Influence of age, sex, body mass index, alcohol, and smoking on shear wave velocity (p-SWE) of the pancreas

Point shear wave elastography application in assessment pancreas tissue stiffness: A pilot study

INTRODUCTION

Recent advancements in medical imaging, such as point shear wave elastography (pSWE), offer non-invasive methods to assess tissue stiffness and structural changes. This study explores the use of pSWE to evaluate pancreatic stiffness and dimensions in three different pancreas parts.

METHODS

This study was conducted at diagnostic radiology department, King Abdulaziz University Hospital, Jeddah, between June 2022 and November,2022. Thirty-one diabetic patients and thirty-one healthy controls were included. Ultrasound pSWE examination was performed using a ultrasound system (Philips Elite Epic 7) to measure stiffness across different pancreatic parts. Pancreatic stiffness was quantified in meters per second (m/s), and the dimensions of each pancreatic part were recorded. Different parameters, including age, sex, height, weight, body mass index (BMI), and comorbidities, were collected and analyzed.

RESULTS

Diabetic patients exhibited significantly higher shear wave velocities (SWVs) compared to healthy controls, indicating increased pancreatic stiffness. The mean shear wave velocity was 1.7 m/s in diabetic versus 0.6 m/s in controls (p < 0.001). Additionally, the pancreatic head dimensions were significantly large in diabetic patients (2.1 cm vs. 1.8 cm; p = 0.003), while the body and tail part showed no significant differences. A positive correlation was found between SWVs and BMI.

CONCLUSION

The findings underscore the potential of pSWE as a non-invasive diagnostic tool for early detection and monitoring of diabetes-related pancreatic alterations. Assessing pancreatic stiffness and dimensions through pSWE can help in identify patients at risk for pancreatic complications and optimize management strategies.

IMPLICATIONS FOR PRACTICE

Point shear wave elastography (pSWE) could be a useful, non-invasive tool for early detection of pancreatic changes in diabetic patients, identifying those at risk for complications. Integrating pSWE into routine diabetes check may enhance early interventions and improve outcomes.

Protocol for acquisition of images and measurement of transabdominal ultrasound pancreatic two-dimensional shear wave elastography (2D-SWE)

INTRODUCTION

Transabdominal ultrasound (TU) pancreatic 2D-SWE elastography is a developing technique that needs to be protocolized.

OBJECTIVES

Establish a protocol for image acquisition and measurement of TU pancreatic - 2D-SWE elastography and estimate the minimum number of measurements to be performed.

MATERIALS AND METHODS

Ten measurements of pancreatic elasticity were taken in healthy volunteers using TU-2D-SWE, following a strict protocol for image acquisition and measurement.

RESULTS

The 70% of the participants were women, with an average age, weight, and BMI of 49.5±15.7 years, 65.9±11.9kg, and 24.5±4.2kg/m2, respectively. Measurements were taken from the body (70%), tail (16.7%), and pancreatic head (13.3%). The median mean velocity and elasticity were 1.46±0.25cm/sec and 6.46±2.87KPa, respectively. The ROI depth was 4.12±1cm and the SP-ROI distance was 5.2mm on average. There were no statistically significant differences between the 10 measurements. The reliability analysis of the measurements showed high internal consistency and repeatability. Taking 5-6 measurements ensured high concordance with the ten reference measurements. The measurements were significantly lower when the SP-ROI values were intermediate (0.3-0.6cm). The measurement accuracy was higher when performed at a depth less than 4.8cm.

CONCLUSION

To measure pancreatic elasticity using TU-2D-SWE, we propose a strict protocol for image acquisition and measurement, taking a minimum of 5 measurements in the best visualized and accessible pancreatic portion, and preferably at a depth of less than 4.8cm.

