Point shear wave elastography of the pancreas in patients with cystic fibrosis: a comparison with healthy controls

Ultrasound Elastography in Children

Ultrasound elastography is a novel ultrasound technique, being extensively researched in children in the last decade. It measures tissue elasticity with the observation of tissue response after an external stimulus. From research to clinical practice, ultrasound elastography has evolved significantly in liver fibrosis evaluation in children; however, several other applications of the technique are available in both clinical practice and research environments. Practically, in children any organ can be assessed, including the brain in early ages, along with muscle and connective tissue elasticity evaluation, spleen, kidney, skin, lymphatic tissue, etc. The elastography method, age, body mass index and technical points should be considered when performing ultrasound elastography. This review highlights its vast potential as a diagnostic tool in the pediatric population, where ultrasound is a dominant imaging tool; however, the indications and exam protocol for its clinical use in several fields in pediatrics have yet to be elucidated.

Pancreatic Steatosis Is Associated with Both Metabolic Syndrome and Pancreatic Stiffness Detected by Ultrasound Elastography

INTRODUCTION

There is increasing evidence that pancreatic steatosis (PS) is associated with metabolic syndrome (MS). However, it is not known whether it is associated with PS grade and pancreatic stiffness, or not. We aimed to evaluate the relationship between PS and its grade detected by transabdominal ultrasound, and pancreatic stiffness determined by two-dimensional shearwave elastography (2D-SWE), whether it has clinical significance and its relationship with MS.

METHODS

Patients with and without PS were evaluated prospectively.

RESULTS

Patients with PS had higher odds ratio for MS (OR 5.49). Also, ultrasonographic grade of PS was associated with MS parameters and hepatosteatosis. Pancreatic SWE value was significantly higher in PS group and positively correlated with PS grade, liver fat, MS, number of MS criteria.

DISCUSSION/CONCLUSION

PS and its grade were associated with MS. In this first comprehensive PS-SWE study, we found that pancreas stiffness increased in the presence of PS, in correlation with PS grade and MS.

Evaluation of children and adolescent with cystic fibrosis by pancreatic elastography

BACKGROUND

Cystic fibrosis (CF) is an autosomal recessively inherited disease. Clinical findings vary by age of the patient, the organ systems involved, and the severity of the CFTR gene mutation. Pancreatic and liver involvement is prominent and exocrine pancreatic insufficiency is observed in the majority of patients. Point shear wave elastography (pSWE) is a non-invasive method that can quantitatively determine tissue elasticity and stiffness. In this study, the morphological evaluation of the pancreas was performed using the pSWE technique in pediatric patients diagnosed with CF. The effectiveness of this method for the early detection of pancreatic insufficiency was investigated.

METHODS

Fifty-five patients with CF (24 girls, 31 boys) and 60 healthy children (29 girls, 31 boys) without any chronic diseases and who were suitable for the pSWE examination were included in the study.

RESULTS

The mean value of pSWE was 1.12 ± 0.16 in the healthy group and 0.97 ± 0.16 in the patients with cystic fibrosis. There was a statistically significant difference between the two groups (P < 0.001). Significant negative correlations were found between pSWE and age (r = -0.319; P = 0.018), height (r = -0.293; P = 0.03), serum glucose (r = -0.346; P = 0.01), HbA1C (r = -0.592; P = 0.02), and duration of the disease (r = -0.806; P < 0.001).

CONCLUSIONS

Investigating pancreatic elasticity and detecting pancreatic insufficiency using pSWE (a simple, inexpensive, and non-invasive method) in the early period before overt laboratory and clinical symptoms of EPI appear can contribute positively to long-term results in young patients with CF.

Pancreas ultrasound two-dimensional shear wave elastography in healthy children

BACKGROUND

Pancreas shear wave speed might be a biomarker of pancreatic disease in children.

OBJECTIVE

This study aimed to measure pancreas shear wave speed by two-dimensional (2-D) ultrasound shear wave elastography (SWE) in a balanced cohort of presumed healthy children.

MATERIALS AND METHODS

This was a prospective study of 120 children (<18 years of age) without a known history of pancreatic disease, who underwent ultrasound 2-D SWE of the pancreas. Five shear wave speed measurements in the pancreas body and/or tail were obtained for each participant using a Canon Aplio i800 system, i8CX1 transducer. The Mann-Whitney U test or Kruskal-Wallis test were used to compare continuous distributions. Spearman's correlation was used to assess univariate relationships between continuous variables. Multivariable regression with stepwise selection was used to evaluate independent predictors of pancreas shear wave speed.

