Highlights in IBD Epidemiology and Its Natural History in the Paediatric Age

Background. The number of patients of all age brackets diagnosed with Inflammatory Bowel Disease (IBD) has risen dramatically worldwide over the past 50 years. IBD's changing epidemiology suggests that environmental factors play a major role in modifying disease expression. Aim. To review studies carried out worldwide analyzing IBD epidemiology. Methods. A Medline search indicating as keywords “Inflammatory Bowel Disease,” “epidemiology,” “natural history,” “Crohn's Disease,” “Ulcerative Colitis,” and “IBD Unclassified” was performed. A selection of clinical cohort and systematic review studies that were carried out between 2002 and 2013 was reviewed. Studies referring to an earlier date were also considered whenever the data were relevant to our review. Results. The current mean prevalence of IBD in the total population of Western countries is estimated at 1/1,000. The highest prevalence and incidence rates of IBD worldwide are reported from Canada. Just as urbanization and socioeconomic development, the incidence of IBD is rising in China. Conclusions. Multicenter national registers and international networks can provide information on IBD epidemiology and lead to hypotheses about its causes and possible management strategies. The rising trend in the disease's incidence in developing nations suggests that its epidemiological evolution is linked to industrialization and modern Westernized lifestyles.

Evaluation of hepatic fibrosis stage (≥ F2) by fibroscan in patients with chronic viral hepatitis: A Meta-analysis

AIM: To evaluate the value of fibroscan (FS) in hepatic fibrosis stage assessment in patients with chronic viral hepatitis, and to examine whether its accuracy is affected by etiology.

METHODS: English and Chinese articles related to assessment of hepatic fibrosis stage by fibroscan in Wanfang, Chinese Journal Full-Text Database (CJFD), Chinese Biomedical Literature Database (CBM), PubMed, Cochrane library and EMBASE database were strictly screened and evaluated. Data of enrolled articles were analyzed using Meta-disc1.4 and Stata12.0 software.

RESULTS: A total of 28 English and Chinese articles were included. The pooled sensitivity, specificity, diagnostic odds ratio and the area under curve (AUC) of summary receiver operating characteristic (SROC) curve for significant fibrosis (F ≥ 2) and cirrhosis (F = 4) in patients with chronic viral hepatitis were 0.72 (0.70-0.73), 0.85 (0.83-0.87), 18.51 (13.28-25.80), 0.88 and 0.86 (0.84-0.88), 0.86 (0.85-0.87), 49.14 (30.53-79.09) and 0.94, respectively. There was no significant difference among the results of meta-analysis according to etiology.

CONCLUSION: Fibroscan has a high diagnostic accuracy for evaluating hepatic fibrosis stage, especially in patients with cirrhosis. The diagnostic accuracy of fibroscan is not affected by etiology.

Role of fibroscan and APRI in detection of liver fibrosis: a systematic review and meta-analysis

BACKGROUND AND STUDY AIMS

Fibroscan and APRI are promising noninvasive alternatives to liver biopsy for detecting hepatic fibrosis. However, their overall test performance in various settings remains questionable. The aim of our study was to perform a systematic review and meta-analysis of diagnostic accuracy studies comparing fibroscan and APRI with liver biopsy for hepatic fibrosis.

PATIENTS AND METHODS

Electronic and manual bibliographic searches to identify potential studies were performed. Selection of studies was based on reported accuracy of fibroscan and APRI compared with liver biopsy. Data extraction was performed independently by two reviewers. Meta-analysis combined the sensitivities, specificities, and likelihood ratios of individual studies. Extent and reasons for heterogeneity were assessed.

RESULTS

23 studies for fibroscan and 20 studies for APRI in full publication were identified. For patients with stage IV fibrosis (cirrhosis), the pooled estimates for sensitivity of fibroscan were 83.4% (95% confidence interval [CI], 71.7-95.0%) and specificity 92.4% (95% CI, 85.6-99.2%). For patients with stage IV fibrosis (cirrhosis), the pooled estimates for sensitivity of APRI at cutoff point of 1.5 were 66.5% (95% CI, 25.0-100%) and specificity 71.7% (95% CI, 35.0-100%). Diagnostic threshold bias was identified as an important cause of heterogeneity for pooled results in both patient groups.

CONCLUSIONS

Fibroscan and APRI appear to be clinically useful tests for detecting cirrhosis however not useful tools in early stages of fibrosis.