The feasibility of point shear wave elastography (pSWE) in the assessment of pancreas stiffness in diabetic patients and healthy volunteers

Type 1 diabetes mellitus (T1DM) is an autoimmune disease characterized by the dysfunctional metabolism of carbohydrates, fats, and proteins caused by impaired insulin secretion and insulin resistance. This study investigated the feasibility of using point shear wave elastography (pSWE) of the pancreas by comparing the shear wave velocity (SWV) measurements of three anatomical areas in patients with T1DM and healthy volunteers. This study included 30 patients with T1DM (9 male, 21 female) and 23 healthy controls (11 men, 12 women). Two experienced certified operators performed the examinations and took the SWV measurements. The mean SWV of the entire pancreas parenchyma differed significantly between patients and controls (1.1 ± 0.29 and 0.74 ± 0.19 m/s, respectively; p ≤ 0.001). Moreover, the SWVs of the pancreatic segments were significantly different in patients and controls; the mean SWV values of the pancreas head, body, and tail (respectively) in patients vs. controls were 0.99 ± 0.36 vs. 0.76 ± 0.26 m/s (p  = 0.012), 1.1 ± 0.52 vs. 0.74 ± 0.23 (p ≤ 0.001), and 1.0 ± 0.34 vs. 0.73 ± 0.28 (p  ≤ 0.001). This study confirmed the feasibility of quantifying pancreas tissue stiffness with pSWE and revealed that patients with T1DM had higher pancreas tissue stiffness than controls. Further studies are required to determine the potential value of pSWE as a screening tool in patients with prediabetes.

Feasibility and Measurement Value of Pancreatic 2-D Shear Wave Elastography in Healthy Adults: Evaluation, Influencing Factors, Reference Range, Measurement Stability and Reproducibility

OBJECTIVE

The present study was aimed at assessing the success rate and measurement value, determining the influencing factors and reference range and examining the intra-operator stability and inter-operator reproducibility of pancreatic 2-D shear wave elastography (SWE) measurement in healthy adults.

METHODS

In 2022, 387 healthy adults were prospectively recruited. Logistic regression and linear regression analyses were used to explore the factors influencing the success rate and the measurement value of pancreatic 2-D SWE measurement, respectively. A two-sided 95% reference range was estimated accordingly. The intraclass correlation coefficient was calculated to evaluate the intra-operator stability and inter-operator reproducibility of the pancreatic 2-D SWE measurement.

RESULTS

The pancreatic body (89.6%) bore the highest while the tail (72.8%) bore the lowest success rate of pancreatic 2-D SWE measurement. Sex and body mass index (BMI) were the independent factors influencing measurement success rate in all three parts of the pancreas. Mean measurement values (Emean) were not the same in the three parts of the pancreas of the same participant. BMI and image depth were the independent factors influencing Emean in the pancreatic body, while region of interest depth and BMI were the only independent factors influencing Emean in the pancreatic head and tail, respectively. The intra-operator stability of pancreatic 2-D SWE measurement was found to be excellent, whereas its inter-operator reproducibility was poor to good.

CONCLUSION

Pancreatic 2-D SWE is a reliable technique for evaluating pancreatic stiffness in healthy adults, but its success rate and measurement value are influenced by multiple factors.

Estimating reference values of parenchymal stiffness of normal pancreatic parenchyma by means of point shear wave elastography

INTRODUCTION

There are numerous imaging modalities available to describe pancreatic parenchyma. None of the broadly accepted diagnostic methods uses elasticity as an indicator of tissue damage.

Lung Ultrasound Elastography by SWE2D and "Fibrosis-like" Computed Tomography Signs after COVID-19 Pneumonia: A Follow-Up Study

The aim of this study was to assess the shear wave velocity by LUS elastography (SWE2D) for the evaluation of superficial lung stiffness after COVID-19 pneumonia, according to "fibrosis-like" signs found by Computed Tomography (CT), considering the respiratory function. Seventy-nine adults participated in the study 42 to 353 days from symptom onset. Paired evaluations (SWE2D and CT) were performed along with the assessment of arterial blood gases and spirometry, three times with 100 days in between. During the follow-up and within each evaluation, the SWE2D velocity changed over time (MANOVA, p < 0.05) according to the extent of "fibrosis-like" CT signs by lung lobe (ANOVA, p < 0.05). The variability of the SWE2D velocity was consistently related to the first-second forced expiratory volume and the forced vital capacity (MANCOVA, p < 0.05), which changed over time with no change in blood gases. Covariance was also observed with age and patients' body mass index, the time from symptom onset until hospital admission, and the history of diabetes in those who required intensive care during the acute phase (MANCOVA, p < 0.05). After COVID-19 pneumonia, SWE2D velocity can be related to the extent and regression of "fibrotic-like" involvement of the lung lobes, and it could be a complementary tool in the follow-up after COVID-19 pneumonia.

