Quantitative edge analysis of pancreatic margins in patients with head pancreatic tumors: correlations between pancreatic margins and the onset of postoperative pancreatic fistula.

OBJECTIVE: To assess the correlation between pancreatic quantitative edge analysis as a surrogate of parenchymal stiffness and the incidence of postoperative pancreatic fistula (POPF), in patients undergoing pancreaticoduodenectomy (PD). METHODS: All consecutive patients who underwent PD at our Institution between March 2018 and November 2019 with an available preoperative CT were included. Pancreatic margin score (PMS) was calculated through computer-assisted quantitative edge analysis on the margins of the pancreatic body and tail (the expected pancreatic remnant) on non-contrast scans with in-house software. Intraoperative assessment of pancreatic stiffness by manual palpation was also performed, classifying pancreatic texture into soft and non-soft. PMS values were compared between groups using an unpaired T-test and correlated with the intraoperative evaluation of stiffness and with the grading of postoperative pancreatic fistula according to the International Study Group on Pancreatic Surgery (ISGPS). RESULTS: Patient population included 200 patients (mean age 64.6 years), 146 without onset of POPF (73%, non-POPF group), and 54 with POPF (27%, POPF group). A significant difference in PMS values was observed between POPF and non-POPF (respectively 1.88 ± 0.05 vs 0.69 ± 0.01; p < 0.0001). PMS values of pancreatic parenchymas intraoperatively considered "soft" were significantly higher than those evaluated as "non-soft" (1.21 ± 0.04 vs 0.73 ± 0.02; p < 0.0001). A significant correlation between PMS values and POPF grade was observed (r = 0.8316), even in subgroups of patients with soft (r = 0.8016) and non-soft (r = 0.7602) pancreas (all p < 0.0001). CONCLUSIONS: Quantitative edge analysis with dedicated software may stratify patients with different pancreatic stiffness, thus potentially improving preoperative risk assessment and strategies for POPF mitigation. CLINICAL RELEVANCE STATEMENT: This study proposes quantitative pancreas edge analysis as a predictor for postoperative pancreatic fistula. The test has high accuracy and correlation with fistula grade according to the International Study Group on Pancreatic Surgery. KEY POINTS: • Prediction of postoperative pancreatic fistula (POPF) onset risk after pancreaticoduodenectomy is based only on intraoperative evaluation. • Quantitative edge analysis may preoperatively identify patients with higher risk of POPF. • Quantification of pancreatic stiffness through the analysis of pancreatic margins could be done on preoperative CT.

Quantitative Edge Analysis of Pancreatic Margins in Patients with Chronic Pancreatitis: A Correlation with Exocrine Function.

BACKGROUND: Many efforts have been made to improve accuracy and sensitivity in diagnosing chronic pancreatitis (CP), obtaining quantitative assessments related to functional data. Our purpose was to correlate a computer-assisted analysis of pancreatic morphology, focusing on glandular margins, with exocrine function-measured by fecal elastase values-in chronic pancreatitis patients. METHODS: We retrospectively reviewed chronic pancreatitis patients who underwent fecal elastase assessment and abdominal MRI in our institute within 1 year. We identified 123 patients divided into three groups based on the fecal elastase value: group A with fecal elastase > 200 µg/g; group B with fecal elastase between 100 and 200 µg/g; and group C with fecal elastase < 100 µg/g. Computer-assisted quantitative edge analysis of pancreatic margins was made on non-contrast-enhanced water-only Dixon T1-weighted images, obtaining the pancreatic margin score (PMS). PMS values were compared across groups using a Kruskal-Wallis test and the correlation between PMS and fecal elastase values was tested with the Spearman's test. RESULTS: A significant difference in PMS was observed between the three groups (p < 0.0001), with a significant correlation between PMS and elastase values (r = 0.6080). CONCLUSIONS: Quantitative edge analysis may stratify chronic pancreatitis patients according to the degree of exocrine insufficiency, potentially contributing to the morphological and functional staging of this pathology.

The Caliber of Segmental and Subsegmental Vessels in COVID-19 Pneumonia Is Enlarged: A Distinctive Feature in Comparison with Other Forms of Inflammatory and Thromboembolic Diseases.

