[Validation of Quantitative Accuracy and Variability in 177Lu Imaging Using Monte Carlo Simulation].

PURPOSE: To predict side effects and optimize injection doses in the dosimetry of 177Lu imaging, highly accurate quantitative SPECT images are required. Monte Carlo simulations were performed to verify the accuracy and variability of quantitative values for 177Lu imaging under various imaging conditions. METHOD: SPECT data of NEMA body phantom were assumed to simulate intrahepatic tumors 6 h after administration of 7.4 GBq of 177Lu-Dotatate. SPECT data were acquired using the SIMIND program with different combinations of collimators and energy windows. For variability evaluation, 30 SPECT images with Poisson noise were generated for each acquisition time. The relative error was evaluated for accuracy evaluation, and the coefficient of variation was estimated for variability evaluation. RESULTS: The accuracy of BG quantification was less than 10% relative error. The accuracy of hot sphere quantification was highest with the combination of MEGP and an energy window of 208 keV±10%. However, the accuracy of hot sphere quantification decreased significantly with decreasing hot sphere diameter. Variability varied with imaging conditions and improved with longer acquisition time. CONCLUSION: Monte Carlo simulations revealed the accuracy and variability of quantitative values for each SPECT imaging condition for 177Lu imaging.

Impact of a new dedicated sheath device for tissue sampling of biliary stricture on pathological diagnostic yield: Retrospective study.

Background and study aims Endoscopic transpapillary biliary forceps biopsy (TBFB) is a common method for obtaining specimens from biliary lesions. Its diagnostic yield is unsatisfactory; to overcome this disadvantage, a dedicated sheath has been developed. This study aimed to evaluate the outcomes of conventional TBFB and TBFB with a novel sheath device. Patients and methods Consecutive patients who underwent TBFB between January 2020 and December 2021 were retrospectively evaluated. The rate of obtaining adequate samples, failed attempts at forceps insertion into the bile duct, and sensitivity were compared between the two groups. Results Ninety-two patients who underwent 115 endoscopic retrograde cholangiopancreatographies (76 in the conventional group vs. 39 in the dedicated sheath group) were included. The rates of obtaining adequate samples, failed attempts of the forceps into the bile duct, and sensitivity were 72.4% vs. 89.7% ( P = 0.03), 28.3% vs. 0% ( P < 0.01), and 66.7% vs. 88.9% ( P = 0.02), respectively. Conclusions TBFB with the novel sheath device contributed to improved sensitivity for diagnosis of biliary stricture without insertion of forceps outside the bile duct.

Efficacy of a Novel Tapered Contrast Catheter for Endoscopic Ultrasound-Guided Hepaticogastrostomy: A Multicenter Study.

Background: Endoscopic ultrasound-guided hepaticogastrostomy (EUS-HGS) is an alternative for failed endoscopic retrograde cholangiopancreatography (ERCP), with current success rates of 65-84% considered suboptimal. A novel ERCP catheter (SHOREN, Kaneka Corporation, Osaka, Japan) with a tapered 3.3-French tip may facilitate smoother insertion, potentially improving outcomes. Methods: This retrospective analysis encompassed EUS-HGS procedures conducted from January 2021 to August 2023 at four institutions. The aim of this study was to compare the performance of conventional and novel ERCP contrast catheters regarding the success rate of single-attempt catheter insertion, failure rates, technical success rates, and incidence of adverse events. Results: The study included 48 patients; 26 underwent EUS-HGS using conventional catheters and 22 with the novel catheter. The novel catheter achieved higher success rates in single-attempt insertions (96.5% vs. 80.8%) and lower failure rates (4.6% vs. 7.7%). The occurrence of bile peritonitis was comparable between the two groups. Conclusions: The novel ERCP contrast catheter with a tapered tip appears to contribute to successful catheter insertion and is useful for EUS-HGS.

EUS-guided hepaticogastrostomy versus EUS-guided hepaticogastrostomy with antegrade stent placement in patients with unresectable malignant distal biliary obstruction: a propensity score-matched case-control study.

