Original article
437
Authors
Gian Eugenio Tontini1, 2, Jonas Mudter1, Michael Vieth3, Raja Atreya1, Claudia Günther1, Yurdagül Zopf1, Dane Wildner1, Ralf Kiesslich4, Maurizio Vecchi2, 5, Markus F. Neurath1, Helmut Neumann1
Institutions
Institutions are listed at the end of article.
submitted 8. October 2013 accepted after revision 27. October 2014
Background and study aim: The differential diagnosis of ulcerative colitis from Crohn’s disease is of pivotal importance for the management of inflammatory bowel diseases, as both entities involve specific therapeutic management strategies. Confocal laser endomicroscopy (CLE) allows on-demand, in vivo characterization of architectural and cellular details during endoscopy. The aim of this study was to assess the efficacy of CLE to differentiate between ulcerative colitis and Crohn’s disease. Patients and methods: This was a prospective study involving consecutive patients with a wellestablished diagnosis of ulcerative colitis or Crohn’s disease who underwent colonoscopy with fluorescein-aided confocal imaging. Results: Overall, 79 patients were included (40 Crohn’s disease, 39 ulcerative colitis). CLE findings in patients with Crohn’s disease, showed significantly more discontinuous inflammation (87.5 % vs. 5.1 %), focal cryptitis (75.0 % vs. 12.8 %), and discontinuous crypt architectural abnormality (87.5 % vs. 10.3 %) than in ulcerative colitis
(P < 0.0001). Conversely, ulcerative colitis was associated with severe, widespread crypt distortion (87.2 % vs. 17.5 % in Crohn’s disease), decreased crypt density (79.5 % vs. 22.5 %), and frankly irregular surface (89.7 % vs. 17.5 %; P < 0.0001 for all comparisons). Statistically significant differences were not seen for heavy, diffuse lamina propria cell increase or mucin preservation. No granulomas were visible. Based on these findings, a CLE scoring system was developed that revealed excellent accuracy (93.7 %) when compared with the historical clinical diagnosis and the histopathological gold standard. Conclusions: CLE could visualize several diseasespecific microscopic features, which are conventionally used in standard histopathology to differentiate between ulcerative colitis and Crohn’s disease. However, because of the limited penetration depth of CLE, submucosal details or granulomas were not visible. The new scoring system may allow in vivo diagnosis of ulcerative colitis or Crohn’s disease. Trial registered at ClinicalTrials.gov: NCT 02238665
Introduction
ongoing endoscopy (i. e. in vivo histology) [8]. Recent data have suggested that CLE enables in vivo confirmation of histological changes associated with ulcerative colitis and Crohn’s disease [5, 9 – 12]. CLE has been utilized in a few studies to assess IBD diagnosis [9, 13, 14], disease activity [10, 11], and prediction of disease relapse [15]. Taken together, these studies have underscored the potential usefulness of CLE for the in vivo diagnosis of IBD. However, no study has evaluated the potential of CLE for the in vivo differentiation of ulcerative colitis and Crohn’s disease. The aim of this prospective study, therefore, was to assess the efficacy of CLE to define the differential diagnosis between ulcerative colitis and Crohn’s disease. In addition, variables allowing the differentiation of the two disease entities
Bibliography DOI http://dx.doi.org/ 10.1055/s-0034-1391226 Published online: 18.12.2014 Endoscopy 2015; 47: 437–443 © Georg Thieme Verlag KG Stuttgart · New York ISSN 0013-726X Corresponding author Helmut Neumann, MD, PhD Department of Medicine I University of ErlangenNuremberg Ulmenweg 18 91054 Erlangen Germany Fax: +49-9131-8535209 helmut.neumann@uk-erlangen. de
!
Scan this QR-Code to watch the video comment.
Inflammatory bowel disease (IBD) encompasses two major entities – ulcerative colitis and Crohn’s disease [1]. The differential diagnosis of the two diseases is of paramount importance to the optimization of clinical management, as modern therapies and reliable prognostic indices often involve disease-specific strategies [2 – 4]. The differential diagnosis is currently based on clinical evaluation and a combination of endoscopic, histological, radiological, and biochemical investigations [4, 5]. However, in about 3 % – 6 % of all initial IBD diagnoses made in adult patients, a distinctive diagnosis is not possible, leading to the term of IBD type unclassified [5 – 7]. In 2004, confocal laser endomicroscopy (CLE) was introduced, enabling real-time histology during
Tontini Gian Eugenio et al. Confocal laser endomicroscopy in inflammatory bowel disease … Endoscopy 2015; 47: 437–443
Downloaded by: IP-Proxy University of California, San Francisco, University of California, San Francisco. Copyrighted material.