RESULTS

The median age for the study population was 5.0 years (range: 7 days to 17.8 years) and 61 (50.8%) of the participants were female. The median depth of shear wave speed measurement was 4.7 cm (interquartile range [IQR]: 4.2-5.3). The median pancreas shear wave speed was 1.31 m/s (IQR: 1.21-1.40). On multivariable analysis, female biological sex (P=0.051), the number of hours nil per os (P=0.097), the median depth of measurement (P=0.001) and the median liver shear wave speed (P=0.020) were positively associated with pancreas shear wave speed.

CONCLUSION

We report pancreas shear wave speed in a large, balanced cohort of children without a known history of pancreatic disease, providing reference values for normal.

Pancreatic complications in children with cystic fibrosis

PURPOSE OF REVIEW

The pancreas is highly affected in cystic fibrosis, with complications occurring early in childhood. This review highlights recent research in exocrine pancreatic function in the era of cystic fibrosis transmembrane conductance regulator (CFTR) modulator therapies and discusses how these are affecting pancreatitis and exocrine pancreatic insufficiency (EPI) in children. Additionally, new research into exocrine--endocrine interactions sheds light on how CFTR dysfunction in ductal cells may affect beta cells.

RECENT FINDINGS

Ivacaftor has disproved the hypothesis that EPI in children with cystic fibrosis is irreversible. Improvements in pancreatic function have increased pancreatitis episodes in some children and reduced them in others. Imaging advances are providing complementary methods for exocrine pancreatic function testing. New research into the interplay between the exocrine and endocrine components of the pancreas are elucidating the intertwined and complex relationship between the exocrine and endocrine pancreas.

SUMMARY

Pancreatic complications contribute to the morbidity and mortality of children with cystic fibrosis. Increasing use of highly effective CFTR modulators will not only abrogate these but will also advance our understanding of pancreatic pathophysiology in cystic fibrosis. New frontiers into pancreatic gene therapy and exocrine--endocrine research will help provide new therapeutic opportunities for pancreatitis, EPI, and diabetes in cystic fibrosis.

Can Point Shear Wave Elastography Be Used as an Early Indicator of Involvement?: Evaluation of the Pancreas and Liver in Children With Cystic Fibrosis

OBJECTIVES

The aim of this study was to determine the effect of cystic fibrosis (CF) on pancreas and liver elasticity in young children using point shear wave elastography and to determine the relationship with clinical findings.

METHODS

Twenty-two patients with genetically proven CF, who were admitted to our pediatric gastroenterology clinic, and 22 healthy control participants were enrolled in the study. The shear wave velocity (SWV) of the liver and pancreas were measured with point shear wave elastography.

RESULTS

The 22 patients with CF included 45.5% girls with a mean age ± SD of 35 ± 35.8 months (range, 5-123 months). The 22 healthy control participants included 41.2% girls with a mean age of 58.9 ± 44.4 months (range, 2-159 months). The mean SWV of the pancreas in the patients with CF (1.06 ± 0.26 m/s) was significantly higher than that of the healthy control participants (0.85 ± 0.23 m/s; P = .01). The mean SWV of the liver in the patients with CF (1.46 ± 0.24 m/s) was significantly higher than that of the healthy control participants (1.12 ± 0.21 m/s; P = .001). The SWV of the pancreas and liver did not show any significant differences depending on ursodeoxycholic acid use, malnutrition status, and the presence of the F508 deletion mutation.

CONCLUSIONS

This study showed an increased SWV of the pancreas in children with CF, contrary to the literature. We also found an increased liver SWV even in the absence of CF-related liver disease. Ultrasound elastography may be a useful method of evaluating early changes in the pancreas and liver before the obvious clinical, laboratory, and B-mode ultrasound signs of CF-related involvement.

Normative values of pancreas stiffness by shear wave elastography in healthy children and adolescents

PURPOSE

To define normal pancreas elasticity and velocity values with shear wave elastography (SWE) in healthy children and assess associations with gender, age, and body mass index (BMI).

METHODS

This prospective study included a total of 100 cases (male: 50; female: 50), aged 3-17 years. Preschool, school, and adolescent periods of 3-6 years (n = 27), 7-12 years (n = 30), and 13-17 years (n = 43), respectively, were created in addition to two groups representing prepubertal and postpubertal periods of 3-10 years (n = 50) and 11-18 years (n = 50), respectively. Demographic data regarding the gender, age, height, body weight, and BMI were recorded. Pancreatic head, corpus, and tail SWE measurements were performed with a convex transducer (3.5-5 MHz). Correlations and comparisons were made for stiffness values between groups. Statistical analyses used Mann-Whitney U, Kruskal-Wallis, and Spearman's correlation tests.

