The Belgian national registry on chronic pancreatitis: A prospective multi-centre study covering more than 800 patients in one year.

BACKGROUND/OBJECTIVES: The epidemiology, natural history, complications, and therapeutic management of chronic pancreatitis (CP) are not well described at the national level. This multi-centre prospective observational study involving eight Belgian hospitals aimed to improve the understanding of these aspects of CP in Belgium. METHODS: All patients with a diagnosis of CP based on imaging were eligible for this study. Data were gathered regarding epidemiology, etiology, CP complications, and treatment modalities. RESULTS: A total of 809 patients were included between 1/9/2014 and 31/8/2015. Most patients (794) were adults ≥16-years old, 74% were male, the median age at symptom onset was 47 (38-57) years, the median disease duration was 7 (3-13) years, and the median Izbicki pain score (IPS) was 96 (0-195). The main etiological risk factors according to the TIGAR-O classification were alcohol and tobacco (67%). Current drinkers had lower body mass index (BMI) (21.4 kg/m2 vs 24.1 kg/m2), higher IPS (110 vs 56), and longer inability to work than non-drinkers. Current smokers had lower BMI (21.5 kg/m2 vs 25 kg/m2) and higher IPS (120 vs 30) than non-smokers. Endocrine insufficiency and/or clinical steatorrhea was recorded in 41% and 36% of patients, respectively. The highest IPS was reported in patients with ongoing endotherapy (166 vs 50 for patients who completed endoscopy). CONCLUSION: This multicentric study on CP patients showed that current alcohol drinking and smoking are associated with pain and malnutrition. Pain scores were higher in patients with ongoing endotherapy, independently of surgery.

A Method for Delineation of Bone Surfaces in Photoacoustic Computed Tomography of the Finger.

Photoacoustic (PA) imaging of interphalangeal peripheral joints is of interest in the context of using the synovial membrane as a surrogate marker of rheumatoid arthritis. Previous work has shown that ultrasound (US) produced by absorption of light at the epidermis reflects on the bone surfaces within the finger. When the reflected signals are backprojected in the region of interest, artifacts are produced, confounding interpretation of the images. In this work, we present an approach where the PA signals known to originate from the epidermis are treated as virtual US transmitters, and a separate reconstruction is performed as in US reflection imaging. This allows us to identify the bone surfaces. Furthermore, the identification of the joint space is important as this provides a landmark to localize a region-of-interest in seeking the inflamed synovial membrane. The ability to delineate bone surfaces allows us to identify not only the artifacts but also the interphalangeal joint space without recourse to new US hardware or a new measurement. We test the approach on phantoms and on a healthy human finger.

Clearing of psoriasis documented by laser Doppler perfusion imaging contrasts remaining elevation of dermal expression levels of CD31.

BACKGROUND: Vascular modifications represent a key feature in psoriatic plaques. Previous research with Laser Doppler Perfusion Imaging (LDPI) revealed a remarkable heterogeneity in the cutaneous perfusion within homogenous-appearing psoriatic lesions. Insights in the relation between perfusion during treatment and related biological changes are lacking. OBJECTIVES: To study the effect of calcipotriol-betamethasone dipropionate ointment on the microcirculation and the expression levels of immunohistochemical markers in psoriatic lesions compared to the distant uninvolved skin. METHODS: Psoriatic lesions of fourteen patients were treated once a day during 8 weeks. Clinical SUM scores and the perfusion intensity by means of LDPI were assessed every 2 weeks. After 8 weeks, a biopsy from the target lesion and one from the distant uninvolved skin were taken and stained for psoriasis-related markers, like IL-17 and CD31. RESULTS: After 8 weeks, seven patients reached a SUM score of 0 or 1, and were classified as good-responders. The other patients were classified moderate-responders. The perfusion intensity decreased in all lesions during therapy. In the good-responders, all investigated psoriasis-related proteins within the treated lesions reached the expression level found within the distant uninvolved skin. The expression of CD31, however, was significantly higher in the treated lesions as compared to the distant uninvolved skin (p = 0.0156). In the moderate responders, almost all expression levels remained significantly elevated compared to the uninvolved skin. CONCLUSIONS: In the skin of good-responders the expression of dermal CD31(+) endothelium remains significantly elevated within the treated lesions compared with the distant uninvolved skin, whereas a marked reduction in the perfusion intensity and SUM score was found. This indicates that clinical improvement might outrun endothelial changes.

