Polyp size measurement during colonoscopy using a virtual scale: variability and systematic differences.

BACKGROUND: Accurate polyp size measurement is important for polyp risk stratification and decision-making regarding polypectomy and surveillance. Recently, a virtual scale (VS) function has been developed that allows polyp size measurement through projection of an adaptive VS onto colorectal polyps during real-time endoscopy. We aimed to evaluate the VS in terms of variability and systematic differences. METHODS: We conducted a video-based study with 120 colorectal polyps, measured by eight dedicated colorectal gastroenterologists (experts) and nine gastroenterology residents following endoscopy training (trainees). Three endoscopic measurement methods were compared: (1) visual, (2) snare and (3) VS measurement. We evaluated the method-specific variance (as measure of variability) in polyp size measurements and systematic differences between these methods. RESULTS: Variance in polyp size measurements was significantly lower for VS measurements compared to visual and snare measurements for both experts (0.52 vs. 1.59 and 1.96, p<0.001) and trainees (0.59 vs. 2.21 and 2.53, p<0.001). VS measurement resulted in a higher percentage of polyps assigned to the same size category by all endoscopists compared to visual and snare measurements (experts: 69% vs. 55% and 59%; trainees: 67% vs. 51% and 47%) and reduced the maximum difference between individual endoscopists regarding the percentage of polyps assigned to the >10 mm size category (experts: 1.7% vs. 10.0% and 5.0%; trainees: 2.5% vs. 6.7% and 11.7%). Systematic differences between methods were <0.5 mm. Conclusions Use of the VS leads to lower polyp size measurement variability and more uniform polyp sizing by individual endoscopists compared to visual and snare measurements.

Limited wedge resection for T1 colon cancer (LIMERIC-II trial) - rationale and study protocol of a prospective multicenter clinical trial.

BACKGROUND: The sole presence of deep submucosal invasion is shown to be associated with a limited risk of lymph node metastasis. This justifies a local excision of suspected deep submucosal invasive colon carcinomas (T1 CCs) as a first step treatment strategy. Recently Colonoscopy-Assisted Laparoscopic Wedge Resection (CAL-WR) has been shown to be able to resect pT1 CRCs with a high R0 resection rate, but the long term outcomes are lacking. The aim of this study is to evaluate the safety, effectiveness and long-term oncological outcomes of CAL-WR as primary treatment for patients with suspected superficial and also deeply-invasive T1 CCs. METHODS: In this prospective multicenter clinical trial, patients with a macroscopic and/or histologically suspected T1 CCs will receive CAL-WR as primary treatment in order to prevent unnecessary major surgery for low-risk T1 CCs. To make a CAL-WR technically feasible, the tumor may not include > 50% of the circumference and has to be localized at least 25 cm proximal from the anus. Also, there should be sufficient distance to the ileocecal valve to place a linear stapler. Before inclusion, all eligible patients will be assessed by an expert panel to confirm suspicion of T1 CC, estimate invasion depth and subsequent advise which local resection techniques are possible for removal of the lesion. The primary outcome of this study is the proportion of patients with pT1 CC that is curatively treated with CAL-WR only and in whom thus organ-preservation could be achieved. Secondary outcomes are 1) CAL-WR's technical success and R0 resection rate for T1 CC, 2) procedure-related morbidity and mortality, 3) 5-year overall and disease free survival, 4) 3-year metastasis free survival, 5) procedure-related costs and 6) impact on quality of life. A sample size of 143 patients was calculated. DISCUSSION: CAL-WR is a full-thickness local resection technique that could also be effective in removing pT1 colon cancer. With the lack of current endoscopic local resection techniques for > 15 mm pT1 CCs with deep submucosal invasion, CAL-WR could fill the gap between endoscopy and major oncologic surgery. The present study is the first to provide insight in the long-term oncological outcomes of CAL-WR. TRIAL REGISTRATION: CCMO register (ToetsingOnline), NL81497.075.22, protocol version 2.3 (October 2022).

Colonoscopy surveillance in Lynch syndrome is burdensome and frequently delayed.