Confocal laser endomicroscopy for the differential diagnosis of ulcerative colitis and Crohn’s disease: a pilot study
Original article
were identified, and a prediction model was developed to enable the in vivo diagnosis of IBD.
Patients and methods !
Patient enrollment, inclusion, and exclusion Consecutive patients with a well-established diagnosis of ulcerative colitis or Crohn’s disease underwent screening or surveillance colonoscopy for the evaluation of disease activity. Patients were prospectively included between October 2009 and April 2013 at the endoscopy unit of the Department of Medicine I at the University of Erlangen-Nuremberg. All patients signed informed consent after the endoscopist or the attending physician had explained the procedure to them in detail. The study was approved by the local ethical committee of the University of Erlangen-Nuremberg and government authorities, and was conducted in accordance with the declaration of Helsinki. (ClinicalTrials Registration number NCT 02238665.) Patients were included if they met the following inclusion criteria: age ≥ 18 years, ability to provide written informed consent, and a well-established diagnosis of ulcerative colitis or Crohn’s disease. Patients with one or more of the following criteria were excluded from the study: history of IBD reclassification in the last 3 years, Boston Bowel Preparation Scale score < 2 in at least one of the three segments of the colon (i. e. rectum plus left-sided colon, transverse colon plus left and right flexures, right colon) [16], inability to provide written informed consent, severe uncontrolled coagulopathy, impaired renal function, pregnancy or breast feeding, active gastrointestinal bleeding, known allergy to fluorescein, and residence in institutions.
Endoscopic and endomicroscopic procedure All colonoscopies were performed after the patient had undergone standard bowel preparation using either oral sodium phosphate or polyethylene glycol electrolyte lavage solution. CLE was performed using two European Conformity-certified and Food and Drug Administration-approved CLE systems (iCLE, Pentax, Tokyo, Japan; and pCLE, Cellvizio, Mauna Kea Technologies, Paris, France). Conscious sedation with constant monitoring of vital signs was employed (e. g. midazolam hydrochloride and pethidine hydrochloride). Initially, the endoscope was advanced to the colon. On withdrawal, all parts of the colon were evaluated. The Boston Bowel Preparation Scale and inflammation changes were recorded. In patients with ulcerative colitis, inflammatory lesions were classified according to the Mayo Ulcerative Endoscopic Score of Severity (Mayo score), and Crohn’s disease was classified according to the Crohn’s Disease Endoscopic Index of Severity (CDEIS). Briefly, the Mayo score considers four degrees of severity: 0 = normal or inactive disease; 1 = mild disease (erythema, decreased vascular pattern, mild friability); 2 = moderate disease (frank friability, marked erythema, absent vascular pattern, erosions); 3 = severe disease (mucopus, spontaneous bleeding, and ulceration) [17]. The CDEIS calculates disease activity according to five endoscopically visualized segments (rectum, sigmoid/left colon, transverse colon, right colon, terminal ileum), and findings, including ulcer size, extent of disease (surface with disease involvement and surface with ulcer involvement), and stenosis. The CDEIS score ranges from 0 to 44, with a higher score indicating more severe disease [18]. In the current study, a CDEIS score of < 3 suggested
inactive disease, ≥ 3 to < 9 mildly active, ≥ 9 to < 12 moderately active, and ≥ 12 severely active disease [19]. For confocal imaging, 5 mL of fluorescein sodium 10 % (Alcon Laboratories, Texas, USA) was administered intravenously to optimize tissue contrast [20]. Endomicroscopy was performed at a minimum of five random sites in the colon after careful washing of the mucosa with water in order to prevent the inclusion of image artefacts from residual stool fragments. Careful attention was paid to ensure high-quality images in focus either by using iCLE or pCLE. The confocal images were first analyzed during the endoscopy. Then, the images were digitally stored and reviewed after the procedure in order to zoom in on details (iCLE) for a higher magnification (approximately 10 000 fold) or by using the Cellvizio Viewer for virtual staining of mucosal structures to enhance tissue contrast. iCLE images were collected at a frame rate of 0.8 /second at 1024 × 1024 pixels or 1.6/second at 1024 × 512 pixels. Normal mucosa and pathological lesions were evaluated according to the Mainz confocal pattern classification for iCLE [21] and the Miami classification for pCLE [22]. Colonoscopy with CLE was performed in vivo by two expert endoscopists who were aware of the patients’ history and endoscopic results. The digitally stored confocal images were reviewed blinded to the true diagnosis. Based on previous histological studies that focused on the diagnosis of ulcerative colitis and Crohn’s disease, the CLE examination aimed at evaluating the following features: severe and widespread architectural distortion, frankly irregular surface, decreased crypt density, discontinuous crypt architecture, focal cryptitis, heavy and diffuse cell infiltration within the lamina propria, mucin preservation at active sites, discontinuous inflammation, and granulomas [5, 12]. Multiple biopsies were taken from both macroscopically normal and abnormal mucosa after confocal examination. Specimens were retrieved and fixed in 4 % buffered formalin for subsequent histopathological analysis to confirm the diagnosis. Patients’ diagnoses, defined according to the Montreal classification [6], were based on medical history, endoscopy, and histopathology.