Towards acousto-optic tissue imaging with nanosecond laser pulses.

We present a way to generate acousto-optical signals in timovssue-like media with nanosecond laser pulses. Our method is based on recording and analyzing speckle patterns formed by interaction of nanosecond laser pulses with tissue, without and with simultaneous application of ultrasound. Stroboscopic application allows visualizing the temporal behavior of speckles while the ultrasound is propagating through the medium. We investigate two ways of quantifying the acousto-optic effect, viz. adding and subtracting speckle patterns obtained at various ultrasound phases. Both methods are compared with the existing speckle contrast method using a 2D scan and are found to perform similarly. Our method gives outlook on overcoming the speckle decorrelation problem in acousto-optics, and therefore brings in-vivo acousto-optic measurements one step closer. Furthermore it enables combining acousto-optics and photoacoustics in one setup with a single laser.

Handheld probe integrating laser diode and ultrasound transducer array for ultrasound/photoacoustic dual modality imaging.

Ultrasound and photoacoustics can be utilized as complementary imaging techniques to improve clinical diagnoses. Photoacoustics provides optical contrast and functional information while ultrasound provides structural and anatomical information. As of yet, photoacoustic imaging uses large and expensive systems, which limits their clinical application and makes the combination costly and impracticable. In this work we present and evaluate a compact and ergonomically designed handheld probe, connected to a portable ultrasound system for inexpensive, real-time dual-modality ultrasound/photoacoustic imaging. The probe integrates an ultrasound transducer array and a highly efficient diode stack laser emitting 130 ns pulses at 805 nm wavelength and a pulse energy of 0.56 mJ, with a high pulse repetition frequency of up to 10 kHz. The diodes are driven by a customized laser driver, which can be triggered externally with a high temporal stability necessary to synchronize the ultrasound detection and laser pulsing. The emitted beam is collimated with cylindrical micro-lenses and shaped using a diffractive optical element, delivering a homogenized rectangular light intensity distribution. The system performance was tested in vitro and in vivo by imaging a human finger joint.

Imaging breast malignancies with the Twente Photoacoustic Mammoscope 2.

Clinical measurements on breast cancer patients were performed with a three-dimensional tomographic photoacoustic prototype imager (PAM 2). Patients with a suspicious lesion, visiting the center for breast care of a local hospital, were included in the study. The acquired photoacoustic images were compared to conventional clinical images. Of 30 scanned patients, 19 were diagnosed with one or more malignancies, of which a subset of four patients was selected for detailed analysis. Reconstructed images were processed to enhance image quality and the visibility of blood vessels. Processed photoacoustic images were compared to contrast-enhanced magnetic resonance images where available, which aided in localizing the expected tumoral region. In two cases, spotty high-intensity photoacoustic signals could be seen in the tumoral region, attributable to the tumor. One of these cases also displayed a relatively high image entropy at the tumor site, likely related to the chaotic vascular networks associated with malignancies. For the other two cases, it was not possible to identify features indicative of malignancy, because of limitations in the illumination scheme and difficulties in locating the region of interest in the photoacoustic image.

Correcting photoacoustic signals for fluence variations using acousto-optic modulation.