The Role of Transabdominal Ultrasound Elastography in Gastrointestinal Non-Liver Diseases: Current Application and Future Prospectives

Ultrasound imaging is the first-line investigation for patients with abdominal symptoms, as it effectively depicts the gastrointestinal tract and enables the diagnosis of multiple pathological conditions. Among different recent ultrasound technological advancements, elastography enables the evaluation of various tissue characteristics, such as neoplastic transformation or fibroinflammatory status. In recent years, ultrasound elastography has been utilized extensively for the study of liver diseases and in numerous other clinical settings, including gastrointestinal diseases. Current guidelines suggest the use of transabdominal ultrasound elastography to characterize bowel wall lesions, to assess gastrointestinal contractility, to diagnose and grade chronic pancreatitis; however, no specific indications are provided. In the present paper, we summarize the evidence concerning the application of different ultrasound elastography modalities in gastrointestinal non-liver diseases.

Clinical significance of dispersion imaging by shear wave elastography in the treatment and diagnosis of pancreatic cancer

BACKGROUND AND AIM

Recently, dispersion imaging by shear wave elastography has been developed to visualize a tissue viscosity-related factor by measuring the dispersion slope. However, clinical significance of dispersion imaging in the field of pancreatic cancer is unknown. This study aimed to investigate the clinical significance of dispersion imaging in the treatment and diagnosis of pancreatic cancer.

METHODS

We measured shear wave dispersion slope (SWD) (m/s/kHz) and shear wave elasticity (SWE) (kPa) in patients with pancreatic ductal adenocarcinoma (PDA). The primary endpoint was the relationship between the changes in SWD and SWE values before and after chemotherapy and the response to chemotherapy. Secondary endpoints included SWD and SWE values in relation to differences between PDA and non-PDA sites and histopathological scores of stroma, inflammation, fibrosis, and necrosis in endoscopic ultrasound-guided fine-needle aspiration specimens.

RESULTS

Fifty-six patients were included, 30 of whom underwent chemotherapy. There was no relationship between the changes of SWD and SWE values and chemotherapy responses. In 56 patients, the median SWD value was 12.20 m/s/kHz (interquartile range [IQR]: 10.88-13.61) at PDA sites and 13.57 m/s/kHz (IQR: 12.28-16.20) at non-PDA sites (P = 0.005). The median SWE value was 8.18 kPa (IQR: 7.00-9.74) at PDA sites and 6.14 kPa (IQR: 5.40-6.77) at non-PDA sites (P < 0.001). Histopathological evaluation revealed that inflammation scores were correlated with SWD values (rs  = 0.42, P < 0.001).

CONCLUSIONS

Dispersion imaging in pancreatic cancer would be useful for diagnosis and assessing inflammation.

Ultrasound Shear Wave Elastography of Normal Pancreas in Adult Subjects

Background and Purpose Transabdominal ultrasound (US)-based shear wave elastography (SWE) provides an attractive method of estimating pancreatic stiffness. There is limited data on the SWE values of the healthy pancreas in Indian subjects. The current study aimed to evaluate SWE of the normal pancreas.

Methods We performed a study from January 2019 to March 2019. We included adult patients who presented for the US of the upper abdomen for vague abdominal symptoms, unrelated to the pancreas. The SWE values were obtained from the pancreatic head and body. The association of pancreatic SWE with age, gender, fatty liver, chronic liver disease, and cholelithiasis was recorded.

Results During the study period, 205 subjects underwent SWE of the pancreas. The mean age of subjects was 41.3 (standard deviation [SD] 15.3) years. There were 93 males and 112 females. The mean SWE value in the head of the pancreas was 8.98 (SD 2.46 kPa), and that in the body region was 8.67 (SD 2.67 kPa). There was a positive correlation of SWE with age. The SWE of the pancreatic body was significantly higher in patients who had a fatty liver on US (p < 0.05). There was no significant association of SWE of the pancreas with gender, presence of chronic liver disease, or gallstones.

Conclusion The normal values of pancreatic SWE are correlated with age and fatty change in the liver.

Multi-frequency magnetic resonance elastography of the pancreas: measurement reproducibility and variance among healthy volunteers

Background

Patients with chronic pancreatitis often have irreversible pancreatic insufficiency before a clinical diagnosis. Pancreatic cancer is a fatal malignant tumor in the advanced stages. Patients having high risk of pancreatic diseases must be screened early to obtain better outcomes using new imaging modalities. Therefore, this study aimed to investigate the reproducibility of tomoelastography measurements for assessing pancreatic stiffness and fluidity and the variance among healthy volunteers.