RESULTS

Medians (25-75th percentage) of age and BMI were 7 (4.25-10) years and 15 (13-17) years and 17.47 (14.94-19.23) kg/m² and 21.22 (17.41-24) kg/m² in the two age groups, respectively. The median (interquartile range) elasticity and velocity values for the head, corpus, and tail sections of the pancreas were measured as 9.35 (2.9) kPa and 1.76 (0.26) m/s; 9.3 (2.5) kPa and 1.74 (0.21) m/s; and 8.75 (2) kPa and 1.69 (0.15) m/s, respectively. No significant differences were identified for stiffness values between gender and pancreatic section. Pancreatic stiffness values were significantly different among two (p = 0.001) and three (p = 0.028) age groups, and presented mild positive correlations with age (r: 0.23, p: 0.002), height (r: 0.18, p: 0.01), body weight (r: 0.38, p: 0.003), and BMI (r: 0.37, p: 0.045).

CONCLUSION

Normal elasticity and velocity values were defined for the pancreas with SWE in children. Pancreatic stiffness does not significantly change among pancreas parts, but it increases with the transition from childhood to adolescence.

Pancreatic Fibrosis and Chronic Pancreatitis: Mini-Review of Non-Histologic Diagnosis for Clinical Applications

Pancreatic fibrosis is the dominant reversible pathological change and diagnostic factor in early chronic pancreatitis, defined by a mechanistic approach proposed in 2016. Main guidelines for chronic pancreatitis were published by the American Pancreas Association in 2014, the Japanese Society of Gastroenterology in 2015, and United European Gastroenterology in 2017. All three sets of guidelines mentioned that the staging of chronic pancreatitis is important but challenging. There are various image modalities for the non-histologic diagnosis of pancreatic fibrosis: (1) shear wave elastography, such as an acoustic radiation force impulse with a cut-off value of 1.4 m/s; (2) strain elastography using grades of strain; (3) endoscopic ultrasonography using the Rosemont criteria or endoscopic ultrasound criteria for early chronic pancreatitis proposed by the Japan Pancreas Society; (4) computed tomography using the Hounsfield scale or number of micro-calcifications; and (5) magnetic resonance imaging using the apparent diffusion coefficient and the T1w flash and T2w HASTE sequences. The clinical applications are to (1) evaluate pancreatic tumors and inflammatory disease; (2) monitor dyspepsia with early chronic pancreatitis; (3) monitor individuals with a high risk of pancreatic cancer; (4) analyze a fatty pancreas with fibrosis; (5) predict a fistula after pancreatic surgery; and (6) predict outcomes for chronic pancreatitis or pancreatic cancer. The selection of tools will be dependent on the clinical scenario. Conclusion: There are various modalities for the non-histologic diagnosis of pancreatic fibrosis. The selection of the optimal device will be dependent on the clinical scenario.

A comparative study of the pancreas in pediatric patients with cystic fibrosis and healthy children using two-dimensional shear wave elastography

PURPOSE

To compare sonographic parameters of the pancreas between healthy children and pediatric cystic fibrosis (CF) patients with pancreatic involvement using shear wave elastography (SWE) and to investigate the efficacy of SWE in the diagnosis of pancreatic involvement in pediatric CF patients.

METHODS

The pancreas was evaluated in 38 patients with CF and 38 healthy children using conventional B-mode ultrasonography (US) and two-dimensional (2D)-SWE.

RESULTS

The pancreatic 2D-SWE values of the CF group were significantly lower than those of the healthy control group (1.01 ± 0.16 vs. 1.31 ± 0.01 m/s for the head, 1.03 ± 0.05 vs. 1.28 ± 0.08 m/s for the pancreatic body, and 1.02 ± 0.05 vs. 1.30 ± 0.10 m/s for the tail; p < 0.005 for all the comparisons). When the threshold values were obtained for the pancreatic head, body, and tail segments for the differentiation of the CF patients and healthy controls, the sensitivity of the test was determined as 81.5%, 76.3%, and 73.3%, respectively, and the specificity as 97.3%, 100%, and 100%, respectively. When the patients were divided into two groups based on the presence of B-mode US characteristics (homogeneity, sharp demarcation, and hyperechoic pancreas), there was a significant difference in the 2D-SWE values of the pancreatic head between the patients with and the patients without these characteristics (p = 0.048 for homogeneity, p = 0.021 for sharp demarcation, and p = 0.006 for hyperechoic pancreas).

