Imaging after Pancreatic Surgery: Expected Findings and Postoperative Complications.

Pancreatic surgery is considered one of the most technically challenging surgical procedures, despite the evolution of modern techniques. Neoplasms remain the most common indication for pancreatic surgery, although inflammatory conditions may also prompt surgical evaluation. The choice of surgical procedure depends on the type and location of the pathologic finding because different parts of the pancreas have separate vascular supplies that may be shared by adjacent organs. The surgical approach could be conventional or minimally invasive (laparoscopic, endoscopic, or robotic assisted). Because of the anatomic complexity of the pancreatic bed, perioperative complications may be frequently encountered and commonly involve the pancreatic-biliary, vascular, lymphatic, or bowel systems, irrespective of the surgical technique used. Imaging plays an important role in the assessment of suspected postoperative complications, with CT considered the primary imaging modality, while MRI, digital subtraction angiography, and molecular imaging are considered ancillary diagnostic tools. Accurate diagnosis of postoperative complications requires a solid understanding of pancreatic anatomy, surgical indications, normal postoperative appearance, and expected postsurgical changes. The practicing radiologist should be familiar with the most common perioperative complications, such as anastomotic leak, abscess, and hemorrhage, and be able to differentiate these entities from normal anticipated postoperative changes such as seroma, edema and fat stranding at the surgical site, and perivascular soft-tissue thickening. In addition to evaluation of the primary operative fossa, imaging plays a fundamental role in assessment of the adjacent organ systems secondarily affected after pancreatic surgery, such as vascular, biliary, and enteric complications. Published under a CC BY 4.0 license. Test Your Knowledge questions are available in the supplemental material. See the invited commentary by Winslow in this issue.

Cross-Sectional Imaging Characteristics of Pancreatic Intraductal Oncocytic Papillary Neoplasms.

PURPOSE: Pancreatic intraductal oncocytic papillary neoplasms (IOPN) are rare precursors to pancreatic ductal adenocarcinoma. We report cross-sectional computed tomography and magnetic resonance imaging (where available) findings of pancreatic IOPNs. MATERIALS AND METHODS: Consecutive cases of pancreatic IOPNs identified on pathology between 2008 and 2020 at University of Pittsburgh and Johns Hopkins University were included in the study. Cross-sectional imaging of all patients was reviewed by two subspecialty trained abdominal radiologists. Patient demographics, cross-sectional imaging appearances and growth characteristics were evaluated. RESULTS: In this dual-center study, 14 patients with IOPNs were included. Median age was 64 years, and 64% were male. The median size of the lesions was 5.4 cm (range, 1.4-12.3 cm). All patients had either an enhancing mural nodule (93% of patients) and/or thick internal septations (29%). Thin/imperceptible outer wall was seen in 93%. Main duct was involved in 64% of the cases. Only 14% of the cases did not demonstrate abutment of the main duct. Histologic evaluation of surgical specimen showed high-grade dysplasia without invasive carcinoma in 57% and invasive carcinoma in 43% of cases. Lesions with invasive carcinoma were larger (7.1 cm vs 4.3 cm, P = 0.05) and tended to have larger mural nodule (3.7 cm vs 1.8 cm) compared with those without invasive carcinoma. CONCLUSION: Pancreatic IOPNs are rare cystic premalignant lesions, which among resected cases, are predominantly seen in middle aged men, are often large, have enhancing mural nodules and frequently harbor invasive carcinoma.

Systemic diseases affecting the GI tract: A review of clinical and histopathologic manifestations.

A variety of systemic diseases may affect the gastrointestinal (GI) tract. Since the GI tract responds to injury in limited ways, identifying these processes may be challenging, especially on small endoscopic biopsies. This article reviews the clinicopathologic features of commonly encountered systemic diseases affecting the tubular GI tract: sarcoidosis, graft vs. host disease, mast cell disorders, systemic sclerosis, and IgG-4 related disease. In addition, we offer guidance in differentiating them from their mimics.

Association between Abdominal CT Measurements of Body Composition before Deceased Donor Liver Transplant with Posttransplant Outcomes.