Methods

Forty-seven healthy volunteers were prospectively enrolled and underwent two tomoelastography examinations at a mean interval of 7 days. Two radiologists blindly and independently measured the pancreatic stiffness and fluidity at the first examination to determine the reproducibility between readers. One radiologist measured the adjacent pancreatic slice at the first examination to determine the reproducibility among slices and measured the pancreas at the second examination to determine short-term repeatability. The stiffness and fluidity of the pancreatic head, body, and tail were compared to determine anatomical differences. The pancreatic stiffness and fluidity were compared based on sex, age, and body mass index (BMI).

Results

Bland–Altman analyses (all P > 0.05) and intraclass correlation coefficients (all >0.9) indicated near perfect reproducibility among readers, slices, and examinations at short intervals. Neither stiffness (P = 0.477) nor fluidity (P = 0.368) differed among the pancreatic anatomical regions. The mean pancreatic stiffness was 1.45 ± 0.09 m/s; the mean pancreatic fluidity was 0.83 ± 0.06 rad. Stiffness and fluidity did not differ by sex, age, or BMI.

Conclusion

Tomoelastography is a promising and reproducible tool for assessing pancreatic stiffness and fluidity in healthy volunteers.

Two-dimensional shear wave elastography of the pancreas: measurement success rate, repeatability, and factors affecting measurement values

PURPOSE

We aimed to evaluate the success rate, repeatability, and factors affecting the measurement values of two-dimensional ultrasonic shear wave elastography (2D-SWE) for measuring pancreatic stiffness.

METHODS

This prospective study recruited 100 healthy participants. 2D-SWE was performed on the pancreatic head, body, and tail. We compared the success rates of pancreatic stiffness measurements of different body positions and ultrasonic scans, with and without probe pressurization, as well as the effects of sex, age, body mass index (BMI), and region of interest (ROI) depth on measurement values. Intra- and inter-operator repeatabilities were assessed in 20 participants. The influence of ROI depth was verified using a tissue-like phantom.

RESULTS

The median 2D-SWE measurements of the pancreatic head, body, and tail were 1.44, 1.45, and 1.56 m/s, respectively. The success rates for the pancreatic head and body were significantly higher than that of the tail. The success rate for the semi-recumbent position was higher than that of the supine position (P < 0.001). The intra-operator values for same-day and inter-operator reliability were excellent. Univariate analyses showed that probe pressurization, age, BMI, and ROI depth were correlated with pancreatic shear wave velocity (SWV) (P < 0.05); only ROI depth had a significant effect on SWV values. The inclusion phantom showed that the SWV value increased as the ROI depth increased.

CONCLUSIONS

2D-SWE had a high success rate and good repeatability for measuring pancreatic head and body stiffness. The ROI depth was the main factor affecting pancreatic SWV, which increased with ROI depth.

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.

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.

Two-Dimensional Shear Wave Elastography of Normal Soft Tissue Organs in Adult Beagle Dogs; Interobserver Agreement and Sources of Variability

Shear wave elastography (SWE) induces lateral shear wave through acoustic pulses of the transducer and evaluates tissue stiffness quantitatively. This study was performed to evaluate feasibility and reproducibility of two-dimensional shear wave elastography (2D SWE) for evaluation of tissue stiffness and to examine technical factors that affect shear wave speed (SWS) measurements in adult dogs. Nine healthy, 2 year-old, adult beagles with the median weight of 9.8 kg were included. In this prospective, experimental, exploratory study, 2D SWE (Aplio 600) from the liver, spleen, kidneys, pancreas, prostate, lymph nodes (submandibular, retropharyngeal, axillary, medial iliac, and inguinal), submandibular salivary gland, and thyroid was performed in anesthetized beagles. Color map was drawn and SWS of each SWE were measured as Young’s modulus (kPa) and shear wave velocity (m/s). The effect of measuring site, scan approach, depth, and anesthesia on SWE was assessed in abdominal organs by two observers independently. A total of 27 SWE examinations were performed in 12 organs by each observer. All SWS measurements were preformed successfully; however, SWE in the renal medulla could not be successfully conducted, and it was excluded from further analysis. Interobserver agreement of SWE was moderate to excellent in all organs, except for the left liver lobe at 10–15 mm depth with the intercostal scan. In the liver, there was no significant effect of the measuring site and scan approach on SWE. SWS of the liver and spleen tended to be higher with increasing the depth, but no significant difference. However, anesthesia significantly increased tissue stiffness in the spleen compared to awake dog regardless of the depth (P < 0.05). There was a significant difference in SWS according to the measuring site in the kidneys and pancreas (P < 0.001). 2D SWE was feasible and highly reproducible for the estimation of tissue stiffness in dogs. Measuring site and anesthesia are sources of variability affecting SWE in abdominal organs. Therefore, these factors should be considered during SWS measurement in 2D SWE. This study provides basic data for further studies on 2D SWE on pathological conditions that may increase tissue stiffness in dogs.