CLE scoring system for prediction of IBD diagnosis A simplified scoring system was developed based on CLE findings that showed a significant difference between patients with ulcerative colitis and those with Crohn’s disease. The score was initially developed based on the method proposed by Pera et al. for ileo-colonoscopy [23], which used the likelihood ratios of the individual endoscopic findings. However, we found that the use of likelihood ratios or any similar method based on accuracy ratios, greatly increased the CLE score range and complexity with no impact on either accuracy or variability. Because of this, for the current study a number of simulations were performed, which involved the allocation of 1 – 5 points for each CLE finding with a positive likelihood ratio for ulcerative colitis, and – 1 to – 5 points for those with a higher sensitivity for Crohn’s disease. Finally, each score system was tested using all possible cutoff levels and assessed for sensibility, specificity, and accuracy. The overall best performance was provided by the endoscopic score system that involved the allocation of 3 points for the presence of each ulcerative colitis-related sign and one additional point for the absence of each Crohn’s disease-related sign, with the diagnosis cutoff level set at 6 points. The score scale ranged from the minimum value of 0 (highly predictive for Crohn’s disease) to the maximum value of 12 points (highly predictive for ulcerative co-
Tontini Gian Eugenio et al. Confocal laser endomicroscopy in inflammatory bowel disease … Endoscopy 2015; 47: 437–443
Downloaded by: IP-Proxy University of California, San Francisco, University of California, San Francisco. Copyrighted material.
438
Original article
litis). The score has been called the IBD Differentiation based on Endomicroscopic Assessment (IDEA) scoring system.
Assessed for eligibility: Patients with ulcerative colitis or Crohn‘s disease submitted for colonoscopy (n = 105)
Statistical analysis
Excluded patients (n = 26): ▪ Suboptimal bowel preparation (n = 7) ▪ IBD-type reclassification within the last 3 years (n = 6) ▪ Poor historical documentation addressing the previous disease classification (n = 13)
All statistical analyses were performed using PASW Statistics 18 (SPSS, Inc., Chicago, USA). A two-sided P value of < 0.05 was considered to be significant. For comparisons of proportions between ulcerative colitis and Crohn’s colitis, such as crypt architecture, presence of microerosions, and vascular pattern between the different groups, the Fisher’s exact test was used. The median is presented for non-normally distributed variables, and the mean is shown for normally distributed variables. The ranges presented indicate the minimum and maximum values.
Confocal laser endomicroscopy (n = 79)
Fig. 1
CONSORT 2010 flow diagram.
!
Patient characteristics The endoscopic disease activity was prospectively evaluated in 105 patients with a previous well-established diagnosis of colonic IBD. A total of 79 of them fulfilled the inclusion criteria and underwent a complete colonoscopic examination using CLE " Fig. 1). There were 40 patients with Crohn’s disease (median (● age 35.5 ± 12.7 years [range 18 – 73]; 17 females) and 39 with ulcerative colitis (median age 39.9 ± 12.0 years [range 21 – 63]; 10 females). The demographic and clinical data of patients are " Table 1 and " Table 2. A total of 26 patients were exshown in ● ● cluded because of suboptimal bowel preparation, IBD-type reclassification in the last 3 years, or poor historical documentation addressing the previous disease classification.
Table 1 Baseline characteristics of patients with Crohn’s disease and ulcerative colitis.
Baseline characteristics
Crohn’s disease
Ulcerative colitis
Patients, n
40
39
Females, n (%)
17 (42.5)
10 (25.6)
Age, median (range), years
35.5 (18 – 73)
39.9 (21 – 63)
Years from diagnosis, median (range)
10 (3 – 30)
11 (3 – 23)
Table 2 Characterization of Crohn’s disease and ulcerative colitis study populations based on clinical data.