BACKGROUND AND AIMS: EUS-guided hepaticogastrostomy (EUS-HGS) is a rescue procedure when ERCP fails. Peritonitis and recurrent biliary obstruction (RBO) are adverse events (AEs) associated with EUS-HGS. Antegrade stent placement across a malignant distal biliary obstruction (DBO) followed by EUS-HGS (EUS-HGAS) creates 2 biliary drainage routes, potentially reducing peritonitis and prolonging time to RBO (TRBO). We compared the outcomes of the 2 techniques. METHODS: Data of consecutive patients with malignant DBO who underwent attempted EUS-HGS or EUS-HGAS across 5 institutions from January 2014 to December 2020 were retrospectively analyzed. A matched cohort of patients was obtained using 1-to-1 propensity score matching. The primary outcome was TRBO, and secondary outcomes were AEs except for RBO and overall survival. RESULTS: Among 360 patients, 283 (176 and 107 in the HGS and HGAS groups, respectively) were eligible. The matched cohorts included 81 patients in each group. AEs developed in 10 (12.3%) and 15 (18.5%) patients (P = .38) in the HGS and HGAS groups, respectively. RBO occurred in 18 and 2 patients in the HGS and HGAS groups, respectively (P < .001). TRBO was significantly longer in the HGAS group (median, 194 days vs 716 days; hazard ratio, .050; 95% confidence interval, .0066-.37; P < .01). However, no significant differences occurred in overall survival between the groups (median, 97 days vs 112 days; hazard ratio, .97; 95% confidence interval, .66-1.4; P = .88). CONCLUSIONS: EUS-HGAS extended TRBO compared with EUS-HGS, whereas AEs, except for RBO and overall survival, did not differ. The longer TRBO of EUS-HGAS could benefit patients with longer life expectancy.

Gap junction beta-4 accelerates cell cycle progression and metastasis through MET-AKT activation in pancreatic cancer.

Despite continuing advances in the development of effective new therapies, including immunotherapies, the prognosis of pancreatic cancer remains extremely poor. Gap junction proteins have become attractive targets for potential cancer therapy. However, the role of gap junction beta-4 (GJB4) protein remains unexplored in pancreatic cancer. Through bioinformatic analyses we discovered pancreatic cancer tissues showed higher levels of GJB4 transcripts compared to normal pancreatic tissues and this had a negative effect on overall survival in patients that had pancreatic cancer. The high expression of nuclear GJB4 was identified as a negative prognostic factor in such patients. Knockdown of GJB4 in cultured pancreatic cancer cells resulted in G0/G1 arrest followed by decreased cell proliferation and suppression of metastatic potential. The overexpression of GJB4 accelerated cell proliferation, migration, and invasion in a SUIT-2 cell line, whereas MET inhibitor canceled the acceleration. GJB4 suppression with siRNA significantly inhibited tumor growth in a mouse xenograft model. Mechanistically, suppression of GJB4 inhibited MET-AKT activities. Such data suggest that targeting the GJB4-MET axis could represent a promising new therapeutic strategy for pancreatic cancer.

Clinical characterization of patients with gBRCA1/2 mutation-positive unresectable pancreatic cancer: a multicenter prospective study.

BACKGROUND: Accumulating evidence has demonstrated platinum-based chemotherapy followed by maintenance therapy with a poly Adenosine diphosphate (ADP)-ribose polymerase inhibitor (olaparib) show benefits in unresectable pancreatic cancer with a germline (g)BRCA1/2 mutation. Evaluation of the germline BRCA1 and BRCA2 mutation is essential for making decisions on a treatment strategy for patients with unresectable pancreatic cancer. However, the detection rates of germline BRCA1 and BRCA2 mutations and efficacy of maintenance with olaparib remain undetermined, prospectively, in Japan. METHODS & RESULTS: In this prospective analysis, the rate of germline BRCA1 and BRCA2 mutations and efficacy of chemotherapy were analyzed in 136 patients with pancreatic cancer who underwent BRACAnalysis® (85 patients) or FoundationOne® CDx (51 patients) between January 2020 and July 2022. A total of six patients (4.4%) had a germline BRCA1 and BRCA2 mutation. Five patients were treated with modified FOLFIRINOX and one with fluorouracil and oxaliplatin. All patients continued platinum-based chemotherapy for ˃4 months and were subsequently treated with olaparib as a maintenance therapy. The response rate to platinum-based chemotherapy in the germline BRCA1 and BRCA2 mutation-positive group was significantly better than that of the germline BRCA1 and BRCA2 mutation-negative group (66% vs 23%, P = 0.04). All patients harbouring a germline BRCA1 and BRCA2 mutation were able to switch to olaparib. The median progression-free survival using olaparib was 5.7 months (range 3.0-9.2). CONCLUSIONS: The rate of germline BRCA1 and BRCA2 mutations found in patients with unresectable pancreatic cancer was comparable to those of previous studies.An analysis of germline BRCA1 and BRCA2 mutations has benefits for all patients with unresectable pancreatic cancer with regard to decisions on therapeutic strategies in a clinical practice setting.