We present a theoretical concept which may lead to quantitative photoacoustic mapping of chromophore concentrations. The approach supposes a technique capable of tagging light in a well-defined tagging volume at a specific location deep in the medium. We derive a formula that expresses the local absorption coefficient inside a medium in terms of noninvasively measured quantities and experimental parameters and we validate the theory using Monte Carlo simulations. Furthermore, we performed an experiment to basically validate the concept as a strategy to correct for fluence variations in photoacoustics. In the experiment we exploit the possibility of acousto-optic modulation, using focused ultrasound, to tag photons. Results show that the variation in photoacoustic signals of absorbing insertions embedded at different depths in a phantom, caused by fluence variations of more than one order of magnitude, can be corrected for to an accuracy of 5%.

Visualizing breast cancer using the Twente photoacoustic mammoscope: what do we learn from twelve new patient measurements?

We acquired images of breast malignancies using the Twente photoacoustic mammoscope (PAM), to obtain more information about the clinical feasibility and limitations of photoacoustic mammography. Results were compared with conventional imaging and histopathology. Ten technically acceptable measurements on patients with malignancies and two measurements on patients with cysts were performed. In the reconstructed volumes of all ten malignant lesions, a confined region with high contrast with respect to the background could be seen. In all malignant cases, the PA contrast of the abnormality was higher than the contrast on x-ray mammography. The PA contrast appeared to be independent of the mammographically estimated breast density and was absent in the case of cysts. Technological improvements to the instrument and further studies on less suspicious lesions are planned to further investigate the potential of PAM.

First experiences of photoacoustic imaging for detection of melanoma metastases in resected human lymph nodes.

BACKGROUND AND OBJECTIVE: Excision and histological assessment of the first draining node (sentinel lymph node) is a frequently used method to assess metastatic lymph node involvement related to cutaneous melanoma. Due to the time required for accurate histological assessment, nodal status is not immediately available to the surgeon. Hence, in case histological examination shows metastases, the patient has to be recalled to perform additional lymphadenectomy. To overcome these drawbacks we studied the applicability of photoacoustic tomographic imaging as an intra-operative modality for examining the status of resected lymph nodes. MATERIALS AND METHODS: In melanoma patients undergoing lymphadectomy for metastatic disease, six suspect lymph nodes were photoacoustically (PA) imaged using multiple wavelengths. Histopathologal examination showed three nodes without tumor cells (benign nodes) and three nodes with melanoma cells (malignant nodes). PA images were compared with histology and anatomical features were analyzed. In addition, PA spectral analysis was performed on areas of increased signal intensity. RESULTS: After correlation with histopathology, multiple areas containing melanoma cells could be identified in the PA images due to their increased response. Malignant nodes showed a higher PA response and responded differently to an increase in excitation wavelength than benign nodes. In addition, differences in anatomical features between the two groups were detected. CONCLUSIONS: Photoacoustic detection of melanoma metastases based on their melanin content proves to be possible in resected human lymph nodes. The amount of PA signal and several specific anatomical features seem to provide additional characteristics for nodal analysis. However, it is as yet preliminary to designate a highly accurate parameter to distinguish between malignant and benign nodes. We expect to improve the specificity of the technique with a future implementation of an adjusted illumination scheme and depth correction for photon fluence.

An unusual case of rectal perforation after liver transplantation.

We present the case of a 50-year-old patient in whom an anastomotic biliary stricture after liver transplantation was treated endoscopically by sphincterotomy, dilatation and stenting using a plastic biliary stent. A distal migration of the stent caused a perforation of the rectum which was treated following stent extraction per anum -- conservatively with antibiotics and temporary bowel rest.

Hospital cost categories of one-stage versus two-stage management of common bile duct stones.