Individuals with Lynch syndrome have an increased colorectal cancer risk, hence, biennial colonoscopy surveillance is recommended. We aimed to investigate patients' perception and preferences regarding surveillance, and to further explore compliance behaviour. Individuals with Lynch syndrome received a validated survey evaluating experiences of their three most recent colonoscopies. Individuals were non-compliant to surveillance if the interval between colonoscopies differed ≥ 6 months from the recommended interval. In total, 197 of 291 (68%) invited individuals returned the survey. They mostly underwent colonoscopy biennially (99%), under mild sedation (79%) and with bowel preparation performed by Moviprep® (99%). Surveillance was perceived as impacting quality of life in 21%, and as moderately to extremely burdensome in 57%, particularly in those below age 40. To lower the burden, patients prioritised improvements in volume and taste of bowel preparation, laxation-related bowel movements, waiting times, and a more personal and respectful approach of endoscopic staff. Additionally, many individuals (60%) would favour less-invasive surveillance modalities such as biomarkers. In total, 28% of individuals had delayed colonoscopy surveillance, predominantly for patient-related reasons. An additional 10% considered quitting/postponing surveillance. Upon multivariable analysis, patient-related delay was associated with low and medium education, history of ≤ 4 colonoscopies and having no hospital recall-system. Colonoscopy surveillance in Lynch syndrome is often experienced as burdensome, and frequently delayed. We identified determinants of surveillance behaviour in this population, and present potential interventions to reduce the burden and non-compliance rates.

Urinary volatile organic compounds for colorectal cancer screening: A systematic review and meta-analysis.

BACKGROUND: The faecal immunochemical test (FIT) suffers from suboptimal performance and participation in colorectal cancer (CRC) screening. Urinary volatile organic compounds (VOCs) may be a useful alternative. We aimed to determine the diagnostic potential of urinary VOCs for CRC/adenomas. By relating VOCs to known pathways, we aimed to gain insight into the pathophysiology of colorectal neoplasia. METHODS: A systematic search was performed in PubMed, EMBASE and Web of Science. Original studies on urinary VOCs for CRC/adenoma detection with a control group were included. QUADAS-2 tool was used for quality assessment. Meta-analysis was performed by adopting a bivariate model for sensitivity/specificity. Fagan's nomogram estimated the performance of combined FIT-VOC. Neoplasm-associated VOCs were linked to pathways using the KEGG database. RESULTS: Sixteen studies-involving 837 CRC patients and 1618 controls-were included; 11 performed chemical identification and 7 chemical fingerprinting. In all studies, urinary VOCs discriminated CRC from controls. Pooled sensitivity and specificity for CRC based on chemical fingerprinting were 84% (95% CI 73-91%) and 70% (95% CI 63-77%), respectively. The most distinctive individual VOC was butanal (AUC 0.98). The estimated probability of having CRC following negative FIT was 0.38%, whereas 0.09% following negative FIT-VOC. Combined FIT-VOC would detect 33% more CRCs. In total 100 CRC-associated urinary VOCs were identified; particularly hydrocarbons, carboxylic acids, aldehydes/ketones and amino acids, and predominantly involved in TCA-cycle or alanine/aspartate/glutamine/glutamate/phenylalanine/tyrosine/tryptophan metabolism, which is supported by previous research on (colorectal)cancer biology. The potential of urinary VOCs to detect precancerous adenomas or gain insight into their pathophysiology appeared understudied. CONCLUSION: Urinary VOCs hold potential for non-invasive CRC screening. Multicentre validation studies are needed, especially focusing on adenoma detection. Urinary VOCs elucidate underlying pathophysiologic processes.

Colonoscopic-Assisted Laparoscopic Wedge Resection for Colonic Lesions: A Prospective Multicenter Cohort Study (LIMERIC-Study).