A Rare Case of Sinonasal Seromucinous Hamartoma Developing from the Nasal Septum.

A 45-year-old man presented with a history of chronic left nasal congestion. Nasal endoscopy revealed a pedunculated polypoid mass with glandular epithelium surface on the posterior nasal septum. Computed tomography revealed a 25-mm mass-like growth in the left posterior nasal cavity attached to the nasal septum with a stalk. The patient underwent transnasal endoscopic surgery, and the tumor was removed under a block with safety margin. The final pathological diagnosis was sinonasal seromucinous hamartoma (SH). Sinonasal SH is a rare tumor with only 31 reported cases. Transnasal endoscopic surgery is currently the first-line treatment for sinonasal SH. Differential diagnoses of this lesion include inflammatory polyps, respiratory epithelial adenomatoid hamartoma, and adenocarcinoma. Although SH is a benign tumor, its progression to adenocarcinoma has been reported. Therefore, unilateral posterior nasal tumors must be diagnosed precisely.

Optimization of endoscopic ultrasound-guided tissue sample acquisition for commercially available comprehensive genome profiling.

BACKGROUND AND AIM: Optimal tumor samples are crucial for successful analysis using commercially available comprehensive genomic profiling (CACGP). However, samples acquired by endoscopic ultrasound-guided tissue acquisition (EUS-TA) are occasionally insufficient, and no consensus on the optimal number of needle passes required for CACGP exists. This study aimed to explore the optimal number of needle passes required for EUS-TA to procure an ideal sample fulfilling the prerequisite criteria of CACGPs. METHODS: Patients who underwent EUS-TA for solid masses between November 2019 and July 2021 were retrospectively studied. The correlation between the acquisition rate of an ideal sample and the number of needle passes mounted on a microscope slide was evaluated. Additionally, the factors predicting a successful analysis were investigated in patients scheduled for CACGP using EUS-TA-obtained samples during the same period. RESULTS: EUS-TAs using 22- and 19-gauge (G) needles were performed in 336 and 57 patients, respectively. There was a positive correlation between the acquisition rate and the number of passes using a 22-G needle (38.9%, 45.0%, 83.7%, and 100% for 1, 2, 3, and 4 passes, respectively), while no correlation was found with a 19-G needle (84.2%, 83.3%, and 85.0% for 1, 2, and 3 passes, respectively). The analysis success rate in patients with scheduled CACGP was significantly higher with ideal samples than with suboptimal samples (94.1% vs 55.0%, P < 0.01). CONCLUSIONS: The optimal estimated number of needle passes was 4 and 1-2 for 22- and 19-G needles, respectively.

Propensity score matching analysis for adverse events of EUS-guided biliary drainage in advanced elderly patients (PEACE study).

Background: Several studies have suggested that elderly patients, as well as younger patients, can be safely treated using endoscopic retrograde cholangiopancreatography (ERCP). However, endoscopic ultrasound-guided biliary drainage (EUS-BD) has not been clinically evaluated for very elderly patients. The present multicenter, retrospective study aimed to determine the safety of EUS-BD for advanced elderly patients. Method: Patients who underwent EUS-BD during this period were retrospectively enrolled, and they were divided into two groups based on age: group A (age < 75 years) and group B (age ⩾ 75). In this study, capnographic monitoring was used only for elderly patients (age ⩾ 75 years). Results: A total of 271 patients who underwent EUS-BD were enrolled in this study (group A = 177, group B = 94). The types of adverse events that were associated with EUS-BD was observed in 38 patients, and they did not differ significantly between two groups (p = 0.855). This result was confirmed after propensity score matching (p = 0.510). Adverse events were associated with sedation after propensity score matching; hypoxemia (p = 0.012) and severe hypoxemia (p = 0.003) were significantly higher in group A compared with group B. According to logistic regression analysis, monitoring (non-capnography) was also only risk factor (odds ratio: 0.317, 95% confidence interval: 0.143-0.705; p = 0.005) for sedation-related adverse events. Conclusion: In conclusion, EUS-BD could be safety performed in advanced elderly patients, the same as in younger patients. Also, capnographic monitoring might be helpful in case of sedation by a gastroenterologist in a non-intubated patient. Further prospective, randomized studies are needed to confirm these conclusions.