BACKGROUND: In the era of cost-conscious healthcare, hospitals are focusing on costs. Analysis of hospital costs per cost category may provide indications for potential cost-saving measures in the management of common bile duct stones (CBDS) with gallbladder in situ. METHODS: Between October 2005 and September 2006, 53 consecutive patients suffering from CBDS underwent either a one-stage procedure [laparoscopic common bile duct exploration (LCBDE) with stone clearance and cholecystectomy (LCCE)] or a two-stage procedure [endoscopic retrograde cholangiopancreatography with sphincterotomy and stone clearance (ERCP/ERS) followed by LCCE]. Costs were defined in different cost categories for each activity centre and were linked to the individual patient via the "bill of activities". Only patients (n = 38) with an uneventful post-procedural course and with available cost data were considered for cost analysis. Total length of hospital stay (LOS) was 2 (0-6) days after one-stage and 8 (3-18) days after two-stage procedure (p < 0.0001). RESULTS: Costs per patient were significantly (p < 0.0001) less after one-stage versus two-stage management, i.e. total hospital costs (euro2,636 versus euro4,608), hospitalisation costs (euro701 versus euro2,190), consumables/pharmacy (euro645 versus euro1,476) and para-medical personnel (euro1,035 versus euro1,860; p = 0.0002). Operation room (OR) costs were comparable for one-stage and two-stage management (euro1,278 versus euro1,232; p = 0.280). Total hospital costs during ERCP were euro2,648 (euro729-4,544), during LCCE without LCBDE were euro2,101 (euro1,033-4,269), and during LCCE with LCBDE were euro2,636 (euro1,176-4,235). CONCLUSION: In the management of patients with CBDS and gallbladder in situ a one-stage procedure is associated with significantly less costs as compared with a two-stage procedure. From the economical point of view these patients should preferably be treated via a one-stage procedure as long as safety and efficacy of this approach are provided.

Clinical models are inaccurate in predicting bile duct stones in situ for patients with gallbladder.

BACKGROUND: The probability that a patient has common bile duct stones (CBDS) is a key factor in determining diagnostic and treatment strategies. This prospective cohort study evaluated the accuracy of clinical models in predicting CBDS for patients who will undergo cholecystectomy for lithiasis. METHODS: From October 2005 until September 2006, 335 consecutive patients with symptoms of gallstone disease underwent cholecystectomy. Statistical analysis was performed on prospective patient data obtained at the time of first presentation to the hospital. Demonstrable CBDS at the time of endoscopic retrograde cholangiopancreatography (ERCP) or intraoperative cholangiography (IOC) was considered the gold standard for the presence of CBDS. RESULTS: Common bile duct stones were demonstrated in 53 patients. For 35 patients, ERCP was performed, with successful stone clearance in 24 of 30 patients who had proven CBDS. In 29 patients, IOC showed CBDS, which were managed successfully via laparoscopic common bile duct exploration, with stone extraction at the time of cholecystectomy. Prospective validation of the existing model for CBDS resulted in a predictive accuracy rate of 73%. The new model showed a predictive accuracy rate of 79%. CONCLUSION: Clinical models are inaccurate in predicting CBDS in patients with cholelithiasis. Management strategies should be based on the local availability of therapeutic expertise.

Assessment of microcirculation in the diabetic foot with laser speckle contrast imaging.

OBJECTIVE: A major challenge for treating diabetic foot ulcers is estimating the severity of ischemia, as the currently used non-invasive diagnostic techniques provide relatively poor prognostic values. Laser speckle contrast imaging (LSCI) is a promising non-invasive technique to assess microcirculation. Our aim was to investigate the stability and reproducibility of LSCI for the assessment of microcirculation in the diabetic foot, the relation of LSCI results to currently used non-invasive blood pressure measurements, and the ability of LSCI to discriminate between the degrees of ischemia. APPROACH: Thirty-three participants with diabetic foot ulcers were included in this prospective, single centre, observational cohort study that was conducted in the Netherlands. They were classified as non-ischemic, ischemic or critical-ischemic based on criteria formulated in the international guidelines. Two clinicians performed LSCI scans of the foot, consisting of baseline measurements, followed by two stress tests (post-occlusion peak and elevation test). With three measurement conditions and five regions of interest of the foot per patient, a total of 15 measurements were available for analyses. MAIN RESULTS: The intra-observer agreement of LSCI was high (interclass correlation coefficient (ICC) = 0.711-0.950; p  < 0.001) for all 15 measurements. The inter-observer agreement was high (ICC = 0.728-0.861; p  ⩽ 0.001) for 10 measurements and moderate (ICC = 0.476-0.570; p  ⩽ 0.005) for the remaining five measurements. The inter-assessor agreement was high and significant (ICC = 0.857-0.996; p  ⩽ 0.001) for all measurements. Correlation between LSCI and non-invasive blood pressure measurements was low (ICC = -0.272-0.582). During both stress tests, microcirculation was significantly lower in critical-ischemic feet compared to non-ischemic feet (67.5 perfusion units (PU) versus 96.3 PU and 41.0 PU versus 63.9 PU; p  < 0.05). SIGNIFICANCE: LSCI is a stable and reproducible technique for assessment of microcirculation in people with diabetic foot ulcers and shows significant differences between non-ischemic, ischemic and critical-ischemic patient populations.