Magnetic resonance elastography vs. point shear wave ultrasound elastography for the assessment of renal allograft dysfunction

PURPOSE

To investigate the utility of magnetic resonance elastography (MRE) vs. ultrasound (US) point shear wave elastography (pSWE) for the assessment of chronic renal allograft dysfunction, prediction of outcome and determine the correlation with Banff pathology scores.

METHODS

In this IRB approved prospective study, 27 enrolled patients with functional (n = 15) and chronic dysfunctional (n = 12) renal allografts underwent same day 2D MRE and pSWE. Histogram parameters [including mean, median, standard deviation, kurtosis and skewness] of the magnitude of the complex shear modulus (MRE) and median Young's modulus (pSWE) were measured in the cortex (MRE and pSWE) and combined corticomedullary regions (MRE). Histopathology was available for 16 patients (4 functional, 12 dysfunctional).

RESULTS

MRE and pSWE stiffness were not significantly different between functional and dysfunctional groups (p range 0.139-0.347). The skewness of MRE corticomedullary stiffness was significantly lower (p = 0.04) in patients with chronic dysfunction and correlated significantly with Banff histopathologic scores (range r=-0.518-0.567, p = 0.035-0.040). MRE cortical and corticomedullary mean stiffness showed strong performance in predicting graft loss/relist (AUC 0.958, p = 0.011 for both). Reliable pSWE measurements were obtained in 13 patients (48 %). pSWE stiffness did not correlate with Banff scores and did not predict outcome.

CONCLUSIONS

The skewness of MRE corticomedullary stiffness is sensitive to changes in chronic allograft dysfunction, while mean/median MRE renal stiffness and median US stiffness did not differentiate patients with stable function vs those with chronic renal allograft dysfunction. MRE corticomedullary mean stiffness appears to be a predictor of graft loss/relist. pSWE was not found to be a useful method for assessing renal allografts.

Normative Pancreatic Stiffness Levels and Related Influences Established by Magnetic Resonance Elastography in Volunteers

BACKGROUND

Large-scale normative studies of pancreatic stiffness and potential influences have yet to be pursued via magnetic resonance elastography (MRE).

PURPOSE

To determine normative MRE-based pancreatic stiffness values and to examine related influential factors.

STUDY TYPE

Prospective.

SUBJECTS

In all, 361 volunteers (men, 199; women, 162) with a median age of 54.0 years and a median body mass index (BMI) of 22.86 kg/m² were prospectively recruited. Those with no histories of smoking, alcohol abuse, and diabetes mellitus (DM) were grouped as healthy volunteers, designating all others as positive controls.

FIELD STRENGTH/SEQUENCE

Each volunteer underwent 3.0T pancreatic MRI at a frequency of 40 Hz.

ASSESSMENT

Pancreatic stiffness values, pancreatic width and volume, waist circumference, and wave distance were measured in all subjects.

STATISTICAL TESTS

Multiple linear regression analyses were performed to determine variables that influence MRE-determined stiffness.

RESULTS

The mean pancreatic stiffness in all volunteers was 1.20 ± 0.16 kPa. Stiffness levels in positive control volunteers proved significantly greater than levels in healthy volunteers (1.29 ± 0.17 kPa vs. 1.14 ± 0.13 kPa; P < 0.001). In multiple linear regression analysis, sex (P = 0.004), BMI (P < 0.001), pancreatic width (P = 0.005), smoking (P < 0.001), alcohol abuse (P < 0.001), and DM (P = 0.001) emerged as significant independent factors impacting pancreatic stiffness. Smoking, alcohol abuse, DM, and wide pancreas were associated with greater pancreatic stiffness (coefficients = 0.202, 0.183, 0.149, and 0.160, respectively), while reduced pancreatic stiffness corresponded with female sex and larger BMI (coefficient = -0.155 and -0.192, respectively).