OBJECTIVE: The aim of this study was to evaluate the safety and efficacy of a modified CAL-WR. SUMMARY BACKGROUND DATA: The use of segmental colectomy in patients with endoscopically unresectable colonic lesions results in significant morbidity and mortality. CAL-WR is an alternative procedure that may reduce morbidity. METHODS: This prospective multicenter study was performed in 13 Dutch hospitals between January 2017 and December 2019. Inclusion criteria were (1) colonic lesions inaccessible using current endoscopic resection techniques (judged by an expert panel), (2) non-lifting residual/recurrent adenomatous tissue after previous polypectomy or (3) an undetermined resection margin after endoscopic removal of a low-risk pathological T1 (pT1) colon carcinoma. Thirty-day morbidity, technical success rate and radicality were evaluated. RESULTS: Of the 118 patients included (56% male, mean age 66 years, standard deviation ± 8 years), 66 (56%) had complex lesions unsuitable for endoscopic removal, 34 (29%) had non-lifting residual/recurrent adenoma after previous polypectomy and 18 (15%) had uncertain resection margins after polypectomy of a pT1 colon carcinoma. CAL-WR was technically successful in 93% and R0 resection was achieved in 91% of patients. Minor complications (Clavien-Dindo i-ii) were noted in 7 patients (6%) and an additional oncologic segmental resection was performed in 12 cases (11%). Residual tissue at the scar was observed in 5% of patients during endoscopic follow-up. CONCLUSIONS: CAL-WR is an effective, organ-preserving approach that results in minor complications and circumvents the need for major surgery. CAL-WR, therefore, deserves consideration when endoscopic excision of circumscribed lesions is impossible or incomplete.

Systematic review: non-endoscopic surveillance for colorectal neoplasia in individuals with Lynch syndrome.

BACKGROUND: Individuals with Lynch syndrome are at high risk for colorectal cancer (CRC). Regular colonoscopies have proven to decrease CRC incidence and mortality. However, colonoscopy is burdensome and interval CRCs still occur. Hence, an accurate, less-invasive screening method that guides the timing of colonoscopy would be of important value. AIM: To outline the performance of non-endoscopic screening modalities for Lynch-associated CRC and adenomas. METHODS: Systematic literature search in MEDLINE and EMBASE to identify studies investigating imaging techniques and biomarkers for detection of CRC and adenomas in Lynch syndrome. The QUADAS-2 tool was used for the quality assessment of included studies. RESULTS: Seven of 1332 screened articles fulfilled the inclusion criteria. Two studies evaluated either CT colonography or MR colonography; both techniques were unable to detect CRC and (advanced) adenomas <10 mm. The other five studies evaluated plasma methylated-SEPTIN9, faecal immunochemical test (FIT), faecal tumour DNA markers (BAT-26, hMLH1, p53, D9S171, APC, D9S162, IFNA and DCC) and faecal microbiome as screening modalities. Sensitivity for CRC varied from 33% (BAT-26) to 70% (methylated-SEPTIN9) to 91% (hMLH1). High specificity (94-100%) for CRC and/or adenomas was observed for methylated-SEPTIN9, FIT and BAT-26. Desulfovibrio was enriched in the stool of patients having adenomas. However, all these studies were characterised by small populations, high/unclear risk of bias and/or low prevalence of adenomas. CONCLUSIONS: Imaging techniques are unsuitable for colon surveillance in Lynch syndrome, whereas biomarkers are understudied. Having outlined biomarker research in Lynch-associated and sporadic CRC/adenomas, we believe that these non-invasive markers may hold potential (whether or not combined) for this population. As they could be of great value, (pre-)clinical studies in this field should be prioritised.

Outcomes of push and pull percutaneous endoscopic gastrostomy placements in 854 patients: A single-center study.

BACKGROUND AND AIMS: Percutaneous endoscopic gastrostomy (PEG) is indicated for prolonged enteral nutrition. This study aimed to analyze the outcome and to identify potential risk factors for complications in PEG procedures. METHODS: A single-center retrospective analysis of the performed PEG procedures during the period January 2010 till January 2020. RESULTS: A PEG placement procedure was performed in 854 patients (64.1% male) and was successful in 833 (97.5%). In total, 513 push (61.6%) and 320 pull (38.6%) PEGs were placed. The mean age was 60.7 years, and the median follow-up was 267 days. The push PEG was associated with peri-procedural bleeding (P = 0.002) and tube dislodgements (P < 0.001), while the pull PEG was significantly associated with buried bumpers (P < 0.001), infected placement sites (P = 0.019), and granulation tissue formation (P = 0.044). The PEG-related mortality rate was 0.2%, but the overall 30-day mortality was 4.0%. CONCLUSION: The current study showed that the push and pull PEG placements are both safe and feasible procedures, with a low PEG-related mortality. Buried bumpers, infected placement sites, and granulation tissue formation are more often seen in the pull PEG, while the push PEG is associated with periprocedural bleeding and tube dislodgements. These complications should be taken into account and there is a need for a prospective trial to identify superiority between the PEG methods.