Clinical data
Endomicroscopic evaluation
Crohn’s disease, n = 40
CLE enabled a clear characterization of seven out of the eight architectural and inflammatory changes investigated in the present study: severe and widespread architectural distortion, frankly irregular surface, decreased crypt density, discontinuous crypt architectural abnormality, focal cryptitis, heavy and diffuse cell infiltration within the lamina propria, mucin preservation at active " Fig. 2 a – c). No granusites, and discontinuous inflammation (● " Table 3 shows the CLE findings in lomas were detected by CLE. ● patients. In ulcerative colitis, CLE images showed higher prevalence of severe and widespread architectural distortion (87.2 %, P < 0.0001), frankly irregular surface (89.7 %, P < 0.0001), and decreased crypt density (79.5 %, P < 0.0001) compared with Crohn’s disease patients (17.5 %, 17.5 %, and 22.5 %, respectively). Conversely, CLE images collected from patients with Crohn’s disease showed a greater amount of discontinuous crypt architectural abnormality (87.5 %, P < 0.0001), focal cryptitis (75.0 %, P < 0.0001), and discontinuous inflammation (87.5 %, P < 0.0001) compared with patients with ulcerative colitis (10.3 %, 12.8 %, and 5.1 %, respectively). In both groups of patients, CLE images presented heavy and diffuse infiltration within the lamina propria (85.0 % in Crohn’s disease and 89.7 % in ulcerative colitis; P = 0.7370) and low grade of mucin preservation at active site (7.5 % and 12.8 %, respectively; P = 0.4814). There were no meaningful differences in the frequencies of CLE findings according to either the Montreal classification or the endoscopic disease severity (i. e. Mayo or CDEIS) for both ulcera" Table 4, tive colitis patients and those with Crohn’s disease (● " Table 5). ●
Montreal classification
Number of patients
L2
11
L3
27
L3 /L4
2
CDEIS score < 3 (mean CRP 11 mg/dL) ≥ 3 to < 9 (mean CRP 4 mg/dL) ≥ 9 to < 12 (mean CRP 24 mg/dL) ≥ 12 (mean CRP 41 mg/dL) Ulcerative colitis, n = 39
8 16 5 11
Montreal classification E1
3
E2
12
E3
24
Mayo endoscopic subscore 0
8
1
15
2
8
3
8
CDEIS, Crohn’s Disease Endoscopic Index of severity; CRP, C-reactive protein.
The mean procedure time was 10 minutes for the in vivo CLE examination and 10 minutes to review the digitally stored confocal images after the endoscopy procedure. No differences in image interpretation were observed between the iCLE and pCLE CLE systems, although this was not an aim of the study.
CLE scoring system for prediction of IBD diagnosis Based on the IDEA scoring system and its performance characteristics in the study population, a diagnosis of ulcerative colitis was
Tontini Gian Eugenio et al. Confocal laser endomicroscopy in inflammatory bowel disease … Endoscopy 2015; 47: 437–443
Downloaded by: IP-Proxy University of California, San Francisco, University of California, San Francisco. Copyrighted material.
Clinical, endoscopic, and histopathological definition of ulcerative colitis (n = 39) and Crohn‘s disease (n = 40)
Analysis
Results
439
Original article
Fig. 2 Confocal laser endomicroscopy findings. a Normal colonic crypts in a healthy individual. b Focal cryptitis in a patient with active Crohn’s colitis. c Crypt architectural distortion in a patient with active ulcerative colitis.
Table 3
Confocal laser endomicroscopy findings in patients with Crohn’s disease or ulcerative colitis.
CLE findings
Ulcerative colitis, %
Crohn’s disease, %
P
Severe and widespread architectural distortion
87.2
17.5
< 0.0001
6.3
2.7 – 14.4
Frankly irregular surface
89.7
17.5
< 0.0001
7.7
3.0 – 19.6
Odds ratio
95 %CI
Decreased crypt density
79.5
22.5
< 0.0001
3.8
2.0 – 7.2
Discontinuous crypt architectural abnormality
10.3
87.5
< 0.0001
0.1
0.0 – 0.3
Focal cryptitis
12.8
75.0
< 0.0001
0.2
0.1 – 0.4
5.1
87.5
< 0.0001
0.1
0.0 – 0.2
Heavy and diffuse infiltration within lamina propria
89.7
85.0
0.7370
1.3
0.6 – 2.8
Mucin preservation at active sites
12.8
7.5
0.4814
1.3
0.7 – 2.3
0
–
–
–
Discontinuous inflammation
Granulomas
0
CLE, confocal laser endomicroscopy; CI, confidence interval.
Table 4 Confocal laser endomicroscopy findings in Crohn’s disease population according to Montreal classification and Crohn’s disease endoscopic index of severity.
