.001). The length of the Crohn's disease segment on imaging was correct to within 5 cm of the value on pathology. It was correct in 30 (55%) patients and was underestimated and overestimated in 6 (11.1%) and 18 (33.3%). A length of disease of less than 20 cm found on imaging in 26 patients was confirmed in 25 (96%) on pathology, whereas a length of more than 20 cm found on imaging in 28 patients was confirmed in 18 (64%) on pathology. The sensitivity, specificity, positive predictive value, negative predictive value and overall accuracy of imaging for predicting a length of less than 20 cm were 71%, 95%, 96%, 64% and 79%.

CONCLUSION

Imaging accurately identifies the length of the ileocolic segment of Crohn's disease when it is 20 cm or less on pathological examination. In patients with more extensive disease, imaging tends to overestimate the length and should be interpreted with caution.

[Renal failure: diagnostic work-up]

The purpose of this article is to review the diagnostic work-up of renal failure, acute or chronic. The role of the radiologist is to exclude the presence of a curable etiology such as urinary tract obstruction or vascular thrombosis. Renal ultrasound with Doppler imaging is the imaging modality of choice for this indication, and the use of a contrast agent is useful to evaluate renal perfusion. Non-contrast CT remains valuable for the diagnosis of some urinary tract pathologies. Finally, MRI is the most comprehensive imaging modality for the evaluation of the urinary tract, but performed as a second line modality mainly for practical reasons but also due to the non-negligible risk of nephrogenic systemic fibrosis secondary to the intravenous administration of gadolinium based contrast agent.

Rôle de la personne compétente dans la sensibilisation au principe ALARA à travers l’application de la directive européenne 97-43

The purpose of this article is to define the role of the radiation safety officer in raising the awareness of the radiology staff to the ALARA (As low as reasonable achievable) principle specified in European directive 97-43. The actions taken and the techniques used in our hospital, as well as the potential improvements that could be achieved with extra funding, will be presented. The didactic value of flow charts recording technical factors and fluoroscopy times for quality improvement will be demonstrated. In the future, a dosimeter incorporated on the new equipment could allow direct recording of the dose. The different items presented in this paper should allow routine implementation of the required elements described in the law 2003-270, i.e the French translation of European Directive 97-43.