Real-life data on the impact of successful downstaging in patients with hepatocellular carcinoma: A Dutch Multicenter Study.

Patients with Barcelona Clinic Liver Cancer intermediate stage hepatocellular carcinoma (HCC) theoretically are an excellent group to consider downstaging using locoregional therapy (LRT) since they do not have extrahepatic spread or vascular invasion. Once successful, this can change the treatment strategy from palliative to curative intention. Although downstaging therapy is suggested in guidelines, it is still not widely accepted. Moreover, studies on downstaging are mainly performed in high-incidence HCC countries. Therefore, our aim was to gain insight in therapeutic strategies in patients with intermediate stage HCC and their impact on intention-to-treat survival in a real-life setting in a low-incidence HCC country. We retrospectively analyzed data from the national Dutch HCC registry. From this database, consisting of 1409 patients with a diagnosis of HCC between 2005-2013 in 5 Dutch tertiary referral centers, we identified 165 patients with intermediate stage HCC. Out of these patients, 63 (38%) were not offered LRT, whereas 102 (62%) did receive LRT. Subsequently, 50 (49%) of the 102 patients who received LRT were successfully downstaged. Eleven patients (22% of successfully downstaged patients) eventually underwent liver transplantation. Cox regression analysis showed that a lower MELD score, an AFP value <100 ng/ml, successful downstaging and liver transplantation (all ≤p = 0.01) were positively associated to overall survival. In conclusion, our results demonstrate that LRT is not routinely offered to intermediate stage HCC patients in the Netherlands. Nevertheless, we showed that patients with intermediate stage HCC who are successfully downstaged have a survival benefit compared to those who were not.

Systematic Review with Meta-Analysis: Diagnostic Accuracy of Pro-C3 for Hepatic Fibrosis in Patients with Non-Alcoholic Fatty Liver Disease.

The prevalence and severity of non-alcoholic fatty liver disease (NAFLD) is increasing, yet adequately validated tests for care paths are limited and non-invasive markers of disease progression are urgently needed. The aim of this work was to summarize the performance of Pro-C3, a biomarker of active fibrogenesis, in detecting significant fibrosis (F ≥ 2), advanced fibrosis (F ≥ 3), cirrhosis (F4) and non-alcoholic steatohepatitis (NASH) in patients with NAFLD. A sensitive search of five databases was performed in July 2021. Studies reporting Pro-C3 measurements and liver histology in adults with NAFLD without co-existing liver diseases were eligible. Meta-analysis was conducted by applying a bivariate random effects model to produce summary estimates of Pro-C3 accuracy. From 35 evaluated reports, eight studies met our inclusion criteria; 1568 patients were included in our meta-analysis of significant fibrosis and 2058 in that of advanced fibrosis. The area under the summary curve was 0.81 (95% CI 0.77-0.84) in detecting significant fibrosis and 0.79 (95% CI 0.73-0.82) for advanced fibrosis. Our results support Pro-C3 as an important candidate biomarker for non-invasive assessment of liver fibrosis in NAFLD. Further direct comparisons with currently recommended non-invasive tests will demonstrate whether Pro-C3 panels can outperform these tests, and improve care paths for patients with NAFLD.

Clinical Course of Nodular Regenerative Hyperplasia in Thiopurine Treated Inflammatory Bowel Disease Patients.

Nodular regenerative hyperplasia (NRH) is a poorly understood liver condition, which is increasingly recognized in thiopurine-treated patients with inflammatory bowel disease (IBD).1 It is difficult to establish an optimal approach to NRH patients, because its manifestations are highly variable (from asymptomatic to symptoms of noncirrhotic portal hypertension [NCPH]) and the prognosis is unknown.2 The aim of this study was to identify NRH cases in IBD patients treated with azathioprine, mercaptopurine, and/or thioguanine, and to describe its clinical course.

Transient elastography to assess liver stiffness in patients with inflammatory bowel disease.