CLE findings
Number of patients
Overall
40
Montreal classification
CDEIS score
L2
L31
B1
B2
B3
437
Authors
Gian Eugenio Tontini1, 2, Jonas Mudter1, Michael Vieth3, Raja Atreya1, Claudia Günther1, Yurdagül Zopf1, Dane Wildner1, Ralf Kiesslich4, Maurizio Vecchi2, 5, Markus F. Neurath1, Helmut Neumann1
Institutions
Institutions are listed at the end of article.
submitted 8. October 2013 accepted after revision 27. October 2014
Background and study aim: The differential diagnosis of ulcerative colitis from Crohn’s disease is of pivotal importance for the management of inflammatory bowel diseases, as both entities involve specific therapeutic management strategies. Confocal laser endomicroscopy (CLE) allows on-demand, in vivo characterization of architectural and cellular details during endoscopy. The aim of this study was to assess the efficacy of CLE to differentiate between ulcerative colitis and Crohn’s disease. Patients and methods: This was a prospective study involving consecutive patients with a wellestablished diagnosis of ulcerative colitis or Crohn’s disease who underwent colonoscopy with fluorescein-aided confocal imaging. Results: Overall, 79 patients were included (40 Crohn’s disease, 39 ulcerative colitis). CLE findings in patients with Crohn’s disease, showed significantly more discontinuous inflammation (87.5 % vs. 5.1 %), focal cryptitis (75.0 % vs. 12.8 %), and discontinuous crypt architectural abnormality (87.5 % vs. 10.3 %) than in ulcerative colitis
(P < 0.0001). Conversely, ulcerative colitis was associated with severe, widespread crypt distortion (87.2 % vs. 17.5 % in Crohn’s disease), decreased crypt density (79.5 % vs. 22.5 %), and frankly irregular surface (89.7 % vs. 17.5 %; P < 0.0001 for all comparisons). Statistically significant differences were not seen for heavy, diffuse lamina propria cell increase or mucin preservation. No granulomas were visible. Based on these findings, a CLE scoring system was developed that revealed excellent accuracy (93.7 %) when compared with the historical clinical diagnosis and the histopathological gold standard. Conclusions: CLE could visualize several diseasespecific microscopic features, which are conventionally used in standard histopathology to differentiate between ulcerative colitis and Crohn’s disease. However, because of the limited penetration depth of CLE, submucosal details or granulomas were not visible. The new scoring system may allow in vivo diagnosis of ulcerative colitis or Crohn’s disease. Trial registered at ClinicalTrials.gov: NCT 02238665
Introduction
ongoing endoscopy (i. e. in vivo histology) [8]. Recent data have suggested that CLE enables in vivo confirmation of histological changes associated with ulcerative colitis and Crohn’s disease [5, 9 – 12]. CLE has been utilized in a few studies to assess IBD diagnosis [9, 13, 14], disease activity [10, 11], and prediction of disease relapse [15]. Taken together, these studies have underscored the potential usefulness of CLE for the in vivo diagnosis of IBD. However, no study has evaluated the potential of CLE for the in vivo differentiation of ulcerative colitis and Crohn’s disease. The aim of this prospective study, therefore, was to assess the efficacy of CLE to define the differential diagnosis between ulcerative colitis and Crohn’s disease. In addition, variables allowing the differentiation of the two disease entities
Bibliography DOI http://dx.doi.org/ 10.1055/s-0034-1391226 Published online: 18.12.2014 Endoscopy 2015; 47: 437–443 © Georg Thieme Verlag KG Stuttgart · New York ISSN 0013-726X Corresponding author Helmut Neumann, MD, PhD Department of Medicine I University of ErlangenNuremberg Ulmenweg 18 91054 Erlangen Germany Fax: +49-9131-8535209 helmut.neumann@uk-erlangen. de
!
Scan this QR-Code to watch the video comment.
Inflammatory bowel disease (IBD) encompasses two major entities – ulcerative colitis and Crohn’s disease [1]. The differential diagnosis of the two diseases is of paramount importance to the optimization of clinical management, as modern therapies and reliable prognostic indices often involve disease-specific strategies [2 – 4]. The differential diagnosis is currently based on clinical evaluation and a combination of endoscopic, histological, radiological, and biochemical investigations [4, 5]. However, in about 3 % – 6 % of all initial IBD diagnoses made in adult patients, a distinctive diagnosis is not possible, leading to the term of IBD type unclassified [5 – 7]. In 2004, confocal laser endomicroscopy (CLE) was introduced, enabling real-time histology during
Tontini Gian Eugenio et al. Confocal laser endomicroscopy in inflammatory bowel disease … Endoscopy 2015; 47: 437–443
Downloaded by: IP-Proxy University of California, San Francisco, University of California, San Francisco. Copyrighted material.