BACKGROUND: The purpose of this study was to compare COVID-19 patients' vessel caliber with that of normal lungs and lungs affected by other inflammatory and thromboembolic processes. METHODS: between March and April 2020, 42 patients affected by COVID-19 pneumonia (COV-P) underwent CT scans of the lungs at Verona University Hospital for clinical indications. The lung images of four different groups of patients were compared (normal lung (NL), distal thromboembolism (DTE), and bacterial and fungal pneumonia (Bact-P, Fung-P)) by a radiologist with four years of experience. RESULTS: The COV-P patients' segmental and subsegmental vessels, evaluated as the ratio with the corresponding bronchial branch (V/B ratio), were larger, with respect to the NL the DTE groups, in the apparently healthy parenchyma, a result confirmed in the zones of opacification with respect to the Bact-P and Fung-P groups. CONCLUSIONS: This was the first study to show, by comparative analysis, that COVID-19 patients' segmental and subsegmental vessel calibers are significantly enlarged. This is a distinctive feature of COVID-19 pneumonia, suggesting its distinct pathophysiology as compared to other inflammatory and thromboembolic diseases and alerting radiologists to consider it when evaluating the CT scans of suspected patients.

Rapid onset of bronchiectasis in COVID-19 Pneumonia: two cases studied with CT.

Since the widespread of acute respiratory syndrome infection caused by Coronavirus-19 unenhanced computed tomography (CT) was considered an useful imaging tool commonly used in early diagnosis and monitoring of patients with complicated COVID-19 pneumonia. Many typical imaging features of this disease were described such as bilateral multilobar ground-glass opacification (GGO) with a prevalent peripheral or posterior distribution, mainly in the lower lobes, and sometimes consolidative opacities superimposed on GGO. As less common findings were mentioned septal thickening, bronchiectasis, pleural thickening, and subpleural involvement. After 3 months from the onset of COVID-19 pneumonia some studies published the evolution of imaging features of COVID-19 pneumonia such as an increase of GGOs and a progressive transformation of GGO into multifocal consolidative opacities, septal thickening, and development of a crazy-paving pattern. As far as we know bronchiectasis were described only as a possible aspecific imaging feature of COVID-19 pneumonia and no studies reporting the onset or evolution of bronchiectasis during imaging follow-up in patients with COVID-19 have been published. Here we describe two cases of rapid evolution of bronchiectasis documented at CT in patients with COVID-19 pneumonia. Further studies are necessary to determine predisposing factors to the onset of bronchiectasis and to evaluate clinical correlation with respiratory distress. Radiologists should always consider bronchial features when they report CT scans of patients with COVID-19 pneumonia.

Solid Pseudopapillary Neoplasms of the Pancreas: Clinicopathologic and Radiologic Features According to Size.

OBJECTIVE. The purpose of this study was to retrospectively analyze and correlate clinicopathologic and radiologic features of resected solid pseudopapillary neoplasms of the pancreas according to their size. MATERIALS AND METHODS. Clinicopathologic and radiologic features of 106 resected solid pseudopapillary neoplasms of the pancreas over a 20-year period were retrospectively analyzed. Tumors were divided into three groups according to their size (≤ 30 mm, 31-50 mm, and ≥ 51 mm). Clinicopathologic and radiologic features were compared among groups using Kruskal-Wallis and Fisher exact tests. RESULTS. Forty-one tumors that were 30 mm or smaller, 30 tumors between 31 and 50 mm, and 35 tumors that were 51 mm or larger were included. Preoperative MRI of 76 patients and CT of 40 patients were examined. Patients with tumors that were 30 mm or smaller were significantly older than the other groups of patients (p = 0.038). Large tumors (31-50 and ≥ 51 mm) were more frequently located in the pancreatic body or tail (p = 0.008). Most tumors had well-defined margins (87.7%) and a mixed solid and cystic appearance (54.7%) at imaging; tumors that were 30 mm or smaller were more frequently entirely solid (p = 0.028). At histologic analysis, 13 tumors had at least one feature of malignancy; nodal and liver metastases were found in one patient (0.9%). No significant differences between groups were found regarding the presence of malignant histologic features (p = 0.932). The rate of incorrect preoperative diagnosis was higher in tumors 30 mm or smaller, albeit without significant differences between groups (p = 0.561). CONCLUSION. Malignancy in solid pseudopapillary neoplasms is not correlated with tumor size; tumors that are 30 mm or smaller may present atypical imaging features, which may overlap those of other solid tumors of the pancreas.

Virtual Autopsy as a Screening Test Before Traditional Autopsy: The Verona Experience on 25 Cases.