Quantification of optical Doppler broadening and optical path lengths of multiply scattered light by phase modulated low coherence interferometry.

We show experimental validation of a novel technique to measure optical path length distributions and path length resolved Doppler broadening in turbid media for different reduced scattering coefficients and anisotropies. The technique involves a phase modulated low coherence Mach-Zehnder interferometer, with separate fibers for illumination and detection. Water suspensions of Polystyrene microspheres with high scattering and low absorption levels are used as calibrated scattering phantoms. The path length dependent diffusion broadening or Doppler broadening of scattered light is shown to agree with Diffusive Wave Spectroscopy within 5%. The optical path lengths are determined experimentally from the zero order moment of the phase modulation peak around the modulation frequency in the power spectrum and the results are validated with Monte Carlo simulations.

Effect of speckles on the depth sensitivity of laser Doppler perfusion imaging.

A theoretical model is presented and experimentally validated that allows the prediction of the effect of speckles on the depth sensitivity of laser Doppler perfusion imaging. It is shown that the influence of speckles on depth sensitivity is large. In particular the sensitivity to particle motion in superficial layers is strongly beam diameter dependent: decreasing the beam diameter on the tissue surface increases the sensitivity to superficial motion to a much stronger extent than sensitivity to motion at a larger depth. This can be explained through the effect of beam diameter changes on the fractional coherence areas generated by photons with different penetration depths in the tissue.

Discrimination between Doppler-shifted and non-shifted light in coherence domain path length resolved measurements of multiply scattered light.

We show a novel technique to distinguish between Doppler shifted and unshifted light in multiple scattering experiments on mixed static and dynamic media. With a phase modulated low coherence Mach- Zehnder interferometer, optical path lengths of shifted and unshifted light and path length dependent Doppler broadening are measured in a two-layer tissue phantom, with a superficial static layer of different thickness covering a semi-infinite dynamic medium having identical optical properties. No Doppler broadening is observed until a certain optical path length depending on the thickness of the superficial static layer. From the minimum optical path length corresponding to the Doppler-shifted light the thickness of the static layer that overlies the dynamic layer can be estimated. Validation of the experimentally determined thickness of the static layer is done with the Doppler Monte Carlo technique. This approach has potential applications in discriminating between statically and dynamically scattered light in the perfusion signal and in determining superficial burn depths.

Tandem pulsed acousto-optics: obtaining the tagged light fraction from modulated non-ideal speckle patterns.

Recently we presented novel methods for acousto-optic (AO) imaging of biological tissues, taking (1) the mean square difference of speckle patterns (subtraction method) or (2) the contrast of the summation of speckle patterns (summation method) acquired from nanosecond pulses of coherent light, fired at different ultrasound phases. In this study we relate the two methods both analytically and experimentally. We experimentally show that these two methods are nearly identical provided that the maximum achievable speckle contrast is determined correctly. We show with simulations that after correction the outcome is independent of experimental detection parameters. This makes the AO methods in this study reliable, allowing quantifying speckle observations in terms of the ultrasonically tagged fractions of light. The use of tandem nanosecond pulses in one burst of ultrasound overcomes the challenge of tissue dynamics.