Confocal laser endomicroscopy for the differential diagnosis of ulcerative colitis and Crohn’s disease: a pilot study
Original article
were identified, and a prediction model was developed to enable the in vivo diagnosis of IBD.
Patients and methods !
Patient enrollment, inclusion, and exclusion Consecutive patients with a well-established diagnosis of ulcerative colitis or Crohn’s disease underwent screening or surveillance colonoscopy for the evaluation of disease activity. Patients were prospectively included between October 2009 and April 2013 at the endoscopy unit of the Department of Medicine I at the University of Erlangen-Nuremberg. All patients signed informed consent after the endoscopist or the attending physician had explained the procedure to them in detail. The study was approved by the local ethical committee of the University of Erlangen-Nuremberg and government authorities, and was conducted in accordance with the declaration of Helsinki. (ClinicalTrials Registration number NCT 02238665.) Patients were included if they met the following inclusion criteria: age ≥ 18 years, ability to provide written informed consent, and a well-established diagnosis of ulcerative colitis or Crohn’s disease. Patients with one or more of the following criteria were excluded from the study: history of IBD reclassification in the last 3 years, Boston Bowel Preparation Scale score < 2 in at least one of the three segments of the colon (i. e. rectum plus left-sided colon, transverse colon plus left and right flexures, right colon) [16], inability to provide written informed consent, severe uncontrolled coagulopathy, impaired renal function, pregnancy or breast feeding, active gastrointestinal bleeding, known allergy to fluorescein, and residence in institutions.
Endoscopic and endomicroscopic procedure All colonoscopies were performed after the patient had undergone standard bowel preparation using either oral sodium phosphate or polyethylene glycol electrolyte lavage solution. CLE was performed using two European Conformity-certified and Food and Drug Administration-approved CLE systems (iCLE, Pentax, Tokyo, Japan; and pCLE, Cellvizio, Mauna Kea Technologies, Paris, France). Conscious sedation with constant monitoring of vital signs was employed (e. g. midazolam hydrochloride and pethidine hydrochloride). Initially, the endoscope was advanced to the colon. On withdrawal, all parts of the colon were evaluated. The Boston Bowel Preparation Scale and inflammation changes were recorded. In patients with ulcerative colitis, inflammatory lesions were classified according to the Mayo Ulcerative Endoscopic Score of Severity (Mayo score), and Crohn’s disease was classified according to the Crohn’s Disease Endoscopic Index of Severity (CDEIS). Briefly, the Mayo score considers four degrees of severity: 0 = normal or inactive disease; 1 = mild disease (erythema, decreased vascular pattern, mild friability); 2 = moderate disease (frank friability, marked erythema, absent vascular pattern, erosions); 3 = severe disease (mucopus, spontaneous bleeding, and ulceration) [17]. The CDEIS calculates disease activity according to five endoscopically visualized segments (rectum, sigmoid/left colon, transverse colon, right colon, terminal ileum), and findings, including ulcer size, extent of disease (surface with disease involvement and surface with ulcer involvement), and stenosis. The CDEIS score ranges from 0 to 44, with a higher score indicating more severe disease [18]. In the current study, a CDEIS score of < 3 suggested
inactive disease, ≥ 3 to < 9 mildly active, ≥ 9 to < 12 moderately active, and ≥ 12 severely active disease [19]. For confocal imaging, 5 mL of fluorescein sodium 10 % (Alcon Laboratories, Texas, USA) was administered intravenously to optimize tissue contrast [20]. Endomicroscopy was performed at a minimum of five random sites in the colon after careful washing of the mucosa with water in order to prevent the inclusion of image artefacts from residual stool fragments. Careful attention was paid to ensure high-quality images in focus either by using iCLE or pCLE. The confocal images were first analyzed during the endoscopy. Then, the images were digitally stored and reviewed after the procedure in order to zoom in on details (iCLE) for a higher magnification (approximately 10 000 fold) or by using the Cellvizio Viewer for virtual staining of mucosal structures to enhance tissue contrast. iCLE images were collected at a frame rate of 0.8 /second at 1024 × 1024 pixels or 1.6/second at 1024 × 512 pixels. Normal mucosa and pathological lesions were evaluated according to the Mainz confocal pattern classification for iCLE [21] and the Miami classification for pCLE [22]. Colonoscopy with CLE was performed in vivo by two expert endoscopists who were aware of the patients’ history and endoscopic results. The digitally stored confocal images were reviewed blinded to the true diagnosis. Based on previous histological studies that focused on the diagnosis of ulcerative colitis and Crohn’s disease, the CLE examination aimed at evaluating the following features: severe and widespread architectural distortion, frankly irregular surface, decreased crypt density, discontinuous crypt architecture, focal cryptitis, heavy and diffuse cell infiltration within the lamina propria, mucin preservation at active sites, discontinuous inflammation, and granulomas [5, 12]. Multiple biopsies were taken from both macroscopically normal and abnormal mucosa after confocal examination. Specimens were retrieved and fixed in 4 % buffered formalin for subsequent histopathological analysis to confirm the diagnosis. Patients’ diagnoses, defined according to the Montreal classification [6], were based on medical history, endoscopy, and histopathology.