DATA CONCLUSION

MRE-based pancreatic stiffness values are impacted by sex, BMI, pancreatic width, smoking, alcohol abuse, and DM. Reference values are essential for future clinical studies.

LEVEL OF EVIDENCE

1 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2020;52:448-458.

Elastography of the Pancreas, Current View

Ultrasound elastography (USE) of the pancreas allows pancreatic tissue stiffness assessment by virtual palpation. Two main types of USE are used. For the pancreas strain elastography applying by endoscopic ultrasound has been established for the characterisation of small solid pancreatic lesions (SPL). In larger SPL >30 mm the results are less convincing mainly due to the heterogenicity of the lesions but also by concomitant changes of the surrounding pancreatic parenchyma. The current role of shear wave elastography has to be determined. This article reviews the current use of elastography of the pancreas.

Increased hardness of the underlying pancreas correlates with the presence of intraductal papillary-mucinous neoplasm in a limited number of cases

PURPOSE

Pancreatic fibrosis or fibrosing reactions have been reported in intraductal papillary-mucinous neoplasm (IPMN) patients. We assessed whether a higher elastic modulus (EM) measured using shear wave elastography (SW-EG) correlated with the existence of branch-duct (BD) IPMN.

METHODS

In total, 183 normal pancreas (NP) and 123 BD-IPMN cases were enrolled. First, we assessed the difference in pancreatic EM (PEM) at different sites (head or tail side of the cyst). Second, a comparison was done between the median PEM of the NP and the BD-IPMN cases. Receiver-operating characteristic analysis was performed to determine the BD-IPMN diagnostic capabilities. Finally, in patients whose cyst was not visualized, the test-positive rate was determined.

RESULTS

No significant difference was seen between the cyst head side PEM (4.61 kPa) and the tail side PEM (5.35 kPa) (P = 0.471). Among these cases matched by age, 73 were selected each from NP and BD-IPMN cases (median age 65 years). The median PEM of the BD-IPMN cases (5.18 kPa) was significantly higher than that of the NP cases (3.17 kPa) (P < 0.001). When the cut-off value was set at 4.75 kPa, the sensitivity, specificity, PPV, NPV, and accuracy were 75.3%, 64.4%, 72.3%, 67.9%, and 69.9%, respectively. The cut-off value of 4.75 kPa helped for the indirect selection of BD-IPMN patients (10/17, 58.8%) whose cyst was not detected on B-mode ultrasonography.

CONCLUSION

SW-EG measurement of the underlying pancreatic parenchyma may correlate with the presence of BD-IPMN.

A score model based on pancreatic steatosis and fibrosis and pancreatic duct diameter to predict postoperative pancreatic fistula after Pancreatoduodenectomy

PURPOSES

To establish a scoring model for the risk of postoperative pancreatic fistula (POPF) following pancreatoduodenectomy (PD).

METHODS

PD Patients from 7 institutions in 2 independent sets: developmental (n = 457) and validation cohort (n = 152) were retrospectively enrolled and analyzed. Pancreatic Fibrosis (PF) and Pancreatic Steatosis (PS) were assessed by pathological examination of the pancreatic stump.

RESULTS

Stepwise univariate and multivariate analysis indicated that pancreatic duct diameter ≤ 3 mm, increased PS and decreased PF were independent risk factors for POPF and Clinically Relevant Postoperative Pancreatic Fistula (CR-POPF). Based on the relative weight and odds ratio of each factor in the POPF, a simplified scoring model was developed. And patients were stratified into high-risk group (22~28 points), medium-risk group (15~21 points) and low-risk group (8~14 points). The receiver operating characteristic curve demonstrated that the Area under the curve for the predictive model was 0.868 and 0.887 in the model design group and the external validation group.

CONCLUSIONS

This study establishes a simplified scoring model based on accurately and quantitatively measuring the PS, PF and pancreatic duct diameter. The scoring model accurately predicted the risk of POPF.

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.

Ultrasound point shear wave elastography of the pancreas: comparison of patients with type 1 diabetes and healthy volunteers - results from a pilot study

Background

The aims of this study were to establish shear wave elastography of the pancreas by comparing measurements in patients with type 1 diabetes (T1D) and healthy volunteers and to consider whether this method could contribute to the screening or prevention of T1D.

