Pre-Operative MDCT Staging Predicts Mesopancreatic Fat Infiltration-A Novel Marker for Neoadjuvant Treatment?

The rates of microscopic incomplete resections (R1/R0CRM+) in patients receiving standard pancreaticoduodenectomy for PDAC remain very high. One reason may be the reported high rates of mesopancreatic fat infiltration. In this large cohort study, we used available histopathological specimens of the retropancreatic fat and correlated high resolution CT-scans with the microscopic tumor infiltration of this area. We found that preoperative MDCT scans are suitable to detect cancerous infiltration of this mesopancreatic tissue and this, in turn, was a significant indicator for both incomplete surgical resection (R1/R0CRM+) and worse overall survival. These findings indicate that a neoadjuvant treatment in PDAC patients with CT-morphologically positive infiltration of the mesopancreas may result in better local control and thus improved resection rates. Mesopancreatic fat stranding should thus be considered in the decision for neoadjuvant therapy. Background: Due to the persistently high rates of R1 resections, neoadjuvant treatment and mesopancreatic excision (MPE) for ductal adenocarcinoma of the pancreatic head (hPDAC) have recently become a topic of interest. While radiographic cut-off for borderline resectability has been described, the necessary extent of surgery has not been established. It has not yet been elucidated whether pre-operative multi-detector computed tomography (MDCT) staging reliably predicts local mesopancreatic (MP) fat infiltration and tumor extension. Methods: Two hundred and forty two hPDAC patients that underwent MPE were analyzed. Radiographic re-evaluation was performed on (1) mesopancreatic fat stranding (MPS) and stranding to peripancreatic vessels, as well as (2) tumor diameter and anatomy, including contact to peripancreatic vessels (SMA, GDA, CHA, PV, SMV). Routinely resected mesopancreatic and perivascular (SMA and PV/SMV) tissue was histopathologically re-analyzed and histopathology correlated with radiographic findings. A logistic regression of survival was performed. Results: MDCT-predicted tumor diameter correlated with pathological T-stage, whereas presumed tumor contact and fat stranding to SMA and PV/SMV predicted and correlated with histological cancerous infiltration. Importantly, mesopancreatic fat stranding predicted MP cancerous infiltration. Positive MP infiltration was evident in over 78%. MPS and higher CT-predicted tumor diameter correlated with higher R1 resection rates. Patients with positive MP stranding had a significantly worse overall survival (p = 0.023). Conclusions: A detailed preoperative radiographic assessment can predict mesopancreatic infiltration and tumor morphology and should influence the decision for primary surgery, as well as the extent of surgery. To increase the rate of R0CRM- resections, MPS should be considered in the decision for neoadjuvant therapy.

Is CT-based cinematic rendering superior to volume rendering technique in the preoperative evaluation of multifragmentary intraarticular lower extremity fractures?

PURPOSE: Cinematic rendering (CR), a recently launched, FDA-approved rendering technique converts CT image datasets into nearly photorealistic 3D reconstructions by using a unique lighting model. The purpose of this study was to compare CR to volume rendering technique (VRT) images in the preoperative visualization of multifragmentary intraarticular lower extremity fractures. METHOD: In this retrospective study, CT datasets of 41 consecutive patients (female: n = 13; male: n = 28; mean age: 52.3 ± 17.9y) with multifragmentary intraarticular lower extremity fractures (calcaneus: n = 16; tibial pilon: n = 19; acetabulum: n = 6) were included. All datasets were acquired using a 128-row dual-source CT. A dedicated workstation was used to reconstruct CR and VRT images which were reviewed independently by two experienced board-certified traumatologists trained in special trauma surgery. Image quality, anatomical accuracy and fracture visualization were assessed on a 6-point-Likert-scale (1 = non-diagnostic; 6=excellent). The regular CT image reconstructions served as reverence standard. For each score, median values between both readers were calculated. Scores of both reconstruction methods were compared using a Wilcoxon-Ranksum test with p < 0.05 indicating statistical significance. Inter-reader agreement was calculated using Spearman's rank correlation coefficient. RESULTS: Compared to VRT, CR demonstrated a higher image quality (VRT:2.5; CR:6.0; p < 0.001), a higher anatomical accuracy (VRT:3.5; CR:5.5; p < 0.001) and provided a more detailed visualization of the fracture (VRT:2.5; CR:6.0; p < 0.001). An additional benefit of CR reconstructions compared to VRT reconstructions was reported by both readers in 65.9 % (27/41) of all patients. CONCLUSIONS: CR reconstructions are superior to VRT due to higher image quality and higher anatomical accuracy. Traumatologists find CR reconstructions to improve visualization of lower extremity fractures which should thus be used for fracture demonstration during interdisciplinary conferences.

Appearance and distinguishing features of retroperitoneal calcifications at computed tomography.

OBJECTIVES: To describe the appearance of retroperitoneal calcifications seen at computed tomography (CT) and to investigate which CT features distinguish benign from malignant retroperitoneal calcifications. METHODS: We identified 25 patients with retroperitoneal calcifications by retrospective review of 39,931 abdominopelvic CT scans. Etiology of retroperitoneal calcifications was determined by examination of medical and histopathological records. By consensus, 2 abdominal radiologists recorded calcification number (solitary or multiple), location (suprarenal or infrarenal), morphology (globular or nonglobular), and the presence of soft-tissue components. The association between CT findings and etiology was assessed using the Fisher exact test. RESULTS: Retroperitoneal calcifications were malignant in 15 patients and benign in 10. Solitary calcifications were seen more commonly in patients with benign disease (6 of 10 vs. 1 of 15, P < 0.01). Suprarenal calcifications were seen only in patients with malignancy (13 of 15 patients, P < 0.01). Nonglobular calcifications were seen only in patients with benign disease (6 of 10, P < 0.01). Soft-tissue components were seen more commonly in patients with malignancy (14 of 15 vs. 4 of 10; P < 0.01). CONCLUSIONS: Retroperitoneal calcifications are rarely seen at CT and may be benign or malignant in etiology. Solitary or nonglobular retroperitoneal calcifications are likely to be benign while calcifications that are multiple, globular, suprarenal, or associated with noncalcified soft-tissue components are likely to be malignant.