CLE scoring system for prediction of IBD diagnosis A simplified scoring system was developed based on CLE findings that showed a significant difference between patients with ulcerative colitis and those with Crohn’s disease. The score was initially developed based on the method proposed by Pera et al. for ileo-colonoscopy [23], which used the likelihood ratios of the individual endoscopic findings. However, we found that the use of likelihood ratios or any similar method based on accuracy ratios, greatly increased the CLE score range and complexity with no impact on either accuracy or variability. Because of this, for the current study a number of simulations were performed, which involved the allocation of 1 – 5 points for each CLE finding with a positive likelihood ratio for ulcerative colitis, and – 1 to – 5 points for those with a higher sensitivity for Crohn’s disease. Finally, each score system was tested using all possible cutoff levels and assessed for sensibility, specificity, and accuracy. The overall best performance was provided by the endoscopic score system that involved the allocation of 3 points for the presence of each ulcerative colitis-related sign and one additional point for the absence of each Crohn’s disease-related sign, with the diagnosis cutoff level set at 6 points. The score scale ranged from the minimum value of 0 (highly predictive for Crohn’s disease) to the maximum value of 12 points (highly predictive for ulcerative co-
Tontini Gian Eugenio et al. Confocal laser endomicroscopy in inflammatory bowel disease … Endoscopy 2015; 47: 437–443
Downloaded by: IP-Proxy University of California, San Francisco, University of California, San Francisco. Copyrighted material.
438
Original article
litis). The score has been called the IBD Differentiation based on Endomicroscopic Assessment (IDEA) scoring system.
Assessed for eligibility: Patients with ulcerative colitis or Crohn‘s disease submitted for colonoscopy (n = 105)
Statistical analysis
Excluded patients (n = 26): ▪ Suboptimal bowel preparation (n = 7) ▪ IBD-type reclassification within the last 3 years (n = 6) ▪ Poor historical documentation addressing the previous disease classification (n = 13)
All statistical analyses were performed using PASW Statistics 18 (SPSS, Inc., Chicago, USA). A two-sided P value of < 0.05 was considered to be significant. For comparisons of proportions between ulcerative colitis and Crohn’s colitis, such as crypt architecture, presence of microerosions, and vascular pattern between the different groups, the Fisher’s exact test was used. The median is presented for non-normally distributed variables, and the mean is shown for normally distributed variables. The ranges presented indicate the minimum and maximum values.
Confocal laser endomicroscopy (n = 79)
Fig. 1
CONSORT 2010 flow diagram.
!
Patient characteristics The endoscopic disease activity was prospectively evaluated in 105 patients with a previous well-established diagnosis of colonic IBD. A total of 79 of them fulfilled the inclusion criteria and underwent a complete colonoscopic examination using CLE " Fig. 1). There were 40 patients with Crohn’s disease (median (● age 35.5 ± 12.7 years [range 18 – 73]; 17 females) and 39 with ulcerative colitis (median age 39.9 ± 12.0 years [range 21 – 63]; 10 females). The demographic and clinical data of patients are " Table 1 and " Table 2. A total of 26 patients were exshown in ● ● cluded because of suboptimal bowel preparation, IBD-type reclassification in the last 3 years, or poor historical documentation addressing the previous disease classification.
Table 1 Baseline characteristics of patients with Crohn’s disease and ulcerative colitis.
Baseline characteristics
Crohn’s disease
Ulcerative colitis
Patients, n
40
39
Females, n (%)
17 (42.5)
10 (25.6)
Age, median (range), years
35.5 (18 – 73)
39.9 (21 – 63)
Years from diagnosis, median (range)
10 (3 – 30)
11 (3 – 23)
Table 2 Characterization of Crohn’s disease and ulcerative colitis study populations based on clinical data.
