Pathologic analysis PA The resected specimens were histologi
Pathologic analysis (PA). The resected specimens were histologically examined according to the Verbeke protocol by a specialized pathologist (author A.F.S.) who noted the tumor’s characteristics, including the ori-gin, differentiation grade, maximum diameter, presence of perineural invasion, lymphatic and/or vascular inva-sion and extension in peripancreatic soft tissue (Verbeke et al. 2006). Margins to all pancreatic surfaces were measured. Radicality was assessed as follows: R0, tumor-free; R1, tumor extension <1 mm; or R2, macro-scopically non-radical. In the event that a vascular recon-struction was performed, the borders of the vascular patch and the depth of invasion in the vascular patch or segment were also assessed for tumor involvement. All resected Cucurbitacin I nodes were scored for tumor positivity.
Assuming that the surgical strategy would be changed in >30% of the patients because of the IOUS assessment, 31 patients should be included. A sample size of 31 patients achieves 80% power using the two-sided McNemar test with a significance level of 0.05.
Differences between correct assessment of vascular contact between preoperative imaging and IOUS were assessed with a McNemar test.
During the study period, IOUS was performed in 31 surgical explorations (Table 1). One patient underwent two explorations: six months after a pancreatic head resection, she underwent a pancreatic tail resection for a second primary malignancy. Vascular contact was sus-pected on nine preoperative scans and vascular involve-ment on one scan; therefore, vascular resection was suggested for this patient. Vascular contact could not be determined from four preoperative scans (13%) because of the isodense appearance on the scans. Twenty-seven malignant tumors and one benign lesion were resected, of which four included a vascular resection. During three explorations, resection was abandoned because of irre-sectable disease.
Primary outcome: Effect of IOUS assessment on surgical strategy
The IOUS-based characteristics of the tumors are summarized in Table 2. The use of IOUS extended the average procedure by 11 § 5 min. All tumors (100%) were detected with IOUS, and vascular contact was detected in 14 patients (45%). The majority of the tumors were clearly visible, hypoechoic and had irregular borders.
Next, the effect of IOUS assessment on the surgical procedure was examined. A detailed overview of the
2022 Ultrasound in Medicine & Biology
Table 1. Patient characteristics
female 14 47 Endoscopic ultrasound yes 22 71
no 26 84 Neoadjuvant treatment gemcitabine 3 10
FOLFIRINOX 1 3
none 27 87 Last imaging CT scan 24 77 before surgery visibility: direct sign 11 46
indirect sign 13 54
density: hypodense 9 37
visibility: direct sign 7 100
dynamic 2 29 Size (max diameter) measurable 17 55
Origin and localization ampulla of Vater 3 10 of tumor distal bile duct 4 13
duodenum 4 13
proc. uncinatus 2 10
tail 2 10 Vascular contact of tumor no vascular contact 17 55
contact with vessel 9 29
involvement of vessel 1 3
contact cannot 4 13
Clinical lymph node status N0 24 77
Type of surgery PPPD/whipple 21 67
tail resection 3 10
total pancreatectomy 3 10
duodenum resection 1 3
no resection 3 10
CT = computed tomography; DWI =; IQR = inter quartile range; MRI = magnetic resonance imaging; N0 =; N1 =; PPPD = pylorus pre-serving pancreatoduodectomy; proc. uncinatus = uncinated process; SD = standard deviation; T1 = .