CONCLUSION

The measurement of 2D-SWE values was found to be an easily applicable non-invasive test with high sensitivity and specificity for the demonstration of changes in the pancreas of pediatric CF patients.

Experimental pancreatic cancer develops in soft pancreas: novel leads for an individualized diagnosis by ultrafast elasticity imaging

Rapid, easy and early pancreatic cancer diagnosis and therapeutic follow up continue to necessitate an increasing attention towards the development of effective treatment strategies for this lethal disease. The non invasive quantitative assessment of pancreatic heterogeneity is limited. Here, we report the development of a preclinical imaging protocol using ultrasonography and shear wave technology in an experimental in situ pancreatic cancer model to measure the evolution of pancreatic rigidity.

Methods: Intrapancreatic tumors were genetically induced by mutated Kras and p53 in KPC mice. We evaluated the feasiblity of a live imaging protocol by assessing pancreas evolution with Aixplorer technology accross 36 weeks. Lethality induced by in situ pancreatic cancer was heterogeneous in time.

Results: The developed method successfully detected tumor mass from 26 weeks onwards at minimal 0.029 cm³ size. Elastography measurements using shear wave methodology had a wide detection range from 4.7kPa to 166.1kPa. Protumorigenic mutations induced a significant decrease of the rigidity of pancreatic tissue before tumors developed in correlation with the detection of senescent marker p16-positive cells. An intratumoral increased rigidity was quantified and found surprisingly heterogeneous. Tumors also presented a huge inter-individual heterogeneity in their rigidity parameters; tumors with low and high rigidity at detection evolve very heterogeneously in their rigidity parameters, as well as in their volume. Increase in rigidity in tumors detected by ultrafast elasticity imaging coincided with detection of tumors by echography and with the detection of the inflammatory protumoral systemic condition by non invasive follow-up and of collagen fibers by post-processing tumoral IHC analysis.

Conclusion: Our promising results indicate the potential of the shear wave elastography to support individualization of diagnosis in this most aggressive disease.

Diagnostic accuracy of MRI with MRCP and B-Mode-sonography with elastography of the pancreas in patients with cystic fibrosis: a point-to-point comparison

Objective

For patients with cystic fibrosis, the imaging of the pancreas is of crucial importance for the early detection of pancreatic carcinoma. Comparative studies between Magnetic Resonance Imaging (MRI) and sonographic pancreas sonography are not yet available. The aim of the study was to compare MRI, sonography and point-shearwave elastography (pSWE). A total of 19 patients were included (10 male, 9 female; age 29.7 ± 14.3 years) in the study. Ultrasonography with pSWE and contrast enhanced MRI with MRCP were performed.

Results

Significant differences between measurements of pancreatic body were registered in MRI with 1.4 ± 0.6 cm vs 1.0 ± 0.4 cm in ultrasound (p = 0.049), however not for pancreatic head and tail. In 10/19 patients (52.6%) pancreatic parenchyma did not show in MRI because of complete lipomatous transformation, but could be detected in ultrasound. pSWE-values showed no significant differences between the full and partial fatty transformation in pancreatic head (p = 0.968), body (p = 0.657) and tail (p = 0.840). pSWE-values did not correlate with measured signal intensity in T1w flash (p = 0.930, r = 0.025) and T2w HASTE sequences (p = 0.152, r = − 0.375). In patients with CF ultrasound is superior to MRI for displaying full fibro-fatty parenchymal transformation, pancreatic duct. Ultrasound elastography did not provide additional clinical relevant information.

Electronic supplementary material

The online version of this article (10.1186/s13104-019-4193-4) contains supplementary material, which is available to authorized users.

Pediatric ultrasonography of the pancreas: normal and abnormal findings

The pancreas is easily investigated in children thanks to the relative lack of fat tissue and the large left hepatic lobe with an optimal acoustic window. The use of high frequency, even linear transducers, usually results in detailed images of all pancreatic areas. A wide spectrum of pancreatic pathologic conditions can be identified and monitored at ultrasound although they are relatively uncommon during childhood compared to the adult. In this paper we briefly review the anatomy, technique, and sonographic aspects of normal and pathological pediatric pancreas.