Clinical data
Endomicroscopic evaluation
Crohn’s disease, n = 40
CLE enabled a clear characterization of seven out of the eight architectural and inflammatory changes investigated in the present study: severe and widespread architectural distortion, frankly irregular surface, decreased crypt density, discontinuous crypt architectural abnormality, focal cryptitis, heavy and diffuse cell infiltration within the lamina propria, mucin preservation at active " Fig. 2 a – c). No granusites, and discontinuous inflammation (● " Table 3 shows the CLE findings in lomas were detected by CLE. ● patients. In ulcerative colitis, CLE images showed higher prevalence of severe and widespread architectural distortion (87.2 %, P < 0.0001), frankly irregular surface (89.7 %, P < 0.0001), and decreased crypt density (79.5 %, P < 0.0001) compared with Crohn’s disease patients (17.5 %, 17.5 %, and 22.5 %, respectively). Conversely, CLE images collected from patients with Crohn’s disease showed a greater amount of discontinuous crypt architectural abnormality (87.5 %, P < 0.0001), focal cryptitis (75.0 %, P < 0.0001), and discontinuous inflammation (87.5 %, P < 0.0001) compared with patients with ulcerative colitis (10.3 %, 12.8 %, and 5.1 %, respectively). In both groups of patients, CLE images presented heavy and diffuse infiltration within the lamina propria (85.0 % in Crohn’s disease and 89.7 % in ulcerative colitis; P = 0.7370) and low grade of mucin preservation at active site (7.5 % and 12.8 %, respectively; P = 0.4814). There were no meaningful differences in the frequencies of CLE findings according to either the Montreal classification or the endoscopic disease severity (i. e. Mayo or CDEIS) for both ulcera" Table 4, tive colitis patients and those with Crohn’s disease (● " Table 5). ●
Montreal classification
Number of patients
L2
11
L3
27
L3 /L4
2
CDEIS score < 3 (mean CRP 11 mg/dL) ≥ 3 to < 9 (mean CRP 4 mg/dL) ≥ 9 to < 12 (mean CRP 24 mg/dL) ≥ 12 (mean CRP 41 mg/dL) Ulcerative colitis, n = 39
8 16 5 11
Montreal classification E1
3
E2
12
E3
24
Mayo endoscopic subscore 0
8
1
15
2
8
3
8
CDEIS, Crohn’s Disease Endoscopic Index of severity; CRP, C-reactive protein.
The mean procedure time was 10 minutes for the in vivo CLE examination and 10 minutes to review the digitally stored confocal images after the endoscopy procedure. No differences in image interpretation were observed between the iCLE and pCLE CLE systems, although this was not an aim of the study.
CLE scoring system for prediction of IBD diagnosis Based on the IDEA scoring system and its performance characteristics in the study population, a diagnosis of ulcerative colitis was
Tontini Gian Eugenio et al. Confocal laser endomicroscopy in inflammatory bowel disease … Endoscopy 2015; 47: 437–443
Downloaded by: IP-Proxy University of California, San Francisco, University of California, San Francisco. Copyrighted material.
Clinical, endoscopic, and histopathological definition of ulcerative colitis (n = 39) and Crohn‘s disease (n = 40)
Analysis
Results
439
Original article
Fig. 2 Confocal laser endomicroscopy findings. a Normal colonic crypts in a healthy individual. b Focal cryptitis in a patient with active Crohn’s colitis. c Crypt architectural distortion in a patient with active ulcerative colitis.
Table 3
Confocal laser endomicroscopy findings in patients with Crohn’s disease or ulcerative colitis.
CLE findings
Ulcerative colitis, %
Crohn’s disease, %
P
Severe and widespread architectural distortion
87.2
17.5
< 0.0001
6.3
2.7 – 14.4
Frankly irregular surface
89.7
17.5
< 0.0001
7.7
3.0 – 19.6
Odds ratio
95 %CI
Decreased crypt density
79.5
22.5
< 0.0001
3.8
2.0 – 7.2
Discontinuous crypt architectural abnormality
10.3
87.5
< 0.0001
0.1
0.0 – 0.3
Focal cryptitis
12.8
75.0
< 0.0001
0.2
0.1 – 0.4
5.1
87.5
< 0.0001
0.1
0.0 – 0.2
Heavy and diffuse infiltration within lamina propria
89.7
85.0
0.7370
1.3
0.6 – 2.8
Mucin preservation at active sites
12.8
7.5
0.4814
1.3
0.7 – 2.3
0
–
–
–
Discontinuous inflammation
Granulomas
0
CLE, confocal laser endomicroscopy; CI, confidence interval.
Table 4 Confocal laser endomicroscopy findings in Crohn’s disease population according to Montreal classification and Crohn’s disease endoscopic index of severity.
CLE findings
Number of patients
Overall
40
Montreal classification
CDEIS score
L2
L31
B1
B2
B3