Background Pre-liver transplant (LT) sarcopenia is associated with poor survival. Methods exist for measuring body composition with use of CT scans; however, it is unclear which components best predict post-LT outcomes. Purpose To quantify the association between abdominal CT-based body composition measurements and post-LT mortality in a large North American cohort. Materials and Methods This was a retrospective cohort of adult first-time deceased-donor LT recipients from 2009 to 2018 who underwent pre-LT abdominal CT scans, including at the L3 vertebral level, at Johns Hopkins Hospital. Measurements included sarcopenia (skeletal muscle index [SMI] <50 in men and <39 in women), sarcopenic obesity, myosteatosis (skeletal muscle CT attenuation <41 mean HU for body mass index [BMI] <25 and <33 mean HU for BMI ≥25), visceral adipose tissue (VAT), subcutaneous adipose tissue (SAT), and VAT/SAT ratio. Covariates in the adjusted models were selected with use of least absolute shrinkage and selection operator regression with lambda chosen by means of 10-fold cross-validation. Cox proportional hazards models were used to quantify associations with post-LT mortality. Model discrimination was quantified using the Harrell C-statistic. Results A total of 454 recipients (median age, 57 years [IQR, 50-62 years]; 294 men) were evaluated. In the adjusted model, pre-LT sarcopenia was associated with a higher hazard ratio (HR) of post-LT mortality (HR, 1.6 [95% CI: 1.1, 2.4]; C-statistic, 0.64; P = .02). SMI was significantly negatively associated with survival after adjustment for covariates. There was no evidence that myosteatosis was associated with mortality (HR, 1.3 [95% CI: 0.86, 2.1]; C-statistic, 0.64; P = .21). There was no evidence that BMI (HR, 1.2 [95% CI: 0.95, 1.4]), VAT (HR, 1.0 [95% CI: 0.98, 1.1]), SAT (HR, 1.0 [95% CI: 0.97, 1.0]), and VAT/SAT ratio (HR, 1.1 [95% CI: 0.90, 1.4]) were associated with mortality (P = .15-.77). Conclusions Sarcopenia, as assessed on routine pre-liver transplant (LT) abdominal CT scans, was the only factor significantly associated with post-LT mortality. © RSNA, 2022 See also the editorial by Ruehm in this issue.

A Novel Patient-like Swine Model of Perianal Crohn's Disease.

