Comparison between multislice CT and MR imaging in the diagnostic evaluation of patients with pancreatic masses

Preoperative assessment of peripheral vascular invasion of pancreatic ductal adenocarcinoma based on high-resolution MRI

OBJECTIVES

Preoperative imaging of vascular invasion is important for surgical resection of pancreatic ductal adenocarcinoma (PDAC). However, whether MRI and CT share the same evaluation criteria remains unclear. This study aimed to compare the diagnostic accuracy of high-resolution MRI (HR-MRI), conventional MRI (non-HR-MRI) and CT for PDAC vascular invasion.

METHODS

Pathologically proven PDAC with preoperative HR-MRI (79 cases, 58 with CT) and non-HR-MRI (77 cases, 59 with CT) were retrospectively collected. Vascular invasion was confirmed surgically or pathologically. The degree of tumour-vascular contact, vessel narrowing and contour irregularity were reviewed respectively. Diagnostic criteria 1 (C1) was the presence of all three characteristics, and criteria 2 (C2) was the presence of any one of them. The diagnostic efficacies of different examination methods and criteria were evaluated and compared.

RESULTS

HR-MRI showed satisfactory performance in assessing vascular invasion (AUC: 0.87-0.92), especially better sensitivity (0.79-0.86 vs. 0.40-0.79) than that with non-HR-MRI and CT. HR-MRI was superior to non-HR-MRI. C2 was superior to C1 on CT evaluation (0.85 vs. 0.79, P = 0.03). C1 was superior to C2 in the venous assessment using HR-MRI (0.90 vs. 0.87, P = 0.04) and in the arterial assessment using non-HR-MRI (0.69 vs. 0.68, P = 0.04). The combination of C1-assessed HR-MRI and C2-assessed CT was significantly better than that of CT alone (0.96 vs. 0.86, P = 0.04).

CONCLUSIONS

HR-MRI more accurately assessed PDAC vascular invasion than conventional MRI and may contribute to operative decision-making. C1 was more applicable to MRI scans, and C2 to CT scans. The combination of C1-assessed HR-MRI and C2-assessed CT outperformed CT alone and showed the best efficacy in preoperative examination of PDAC.

Mucinous non neoplastic cyst of the pancreas: a case report

The aim of this study was to introduce a patient with mucinous nonneoplastic cyst (MNNC) at an unusual age. MNNCs of the pancreas are uncommon primary tumors, which affect middle-aged women in their fifth decade of life and have significant malignant potential. Therefore, it is important to accurately diagnose and remove them. This case is a 28-year-old woman patient who presented with a pain in the right and upper abdomen from 3 months ago and worsened at night. A cystic lesion was observed near the upper bridge of the left kidney in abdominal ultrasonography. Contrast-enhanced abdominal computed tomography (CT) scan showed a cystic lesion in the trunk and umbilical cord of the pancreas. The patient underwent surgery and the mass was removed and the MNNC was diagnosed.

Benefits of Dual-Layer Spectral CT Imaging in Staging and Preoperative Evaluation of Pancreatic Ductal Adenocarcinoma

Imaging of pancreatic malignancies is challenging but has a major impact on the patients therapeutic approach and outcome. In particular with pancreatic ductal adenocarcinoma (PDAC), usually a hypovascularized tumor, conventional CT imaging can be prone to errors in determining tumor extent and presence of metastatic disease. Dual-layer spectral detector CT (SDCT) is an emerging technique for acquiring spectral information without the need for prospective patient selection or specific protocols, with a detector capable of differentiating high- and low-energy photons to acquire full spectral images. In this review, we present the diagnostic benefits and capabilities of modern SDCT imaging with a focus on PDAC. We highlight the most useful virtual reconstructions in oncologic imaging and their benefits in staging and assessment of resectability in PDAC, including the assessment of tumor extent, vascular infiltration, and metastatic disease. We present imaging examples on a latest-generation SDCT scanner.

Multiparameter Magnetic Resonance Quantitative Evaluation of Pancreatic Cancer with Vascular Invasion

Objective

To analyze the value of multiparameter magnetic resonance (mpMRI) in the diagnosis of pancreatic cancer with vascular invasion from two aspects: morphology and function, so as to provide a reliable diagnostic basis for preparing the clinical treatment plans.

Methods

Totally 31 case data of pancreatic cancer patients diagnosed in our hospital from January 2020 to March 2021 were enrolled in this study. All patients underwent multiparameter magnetic resonance imaging (T1WI, T2WI, DKI, and DCE-MRI) before surgery, and then all patients underwent pancreatic cancer surgery. Two experienced radiologists analyzed these obtained images according to the image reports and combined them with the pathological results. Taking pathological results as gold standard, the sensitivity, specificity, and accuracy of quantitative parameters derived from T2WI, DKI, DCE, T2WI + DKI, T2WI + DCE, and T2WI + DKI + DCE for the diagnostic capabilities of pancreatic cancer vascular invasion were calculated using diagnostic laboratory methods. Kappa consistency test was used to estimate the consistency of two radiologists' diagnosis and analysis. The images obtained by DKI sequence were input into the postprocessing software MITK-Diffusion v2014.10.02, The images obtained from DCE sequence were processed by the Tissue 4D software on the Siemens syngo via workstation to calculate and analyze each tumor ROI's MD, MK values from DKI, and K trans, K ep, V e values from DCE. Independent samples t-test was used to compare the parameters of pancreatic cancer with vascular invasion group (16 cases) and nonvascular invasion group (15 cases). ROC curve was used to analyze the efficacy of each parameter in diagnosing pancreatic cancer vascular invasion.