BACKGROUND: Interest has grown into the use of multidetector computed tomography (CT) and magnetic resonance imaging as an adjunct or alternative to the invasive autopsy. We sought to investigate these possibilities in postmortem CT scan using an innovative virtual autopsy approach. METHODS: Twenty-five postmortem cases were scanned with the Philips Brilliance CT-64 and then underwent traditional autopsy. The images were interpreted by two blinded forensic pathologists assisted by a radiologist with the INFOPSY® Digital Autopsy Software System which provides three-dimensional images in Digital Imaging and Communications in Medicine format. Diagnostic validity of virtual autopsy (accuracy rate, sensitivity, specificity, and predictive values) and concordance between the two forensic pathologists (kappa intraobserver coefficients) were determined. RESULTS: The causes of death at traditional autopsies were hemorrhage due to traumatic injuries (n = 8), respiratory failure (5), asphyxia due to drowning (4), asphyxia due to hanging or strangulation (2), heart failure (2), nontraumatic hemorrhage (1), and severe burns (1). In two cases, the cause of death could not be ascertained. In 15/23 (65%) cases, the cause of death diagnosed after virtual autopsy matched the diagnosis reported after traditional autopsy. In 8/23 cases (35%), traditional autopsy was necessary to establish the cause of death. Digital data provided relevant information for inferring both cause and manner of death in nine traumatic cases. The validity of virtual autopsy as a diagnostic tool was higher for traumatic deaths than other causes of death (accuracy 84%, sensitivity 82%, and specificity 86%). The concordance between the two forensic pathologists was almost perfect (>0.80). CONCLUSIONS: Our experience supports the use of virtual autopsy in postmortem investigations as an alternative diagnostic practice and does suggest a potential role as a screening test among traumatic deaths.

CT imaging of primary pancreatic lymphoma: experience from three referral centres for pancreatic diseases.

PURPOSE: To describe CT characteristics of primary pancreatic lymphoma (PPL), a rare disease with features in common with adenocarcinoma. MATERIALS AND METHODS: Fourteen patients were enrolled. CT: unenhanced scan, contrast-enhanced pancreatic and venous phases. Image analysis: tumour location; peri-pancreatic vessel encasement; necrosis; enlarged lymph nodes; fat stranding; enlarged bile duct and pancreatic duct; neoplasm longest dimension, volume and density. RESULTS: Histopathological diagnoses: follicular non-Hodgkin lymphoma (5/14), diffuse large B-cell lymphoma (6/14) and high-grade B-cell lymphoma not otherwise specified (3/14). Six of 14 PPLs were located in the pancreatic head and 7/14 in the body-tail; 1/14 involved the whole gland. In 5/14 cases the superior mesenteric artery and vein were encased; splenic vein and artery encasement was depicted in 2 PPLs. Necrosis was present in 2/14. Enlarged retroperitoneal lymph nodes were found in 11 cases and fat stranding in all patients. The bile duct was dilated in six cases and the pancreatic duct in five. Mean neoplasm longest diameter and volume were 8.05 cm and 210.8 cm3. Mean tumour attenuation values were 39.1 HU at baseline, 60.6 HU in the pancreatic phase and 71.4 HU in the venous phase. CONCLUSIONS: PPL presents as a large mass lesion with delayed homogeneous enhancement; peri-pancreatic fat stranding and vessel encasement are present, without vascular infiltration. Pancreatic duct dilatation is rare. KEY POINTS: • Primary pancreatic lymphoma (PPL) is a rare haematological disease • PPL presents imaging features in common with pancreatic carcinoma but also some distinctive findings • The majority of PPLs are large lesions with delayed homogeneous enhancement • Peri-pancreatic fat stranding and vessel encasement are common in PPL • Vascular infiltration and pancreatic duct dilatation are rare in PPL.

Solid non-functioning endocrine tumors of the pancreas: correlating computed tomography and pathology.

BACKGROUND: Since prognosis and treatment of pancreatic endocrine tumors (pNET) are based on tumor grade, contrast-enhanced multidetector computed tomography (MDCT) features of solid non-functioning pNETs were studied and correlated with pathology tumor grading. METHODS: MDCTs of diagnosed pNETs were reviewed retrospectively. Each tumor was analyzed for location, size, homogeneity, margins, arterial and venous phase enhancement, main pancreatic duct diameter, calcifications, vascular invasion, lymph-nodes enlargement, and liver metastases. RESULTS: Of 154 pNETs presenting between January 2000 and May 2016 with available histology from resected specimen or biopsy, there were 65 G1, 72 G2 and 17 G3 pNETs. Tumor diameter varied significantly between the three groups. Tumors >20 mm were more frequently malignant and non-homogeneous than smaller tumors. G1 tumors were more commonly hypervascular and G3 tumors more often non-hypervascular in the arterial phase. Arterial phase non-hyperdensity and tumor non-homogeneity had a higher rate of metastatic lesions. Vascular invasion correlated with presence of metastases and histological grade. G3 tumors were all >20 mm (p = 0.007), more often non-hypervascular in the arterial phase (p = 0.0025), and non-hyperdense in the venous phase (p = 0.009), and showed more often vascular invasion (p = 0.0198). CONCLUSION: CT correlated with tumor grade; differentiating low-grade and high-grade pNETs through routine CT imaging might improve patient management.

