Advances in endoscopic ultrasound-guided shear wave elastography: A comprehensive review of its clinical applications

Table 1 Endoscopic ultrasound-guided shear wave elastography in pancreatic diseases

Ref.	Design	Population	Techniques	Reference standard	Results
Kojima et al[39]	Single-center, retrospective observational study (pilot + SWE sub-study)	Diagnostic EUS in 16 cases (normal pancreas, IPMN, CP, PC, etc.); SWE study: 32 PC, 17 AIP, 14 controls	EUS-SWE (10 measurements, ROI 5 mm × 10 mm; Vs and VsN measured)	Clinical diagnosis (PC, AIP; normal controls)	PC: Vs not significantly different vs controls (2.22 m/second vs 1.96 m/second, P = 0.063), but VsN significantly lower in lesions (21% vs 87%, P < 0.001); AUROC 0.918 for VsN cut-off 50%. AIP: Vs not significantly different vs controls (2.35 m/second vs 1.96 m/second, P = 0.065), but VsN significantly lower (17% vs 87%, P < 0.001); AUROC 0.929. Treatment monitoring: In AIP, Vs and VsN improved after 16 weeks of steroid therapy
Shintani et al[31]	Retrospective, single-center	657 screened; 22 patients with ECP vs 22 matched controls (JPSC)	EUS-SWE (≥ 5 measurements in pancreatic body, ROI 10 mm × 5 mm; VsN > 50% considered reliable)	JPSC 2019 for ECP	Mean Vs significantly higher in ECP vs normal (2.31 ± 0.67 m/second vs 1.59 ± 0.40 m/second, P < 0.001). Optimal cut-off 2.24 m/second (AUROC 0.82, 95%CI: 0.69-0.94). Vs strongly correlated with number of EUS findings (rs = 0.626, P < 0.001). Independent predictors of high Vs: History of acute pancreatitis and ≥ 2 positive EUS findings
Shintani et al[30]	Retrospective, single-center	50 patients with CP or suspected CP	EUS-SWE in three pancreatic regions (head, body, tail; ≥ 5 measurements per site, ROI 10 mm × 5 mm, VsN > 50%)	RC	Vs values significantly higher in CP vs non-CP across all regions. Diagnostic accuracy highest in pancreatic body: AUROC 0.87 (cut-off 2.33 m/second; sensitivity 824%, specificity 87.5%). Head and tail AUROCs 0.79 and 0.81, respectively. Vs correlated with number of RC features in all regions (strongest in body, rs = 0.55). Lobularity with honeycombing was independent predictor of stiffness
Yamashita et al[34]	Prospective, single-center	49 patients with suspected/confirmed CP	EUS-SWE vs EUS-SE	CT, RC, JPSC 2019, pancreatic exocrine dysfunction	EUS-SWE values positively correlated with RC and JPSC severity grades and number of EUS features; EUS-SE showed no correlation. Diagnostic accuracy (AUROC SWE vs SE): CT 077 vs 0.61; RC 0.85 vs 0.56; JPSC 0.83 vs 0.53; exocrine dysfunction 0.78 vs 0.61
Abboud et al[38]	Prospective, single-center	117 consecutive patients undergoing EUS for various indications (cysts, CP, recurrent acute pancreatitis, mass, screening)	EUS-SWE (10 measurements in head, body, tail; ROI 5-15 mm; VsN > 50% considered reliable)	Not disease-specific (technical feasibility/reproducibility study)	Safety/feasibility: 3320 measurements, 100% success, no peri-procedural complications. Reliability: Higher in head (85.1% reliable), vs body (75.5%) and tail (64.2%). Reproducibility: ICC good across all sites (0.80-0.89)
Yamashita et al[33]	Prospective, single-center	40 patients (normal, early, probable, and definite CP)	EUS-SWE (10 measurements in pancreatic body; ROI 5 mm × 10 mm)	JPSC 2010; BT-PABA for exocrine function; DM for endocrine dysfunction	EUS-SWE positively correlated with JPSC stages and with pancreatic function diagnostic test. Diagnostic accuracy: CP AUROC 0.92 (cut-off 1.96 m/second; sensitivity 83%, specificity 100%); exocrine dysfunction AUROC 0.78 (cut-off 1.96 m/second; sensitivity 90%, specificity 65%); DM AUROC 0.63 (cut-off 2.34 m/second; sensitivity 75%, specificity 64%)
Ohno et al[35]	Retrospective, single-center	64 patients with solid pancreatic lesions (43 PC, 9 MFP, 9 PanNEN, 3 metastases)	EUS-SWE vs EUS-SE	Histology or ≥ 12 months clinical follow-up	Vs: No significant difference between PC, MFP, PanNEN, metastases (PC 2.19 m/second vs MFP 2.56 m/second, P = 0.57); AUROC for PC vs non-PC = 0.56. VsN: Low across SPLs (PC 19%, MFP 13%, PanNEN 18%). Strain histogram: Mean strain significantly lower in PC vs MFP (45.4 vs 74.5, P = 0.0007); AUROC = 0.68
Yamashita et al[32]	Retrospective, single-center	52 patients (normal, indeterminate, suggestive, and consistent CP)	EUS-SWE (10 measurements in pancreatic body; ROI 5 mm × 10 mm)	RC; DM as marker of endocrine dysfunction	EUS-SWE values significantly correlated with RC stages (rs = 0.81) and number of EUS features (rs = 0.72). Diagnostic performance: CP AUROC 0.97 (cut-off 2.19 m/second; sensitivity 100%, specificity 94%); DM AUROC 0.75 (cut-off 2.78 m/second; sensitivity 70%, specificity 56%)
Ohno et al[29]	Prospective, single-center exploratory study	160 patients undergoing EUS; subgroup: 14 with AIP, 16 normal controls	EUS-SWE (≥ 5-10 measurements in pancreatic head, body, tail; ROI 5 mm × 10 mm; VsN reliability index, ≥ 50% accepted)	International Consensus Diagnostic Criteria for AIP	Overall feasibility: 97.6% success rate (3743/3837 measurements). Median Vs in AIP group significantly higher than controls (2.57 m/second vs 1.89 m/second, P = 0.0185). In 6 patients, Vs decreased after steroid therapy (3.32 m/second to 2.46 m/second, P = 0.0234), paralleling pancreatic size reduction

SWE: Shear wave elastography; EUS: Endoscopic ultrasound; IPMN: Intraductal papillary mucinous neoplasm; CP: Chronic pancreatitis; PC: Pancreatic cancer; AIP: Autoimmune pancreatitis; ECP: Early chronic pancreatitis; MFP: Mass-forming pancreatitis; PanNEN: Pancreatic neuroendocrine neoplasms; ROI: Region of interest; Vs: Shear wave velocity; VsN: Net effective shear wave velocity; SE: Strain elastography; JPSC: Japanese diagnostic criteria 2019; RC: Rosemont criteria; CT: Computed tomography; BT-PABA: N-benzoyl-L-tyrosyl-p-aminobenzoic acid; DM: Diabetes mellitus; AUROC: Area under the receiver operating characteristic; CI: Confidence interval; ICC: Intraclass correlation coefficient; SPLs: Solid pancreatic lesions.