Results

The sensitivity, specificity, and accuracy of T2WI were 62.5%, 53.5%, and 58.1%; those of DKI were 56.3%, 60.0%, and 58.1%; those of DCE were 68.8%, 60.0%, and 64.5%; those of T2WI + DKI were 68.8%, 66.7%, and 67.7%; those of T2WI + DCE were 75.0%, 66.7%, and 71.1%; those of T2WI + DKI + DCE were 81.2%, 73.3%, and 77.4%, respectively. These two diagnostic radiologists analyzed image data with good consistency, Kappa = 0.834. MD, MK, K trans, K ep, and V e were significantly different between the vascular invasion group and the nonvascular invasion group (p < 0.05). Each parameter's AUC of ROC curve was 0.773, 0.829, 0.794, 0.802, and 0.846 (p < 0.05). Take MD = 2.285 × 10-3 mm/s2, MK = 0.72, K trans = 0.103, K ep = 0.337, and V e = 0.353 as thresholds; the sensitivity of these parameters to diagnose vascular invasion of pancreatic cancer was 73.33%, 75%, 87.5%, 68.8%, and 68.8%. The specificity of them was 75%, 80%, 60%, 86.7%, and 86.7%, respectively.

Conclusion

The combined analysis of T2WI + DKI + DCE can improve the specificity and accuracy of diagnostic efficiency of vascular invasion of pancreatic cancer and provide an important diagnostic basis for pancreatic cancer's preoperative treatment.

Diagnostic Accuracy of Computed Tomography Scores in Chronic Pancreatitis

OBJECTIVES

Computed tomography (CT) is the most commonly used imaging modality when diagnosing chronic pancreatitis (CP). We aimed to evaluate the diagnostic accuracy of CT scores for diagnosing CP.

METHODS

One hundred eighteen patients were retrospectively included from an observational cohort study that comprised patients referred because of suspected CP. Patients were categorized as CP or non-CP using a modified Mayo score based on biochemistry, clinical presentation, and findings on endoscopic ultrasound and/or transabdominal ultrasound. The CT scans were scored according to the modified Cambridge classification and the unweighted CT score. Diagnostic performance indices were calculated using the modified Mayo score as reference standard.

RESULTS

Seventy-six of the 118 patients fulfilled the CP diagnostic criteria (Mayo score ≥4). The modified Cambridge classification and the unweighted CT score yielded sensitivities of 63% and 67% and specificities of 91% and 91%, respectively, and similar areas under the receiver operating characteristic curves (95% confidence interval) of 0.79 (0.71-0.88)/0.81 (0.73-0.89), respectively (P, not significant).

CONCLUSIONS

Both CT scores had similar, moderate accuracies for diagnosing CP. The limitation in diagnostic accuracy makes CT ineligible as a single method to diagnose CP, supporting that the diagnostic process for CP needs to incorporate other imaging methods and/or markers for better diagnostics.

Swedish national guidelines for chronic pancreatitis

Chronic pancreatitis (CP) should be suspected in the case of recurrent upper abdominal pain of unknown origin and/or clinical signs of exocrine pancreatic insufficiency (EPI). Alcohol is the most common etiological factor associated with CP, others being smoking, male gender, and hereditary forms. CP is often associated with recurrent episodes of acute exacerbations.As of today, there is no accepted clinical definition of CP. However, irreversible morphological changes within the pancreas often occur, including dilatation of the main and branch pancreatic ducts, calcifications in ducts and parenchyma, parenchymal atrophy, and development of pseudocysts, though less so in the early phase of CP.

Diagnostic Process Using Endoscopy for Biliary Strictures: A Narrative Review

The diagnostic process for biliary strictures remains challenging in some cases. A broad differential diagnosis exists for indeterminate biliary strictures, including benign or malignant lesions. The diagnosis of indeterminate biliary strictures requires a combination of physical examination, laboratory testing, imaging modalities, and endoscopic procedures. Despite the progress of less invasive imaging modalities such as transabdominal ultrasonography, computed tomography, and magnetic resonance imaging, endoscopy plays an essential role in the accurate diagnosis, including the histological diagnosis. Imaging findings and brush cytology and/or forceps biopsy under fluoroscopic guidance with endoscopic retrograde cholangiopancreatography (ERCP) are widely used as the gold standard for the diagnosis of biliary strictures. However, ERCP cannot provide an intraluminal view of the biliary lesion, and its outcomes are not satisfactory. Recently, peroral cholangioscopy, confocal laser endomicroscopy, endoscopic ultrasound (EUS), and EUS-guided fine-needle aspiration have been reported as useful for indeterminate biliary strictures. Appropriate endoscopic modalities need to be selected according to the patient's condition, the lesion, and the expertise of the endoscopist. The aim of this review article is to discuss the diagnostic process for indeterminate biliary strictures using endoscopy.