Biliary obstruction and pancreatitis after duodenal stent placement in the descending duodenum: a retrospective study.

BACKGROUND: Metallic stents placed in the descending duodenum can cause compression of the major duodenal papilla, resulting in biliary obstruction and pancreatitis. These are notable early adverse events of duodenal stent placement; however, they have been rarely examined. This study aimed to assess the incidence of and risk factors for biliary obstruction and/or pancreatitis after duodenal stent placement in the descending duodenum. METHODS: We retrospectively reviewed data of consecutive patients who underwent metallic stent placement in the descending duodenum for malignant gastric outlet obstruction at a tertiary referral cancer center between April 2014 and December 2019. Risk factors for biliary obstruction and/or pancreatitis were analyzed using a logistic regression model. RESULTS: Sixty-five patients were included. Biliary obstruction and/or pancreatitis occurred in 12 patients (18%): 8 with biliary obstruction, 2 with pancreatitis, and 2 with both biliary obstruction and pancreatitis. Multivariate analysis indicated that female sex (odds ratio: 9.2, 95% confidence interval: 1.4-58.6, P = 0.02), absence of biliary stents (odds ratio: 12.9, 95% confidence interval: 1.8-90.2, P = 0.01), and tumor invasion to the major duodenal papilla (odds ratio: 25.8, 95% confidence interval: 2.0-340.0, P = 0.01) were significant independent risk factors for biliary obstruction and/or pancreatitis. CONCLUSIONS: The incidence of biliary obstruction and/or pancreatitis after duodenal stent placement in the descending duodenum was non-negligible. Female sex, absence of biliary stents, and tumor invasion to the major duodenal papilla were the primary risk factors. Risk stratification can allow endoscopists to better identify patients at significant risk and permit detailed informed consent.

Endoscopic ultrasound-guided hepaticogastrostomy versus hepaticogastrostomy with antegrade stenting for malignant distal biliary obstruction.

BACKGROUND: Recurrent biliary obstruction (RBO) is a possible complication of endoscopic ultrasound-guided hepaticogastrostomy (EUS-HGS) in patients with malignant distal biliary obstruction (MDBO). Therefore, adding antegrade stenting across MDBO, followed by EUS-HGS (EUS-HGAS), may prolong the time to RBO (TRBO). We aimed to compare the outcomes of EUS-HGS and HGAS. METHODS: We retrospectively evaluated consecutive patients who underwent EUS-HGS or HGAS between July 2016 and November 2020. The TRBO, overall survival (OS), and adverse event (AE) rate were compared between the groups. The risk factors for RBO were determined using a multivariable Cox proportional hazards model. RESULTS: This study included 96 patients (EUS-HGS, n = 58; HGAS, n = 38). There was a significant difference in the cause of endoscopic retrograde cholangiopancreatography failure and the HGS stent type between the groups. A significant difference was found in TRBO (234 days vs not reached, P = .036), whereas no significant difference was found in the OS (123 vs 126 days, P = .76). The AE rate was not significantly different. Multivariable analysis revealed that EUS-HGS was an independent risk factor for RBO (hazard ratio: 4.01, 95% confidence interval: 1.16-13.9). CONCLUSIONS: Endoscopic ultrasound-guided hepaticogastrostomy prolonged the TRBO compared with EUS-HGS for biliary drainage in patients with MDBO.

Microsatellite instability is biased in Amsterdam II-defined Lynch-related cancer cases with family history but is rare in other cancers: a summary of 1000 analyses.