BACKGROUND: Perianal Crohn's disease is associated with poor outcomes and high medical costs. It is notoriously difficult to treat despite therapeutic advancements for luminal disease. A large animal model that mimics human perianal disease is needed to test innovative therapies. OBJECTIVE: This study aimed to create a swine model that replicates the inflammatory component and therapeutic challenges found in patients with perianal Crohn's disease. DESIGN: This was an animal preclinical study. SETTINGS: The experiments were performed at the animal laboratory at the Johns Hopkins University. PATIENTS: Four sus scrufus female pigs were included in the study. INTERVENTIONS: Four female pigs underwent creation of 3 surgical perianal fistulas each, 1 rectovaginal and 2 perianal. Size 24 French setons were placed to maintain patency of the fistula tracts for 4 weeks. After removal of the setons, trinitrobenzene sulfonic acid was administered into the fistula tract to create and maintain local inflammation mimicking perianal Crohn's disease. MAIN OUTCOMES MEASURES: An MRI was obtained to assess the fistulas and the pigs were euthanized to review histopathology. RESULTS: Three inflammatory chronic fistula tracts were successfully created in each pig as confirmed by MRI and examination under anesthesia. This is the first report of maintaining patent fistulas in swine 2 weeks after removal of setons. For the first time, we reported that 2 pigs developed branching fistulas and small abscesses reminiscent of human perianal Crohn's disease. The corresponding histopathologic examination found significant chronic active inflammation on standard hematoxylin and eosin staining. LIMITATIONS: The fistulas were surgically induced and did not occur naturally. CONCLUSIONS: A chronic perianal fistula model in pigs that strongly resembles human perianal Crohn's disease was successfully created. This model can be used to test novel therapeutics and techniques to pave the path for human trials. See Video Abstract at http://links.lww.com/DCR/B969 . UN NUEVO MODELO PORCINO SIMILAR A UN PACIENTE DE LA ENFERMEDAD DE CROHN PERIANAL ANTECEDENTES: La enfermedad de Crohn perianal se asocia con malos resultados y altos costos médicos. Es notoriamente difícil de tratar a pesar de los avances terapéuticos para la enfermedad luminal. Se precisa de un modelo animal grande que imite la enfermedad perianal humana para probar terapias innovadoras.OBJETIVO:Nuestro objetivo de este estudio fue crear un modelo porcino que replique el componente inflamatorio y los desafíos terapéuticos que se encuentran en los pacientes con enfermedad de Crohn perianal.DISEÑO:Este fue un estudio preclínico en animales.AJUSTES:Los experimentos se realizaron en el laboratorio de animales de la Universidad Johns Hopkins.PACIENTES:Se incluyeron en el estudio cuatro cerdas sus scrofa.INTERVENCIONES:Cuatro cerdas fueron sometidas a la creación de 3 fístulas perianales quirúrgicas cada una: 1 recto vaginal y 2 perianales. Se colocaron sedales de 24 French para mantener la permeabilidad de los trayectos fistulosos durante 4 semanas. Tras el retiro de los sedales, se administró ácido trinitrobenceno sulfónico en el trayecto de la fístula para crear y mantener la inflamación local simulando la enfermedad de Crohn perianal.PRINCIPALES MEDIDAS DE RESULTADOS:Se obtuvo una resonancia magnética para evaluar las fístulas y los cerdos fueron sacrificados para revisar la histopatología.RESULTADOS:Se crearon de manera exitosa tres trayectos fistulosos inflamatorios crónicos en cada cerdo, confirmados por imágenes de resonancia magnética y examen bajo anestesia. Este es el primer informe de preservación de fístulas permeables en cerdos 2 semanas tras el retiro de los setones. Por primera vez, informamos que dos cerdos desarrollaron fístulas ramificadas y pequeños abscesos que recuerdan a la enfermedad de Crohn perianal humana. El examen histopatológico correspondiente encontró una significativa inflamación crónica activa en la tinción estándar de hematoxilina y eosina.LIMITACIONES:Las fístulas se indujeron quirúrgicamente y no se produjeron de forma natural.CONCLUSIONES:Se logro recrear con éxito un modelo de fístula perianal crónica en cerdos que se asemeja mucho a la enfermedad de Crohn perianal humana. Este modelo se puede utilizar para probar nuevas terapias y técnicas para allanar el camino para los ensayos en humanos. Consulte Video Resumen en http://links.lww.com/DCR/B969 . (Traducción-Dr Osvaldo Gauto).

Invasive and Noninvasive Progression After Resection of Noninvasive Intraductal Papillary Mucinous Neoplasms.

OBJECTIVE: To define frequencies, pattern of progression (invasive vs noninvasive), and risk factors of progression of resected noninvasive intraductal papillary mucinous neoplasms (IPMNs). BACKGROUND: There is a risk of progression in the remnant pancreas after resection of IPMNs. METHODS: Four hundred forty-nine consecutive patients with resected IPMNs from 1995 to 2018 were included to the study. Patients with invasive carcinoma or with follow-up <6 months were excluded. Noninvasive progression was defined as a new IPMN, increased main pancreatic duct size, and increased size of an existing lesion (5 mm compared with preoperative imaging). Invasive progression was defined as development of invasive cancer in the remnant pancreas or metastatic disease. RESULTS: With a median follow-up of 48.9 months, progression was identified in 124 patients (27.6%); 108(24.1%) with noninvasive and 16(3.6%) with invasive progression. Median progression follow-up was longer for invasive progression (85.4 vs 55.9 months; P = 0.001). Five-and 10-year estimates for a cumulative incidence of invasive progression were 6.4% and 12.9% versus 26.9% and 41.5% for noninvasive progression. After risk adjustment, multifocality (HR 4.53, 95% CI 1.34-15.26; P = 0.02) and high-grade dysplasia (HGD) in the original resection (HR 3.60, 95% CI 1.13-11.48; P = 0.03) were associated with invasive progression. CONCLUSIONS: Progression to invasive carcinoma can occur years after the surgical resection of a noninvasive IPMN. HGD in the original resection is a risk factor for invasive progression but some cases of low-grade dysplasia also progressed to cancer. Patients with high-risk features such as HGD and multifocal cysts should be considered for more intensive surveillance and represent an important cohort for future trials such as anti-inflammatory or prophylactic immunotherapy.

Impact of genetic testing and smoking on the distribution of risk factors in patients with recurrent acute and chronic pancreatitis.