Using magnetic resonance imaging to measure the depth of acupotomy points in the lumbar spine: A retrospective study

Background

The acupotomy is an acupuncture device recently used to stimulate lumbar vertebrae such as transverse processes (TPs) and facet joints (FJs). However, there are many organs, nerves, and blood vessels, which can lead to side effects if the needle misses the treatment target. Therefore, information regarding appropriate insertion depths, which is currently lacking, could facilitate its safe use. We retrospectively investigated the depth from the skin to the TP and FJ of the lumbar vertebrae, using magnetic resonance imaging (MRI).

Methods

This retrospective chart review was conducted at a single medical centre in Korea. From 55,129 patient records, 158 subjects were selected. Perpendicular depth from the skin to the left and right TPs and FJs was measured using T1-weighted sagittal plane MRI. Depth differences between the left and right sides were evaluated using the paired t-test and analysis of covariance (body mass index [BMI] as a covariate). The influence of BMI on depth at each location was evaluated by simple linear regression analysis.

Results

The mean age was 43.2 years and mean BMI was 23.6 kg/m². The depth from skin to the TPs or FJs was unaffected by age, sex, or side. Mean depths (cm) were as follows: (TPs) L1 = 4.5, L2 = 4.9, L3 = 5.3, L4 = 5.7, L5 = 5.9; (FJs) L12 = 3.8, L23 = 4.0, L34 = 4.4, L45 = 4.6, L5S1 = 4.6. Depth was highly correlated with BMI at each location.

Conclusion

The depth of TPs and FJs adjusted for BMI can safely and effectively be used for treatment via various invasive interventions, including acupotomy treatment, in the lumbar region.

International consensus statements for endoscopic management of distal biliary stricture

Distal biliary strictures (DBS) are common and may be caused by both malignant and benign pathologies. While endoscopic procedures play a major role in their management, a comprehensive review of the subject is still lacking. Our consensus statements were formulated by a group of expert Asian pancreatico-biliary interventional endoscopists, following a proposal from the Digestive Endoscopy Society of Taiwan, the Thai Association for Gastrointestinal Endoscopy, and the Tokyo Conference of Asian Pancreato-biliary Interventional Endoscopy. Based on a literature review utilizing Medline, Cochrane library, and Embase databases, a total of 19 consensus statements on DBS were made on diagnosis, endoscopic drainage, benign biliary stricture, malignant biliary stricture, and management of recurrent biliary obstruction and other complications. Our consensus statements provide comprehensive guidance for the endoscopic management of DBS.

Prediction of pancreatic atrophy after steroid therapy using equilibrium-phase contrast computed tomography imaging in autoimmune pancreatitis

Background and Aims

Imaging tools for predicting pancreatic atrophy after steroid therapy in autoimmune pancreatitis (AIP) have not been established. As delayed equilibrium‐phase contrast enhancement in computed tomography (CE‐CT) may reflect interstitial fibrosis, we evaluated the ability of equilibrium‐phase CT imaging for predicting pancreatic atrophy.

Methods

Forty‐six steroid‐treated AIP patients who underwent contrast‐enhanced CT at our university hospital were included in this retrospective study. CT attenuation (Hounsfield units [HU]) values in noncontrast images (NC) and equilibrium‐phase images (EP) and the differences in HU values between NC and EP images (SUB) were measured. Pancreatic volume was measured in CE‐CT before (Vol_pre) and after (Vol_post) steroid therapy. The volume reduction rate was calculated. The relationships of CT values with pancreatic atrophy, Vol_post, volume reduction rate, and diabetes exacerbation were investigated.

Results

CT values in the EP and SUB images before steroid therapy were associated with pancreatic atrophy after steroid therapy (atrophy vs nonatrophy 114.5 ± 12.8 vs 99.5 ± 11.1, P = 0.0002; 70.9 ± 14.72 vs 57.2 ± 13.1, P = 0.003, respectively), but CT values in NC images were not (P = 0.42). CT values in EP and SUB images before steroid therapy were correlated with Vol_post (EP images r = −0.70, P = 0.002; SUB images r = −0.68, P = 0.03) and volume reduction rate after steroid therapy (EP images: r = −0.55, P < 0.0001; SUB images r = −0.45, P = 0.002). Diabetes exacerbation was associated with higher EP and SUB values (P = 0.009 and P = 0.04, respectively).

Conclusion

Equilibrium‐phase contrast CT imaging may facilitate prediction of pancreatic atrophy after steroid therapy in AIP.

Early Diagnosis And Management Of Malignant Distal Biliary Obstruction: A Review On Current Recommendations And Guidelines

Malignant biliary obstruction is a challenging condition, requiring a multimodal approach for both diagnosis and treatment. Pancreatic adenocarcinoma and cholangiocarcinoma are the leading causes of malignant distal biliary obstruction. Early diagnosis is difficult to establish as biliary obstruction can be the first presentation of the underlying disease, which can already be at an advanced stage. Consequently, the majority of patients (70%) with malignant distal biliary obstruction are unresectable at the time of diagnosis. The association of clinical findings, laboratory tests, imaging, and endoscopic modalities may help in identifying the underlying cause. Novel endoscopic techniques such as cholangioscopy, intraductal ultrasonography, or confocal laser endomicroscopy have been developed with promising results, but are not used in routine clinical practice. As the number of patients with malignant distal biliary obstruction who will undergo curative surgery is limited, endoscopy has a crucial role in palliation, to relieve biliary obstruction. According to the last European guidelines published in the management of biliary obstruction, self-expandable metal stents have a central place in biliary drainage compared to plastic stents. Endoscopic ultrasound has evolved impressively in the last decades. When standard techniques of biliary cannulation by endoscopic retrograde cholangiopancreatography fail, endoscopic ultrasound-guided biliary drainage is a good option compared to percutaneous drainage.