Acoustic radiation force elasticity imaging in diagnostic ultrasound

The development of ultrasound-based elasticity imaging methods has been the focus of intense research activity since the mid-1990s. In characterizing the mechanical properties of soft tissues, these techniques image an entirely new subset of tissue properties that cannot be derived with conventional ultrasound techniques. Clinically, tissue elasticity is known to be associated with pathological condition and with the ability to image these features in vivo; elasticity imaging methods may prove to be invaluable tools for the diagnosis and/or monitoring of disease. This review focuses on ultrasound-based elasticity imaging methods that generate an acoustic radiation force to induce tissue displacements. These methods can be performed noninvasively during routine exams to provide either qualitative or quantitative metrics of tissue elasticity. A brief overview of soft tissue mechanics relevant to elasticity imaging is provided, including a derivation of acoustic radiation force, and an overview of the various acoustic radiation force elasticity imaging methods.

Experimental mechanical characterization of abdominal organs: liver, kidney & spleen

Abdominal organs are the most vulnerable body parts during vehicle trauma, leading to high mortality rate due to acute injuries of liver, kidney, spleen and other abdominal organs. Accurate mechanical properties and FE models of these organs are required for simulating the traumas, so that better designing of the accident environment can be done and the organs can be protected from severe damage. Also from biomedical aspect, accurate mechanical properties of organs are required for better designing of surgical tools and virtual surgery environments. In this study porcine liver, kidney and spleen tissues are studied in vitro and hyper-elastic material laws are provided for each. 12 porcine kidneys are used to perform 40 elongation tests on renal capsule and 60 compression tests on renal cortex, 5 porcine livers are used to perform 45 static compression tests on liver parenchyma and 5 porcine spleens are used to carry out 20 compression tests. All the tests are carried out at a static speed of 0.05 mm/s. A comparative analysis of all the results is done with the literature and though the results are of same order of magnitude, a slight dissonance is observed for the renal capsule. It is also observed that the spleen is the least stiff organ in the abdomen whereas the kidney is the stiffest. The results of this study would be essential to develop the FE models of liver, kidney and spleen which can be further used for impact biomechanical and biomedical applications.

Correlation between liver stiffness measurement by Fibroscan and liver fibrosis staging based on a liver biopsy in patients with NAFLD

AIM: To evaluate the role of Fibroscan (FS) in the diagnosis of liver fibrosis in patients with nonalcoholic fatty liver disease (NAFLD).

METHODS: A total of 83 patients who were pathologically diagnosed with NAFLD and underwent liver stiffness measurement using FibroScan at Beijing Youan Hospital from April 2008 to February 2011 were included in this study. Staging of liver fibrosis based on a liver biopsy was performed in all patients. Other clinical tests included liver function, FBG, blood lipids and UA The correlation between liver stiffness and liver fibrosis degree was analyzed. The receive operating characteristic (ROC) curve was used to analyze the accuracy of Fibroscan in diagnosing liver fibrosis with NAFLD.

RESULTS: The liver stiffness differed among patients with different stages of liver fibrosis. The Fibroscan values were 4.28 kPa ± 1.32 kPa, 7.40 kPa ± 2.13 kPa, 11.52 kPa ± 3.86 kPa, and 19.99 kPa ± 5.42 kPa for patients with S0 to S3 liver fibrosis, respectively, and liver stiffness was closely related to stage of liver fibrosis (r = 0.768, P < 0.001). Fibroscan score was positively correlated with ALT and AST, but negatively with HDL and ApoA (all P < 0.05). The area under the ROC curve for FibroScan score in assessing liver fibrosis was 0.889 (0.813, 0.965) in patients with S1 liver fibrosis, 0.838 (0.729, 0.948) in those with S2, and 0.938 (0.000, 1.000) in those with S3. The cut off values were 8.95 kPa, 10.60 kPa and 15.66 kPa, respectively.

CONCLUSION: Fibroscan is valuable for the diagnosis of liver fibrosis in patients with NAFLD.

Serial changes of liver stiffness measured by acoustic radiation force impulse imaging in acute liver failure: a case report

Acoustic radiation force impulse (ARFI) imaging is a new technology used to determine liver elasticity. We report the case of a patient that survived hyperacute-type acute liver failure (ALF) and who showed a dramatic change in the value of shear wave velocity (SWV) measured by ARFI, which corresponded with the severity of her liver damage. The value of SWV increased significantly up to 3.6 ± 0.3 m/s during the encephalopathy phase and then decreased along with the recovery of liver function, the blood flow of the right portal vein, and the liver volume. These findings suggest the value of SWV in ALF as a reliable marker of liver tissue damage. Further investigations of the pathophysiological significance of SWV in ALF are warranted.