OBJECTIVE: The aim of the present study is to assess the impact of smoking dose and duration on the distribution of risk factor(s) in patients with RAP and CP, and the impact of genetic testing on the distribution of risk factor(s) in patients with idiopathic RAP and CP. METHODS: All adult patients with RAP and CP referred to a multidisciplinary pancreatitis clinic between 2010 and 2017 were evaluated. Risk factors included alcohol and smoking, hypertriglyceridemia, biliary, and other etiologies. Genetic testing was only pursued in patients with idiopathic RAP or CP. RESULTS: Among the 1770 patients evaluated, 167 had RAP and 303 had CP. After genetic testing and smoking, the most common risk factors for RAP and CP were pathogenic variant(s) (23%) and the combination of alcohol and smoking (23%), respectively. Genetic testing and smoking assessment decreased the proportion of patients with alcoholic RAP from 17% to 5%, alcoholic CP from 33% to 10%, idiopathic RAP from 49% to 12%, and idiopathic CP from 54% to 14%. Pathogenic CFTR variants were the most common variant in patients with RAP (51%) and CP (43%). Among the 68 patients with pancreas divisum, other risk factor(s) were identified in 72%. CONCLUSION: Genetic testing and a detailed assessment of smoking dose and duration reduce the proportion of patients with alcoholic and idiopathic pancreatitis. Other risk factor(s) for pancreatitis are found in the majority of patients with pancreas divisum further questioning its role as an independent risk factor.1. What is the current knowledge?Approximately 30% of patients with pancreatitis have no clear risk factor(s) and are categorized as having an idiopathic etiology.Pathogenic variant(s) as well as smoking dose and duration are well-established risk factors for recurrent acute and chronic pancreatitis but are not widely recognized or incorporated into clinical practice.2. What is new here?Genetic testing and a detailed assessment of smoking dose and duration reduced the proportion of patients with alcoholic and idiopathic acute recurrent and chronic pancreatitis.Approximately three-fourths of patients with pancreas divisum have a risk factor for pancreatitis.

Morphologic Severity of Acute Pancreatitis on Imaging Is Independently Associated with Opioid Dose Requirements in Hospitalized Patients.

BACKGROUND: Prior studies have evaluated clinical characteristics associated with opioid dose requirements in hospitalized patients with acute pancreatitis (AP) but did not incorporate morphologic findings on CT imaging. AIMS: We sought to determine whether morphologic severity on imaging is independently associated with opioid dose requirements in AP. METHODS: Adult inpatients with a diagnosis of AP from 2006 to 2017 were reviewed. The highest modified CT severity index (MCTSI) score and the daily oral morphine equivalent (OME) for each patient over the first 7 days of hospitalization were used to grade the morphologic severity of AP and calculate mean OME per day(s) of treatment (MOME), respectively. Multiple regression analysis was used to evaluate the association of MOME with MCSTI. RESULTS: There were 249 patients with AP, of whom 196 underwent contrast-enhanced CT. The mean age was 46 ± 13.6 years, 57.9% were male, and 60% were black. The mean MOME for the patient cohort was 60 ± 52.8 mg/day. MCTSI (ß = 3.5 [95% CI 0.3, 6.7], p = 0.03), early hemoconcentration (ß = 21 [95% CI 4.6, 39], p = 0.01) and first episode of AP (ß = - 17 [95% CI - 32, - 2.7], p = 0.027) were independently associated with MOME. Among the 19 patients undergoing ≥ 2 CT scans, no significant differences in MOME were seen between those whose MCTSI score increased (n = 12) versus decreased/remained the same (n = 7). CONCLUSION: The morphologic severity of AP positively correlated with opioid dose requirements. No difference in opioid dose requirements were seen between those who did versus those who did not experience changes in their morphologic severity.

Secretin-Enhanced MRCP: How and Why-AJR Expert Panel Narrative Review.