Split-bolus vs. multiphasic contrast bolus protocol in patients with pancreatic cancer or cholangiocarcinoma

PURPOSE

To investigate the image quality, diagnostic accuracy, and dose reduction potential of a split-bolus protocol(SBP) compared with a multiphasic protocol(MPP) in the detection of recurrent or progressive pancreatic ductal adenocarcinoma(PDAC) or cholangiocarcinoma(CC) using contrast- enhanced computed tomography(CECT).

MATERIALS AND METHODS

This prospective study included 56 patients who underwent CECT, 28 with our institutional standard MPP(100 ml contrast bolus) and 28 with a novel SBP(110 ml). Radiation exposure was determined in terms of total dose- length product(DLP) and computed tomography dose index(CTDI). Image quality was measured objectively by analysis of attenuation in Hounsfield units(HU) in regions of interest(ROIs) and subjectively by two blinded readers using a Likert scale. Diagnostic accuracy and interreader variability were tested.

RESULTS

The total DLP of the SBP group(498.1 ± 43.7 mGy*cm) was significantly lower than in the MPP group(1,092.5 ± 106.9 mGy*cm; p < 0.001). The SBP showed higher contrast enhancement of all critical anatomical structures including portal vein, liver, and pancreas compared with the MPP, except for the aorta(SBP: 326.9 ± 15.7 HU vs. MPP: 246.7 ± 12.2 HU; p < 0.001). Subjective analysis revealed poorer image quality ratings for important landmarks with the MPP (resection surface: p = 0.624, portal vein: p = 0.395, liver p = 0.361). The two blinded readers correlated significantly. Sensitivity, specificity, positive and negative predictive values (PPV/NPV), and overall interreader variabilities correlated significantly. Furthermore, significantly fewer slices per exam were required for the SBP(1,823 vs. 3,235; p < 0.001).

CONCLUSION

The SBP provides the same image quality and diagnostic accuracy as an MPP while significantly lowering radiation exposure in CT follow-up of PDAC or CC.

Screening for Pancreatic Cancer: Current Status and Future Directions

Pancreatic ductal adenocarcinoma is a lethal disease for a multitude of reasons, including difficulty of early detection, early metastatic spread, and absence of more effective therapies. Even with the advent of newer systemic therapies, the 1-year survival for metastatic disease ranges from 17–23% and 5-year survival is <5%. This necessitates an urgent need for the development of more effective modalities for early detection, particularly due to the long latent period between the genomic cellular changes and the development of metastatic disease. Currently available biochemical and molecular markers have significant potential; however, they require further clinical validation. Endoscopic ultrasound is one of the most sensitive modalities used to both screen and sample lesions, but is limited to use in high-risk patients due to its invasive nature and associated risks. Although clinically meaningful progress has been made in screening the high-risk cohorts in terms of detection of pancreatic ductal adenocarcinoma, intraductal papillary mucinous neoplasms, and mucinous cystic neoplasms, leading to early diagnosis and treatment, nonselective population-based screening is not yet available for widespread use. Currently there is no consensus on the most appropriate screening protocol for early pancreatic cancer detection. In this review, we focus on understanding the potential role of molecular and radiogenomic markers in the early detection of pancreatic cancer.

Diagnosis and treatment in chronic pancreatitis: an international survey and case vignette study

BACKGROUND

The aim of the study was to evaluate the current opinion and clinical decision-making process of international pancreatologists, and to systematically identify key study questions regarding the diagnosis and treatment of chronic pancreatitis (CP) for future research.

METHODS

An online survey, including questions regarding the diagnosis and treatment of CP and several controversial clinical case vignettes, was send by e-mail to members of various international pancreatic associations: IHPBA, APA, EPC, ESGE and DPSG.

RESULTS

A total of 288 pancreatologists, 56% surgeons and 44% gastroenterologists, from at least 47 countries, participated in the survey. About half (48%) of the specialists used a classification tool for the diagnosis of CP, including the Mayo Clinic (28%), Mannheim (25%), or Büchler (25%) tools. Overall, CT was the preferred imaging modality for evaluation of an enlarged pancreatic head (59%), pseudocyst (55%), calcifications (75%), and peripancreatic fat infiltration (68%). MRI was preferred for assessment of main pancreatic duct (MPD) abnormalities (60%). Total pancreatectomy with auto-islet transplantation was the preferred treatment in patients with parenchymal calcifications without MPD abnormalities and in patients with refractory pain despite maximal medical, endoscopic, and surgical treatment. In patients with an enlarged pancreatic head, 58% preferred initial surgery (PPPD) versus 42% initial endoscopy. In patients with a dilated MPD and intraductal stones 56% preferred initial endoscopic ± ESWL treatment and 29% preferred initial surgical treatment.