Is ultrasound elastography of the liver ready to replace biopsy? A critical review of the current techniques

Accurate assessment of liver fibrosis in patients with chronic liver disease is necessary to determine prognosis, monitor disease progression and formulate treatment decisions. Currently, histological staging of liver biopsy is the most widely used reference standard for this purpose. Liver biopsy, however, has recognized risks, as well as sampling and observer error. These limitations have stimulated the search for new non-invasive approaches. Numerous methodologies, including serum markers, magnetic resonance elastography and ultrasound elastography, have evolved in the last decade to predict fibrosis in those with chronic liver disease. Ultrasound elastography methods assess liver fibrosis by determining liver stiffness and translate this into a quantifiable measurement for analysis. As these tests are non-invasive, without side-effect or discomfort, it is possible to conduct repeat examinations at much closer intervals than biopsy. The three most investigated ultrasound elastography methods are transient elastography, realtime elastography and acoustic radiation force impulse. Although significant strides have been made in the development of the technology, an unequivocal advocacy of elastography as a surrogate for biopsy is still not established. The aim of this review is to evaluate the advantages, limitations and clinical relevance of the three ultrasound-based modalities. Also, the review shall assess the current and possible future clinical application the modalities may serve both separate and in conjunction with liver biopsy.

Reduction of liver stiffness by antiviral therapy in chronic hepatitis B

BACKGROUND

Liver stiffness (LS) has been reported to correlate with fibrosis stage (F). The correlation between LS and fibrosis stage and the reduction of LS by antiviral therapy were examined in patients with hepatitis B infection.

METHODS

LS was measured by FibroScan in 212 patients infected with hepatitis B virus. Liver biopsies were done in 51 patients. Changes of LS were assessed in 29 patients treated with nucleotide or nucleoside analogs and 52 patients without antiviral therapy.

RESULTS

LS was significantly correlated with fibrosis stage (ρ = 0.686, P < 0.0001). The optimal cut-off values of LS were 7.1 kPa for F ≥ 2, 10.7 kPa for F ≥ 3, and 16.0 kPa for F4. LS was significantly reduced by antiviral therapy, from 12.9 (range 6.2-17.9) kPa to 6.6 (4.4-10.3) kPa measured at an interval of 512 (range 366-728) days (P < 0.0001). Eleven of 19 (58%) patients with baseline fibrosis stages of F3-4 deduced from LS had 2-point or greater reductions of deduced stage at the last LS measurement. The change ratio of hyaluronic acid (P = 0.0390) was associated with a 2-point or greater reduction of deduced fibrosis stage. Without antiviral therapy, LS tended to increase, increasing from 6.1 (range 3.9-8.5) kPa to 6.3 (range 4.4-9.7) kPa at an interval of 422 (range 358-709) days (P = 0.0682).

CONCLUSIONS

LS was significantly correlated with fibrosis stage in patients with chronic hepatitis B. The reduction of LS by antiviral therapy was significantly correlated with the reduction of hyaluronic acid. Thus, we conclude that LS can be useful to assess the progression and regression of liver fibrosis stage noninvasively.

How efficient is acoustic radiation force impulse elastography for the evaluation of liver stiffness?

BACKGROUND

In chronic liver diseases, a correct estimation of the severity of liver fibrosis is important for recommendations regarding the treatment. Nowadays, evaluation of fibrosis is done by noninvasive methods such as biochemical scores and transient elastography instead of liver biopsy. The lack of sensitivity to detect fibrosis, because of its heterogeneity is a drawback of liver biopsy (LB).

OBJECTIVES

To compare transient elastography (TE) and acoustic radiation force impulse (ARFI) for the evaluation of liver stiffness (LS), against percutaneous LB.

PATIENTS AND METHODS

Our study comprised of 223 subjects; 52 without fibrosis (38 volunteers and 14 patients with F0 on LB), 36 with F1, 40 with F2, 26 with F3 and 69 with liver cirrhosis (46 with LB and 23 with signs of cirrhosis). For each patient we performed in the same session 10 TE and 5 ARFI measurements. The median values were calculated.

RESULTS

A strong linear correlation (Spearman rho = 0.870) was found between TE and fibrosis (P < 0.0001); there was also a weaker correlation between ARFI and fibrosis (Spearman rho = 0.646; P < 0.0001). TE measurements were also correlated with ARFI measurements (Spearman rho = 0.733, P < 0.0001). The best test for predicting significant fibrosis (F ≥ 2) was TE with a cut-off value of 7.1 kPa (AUROC 0.953). For ARFI, the cut-off value was 1.27 m/s-area under ROC curve (AUROC): 0.890, sensitivity (Se) of 88.7%, specificity (Sp) of 67.5%, positive predictive value (PPV) of 64.5%, and negative predictive value (NPV) of 90% (P = 0.0044). For predicting cirrhosis (F = 4), the optimum cut-off values were 14.4 kPa for TE (AUROC: 0.985, Se: 95.6%, Sp: 94.7%, PPV: 89.2%, NPV: 98%) and 1.7 m/s for ARFI (AUROC: 0.931, Se: 93%, Sp: 86.7%, PPV: 73.6%, NPV: 96.9%) (P = 0.0102).