Secretin-enhanced MRCP (S-MRCP) has advantages over standard MRCP for imaging of the pancreaticobiliary tree. Through the use of secretin to induce fluid production from the pancreas and leveraging of fluid-sensitive MRCP sequences, S-MRCP facilitates visualization of ductal anatomy, and the findings provide insight into pancreatic function, allowing radiologists to provide additional insight into a range of pancreatic conditions. This narrative review provides detailed information on the practical implementation of S-MRCP, including patient preparation, logistics of secretin administration, and dynamic secretin-enhanced MRCP acquisition. Also discussed are radiologists' interpretation and reporting of S-MRCP examinations, including assessments of dynamic compliance of the main pancreatic duct and of duodenal fluid volume. Established indications for S-MRCP include pancreas divisum, anomalous pancreaticobiliary junction, Santorinicele, Wirsungocele, chronic pancreatitis, main pancreatic duct stenosis, and assessment of complex postoperative anatomy. Equivocal or controversial indications are also described along with an approach to such indications. These indications include acute and recurrent acute pancreatitis, pancreatic exocrine function, sphincter of Oddi dysfunction, and pancreatic neoplasms.

Minimal main pancreatic duct dilatation in small branch duct intraductal papillary mucinous neoplasms associated with high-grade dysplasia or invasive carcinoma.

BACKGROUND: The aim of this study was to determine the incidence of high-grade dysplasia (HGD) or invasive carcinoma in patients with small branch duct intraductal papillary mucinous neoplasms (BD-IPMNs). METHODS: 923 patients who underwent surgical resection for an IPMN were identified. Sendai-negative patients were identified as those without history of pancreatitis or jaundice, main pancreatic duct size (MPD) <5 mm, cyst size <3 cm, no mural nodules, negative cyst fluid cytology for adenocarcinoma, or serum carbohydrate antigen 19-9 (CA 19-9) <37 U/L. RESULTS: BD-IPMN was identified in 388 (46.4%) patients and 89 (22.9%) were categorized as Sendai-negative. Overall, 68 (17.5%) of BD-IPMN had HGD and 62 (16.0%) had an associated invasive-carcinoma. Among the 89 Sendai-negative patients, 12 (13.5%) had IPMNs with HGD and only one patient (1.1%) had invasive-carcinoma. Of note, older age (OR 1.13, 95% CI 1.03-1.23; P = 0.008) and minimal dilation of MPD (OR 11.3, 95% CI 2.40-53.65; P = 0.002) were associated with high-risk disease in Sendai-negative patients after multivariable risk adjustment. CONCLUSION: The risk of harboring a high-risk disease remains low in small BD-IPMNs. However, Sendai-negative patients who are older than 65 years old and those with minimal dilation of MPD (3-5 mm) are at greater risk of high-risk lesions and should be given consideration to be included as a "worrisome feature" in a future guidelines update.

Pancreatic volume does not correlate with histologic fibrosis in adult patients with recurrent acute and chronic pancreatitis.

OBJECTIVES: Reduced pancreatic volume, often referred to as atrophy, is a commonly reported imaging feature of chronic pancreatitis (CP). This study evaluated whether there is an association between pancreatic volume and fibrosis, the criterion standard of CP, in patients undergoing total pancreatectomy with islet autotransplantation (TPIAT) for recurrent acute pancreatitis (RAP) and CP. METHODS: All adult patients who underwent TPIAT between 2010 and 2019 were categorized into 3 groups: RAP, definite CP and indeterminate CP. Pancreatic volume was calculated by summing up the areas from each thin section of the pancreas on 3D CT imaging. Excisional biopsies of the pancreatic head as well as body/tail region were obtained at the time of TPIAT. Two different fibrosis scores were used for histologic assessment. RESULTS: A total of 16, 29 and 15 patients underwent TPIAT for RAP, definite CP and indeterminate CP, respectively. The mean pancreatic volumes for patients with RAP, definite CP and indeterminate CP were 65.7 ± 28.5 cc, 54.9 ± 22.9 cc and 61.8 ± 23.6 cc, respectively (p = 0.3). The mean fibrosis scores were significantly higher in patients with definite CP compared to RAP (p < 0.001) and indeterminate CP (p < 0.001). Pancreatic volume was not associated with either fibrosis score after adjusting for age, gender, duration of disease, BMI and diabetes in the multivariable analysis. CONCLUSIONS: While the fibrosis scores were higher in definite CP compared to both RAP and indeterminate CP, there was no correlation between pancreatic volume and fibrosis. This suggests that atrophy alone cannot be used to diagnose CP.

Updates on Imaging of Liver Tumors.