CONCLUSION

Worldwide, clinical decision-making in CP is largely based on local expertise, beliefs and disbeliefs. Further development of evidence-based guidelines based on well designed (randomized) studies is strongly encouraged.

Early detection of sporadic pancreatic cancer: time for change

Sporadic pancreatic cancer amounts to ∼90% of all pancreatic cancers. It is a gloomy depressive disease and the most recalcitrant malignancy, with a very low 5-year survival (3-6%). At present, diagnostic methods are commonly applied, as used half a century ago, after the appearance of local and systemic symptoms (abdominal and back pain, cholestasis, painless jaundice, fatigue, anorexia, weight loss, anemia, peripheral phlebitis, and cachexia). Unfortunately, these symptoms are harbingers of an advanced disease. The subsequent imaging methods may offer additional information on the location, size, and morphology of the lesion, but they do not influence the prognosis. Radical surgery may be offered to 15-20% of patients. The relapses after surgery are frequent and chemotherapy may be palliative. Preventive programs represent the only possibility of improvement. We propose the first multistep and multidisciplinary preventive program for early detection of sporadic pancreatic cancer for the differential identification of average-risk patients who probably have the disease from those who do not.

Optimized ROI size on ADC measurements of normal pancreas, pancreatic cancer and mass-forming chronic pancreatitis

Objectives

To investigate the effects of region of interest (ROI) sizes on apparent diffusion coefficient (ADC) measurements for the differentiation of normal pancreas (NP), pancreatic ductal adenocarcinoma (PDAC) and mass-forming chronic pancreatitis (MFCP).

Results

There were no significant differences for the mean ADCs measured by 12 different-size ROIs for MFCP, or PDAC and NP (P = 0.858–1.0). With the increase of ROI size (≥ 55 mm²), ADCs of PDAC were significantly lower than those of NP (all P < 0.05), but there was no difference of the accuracy in ADC for differentiating the two groups only at a ROI size of 214 mm². When ROI size was above 99 mm², ADCs of MFCP were significantly lower than those of NP (all P < 0.05). There were no significant differences for any of the mean ADCs measured by 12 different-size ROIs between PDAC and MFCP (P > 0.05).

Materials and Methods

Diffusion-weighted imaging (DWI) was performed on 89 participants: 64 with PDAC, 7 with MFCP, as well as 18 healthy volunteers. ADC maps were created using mono-exponential model. A homemade software was used to measure the mean ADC values of 12 concentric round ROIs (areas: 15, 46, 55, 82, 99, 121, 134, 152, 161, 189, 214, 223, and 245 mm²) for the mass of lesions and the NP tissue.

Conclusions

In ADC measurements, the optimized ROI size is 214 mm² for the differentiation of PDAC and NP; ROI size of ≥ 99 mm² is recommended to differentiate between MFCP and NP. ADC was not useful for the differentiation of PDAC and MFCP.

Imaging modalities for characterising focal pancreatic lesions

BACKGROUND

Increasing numbers of incidental pancreatic lesions are being detected each year. Accurate characterisation of pancreatic lesions into benign, precancerous, and cancer masses is crucial in deciding whether to use treatment or surveillance. Distinguishing benign lesions from precancerous and cancerous lesions can prevent patients from undergoing unnecessary major surgery. Despite the importance of accurately classifying pancreatic lesions, there is no clear algorithm for management of focal pancreatic lesions.

OBJECTIVES

To determine and compare the diagnostic accuracy of various imaging modalities in detecting cancerous and precancerous lesions in people with focal pancreatic lesions.

SEARCH METHODS

We searched the CENTRAL, MEDLINE, Embase, and Science Citation Index until 19 July 2016. We searched the references of included studies to identify further studies. We did not restrict studies based on language or publication status, or whether data were collected prospectively or retrospectively.

SELECTION CRITERIA

We planned to include studies reporting cross-sectional information on the index test (CT (computed tomography), MRI (magnetic resonance imaging), PET (positron emission tomography), EUS (endoscopic ultrasound), EUS elastography, and EUS-guided biopsy or FNA (fine-needle aspiration)) and reference standard (confirmation of the nature of the lesion was obtained by histopathological examination of the entire lesion by surgical excision, or histopathological examination for confirmation of precancer or cancer by biopsy and clinical follow-up of at least six months in people with negative index tests) in people with pancreatic lesions irrespective of language or publication status or whether the data were collected prospectively or retrospectively.

DATA COLLECTION AND ANALYSIS

Two review authors independently searched the references to identify relevant studies and extracted the data. We planned to use the bivariate analysis to calculate the summary sensitivity and specificity with their 95% confidence intervals and the hierarchical summary receiver operating characteristic (HSROC) to compare the tests and assess heterogeneity, but used simpler models (such as univariate random-effects model and univariate fixed-effect model) for combining studies when appropriate because of the sparse data. We were unable to compare the diagnostic performance of the tests using formal statistical methods because of sparse data.