BACKGROUND: Microsatellite instability (MSI) is a key marker for predicting the response of immune checkpoint inhibitors (ICIs) and for screening Lynch syndrome (LS). AIM: This study aimed to see the characteristics of cancers with high level of MSI (MSI-H) in genetic medicine and precision medicine. METHODS: This study analyzed the incidence of MSI-H in 1000 cancers and compared according to several clinical and demographic factors. RESULTS: The incidence of MSI-H was highest in endometrial cancers (26.7%, 20/75), followed by small intestine (20%, 3/15) and colorectal cancers (CRCs)(13.7%, 64/466); the sum of these three cancers (15.6%) was significantly higher than that of other types (2.5%)(P < 0.0001). MSI-H was associated with LS-related cancers (P < 0.0001), younger age (P = 0.009), and family history, but not with smoking, drinking, or serum hepatitis virus markers. In CRC cases, MSI-H was significantly associated with a family history of LS-related cancer (P < 0.0001), Amsterdam II criteria [odds ratio (OR): 5.96], right side CRCs (OR: 4.89), and multiplicity (OR: 3.31). However, MSI-H was very rare in pancreatic (0.6%, 1/162) and biliary cancers (1.6%, 1/64) and was null in 25 familial pancreatic cancers. MSI-H was more recognized in cancers analyzed for genetic counseling (33.3%) than in those for ICI companion diagnostics (3.1%)(P < 0.0001). Even in CRCs, MSI-H was limited to 3.3% when analyzed for drug use. CONCLUSIONS: MSI-H was predominantly recognized in LS-related cancer cases with specific family histories and younger age. MSI-H was limited to a small proportion in precision medicine especially for non-LS-related cancer cases.

Comparing the 14-mm uncovered and 10-mm covered metal stents in patients with distal biliary obstruction caused by unresectable pancreatic cancer: a multicenter retrospective study.

BACKGROUND: Endoscopic biliary drainage using metal stent (MSs) is an established palliative treatment for patients with unresectable malignant distal biliary obstruction (MDBO). However, a major drawback of MS is recurrent biliary obstruction (RBO). Uncovered MSs with a diameter of 14 mm (UMS-14) were developed to overcome this. We aimed to compare the clinical outcomes of UMS-14 with those of conventional covered MSs having a diameter of 10 mm (CMS-10). METHODS: Consecutive patients with MDBO caused by unresectable pancreatic cancer, who underwent UMS-14 or CMS-10 placement at two tertiary-care centers, were retrospectively examined according to the Tokyo Criteria 2014. RESULTS: Two hundred and thirty-eight patients who underwent UMS-14 (the UMS-14 group, n = 80) or CMS-10 (the CMS-10 group, n = 158) over a 62-month period were included. The technical and clinical success rates were similar between the two groups. RBO occurred in 20 (25%) and 59 (37%) patients of the UMS-14 and CMS-10 groups, respectively (p = 0.06). Median time till RBO was significantly longer in the UMS-14 group than in the CMS-10 group (not reached vs. 290 days, p = 0.04). Multivariate analysis revealed that CMS-10 placement was an independent risk factor for RBO (hazard ratio: 1.66, 95% confidence interval: 1.00-2.76). The incidence of early complications, including pancreatitis, and the overall survival (UMS-14 vs. CMS-10: 169 vs. 167 days, p = 0.83) were comparable between the two groups. CONCLUSIONS: UMS-14 stents were safe and effective for treating patients with MDBO secondary to unresectable pancreatic cancer. The insertion of UMS-14 is recommended, because it is less likely to get occluded as compared to CMS-10.

Macroscopic visible core length can predict the histological sample quantity in endoscopic ultrasound-guided tissue acquisition: Multicenter prospective study.

OBJECTIVES: Measurement of the macroscopic visible core (MVC) length during macroscopic on-site quality evaluation (MOSE) may allow estimation of sample adequacy for next-generation sequencing (NGS), and prediction of correct diagnosis in endoscopic ultrasound-guided tissue acquisition (EUS-TA) of pancreatic masses. METHODS: This multicenter prospective study included consecutive patients who underwent EUS-TA for pancreatic masses using a 22-G Franseen needle. MVC length and pathological samples obtained from two needle passes were analyzed on a per-pass basis. Outcome measures included respective correlations of MVC length with histological sample quantity and diagnostic yields. RESULTS: The analysis included 204 passes from 102 EUS-TAs. MVC length correlated positively with histological sample quantity (P < 0.01). On the receiver operating characteristic curve for MVC length, the cut-off value and area under the curve for obtaining a candidate sample for NGS were 30 mm and 0.74 (95% confidence interval [CI] 0.65-0.83), respectively. On multivariate analysis, MVC length ≥30 mm was a significant factor affecting suitability for NGS (odds ratio 6.19; 95% CI 2.72-14.10). Histologic diagnostic yield correlated positively with MVC length (P = 0.01); however, there was no positive correlation between MVC length and overall (histology plus cytology) diagnostic yield. CONCLUSIONS: Measuring MVC length to predict histological sample quantity on MOSE may be of clinical significance during EUS-TA using a 22-G Franseen needle. It may be an effective method, particularly while submitting samples for NGS. REGISTRATION: University Hospital Medical Information Network Trials Registry (UMIN000036528).