PURPOSE OF REVIEW: We review advances in imaging of liver tumors, by particularly focusing on the utility of novel imaging in diagnosis and management of these lesions. RECENT FINDINGS: Contrast-enhanced CT and/or MRI are currently utilized for accurate diagnosis of liver tumors, but several ongoing studies are examining the use of other advanced techniques. Novel CT (i.e., dual-energy CT and perfusion CT), MRI (diffusion-weighted imaging, MR elastography, and T1 mapping), and image processing (texture analysis and artificial intelligence-based methods) techniques have emerged and can be used for precise characterization of liver tumors, quantification of treatment responses, and prediction of overall survival rate of patients. Recent advancements in imaging of liver tumors allowed for a precise assessment of tumor features. These evolving technologies can be utilized for applying individualized treatment based on the presence of specific imaging biomarkers.

Repeat CT Performed Within One Month of CT Conducted in the Emergency Department for Abdominal Pain: A Secondary Analysis of Data From a Prospective Multicenter Study.

OBJECTIVE: The purpose of this study is to determine both the frequency of repeat CT performed within 1 month after a patient visits the emergency department (ED) and undergoes CT evaluation for abdominal pain and the frequency of worsened or new CT-based diagnoses. SUBJECTS AND METHODS: Secondary analysis was performed on data collected during a prospective multicenter study. The parent study included patients who underwent CT in the ED for abdominal pain between 2012 and 2014, and these patients constituted the study group of the present analysis. The proportion of patients who underwent (in any setting) repeat abdominal CT within 1 month of the index CT examination was calculated. For each of these patients, results of the index and repeat CT scans were compared by an independent panel and categorized as follows: no change (group 1); same process, improved (group 2); same process, worse (group 3); or different process (group 4). The proportion of patients in groups 1 and 2 versus groups 3 and 4 was calculated, and patient and ED physician characteristics were compared. RESULTS: The parent study included 544 patients (246 of whom were men [45%]; mean patient age, 49.4 years). Of those 544 patients, 53 (10%; 95% CI, 7.5-13%) underwent repeat abdominal CT. Patients' CT comparisons were categorized as follows: group 1 for 43% of patients (23/53), group 2 for 26% (14/53), group 3 for 15% (8/53), and group 4 for 15% (8/53). New or worse findings were present in 30% of patients (16/53) (95% CI, 19-44%). When patients with findings in groups 1 and 2 were compared to patients with findings in groups 3 and 4, no significant difference was noted in patient age (p = 0.25) or sex (p = 0.76), the number of days between scans (p = 0.98), and the diagnostic confidence of the ED physician after the index CT scan was obtained (p = 0.33). CONCLUSION: Short-term, repeat abdominal CT was performed for 10% of patients who underwent CT in the ED for abdominal pain, and it yielded new or worse findings for 30% of those patients.

PD-1 Blockade in Tumors with Mismatch-Repair Deficiency.

BACKGROUND: Somatic mutations have the potential to encode "non-self" immunogenic antigens. We hypothesized that tumors with a large number of somatic mutations due to mismatch-repair defects may be susceptible to immune checkpoint blockade. METHODS: We conducted a phase 2 study to evaluate the clinical activity of pembrolizumab, an anti-programmed death 1 immune checkpoint inhibitor, in 41 patients with progressive metastatic carcinoma with or without mismatch-repair deficiency. Pembrolizumab was administered intravenously at a dose of 10 mg per kilogram of body weight every 14 days in patients with mismatch repair-deficient colorectal cancers, patients with mismatch repair-proficient colorectal cancers, and patients with mismatch repair-deficient cancers that were not colorectal. The coprimary end points were the immune-related objective response rate and the 20-week immune-related progression-free survival rate. RESULTS: The immune-related objective response rate and immune-related progression-free survival rate were 40% (4 of 10 patients) and 78% (7 of 9 patients), respectively, for mismatch repair-deficient colorectal cancers and 0% (0 of 18 patients) and 11% (2 of 18 patients) for mismatch repair-proficient colorectal cancers. The median progression-free survival and overall survival were not reached in the cohort with mismatch repair-deficient colorectal cancer but were 2.2 and 5.0 months, respectively, in the cohort with mismatch repair-proficient colorectal cancer (hazard ratio for disease progression or death, 0.10 [P<0.001], and hazard ratio for death, 0.22 [P=0.05]). Patients with mismatch repair-deficient noncolorectal cancer had responses similar to those of patients with mismatch repair-deficient colorectal cancer (immune-related objective response rate, 71% [5 of 7 patients]; immune-related progression-free survival rate, 67% [4 of 6 patients]). Whole-exome sequencing revealed a mean of 1782 somatic mutations per tumor in mismatch repair-deficient tumors, as compared with 73 in mismatch repair-proficient tumors (P=0.007), and high somatic mutation loads were associated with prolonged progression-free survival (P=0.02). CONCLUSIONS: This study showed that mismatch-repair status predicted clinical benefit of immune checkpoint blockade with pembrolizumab. (Funded by Johns Hopkins University and others; ClinicalTrials.gov number, NCT01876511.).