MAIN RESULTS

We included 54 studies involving a total of 3,196 participants evaluating the diagnostic accuracy of various index tests. In these 54 studies, eight different target conditions were identified with different final diagnoses constituting benign, precancerous, and cancerous lesions. None of the studies was of high methodological quality. None of the comparisons in which single studies were included was of sufficiently high methodological quality to warrant highlighting of the results. For differentiation of cancerous lesions from benign or precancerous lesions, we identified only one study per index test. The second analysis, of studies differentiating cancerous versus benign lesions, provided three tests in which meta-analysis could be performed. The sensitivities and specificities for diagnosing cancer were: EUS-FNA: sensitivity 0.79 (95% confidence interval (CI) 0.07 to 1.00), specificity 1.00 (95% CI 0.91 to 1.00); EUS: sensitivity 0.95 (95% CI 0.84 to 0.99), specificity 0.53 (95% CI 0.31 to 0.74); PET: sensitivity 0.92 (95% CI 0.80 to 0.97), specificity 0.65 (95% CI 0.39 to 0.84). The third analysis, of studies differentiating precancerous or cancerous lesions from benign lesions, only provided one test (EUS-FNA) in which meta-analysis was performed. EUS-FNA had moderate sensitivity for diagnosing precancerous or cancerous lesions (sensitivity 0.73 (95% CI 0.01 to 1.00) and high specificity 0.94 (95% CI 0.15 to 1.00), the extremely wide confidence intervals reflecting the heterogeneity between the studies). The fourth analysis, of studies differentiating cancerous (invasive carcinoma) from precancerous (dysplasia) provided three tests in which meta-analysis was performed. The sensitivities and specificities for diagnosing invasive carcinoma were: CT: sensitivity 0.72 (95% CI 0.50 to 0.87), specificity 0.92 (95% CI 0.81 to 0.97); EUS: sensitivity 0.78 (95% CI 0.44 to 0.94), specificity 0.91 (95% CI 0.61 to 0.98); EUS-FNA: sensitivity 0.66 (95% CI 0.03 to 0.99), specificity 0.92 (95% CI 0.73 to 0.98). The fifth analysis, of studies differentiating cancerous (high-grade dysplasia or invasive carcinoma) versus precancerous (low- or intermediate-grade dysplasia) provided six tests in which meta-analysis was performed. The sensitivities and specificities for diagnosing cancer (high-grade dysplasia or invasive carcinoma) were: CT: sensitivity 0.87 (95% CI 0.00 to 1.00), specificity 0.96 (95% CI 0.00 to 1.00); EUS: sensitivity 0.86 (95% CI 0.74 to 0.92), specificity 0.91 (95% CI 0.83 to 0.96); EUS-FNA: sensitivity 0.47 (95% CI 0.24 to 0.70), specificity 0.91 (95% CI 0.32 to 1.00); EUS-FNA carcinoembryonic antigen 200 ng/mL: sensitivity 0.58 (95% CI 0.28 to 0.83), specificity 0.51 (95% CI 0.19 to 0.81); MRI: sensitivity 0.69 (95% CI 0.44 to 0.86), specificity 0.93 (95% CI 0.43 to 1.00); PET: sensitivity 0.90 (95% CI 0.79 to 0.96), specificity 0.94 (95% CI 0.81 to 0.99). The sixth analysis, of studies differentiating cancerous (invasive carcinoma) from precancerous (low-grade dysplasia) provided no tests in which meta-analysis was performed. The seventh analysis, of studies differentiating precancerous or cancerous (intermediate- or high-grade dysplasia or invasive carcinoma) from precancerous (low-grade dysplasia) provided two tests in which meta-analysis was performed. The sensitivity and specificity for diagnosing cancer were: CT: sensitivity 0.83 (95% CI 0.68 to 0.92), specificity 0.83 (95% CI 0.64 to 0.93) and MRI: sensitivity 0.80 (95% CI 0.58 to 0.92), specificity 0.81 (95% CI 0.53 to 0.95), respectively. The eighth analysis, of studies differentiating precancerous or cancerous (intermediate- or high-grade dysplasia or invasive carcinoma) from precancerous (low-grade dysplasia) or benign lesions provided no test in which meta-analysis was performed.There were no major alterations in the subgroup analysis of cystic pancreatic focal lesions (42 studies; 2086 participants). None of the included studies evaluated EUS elastography or sequential testing.

AUTHORS' CONCLUSIONS

We were unable to arrive at any firm conclusions because of the differences in the way that study authors classified focal pancreatic lesions into cancerous, precancerous, and benign lesions; the inclusion of few studies with wide confidence intervals for each comparison; poor methodological quality in the studies; and heterogeneity in the estimates within comparisons.

Diagnostic performance of imaging modalities in chronic pancreatitis: a systematic review and meta-analysis

OBJECTIVES

Obtain summary estimates of sensitivity and specificity for imaging modalities for chronic pancreatitis (CP) assessment.

METHODS

A systematic search was performed in Cochrane Library, MEDLINE, Embase and CINAHL databases for studies evaluating imaging modalities for the diagnosis of CP up to September 2016. A bivariate random-effects modeling was used to obtain summary estimates of sensitivity and specificity.