Distribution of liver metastases based on the site of primary pancreatic carcinoma.

OBJECTIVES: To investigate whether the different location of pancreatic adenocarcinoma affects the lobar distribution of metastases to the liver. METHODS: From all patients who underwent multidetector computed tomography (MDCT) examinations for staging of pancreatic adenocarcinoma in the last 4 years we selected 80 patients (42 men, 38 women; mean age, 60.56 years) with liver metastases and a pancreatic adenocarcinoma of the head (group A, 40 patients; diameter, 32.41 ± 2.28 mm) or body-tail (group B, 40 patients; diameter, 52.21 ± 2.8 mm). We analysed tumour site, diameter, vascular invasion and number of metastases in each lobe of the liver. The total number of metastases was compared between the two groups with an unpaired t-test, while Fisher's test was used to compare the number of metastases within the two lobes. RESULTS: As expected, the number of liver metastases was higher in group B than in group A. The ratio of metastases in the right-to-left hemi-liver was 7.4:1 for group A compared with 3.3:1 for group B (p < 0.0001). CONCLUSIONS: Although the number of liver metastases is higher in the right lobe than in the left lobe in both groups, there is a significant difference in the ratio of metastases between the right and the left hemi-liver. This supports the existence of a streamline phenomenon and a selective lobar distribution of metastases within the liver. KEY POINTS: • Pancreatic adenocarcinoma presents with liver metastases in 40% of cases • The presence of liver metastases disqualifies the patient from curative surgery • The distribution of metastases within the liver depends on the site of pancreatic adenocarcinoma • The distribution of liver metastases is due to the streamline phenomenon.

Autoimmune pancreatitis: multidetector-row computed tomography (MDCT) and magnetic resonance (MR) findings in the Italian experience.

Multidetector-row computed tomography (MDCT) and magnetic resonance (MR) imaging are currently the most frequently performed imaging modalities for the study of pancreatic disease. In cases of suspected autoimmune pancreatitis (AIP), a dynamic quadriphasic (precontrast, contrast-enhanced pancreatic, venous and late phases) study is recommended in both techniques. In the diffuse form of autoimmune pancreatitis (DAIP), the pancreatic parenchyma shows diffuse enlargement and appears, during the MDCT and MR contrast-enhanced pancreatic phase, diffusely hypodense and hypointense, respectively, compared to the spleen because of lymphoplasmacytic infiltration and pancreatic fibrosis. During the venous phase of MDCT and MR imaging, the parenchyma appears hyperdense and hyperintense, respectively, in comparison to the pancreatic phase. In the delayed phase of both imaging modalities, it shows retention of contrast media. A "capsule-like rim" may be recognised as a peripancreatic MDCT hyperdense and MR hypointense halo in the T2-weighted images, compared to the parenchyma. DAIP must be differentiated from non-necrotizing acute pancreatitis (NNAP) and lymphoma since both diseases show diffuse enlargement of the pancreatic parenchyma. The differential diagnosis is clinically difficult, and dynamic contrast-enhanced MDCT has an important role. In the focal form of autoimmune pancreatitis (FAIP), the parenchyma shows segmental enlargement involving the head, the body-tail or the tail, with the same contrast pattern as the diffuse form on both modalities. FAIP needs to be differentiated from pancreatic adenocarcinoma to avoid unnecessary surgical procedures, since both diseases have similar clinical and imaging presentation. The differential diagnosis is clinically difficult, and dynamic contrast-enhanced MDCT and MR imaging both have an important role. MR cholangiopancreatography helps in the differential diagnosis. Furthermore, MDCT and MR imaging can identify the extrapancreatic manifestations of AIP, most commonly biliary, renal and retroperitoneal. Finally, in all cases of uncertain diagnosis, MDCT and/or MR follow-up after short-term treatment (2-3 weeks) with high-dose steroids can identify a significant reduction in size of the pancreatic parenchyma and, in FAIP, normalisation of the calibre of the upstream main pancreatic duct.

Single-energy low-voltage arterial phase MDCT scanning increases conspicuity of adenocarcinoma of the pancreas.