Persistent SIRS and acute fluid collections are associated with increased CT scanning in acute interstitial pancreatitis.

BACKGROUND: The use of computed tomography (CT) in acute pancreatitis (AP) continues to increase in parallel with the increasing use of diagnostic imaging in clinical medicine. AIM: To determine the factors associated with obtaining >1 CT scan in acute interstitial pancreatitis (AIP). METHODS: Demographic and clinical data of all adult patients admitted between 1/2010 and 1/2015 with AP (AP) were evaluated. Only patients with a CT severity index (CTSI) ≤ 3 on a CT obtained within 48 h of presentation were included. RESULTS: A total of 229 patients were included, of whom 206 (90%) had a single CT and 23 (10%) had >1 CT during the first week of hospitalization. Patients undergoing >1 CT had significantly higher rates of acute fluid collection (AFC), persistent SIRS, opioid use ≥4 days, and persistent organ failure compared to those undergoing 1 CT (p < .05 for all). On multivariable analysis, only persistent SIRS (OR = 3.6, 95% CI 1.4-9.6, p = .01) and an AFC on initial CT (OR = 3.5, 95% CI 1.4-9, p = .009) were independently associated with obtaining >1 CT. CONCLUSION: An AFC on initial CT and persistent SIRS are associated with increased CT imaging in AIP patients. However, these additional CT scans did not change clinical management.

Neutrophil-to-lymphocyte Ratio is a Predictive Marker for Invasive Malignancy in Intraductal Papillary Mucinous Neoplasms of the Pancreas.

OBJECTIVE: To evaluate the correlation between neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (PLR) values, and the presence of invasive carcinoma in patients with intraductal papillary mucinous neoplasm (IPMN). BACKGROUND: NLR and (PLR) are inflammatory markers that have been associated with overall survival in patients with invasive malignancies, including pancreatic cancer. METHODS: We retrospectively reviewed 272 patients who underwent surgical resection for histologically confirmed IPMN from January 1997 to July 2015. NLR and PLR were calculated and coevaluated with additional demographic, clinical, and imaging data for possible correlation with IPMN-associated carcinoma in the form of a predictive nomogram. RESULTS: NLR and PLR were significantly elevated in patients with IPMN-associated invasive carcinoma (P < 0.001). In the multivariate analysis, NLR value higher than 4 (P < 0.001), IPMN cyst of size more than 3 cm (P < 0.001), presence of enhanced solid component (P = 0.014), main pancreatic duct dilatation of more than 5 mm (P < 0.001), and jaundice (P < 0.001) were statistically significant variables. The developed statistical model has a c-index of 0.895. Implementation of the statistically significant variables in a predictive nomogram provided a reliable point system for estimating the presence of IPMN-associated invasive carcinoma. CONCLUSIONS: NLR is an independent predictive marker for the presence of IPMN-associated invasive carcinoma. Further prospective studies are needed to assess the predictive ability of NLR and how it can be applied in the clinical setting.

Prevalence and predictors of pain and opioid analgesic use following total pancreatectomy with islet autotransplantation for pancreatitis.