RESULTS

We included 43 studies evaluating 3460 patients. Sensitivity of endoscopic retrograde cholangiopancreatography (ERCP) (82%; 95%CI: 76%-87%) was significant higher than that of abdominal ultrasonography (US) (67%; 95%CI: 53%-78%; P=0.018). The sensitivity estimates of endoscopic ultrasonography (EUS), magnetic resonance imaging (MRI), and computed tomography (CT) were 81% (95%CI: 70%-89%), 78% (95%CI: 69%-85%), and 75% (95%CI: 66%-83%), respectively, and did not differ significantly from each other. Estimates of specificity were comparable for EUS (90%; 95%CI: 82%-95%), ERCP (94%; 95%CI: 87%-98%), CT (91%; 95% CI: 81%-96%), MRI (96%; 95%CI: 90%-98%), and US (98%; 95%CI: 89%-100%).

CONCLUSIONS

EUS, ERCP, MRI and CT all have comparable high diagnostic accuracy in the initial diagnosis of CP. EUS and ERCP are outperformers and US has the lowest accuracy. The choice of imaging modality can therefore be made based on invasiveness, local availability, experience and costs.

KEY POINTS

• EUS, ERCP, MRI and CT have high diagnostic sensitivity for chronic pancreatitis • Diagnostic specificity is comparable for all imaging modalities • EUS and ERCP are outperformers and US has the lowest accuracy • The choice of imaging can be made based on clinical considerations.

Differentiation of pancreatic carcinoma and mass-forming focal pancreatitis: qualitative and quantitative assessment by dynamic contrast-enhanced MRI combined with diffusion-weighted imaging

Differentiation between pancreatic carcinoma (PC) and mass-forming focal pancreatitis (FP) is invariably difficult. For the differential diagnosis, we qualitatively and quantitatively assessed the value of dynamic contrast-enhanced MRI (DCE-MRI) and diffusion-weighted imaging (DWI) in PC and FP in the present study. This study included 32 PC and 18 FP patients with histological confirmation who underwent DCE-MRI and DWI. The time-signal intensity curve (TIC) of PC and FP were classified into 5 types according to the time of reaching the peak, namely, type I, II, III, IV, and V, respectively, and two subtypes, namely, subtype-a (washout type) and subtype-b (plateau type) according to the part of the TIC profile after the peak. Moreover, the mean and relative apparent diffusion coefficient (ADC) value between PC and FP on DWI were compared. The type V TIC was only recognized in PC group (P < 0.01). Type IV b were more frequently observed in PC (P = 0.036), while type- IIa (P < 0.01), type- Ia (P = 0.037) in FP. We also found a significant difference in the mean and relative ADC value between PC and FP. The combined image set of DCE-MRI and DWI yielded an excellent sensitivity, specificity, and diagnostic accuracy (96.9%, 94.4%, and 96.0%). The TIC of DCE-MRI and ADC value of DWI for pancreatic mass were found to provide reliable information in differentiating PC from FP, and the combination of DCE-MRI and DWI can achieve a higher sensitivity, specificity, and diagnostic accuracy.

Early detection of pancreatic cancer: impact of high-resolution imaging methods and biomarkers

High-resolution imaging methods (HRIMs) and biomarkers present the second step of pancreatic cancer (PC) diagnostics in at-risk individuals. These include patients with positive risk factors, early symptoms, nonresponders to the initial antidiabetic therapy, patients older than 50 years of age with new-onset unstable diabetes requiring insulin as well as patients with long-term insulin-non-dependent diabetes and recent (up to 6 months) failure of antidiabetic therapy. The procedures should be started without delay and the co-operation between the primary and tertiary medical centers is highly desirable. An early indication of HRIMs and biomarkers is a prerequisite for the diagnosis of a resectable PC. This publication reviews the recent contribution of HRIMs and biomarkers toward an early diagnosis of PC.

Distinguishing benign from malignant main duct intraductal papillary mucinous neoplasms of the pancreas by multislice helical computed tomography

Main duct intraductal papillary mucinous neoplasms (MD-IPMNs) of the pancreas are located in the dilated main pancreatic duct and associated with mucin overproduction. They may have a high degree of malignancy and lack specific clinical manifestations. With advantages of thin slice thickness, high resolution, multi-phase dynamic scan and multiple post-processing techniques, multislice helical computed tomography (MSCT) can accurately diagnose and differentiate malignant from benign MD-IPMNs. This paper will review the current advances in differentiating malignant from benign MD-IPMNs by MSCT.

Pancreatic cancer: diagnosis and treatments

Pancreatic cancer is one of the deadliest cancers, with exceptionally high mortality. Despite the relatively low incidence rate (10th), it is the fourth leading cause of cancer-related deaths in most developed countries. To improve the early diagnosis of pancreatic cancer and strengthen the standardized comprehensive treatment are still the main focus of pancreatic cancer research. Here, we summarized the rapid developments in the diagnosis and treatments of pancreatic cancer. Regarding diagnosis, we reviewed advances in medical imaging technology, tumor markers, molecular biology (e.g., gene mutation), and proteomics. Moreover, great progress has also been made in the treatments of this disease, including surgical resection, chemotherapy, targeted radiotherapy, targeted minimally invasive treatment, and molecular targeted therapy. Therefore, we also recapitulated the development, advantages, and disadvantages of each of the treatment methods in this review.