Methods

This pilot study included 15 patients with T1D (10 men, 5 women) and 15 healthy volunteers (10 men, 5 women) as controls. Measurements were performed with a Siemens Acuson S3000 (Siemens Healthcare, Erlangen, Germany) using a 6C1 convex transducer and the Virtual Touch™ tissue quantification (VTQ) method.

Results

The mean shear wave velocity of the head of the pancreas was 1.0 ± 0.2 m/s (median: 1.1 m/s) for the study group and likewise 1.0 ± 0.2 m/s (median: 0.9 m/s) for the control group. Velocities of 1.2 ± 0.2 m/s (median: 1.2 m/s) were measured in the body of the pancreas in both groups. There was a significant difference between the values obtained in the tail of the pancreas: patients 1.1 ± 0.1 m/s (median: 1.0 m/s) versus controls 0.9 ± 0.1 m/s (median: 0.8 m/s) (p = 0.0474). The mean value in the whole pancreas of the study group was not significantly above that of the control group: 1.1 ± 0.1 m/s (median: 1.0 m/s) versus 1.0 ± 0.1 m/s (median: 1.0 m/s) (p = 0.2453).

Conclusions

Sonoelastography of the pancreas revealed no overall difference between patients with T1D and healthy volunteers. Patients with T1D showed higher values only in the tail segment. Future studies need to determine whether specific regional differences can be found in a larger study population.

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

PURPOSE

Manifestations of cystic fibrosis in the pancreas are gaining in clinical importance as patients live longer. Conventional ultrasonography and point shear wave elastography (pSWE) imaging are non-invasive and readily available diagnostic methods that are easy to perform. The aim of this study was to perform conventional ultrasonography and obtain pSWE values in the pancreases of patients with cystic fibrosis and to compare the findings with those of healthy controls.

METHODS

27 patients with cystic fibrosis (13 women/14 men; mean age 27.7 ± 13.7 years; range 9-58 years) and 60 healthy control subjects (30 women/30 men; mean age 30.3 ± 10.0 years; range 22-55 years) underwent examinations of the pancreas with conventional ultrasound and pSWE imaging.

RESULTS

Patients with cystic fibrosis have an echogenic pancreatic parenchyma. We found cystic lesions of the pancreas in six patients. pSWE imaging of the pancreatic parenchyma gave significantly lower shear wave velocities in patients with cystic fibrosis than in the control group (1.01 m/s vs 1.30 m/s; p < 0.001).

CONCLUSIONS

Using pSWE imaging in vivo, we have shown that the pancreas is considerably softer in patients with cystic fibrosis than in a healthy control population.

Acoustic radiation force impulse shear wave elastography (ARFI) of acute and chronic pancreatitis and pancreatic tumor

INTRODUCTION

Acoustic Radiation Force Impulse (ARFI) elastography evaluates tissue stiffness non-invasively and has rarely been applied to pancreas examinations so far. In a prospective and retrospective analysis, ARFI shear wave velocities of healthy parenchyma, pancreatic lipomatosis, acute and chronic pancreatitis, adenocarcinoma and neuroendocrine tumor (NET) of the pancreas were evaluated and compared.

MATERIAL AND METHODS

In 95 patients ARFI elastography of the pancreatic head, and also of the tail for a specific group, was analysed retrospectively. Additionally, prospectively in 100 patients ARFI was performed in the head and tail of the pancreas.

RESULTS

A total of 195 patients were included in the study. Healthy parenchyma (n=21) and lipomatosis (n=30) showed similar shear wave velocities of about 1.3m/s. Acute pancreatitis (n=35), chronic pancreatitis (n=53) and adenocarcinoma (n=52) showed consecutively increasing ARFI values, respectively. NET (n=4) revealed the highest shear wave velocities amounting to 3.62m/s. ARFI elastography showed relevant differences between acute pancreatitis and chronic pancreatitis or adenocarcinoma. With a cut-off value of 1.74m/s for the diagnosis of a malignant disease the sensitivity was 91.1% whereas the specificity amounted to 60.4%.

CONCLUSION

ARFI shear wave velocities present differences in various pathologies of the pancreas. Acute and chronic pancreatitis as well as neoplastic lesions show high ARFI values. Very high elasticity values may indicate malignant disease of the pancreas. However, there is a considerable overlap between the entities.