Efficacy of endoscopic samplings during initial biliary drainage for cases of pancreatic head cancer: United diagnostic yields of multiple pathological samplings.

BACKGROUND/OBJECTIVES: The diagnostic ability of endoscopic ultrasound-guided fine needle aspiration (EUS-FNA) has been fully studied; however, the efficacy of other endoscopic samplings (OESs) is less clear. The aim of this study was to examine the diagnostic efficacies of OESs for pancreatic head cancer (PHC). METHODS: The diagnostic efficacies of endoscopic samplings were retrospectively analyzed in 448 PHC cases and 63 cases of mass-forming pancreatitis (MFP) during initial transpapillary biliary drainage. The OESs included duodenal biopsy (118 PHCs and 50 MFPs), biliary biopsy (218 and 51) with cytology (368 and 53), and pancreatic duct biopsy (23 and 13) with cytology (56 and 43). EUS-FNA was conducted in a different session (149 and 62). Factors associated with OES sensitivity were analyzed. The sensitivity of biliary biopsy was compared between 1.95 mm and 1.8 mm forceps. RESULTS: Cancer cells were confirmed in 87.9% of the EUS-FNA samplings and in 64.1% (268/418) obtained by combined OESs (average 1.7 OES types per case): 68.6% by duodenal biopsy, 59.6% by biliary biopsy, 32.6% by biliary cytology, 73.9% by pancreatic duct biopsy, and 33.9% by pancreatic duct cytology. No MFP cases revealed cancer by any sampling. OESs did not increase adverse events. Duodenal stenosis, serum bilirubin, tumor size, and pancreatic juice amounts were associated with OES sensitivity. Biliary biopsy had the same sensitivity with different forceps. CONCLUSION: EUS-FNA was the most diagnostic protocol; however, OESs can be safely applied during the initial biliary drainage to reduce the demand for EUS-FNA while providing good diagnostic yields.

[A case of intraductal tubulopapillary adenocarcinoma with bone metastases].

A woman in her 70s with main pancreatic duct dilatation was referred to our hospital. Various imaging examinations showed an extensive mass within the lumen of the main pancreatic duct in the head and body of the pancreas. The microscopic examination of a biopsy specimen revealed an adenocarcinoma. She was diagnosed with intraductal tubulopapillary adenocarcinoma of the pancreas;a pylorus-preserving total pancreatectomy was subsequently performed. However, 30 days after surgery, the patient presented with neck pain and left upper arm numbness. Results of magnetic resonance imaging and bone scintigraphy revealed a cervical spinal tumor that was subsequently biopsied. The patient was diagnosed with intraductal tubulopapillary adenocarcinoma with bone metastasis.

Comparison of five-phase computed tomography images of type 1 autoimmune pancreatitis and pancreatic cancer: Emphasis on cases with atypical images.

BACKGROUND/OBJECTIVES: International consensus diagnostic criteria (ICDC) include characteristic images of autoimmune pancreatitis (AIP); however, reports on atypical cases are increasing. The aims of this study were to compare CT findings between AIP and pancreatic cancer (PC), and to analyze type 1 AIPs showing atypical images. METHODS: Five-phase CT images were compared between 80 type 1-AIP lesions and 80 size- and location-matched PCs in the case-control study. Atypical AIPs were diagnosed based on the four ICDC items. RESULTS: ICDC items were recognized in most AIP lesions; pancreatic enlargement (87.7%), narrowing of the main pancreatic duct (98.8%), delayed enhancement (100%), and no marked upstream-duct dilation (97.5%). CT values of AIPs increased rapidly until the pancreatic phase and decreased afterward, while those of PCs gradually increased until the delayed phase (P < 0.0001). Atypical images were recognized in 14.8% of AIPs, commonly without pancreatic enlargement (18.5 mm) and sometimes mimicking intraductal neoplasms. The CT values and their ratios were different between atypical AIPs and size-matched PCs most significantly in the pancreatic phase, but similar in the delayed phase. CONCLUSIONS: Ordinary type 1 AIPs can be diagnosed with the ICDC, but atypical AIPs represented a small fraction. "Delayed enhancement" is characteristic to ordinary AIPs, however, "pancreatic-phase enhancement" is more diagnostic for atypical AIPs.