PURPOSE: To test a single-energy low-voltage CT protocol for pancreatic adenocarcinoma. METHODS AND MATERIALS: A total of 30 patients with pathology-proven pancreatic adenocarcinoma underwent 64-row MDCT with arterial phase at 80 kV and were compared to a similar group of 30 patients scanned with a 120 kV protocol. Scans were compared for quantitative image parameters (attenuation and standard deviation in the pancreas, tumor, aorta), CTDI and DLP using an unpaired t-test. Image noise values for each protocol (SD of the psoas) were compared using an unpaired t-test. Effective dose was calculated for each protocol. CNR (=conspicuity/SDnoise) and FOM (CNR2/ED) were calculated. The Catphan600 phantom was used to evaluate image non-uniformity, noise, spatial resolution, and low contrast detectability. RESULTS: Mean patient weight was 68 kg in the study group and 73 kg in the control group (p=0.0355), while patient diameters at the celiac axis were not significantly different. Mean attenuation was significantly higher at 80 kV in the aorta (517.5±116.4 vs 290.3±76.4 HU) and normal pancreas (154.0±39.95 vs 90.02±19.01 HU) (all p<0.0001), while no significant difference was observed for adenocarcinoma (61.43±35.61 vs 47.45±18.95; p=n.s.). CTDI and DLP were significantly lower at 80 kV (6.00±0.90 mGy vs 10.24±2.93 mGy, and 180.4±35.49 mGy cm vs 383.8±117 mGy cm, respectively; all p<0.0001). Tumor conspicuity (HUpancreas-HUtumor) was significantly higher at 80 kV (94.2±39.3 vs 39.5±22 HU; p<0.0001). Mean image noise was significantly higher at 80kV (28.32±10.06 vs 19.7±7.1HU; p<0.0001). Effective dose was significantly lower at 80 kV (1.984±0.39 vs 5.75±1.75 mSv; p<0.0001). The total DLP for the exam was 1024±31.86 mGy cm for the 80 kV protocol and 1357±62.60 mGy cm for the 120 kV protocol (p<0.0001). Phantoms showed higher non-uniformity, slightly higher noise, slightly lower MTF (50%) and slightly higher percentage contrast for the 80 kV protocol. CONCLUSION: Single-source 80 kV pancreatic phase scanning results in higher conspicuity of pancreatic adenocarcinoma and FOM and in significant dose reduction while maintaining acceptable image quality.

Autoimmune pancreatitis and non-necrotizing acute pancreatitis: computed tomography pattern.

OBJECTIVES: To retrospectively differentiate diffuse autoimmune pancreatitis from non-necrotizing acute pancreatitis at clinical onset with multi detector row computed tomography. METHODS: 36 Patients suffering from diffuse autoimmune pancreatitis (14) or non-necrotizing acute pancreatitis (22) were enrolled. Qualitative analysis included stranding, retroperitoneal fluid film, capsule-like rim enhancement and pleural effusion. In quantitative analysis pancreatic density was measured in all phases. The vascularization behaviour was assessed using the relative enhancement rate across all phases. RESULTS: Pancreatic density resulted lower in non-necrotizing acute pancreatitis compared to diffuse autoimmune pancreatitis patients in pre-contrast phase and higher in pancreatic phase. Relative enhancement rate evaluation confirmed different vascularization behaviours of the two diseases. Only non-necrotizing acute pancreatitis Patients presented peripancreatic stranding and fluid in the retromesenteric interfascial plane. CONCLUSIONS: Multi detector row computed tomography is a useful technique for differentiating diffuse autoimmune pancreatitis from non-necrotizing acute pancreatitis at clinical onset. Peripancreatic stranding and retroperitoneal fluid film, characteristic of non-necrotizing acute pancreatitis, and late-phase peripheral rim enhancement, characteristic of diffuse autoimmune pancreatitis, provide qualitative clues to the differentiation. A quantitative study of contrast enhancement patterns, considering the relative enhancement rate, can assist in the differential diagnoses of two diseases.

Ultrasonography of the pancreas.

Although the pancreas is often thought of as an organ that is difficult to explore using ultrasound (US), because of its deep retroperitoneal location, with the appropriate technique it can be studied successfully in most patients. In this article, the authors discuss the use of available US techniques in the diagnosis of the most common pancreatic diseases, the use of US intraoperatively, and the use of sonographic guidance for diagnostic and therapeutic procedures. The authors also briefly discuss the potential use of elastosonography techniques in the evaluation of pancreatic disease.