CONCLUSIONS

LS evaluation by means of ARFI is not superior to TE for the assessment of liver fibrosis. ARFI is an accurate test for the diagnosis of cirrhosis.

Elastography for the diagnosis of severity of fibrosis in chronic liver disease: a meta-analysis of diagnostic accuracy

BACKGROUND & AIMS

Transient elastography is a non-invasive method, for the assessment of hepatic fibrosis, developed as an alternative to liver biopsy. We studied the performance of elastography for diagnosis of fibrosis using meta-analysis.

METHODS

MEDLINE, EMBASE, SCI, Cochrane Library, conference abstracts books, and article references were searched. We included studies using biopsy as a reference standard, with the data necessary to calculate the true and false positive, true and false negative diagnostic results of elastography for a fibrosis stage, and with a 3-month maximum interval between tests. The quality of the studies was rated with the QUADAS tool.

RESULTS

We identified 40 eligible studies. Summary sensitivity and specificity was 0.79 (95% CI 0.74-0.82) and 0.78 (95% CI 0.72-0.83) for F2 stage and 0.83 (95% CI 0.79-0.86) and 0.89 (95% CI 0.87-0.91) for cirrhosis. After an elastography result at/over the threshold value for F2 or cirrhosis ("positive" result), the corresponding post-test probability for their presence (if pre-test probability was 50%) was 78%, and 88% respectively, while, if values were below these thresholds ("negative" result), the post-test probability was 21% and 16%, respectively. No optimal stiffness cut-offs for individual fibrosis stages were validated in independent cohorts and cut-offs had a wide range and overlap within and between stages.

CONCLUSIONS

Elastography theoretically has good sensitivity and specificity for cirrhosis (and less for lesser degrees of fibrosis); however, it should be cautiously applied to everyday clinical practice because there is no validation of the stiffness cut-offs for the various stages. Such validation is required before elastography is considered sufficiently accurate for non-invasive staging of fibrosis.

Non-invasive assessment of liver fibrosis in chronic hepatitis C

Quantification of hepatic fibrosis is of critical importance in chronic hepatitis C not only for prognosis, but also for antiviral treatment indication. Two end points are clinically relevant: detection of significant fibrosis (indication for antiviral treatment) and detection of cirrhosis (screening for eosphageal varices and hepatocellular carcinoma). Until recently, liver biopsy was considered the reference method for the evaluation of liver fibrosis. Limitations of liver biopsy (invasiveness, sampling error, and inter-observer variability) have led to the development of non-invasive methods. Currently available methods rely on two different approaches: a "biological" approach based on the dosage of serum fibrosis biomarkers; and a "physical" approach based on the measurement of liver stiffness, using transient elastography (TE). This review is aimed at discussing the advantages and limits of non-invasive methods and liver biopsy and the perspectives for their rational use in clinical practice in the management of patients with chronic hepatitis C.

The Diagnostic Value of Ultrasound Elastography in Patients with Hepatitis B Virus Infection: A Prospective Study

The aim of this prospective study was to investigate the diagnostic value of ultrasound elastography for evaluating liver stiffness measurement (LSM) in 74 patients with hepatitis B virus (HBV) infection, treated with telbivudine (22 with chronic HBV infection, 32 with compensated cirrhosis and 20 with decompensated cirrhosis). Each patient underwent ultrasound elastography measurements and serum liver marker assays before and after 6 months' treatment with 600 mg telbivudine, orally, once daily. In the 22 patients with chronic HBV infection, LSM values measured by ultrasound elastography decreased significantly following the treatment period compared with baseline. The LSM values were significantly higher in the 20 patients with decompensated cirrhosis than in the 32 patients with compensated cirrhosis after treatment. Significant decreases in serum hepatic fibrosis indices occurred in all patients following treatment. The correlation between fibrosis index, hyaluronic acid level and LSM was statistically significant in all patients, whereas the correlation between alanine aminotransferase and LSM was not. The findings suggest that liver stiffness in patients with HBV can be measured simply with ultrasound elastography and that it is reduced within 6 months by treatment with telbivudine. The main adverse events noted during the study period were that creatine kinase levels were increased in seven patients and that seven patients had influenza-like symptoms.