BACKGROUND: Liver injury during inflammatory bowel disease (IBD) is primarily diagnosed by liver biopsy, which has a small but serious risk of severe complications. The aim of this study was to assess liver stiffness, and subsequently the prevalence and associations of liver fibrosis in IBD patients with thiopurine therapy and other clinical factors, by using transient elastography (TE). METHODS: In this prospective, international two-center study, included IBD-patients underwent TE measurements. Laboratory results and medication reports, radiology results and historical liver biopsy results were extracted from the patient charts. RESULTS: Transient elastography results of 168 patients were presented. Moderate and severe fibrosis were detected in 4% (7/168) and 1% (1/168) of the cohort, respectively. Factors contributing to lower liver stiffness were female gender and (historical) exposure to azathioprine. Further, there was a statistical trend towards lower liver stiffness in patients using thiopurines overall (4.7 vs. 5.2kPa, p=0.07). Liver stiffness correlated positively with waist circumference, liver enzyme tests, hemoglobin and 6-methylmercaptopurine concentration and negatively with platelet count. CONCLUSION: Exposure to thiopurine therapy was not associated with higher liver stiffness, although no clinical difference in severity of fibrosis was detected. Further research should robustly determine the accuracy of TE as an evaluation of liver fibrosis in IBD patients.

Reversible severe hepatitis in anorexia nervosa: a case report and overview.

Mildly elevated transaminases are often observed in anorexia nervosa patients, but severe hepatitis is less common. We suggest that hypoperfusion is the pathogenetic factor that causes severe hepatitis in a patient with a very poor nutritional status and present an overview of previous case reports. In our patient, early initiation of intravenous fluids resulted in rapid recovery of the liver test abnormalities, despite minimal oral caloric intake, the refusal of enteral feeding and the development of a hypoglycemic coma. Two months after admission, transaminases had normalized. Reversible severe hepatitis has been described in most of the cases, with only one anorexia nervosa-related fatal hepatitis. In general, both adequate hydration and gradual enteral feeding with monitoring of electrolytes are essential in the management of anorexia patients with severe hepatitis.

Yield of routine molecular analyses in colorectal cancer patients ≤70 years to detect underlying Lynch syndrome.

Although early detection of Lynch syndrome (LS) is important, a considerable proportion of patients with LS remains unrecognized. We aimed to study the yield of LS detection by routine molecular analyses in colorectal cancer (CRC) patients until 70 years of age. We prospectively included consecutive CRC patients ≤70 years. Tumour specimens were analysed for microsatellite instability (MSI), immunohistochemical mismatch-repair protein expression and MLH1-promoter methylation. Tumours were classified as either: (a) likely caused by LS; (b) sporadic microsatellite-unstable (MSI-H); or (c) microsatellite-stable (MSS). Predictors of LS were determined by multivariable logistic regression. A total of 1117 CRC patients (57% males, median age 61 years) were included. Fifty patients (4.5%, 95% CI 3.4-5.9) were likely to have LS, and 71 had a sporadic MSI-H tumour (6.4%, 95% CI 5.1-8.0). Thirty-five patients likely to have LS (70%) were aged > 50 years. A molecular profile compatible with LS was detected in 10% (15/144) of patients aged ≤50, in 4% (15/377) of those aged 51-60 and in 3% (20/596) of patients > 61 years. Compared to MSS cases, patients likely to have LS were significantly younger (OR 3.9, 95% CI 1.7-8.7) and more often had right-sided CRCs (OR 14, 95% CI 6.0-34). In conclusion, molecular screening for LS in CRC patients ≤70 years leads to identification of a molecular profile compatible with LS in 4.5% of patients, with most of them not fulfilling the age criterion (≤50 years) routinely used for LS assessment. Routine use of MSI testing may be considered in CRC patients up to the age of 70 years, with a central role for the pathologist in the selection of patients.

[Reactivation of hepatitis B infection due to glucocorticoids]. / Reactivatie van hepatitis B door glucocorticoïden.

A 55-year-old female started treatment with prednisone for peripheral facial nerve paralysis. After three months she was admitted to hospital with suspected cholecystitis. However, while in hospital her liver function deteriorated. Virological tests showed she had a hepatitis B infection. Another patient, a 71-year-old male, was treated with prednisone for polymyalgia rheumatica. A few weeks after starting therapy he was admitted to hospital with general malaise and weight loss. Laboratory results showed elevated values of liver function tests. Viral serology was positive for hepatitis B infection. Both patients proved to have reactivation of hepatitis B due to using prednisone. Neither patient had received preventive antiviral therapy. In patients with chronic hepatitis B infection, preventive antiviral therapy should be started before treatment with glucocorticoids is initiated.

A back-to-back comparison of white light video endoscopy with autofluorescence endoscopy for adenoma detection in high-risk subjects.