Patients with large-duct primary sclerosing cholangitis and Crohn's disease have a better outcome than those with ulcerative colitis, or without IBD.

BACKGROUND: Approximately 20% of primary sclerosing cholangitis (PSC) patients with concomitant inflammatory bowel disease (IBD) have Crohn's disease (CD). AIM: To compare PSC/CD with other PSC patients. METHODS: Retrospective study of 240 PSC patients diagnosed between 1975 and 2012 (median follow-up 12 years). Activity of PSC at diagnosis was assessed by liver biopsy, Mayo risk and ERC scores. Survival without liver transplantation, number of transplantations and liver-related death were endpoints. RESULTS: Sixty-three per cent of patients had IBD: 105 UC, 32 CD and 14 IBD unclassified (IBDu). IBD was diagnosed before PSC in 50%. The yearly development of PSC after diagnosing IBD was similar in UC, CD or IBDu. Small-duct PSC was present in 28% of PSC/CD compared to 3% of PSC/UC. Small-duct PSC had a markedly better survival than large-duct PSC: no patient developed cholangiocarcinoma or liver-related death, but colorectal cancer occurred in three patients. In large-duct PSC, a more favourable outcome was evident in patients with CD. The liver disease was less progressive: one patient underwent liver transplantation compared to 28% and liver-related deaths were absent compared to 7% in the other PSC groups. CONCLUSIONS: The prevalence of PSC with concomitant Crohn's disease is relatively rare, but the outcome is more benign than PSC with UC or without IBD. Approximately one-fourth has small-duct PSC. In large-duct PSC/CD, liver disease is less aggressive and the outcome is much better. The outcome of PSC patients with UC resembled that of PSC without IBD.

Serial noninvasive photoacoustic imaging of neovascularization in tumor angiogenesis.

We present photoacoustic images of tumor neovascularization obtained over a 10-day period after subcutaneous inoculation of pancreatic tumor cells in a rat. The images were obtained from ultrasound generated by absorption in hemoglobin of short laser pulses at a wavelength of 1064 nm. The ultrasound signals were measured in reflection mode using a single scanning piezodetector, and images were reconstructed with a weighted delay-and-sum algorithm. Three-dimensional data visualize the development and quantify the extent of individual blood vessels around the growing tumor, blood concentration changes inside the tumor and growth in depth of the neovascularized region.

Diagnosis and treatment of autoimmune hepatitis at age 65 and older.

AIM: To study features in older patients with autoimmune hepatitis, as this was considered mainly a disease of young females. METHODS: Analysis of 28 patients diagnosed at age > or =65 years compared with 84 younger patients. RESULTS: The incidence was similar at all age decades. The ratio M:F was 1:3 (> or =65 years) vs. 1:2 (<65 years). Presenting symptoms were not different when compared with younger patients and consisted of general malaise and fatigue (36%), jaundice +/- other symptoms (50%), or ascites (11%). Antinuclear antibodies (ANA) > or = 1/80 were positive in 93%, smooth muscle antibodies (SMA) > 1/40 in 50%, anti-liver kidney microsomes (anti-LKM) proved always negative. Histology showed acute necrotizing hepatitis in 19%, severe interphase hepatitis in 15%, chronic hepatitis with plasmo-lymphocytic infiltrate in 30%, cirrhosis in 29% (with active inflammation in one-third); biopsy was refused in 11%. The elderly responded very well to low doses of methylprednisolone (< or =8 mg) and azathioprine (1 mg/kg). This schedule obviates side-effects such as infections seen with higher dosages. CONCLUSION: Autoimmune hepatitis has to be also looked for in the elderly with acute and chronic hepatitis. The steroid therapy should be individualized but kept at a low dose.