Liver stiffness measurements in patients with HBV vs HCV chronic hepatitis: a comparative study

AIM

To assess the values of liver stiffness (LS) in patients with hepatitis B virus (HBV) chronic hepatitis and to compare them with those in patients with hepatitis C virus (HCV) chronic hepatitis.

METHODS

The study included 140 patients with HBV chronic hepatitis, and 317 patients with HCV chronic hepatitis, in which LS was measured (FibroScan®-Echosens®) and liver biopsy was performed in the same session (assessed according to the Metavir score).

RESULTS

According to the Metavir score of the 140 HBV patients: one had F0, 32 had F1, 67 had F2, 33 had F3 and 7 had F4. Of the 317 HCV patients: 5 had F0, 34 had F1, 146 had F2, 93 had F3 and 39 had F4. For the same severity of fibrosis, the mean values of LS in HBV patients were similar to those in HCV patients: F1, 6.5 ± 1.9 kPa vs 5.8 ± 2.1 kPa (P = 0.0889); F2, 7.1 ± 2 kPa vs 6.9 ± 2.5 kPa (P = 0.3369); F3, 9.1 ± 3.6 kPa vs 9.9 ± 5 kPa (P = 0.7038); F4, 19.8 ± 8.6 kPa vs 17.3 ± 6.1 kPa (P = 0.6574). A significant direct correlation between LS measurements and fibrosis was found in HCV patients (Spearman's r = 0.578, P < 0.0001), as well as in HBV patients (r = 0.408, P < 0.0001). The correlation was more significant in HCV than in HBV patients (Fisher's Z-test, Z = 2.210, P = 0.0271).

CONCLUSION

In our group, the mean values of LS in patients with chronic B hepatitis were similar to those in patients with chronic HCV hepatitis, for the same stage of fibrosis. Also, LS was correlated with the severity of fibrosis both in HBV and HCV chronic hepatitis patients.

Ultrasonic elastography in clinical quantitative assessment of fatty liver

AIM: To investigate the clinical application of ultrasonic elastography in quantitative assessment of fatty liver grading.

METHODS: A total of 105 patients with fatty liver were divided into mild group (n = 46), moderate group (n = 39), and severe group (n = 20). Forty-five healthy individuals served as a normal control group. All patients who underwent routine ultrasound scan and further ultrasonic elastography were evaluated accordingly to the evaluation standards for ultrasonic elastography. The ratio of surface areas of blue region/total surface area in the desired region was measured.

RESULTS: Ultrasonic elastography technique, in comparison to traditional ultrasound, had a rather high consistence in grading of fatty liver [κ value = (95.3%-63.6%)/(1%-63.6%) = 0.87, P = 0.001]. The score of ultrasonic elastography increased with the severity of fatty liver with a sensitivity of 97.14% and a specificity of 91.11%. A significant difference was found in the ratio of surface areas of blue regions between different groups (P < 0.05).

CONCLUSION: Ultrasonic elastography can be used in quantitative assessment of the severity of fatty liver.

Food intake increases liver stiffness in patients with chronic or resolved hepatitis C virus infection

BACKGROUND AND AIMS

Transient elastography is increasingly being used in patients with chronic liver disease. It has proven particularly useful to identify patients with advanced fibrosis or cirrhosis, while classification of no or little fibrosis appears to be difficult. In general, stiffness values <6 kPa are considered normal, whereas patients with higher levels are candidates for a disease-specific treatment or further diagnostic evaluation. Parameters influencing liver stiffness may include food intake that increases liver blood flow.

METHODS

In a pilot study, transient elastography was performed in eight patients with chronic hepatitis C at fasting and serially for 180 min after intake of a standardized breakfast. Confirmatory, 56 patients and 19 controls underwent liver stiffness determination at fasting, directly after meal intake and 1 h after breakfast.

RESULTS

Liver stiffness significantly increased immediately after food intake for up to 60 min (P=0.01) before normalizing after 180 min. An intraindividual analysis showed a significant increase in 22 out of 43 patients with an initial liver stiffness <or=10 kPa. An increase of at least 1 kPa after food intake was found in 24 out of 43 (56%) patients with initial stiffness <or=10 kPa. Notably, nine out of 23 (39%) patients with normal initial liver stiffness (<6 kPa) had a value of >6 kPa after food intake, potentially leading to unnecessary treatment or diagnostic procedures.

CONCLUSION

Food intake increases liver stiffness in patients with hepatitis C virus infection and healthy controls. To standardize liver stiffness evaluation, we suggest measurement in the fasting condition.