OBJECTIVE: To compare the sensitivity of autofluorescence endoscopy (AFE) and white light video endoscopy (WLE) for the detection of colorectal adenomas in high-risk patients belonging to Lynch syndrome (LS) or familial colorectal cancer (CRC) families. METHODS: This was a prospective single-centre study carried out in a tertiary referral centre. The subjects were 75 asymptomatic patients originating from LS or familial CRC families. Patients were examined with either WLE followed by AFE or AFE followed by WLE. Back-to-back colonoscopy was performed by two blinded endoscopists. All lesions were removed during the second endoscopic procedure. Lesions missed during the second procedure were identified and removed on third pass. The sensitivity calculations for colorectal adenomas were based on histology results. The main outcome measures were the difference in sensitivity between WLE and AFE for the detection of adenomas in patients with LS or familial CRC. RESULTS: At least one adenoma was detected in 41 (55%) patients. WLE identified adenomas in 28/41 patients and AFE in 37/41 patients, corresponding to a 32% increase. In total 95 adenomas were detected, 65 by WLE and 87 by AFE, resulting in a significantly higher sensitivity of AFE compared with WLE (92% vs 68%; p=0.001). The additionally detected adenomas with AFE were significantly smaller than the adenomas detected by WLE (mean 3.0 mm vs 4.9 mm, p<0.01). CONCLUSIONS: AFE improves the detection of colorectal adenomas in patients with LS or familial CRC. The results of this study suggest that AFE may be preferable for surveillance of these high-risk patients.

Cancer risk in MLH1, MSH2 and MSH6 mutation carriers; different risk profiles may influence clinical management.

BACKGROUND: Lynch syndrome (LS) is associated with a high risk for colorectal cancer (CRC) and extracolonic malignancies, such as endometrial carcinoma (EC). The risk is dependent of the affected mismatch repair gene. The aim of the present study was to calculate the cumulative risk of LS related cancers in proven MLH1, MSH2 and MSH6 mutation carriers. METHODS: The studypopulation consisted out of 67 proven LS families. Clinical information including mutation status and tumour diagnosis was collected. Cumulative risks were calculated and compared using Kaplan Meier survival analysis. RESULTS: MSH6 mutation carriers, both males and females had the lowest risk for developing CRC at age 70 years, 54% and 30% respectively and the age of onset was delayed by 3-5 years in males. With respect to endometrial carcinoma, female MSH6 mutation carriers had the highest risk at age 70 years (61%) compared to MLH1 (25%) and MSH2 (49%). Also, the age of EC onset was delayed by 5-10 years in comparison with MLH1 and MSH2. CONCLUSIONS: Although the cumulative lifetime risk of LS related cancer is similar, MLH1, MSH2 and MSH6 mutations seem to cause distinguishable cancer risk profiles. Female MSH6 mutation carriers have a lower CRC risk and a higher risk for developing endometrial carcinoma. As a consequence, surveillance colonoscopy starting at age 30 years instead of 20-25 years is more suitable. Also, prophylactic hysterectomy may be more indicated in female MSH6 mutation carriers compared to MLH1 and MSH2 mutation carriers.

The temporal course of mucoperiosteal flap revascularization at guided bone regeneration-treated implant sites: a pilot study.

AIMS: To investigate post-operative capillary density regeneration in healing mucoperiosteal flaps at guided bone regeneration-treated implant sites. MATERIAL AND METHODS: A non-invasive post-operative investigation was performed in 10 patients using orthogonal polarization spectral (OPS) imaging for assessment of capillary density during the course of mucoperiosteal flap wound healing for 6 weeks in patients receiving dental implants. RESULTS: The greatest increase in capillary regeneration occurred in the early wound-healing phase, during weeks 1 and 2, and recovery to baseline was achieved between weeks 4 and 5. A comparison of adjacent OPS measurements indicated that differences between the time point immediately following administration of local anaesthesia and directly post-operatively ( p=0.002), between a directly post-operative time point and after 1 week (p=0.009), and between post-operative weeks 1 and 2 (p=0.036) were statistically significant. CONCLUSIONS: The early healing phase of mucoperiosteal flaps is characterized by rapid capillary regeneration. OPS imaging enabled the possibility to monitor and quantify the temporal development of mucoperiosteal flap revascularization following periodontal surgery.