BACKGROUND & OBJECTIVES: Total pancreatectomy with islet autotransplantation (TPIAT) is employed for the management of refractory pain in chronic pancreatitis (CP) with the prospect of partial beta cell preservation. The primary aim of this study is to evaluate the prevalence and predictors of abdominal pain and opioid use following TPIAT. METHODS: A single center cohort study of all adult patients who underwent TPIAT from 2011 to 2015 for CP. Postoperative pain outcomes included: opioid use, ongoing abdominal pain and new characteristic abdominal pain. Multiple logistic regression analysis was used to evaluate known and potential predictors of postoperative pain outcomes. RESULTS: During the study period, 46 patients underwent TPIAT. Following surgery, 89% of patients had resolution of their pre-operative abdominal pain; however, 83% of patients developed a new characteristic abdominal pain. Opioid independence was achieved in 46% of patients. Acute recurrent pancreatitis (ARP) (OR: 11.66; 95%CI: 1.47-92.39; p = 0.02) but not pain duration >3 years or ≥ 5 ERCPs was independently associated with resolution of pre-operative abdominal pain on multiple logistic regression. None of these factors were associated with cessation of opioid use. CONCLUSION: While the majority of patients have resolution of their initial abdominal pain following TPIAT, many will also develop a new characteristic abdominal pain and only half of all patients achieve opioid independence. ARP is the only independent factor associated with positive postoperative pain outcomes and should be considered a standard criterion for patient selection.

Role of CT in the Diagnosis of Nonspecific Abdominal Pain: A Multicenter Analysis.

OBJECTIVE: The objective of our study was to determine whether specific patient and physician factors-known before CT-are associated with a diagnosis of nonspecific abdominal pain (NSAP) after CT in the emergency department (ED). MATERIALS AND METHODS: We analyzed data originally collected in a prospective multicenter study. In the parent study, we identified ED patients referred to CT for evaluation of abdominal pain. We surveyed their physicians before and after CT to identify changes in leading diagnoses, diagnostic confidence, and admission decisions. In the current study, we conducted a multiple regression analysis to identify whether the following were associated with a post-CT diagnosis of NSAP: patient age; patient sex; physicians' years of experience; physicians' pre-CT diagnostic confidence; and physicians' pre-CT admission decision if CT had not been available. We analyzed patients with and those without a pre-CT diagnosis of NSAP separately. For the sensitivity analysis, we excluded patients with different physicians before and after CT. RESULTS: In total, 544 patients were included: 10% (52/544) with a pre-CT diagnosis of NSAP and 90% (492/544) with a pre-CT diagnosis other than NSAP. The leading diagnoses changed after CT in a large proportion of patients with a pre-CT diagnosis of NSAP (38%, 20/52). In regression analysis, we found that physicians' pre-CT diagnostic confidence was inversely associated with a post-CT diagnosis of NSAP in patients with a pre-CT diagnosis other than NSAP (p = 0.0001). No other associations were significant in both primary and sensitivity analyses. CONCLUSION: With the exception of physicians' pre-CT diagnostic confidence, the factors evaluated were not associated with a post-CT diagnosis of NSAP.

Tumor-Vessel Relationships in Pancreatic Ductal Adenocarcinoma at Multidetector CT: Different Classification Systems and Their Influence on Treatment Planning.

Treatment of pancreatic ductal adenocarcinoma (PDAC) remains a challenge, given its propensity for early systemic spread and growth into the adjacent vital vascular structures. With the advent of newer surgical techniques and chemoradiation therapies, multidetector computed tomography (CT) plays a crucial role in the identification of patients with borderline resectable disease who may benefit from such treatments. Stage III PDAC is divided into two categories-locally advanced, defined by arterial encasement or nonreconstructible portovenous axis involvement; and borderline resectable, defined by limited arterial involvement and/or reconstructible portovenous involvement. A consensus definition for stage III borderline resectable PDAC has been proposed by the Americas Hepato-Pancreato-Biliary Association, the Society of Surgical Oncology, and the Society for Surgery of the Alimentary Tract and has gained widespread use. Evaluation of borderline resectable disease involves the identification of the circumferential and longitudinal relationship of the tumor with its neighboring vessels, markers of vascular invasion, and aberrant anatomic structures that alter the surgical approach. Furthermore, the use of template-based radiology reporting may increase the objectivity of the evaluation and mandate the provision of all of the key descriptors required for a comprehensive evaluation of the disease. In this review, the staging of PDAC at multidetector CT is described, with reference to the evaluation of the tumor-vessel interface as it guides treatment planning, along with a discussion of the key descriptors of PDAC at multidetector CT and their importance. Examples are provided of the imaging findings of borderline resectable disease and different surgical approaches, along with a discussion on the importance of standardized terminology and template-based reporting. ©RSNA, 2016.