Role of endoscopic ultrasound in the diagnosis of pancreatic cancer

Endoscopic ultrasonography (EUS) with or without fine needle aspiration has become the main technique for evaluating pancreatobiliary disorders and has proved to have a higher diagnostic yield than positron emission tomography, computed tomography (CT) and transabdominal ultrasound for recognising early pancreatic tumors. As a diagnostic modality for pancreatic cancer, EUS has proved rates higher than 90%, especially for lesions less than 2-3 cm in size in which it reaches a sensitivity rate of 99% vs 55% for CT. Besides, EUS has a very high negative predictive value and thus EUS can reliably exclude pancreatic cancer. The complication rate of EUS is as low as 1.1%-3.0%. New technical developments such as elastography and the use of contrast agents have recently been applied to EUS, improving its diagnostic capability. EUS has been found to be superior to the recent multidetector CT for T staging with less risk of overstaying in comparison to both CT and magnetic resonance imaging, so that patients are not being ruled out of a potentially beneficial resection. The accuracy for N staging with EUS is 64%-82%. In unresectable cancers, EUS also plays a therapeutic role by means of treating oncological pain through celiac plexus block, biliary drainage in obstructive jaundice in patients where endoscopic retrograde cholangiopancreatography is not affordable and aiding radiotherapy and chemotherapy.

Quantified ADC histogram analysis: a new method for differentiating mass-forming focal pancreatitis from pancreatic cancer

BACKGROUND

As their prognosis and management are different, differentiation of mass-forming focal pancreatitis (FP) from pancreatic adenocarcinoma (PC) is important. However, the similar clinical presentations and imaging features of these conditions, along with inconclusive biopsy results can make such differentiation difficult.

PURPOSE

To determine whether apparent diffusion coefficient (ADC) histogram analysis can discriminate between a normal pancreas, FP, and PC.

MATERIAL AND METHODS

In a retrospective study, 25 PC patients, 14 FP patients, and 25 subjects with a normal pancreas underwent breath-hold diffusion-weighted imaging (DWI) on a 3.0 T magnetic resonance (MR) scanner. Regions of interest (ROIs) were drawn on the normal pancreases and on the entire focal lesions of both PC and FP. The ADC value was averaged from the lowest to 10th, 30th, 50th, and 100th percentile of the histogram (i.e. ADC10, ADC30, ADC50, and ADC100, respectively), and the results were analyzed statistically.

RESULTS

There were no significant differences among the head, body, and tail of normal pancreases for any of the mean ADC values (P > 0.05). ADC10, ADC30, and ADC50 values demonstrated significant differences between lesion and non-lesion areas of both PC (P < 0.05) and FP (P < 0.05). Differences in lesion areas between PC and FP were found with ADC50 and ADC100 values (P < 0.05), and helped differentiate a normal pancreas from FP and PC, and FP from PC.

CONCLUSION

Quantified ADC histogram can specifically reflect tissue heterogeneity and help differentiate a normal pancreas from FP and PC.

Strategies for early detection of resectable pancreatic cancer

Pancreatic cancer is difficult to diagnose at an early stage and generally has a poor prognosis. Surgical resection is the only potentially curative treatment for pancreatic carcinoma. To improve the prognosis of this disease, it is essential to detect tumors at early stages, when they are resectable. The optimal approach to screening for early pancreatic neoplasia has not been established. The International Cancer of the Pancreas Screening Consortium has recently finalized several recommendations regarding the management of patients who are at an increased risk of familial pancreatic cancer. In addition, there have been notable advances in research on serum markers, tissue markers, gene signatures, and genomic targets of pancreatic cancer. To date, however, no biomarkers have been established in the clinical setting. Advancements in imaging modalities touch all aspects of the clinical management of pancreatic diseases, including the early detection of pancreatic masses, their characterization, and evaluations of tumor resectability. This article reviews strategies for screening high-risk groups, biomarkers, and current advances in imaging modalities for the early detection of resectable pancreatic cancer.

Diagnostic evaluation of solid pancreatic masses

Determining the etiology of a solid pancreatic lesion is a critical first step toward developing an appropriate treatment plan for patients with a benign or malignant pancreatic mass. Technological advances in cross-sectional and endoscopic imaging modalities offer pancreatic imaging options with degrees of resolution that were not available even 15-20 years ago. In most cases, the nature of a solid pancreatic mass can be determined using computerized tomography, magnetic resonance imaging, and endoscopic ultrasound with fine-needle aspiration. Knowledge about the basics of these modalities, as well as their strengths and limitations, plays an important role in understanding how patients with solid pancreatic masses should be evaluated.

Multimodality imaging of pancreatic cancer-computed tomography, magnetic resonance imaging, and positron emission tomography

Pancreatic adenocarcinoma continues to have a dismal prognosis, with curative surgery (resection with negative margins) possible in only a small percentage of patients. Not only does radiological imaging play a major role in diagnosing the primary lesion at presentation, but it is also crucial for staging of locoregional disease and distant metastases, both of which are critical for selecting appropriate candidates for surgery. Over the last 2 decades, computed tomography has become the dominant imaging modality for both the diagnosis and staging of pancreatic cancer, with advances in multidetector computed tomography technology improving the ability to identify small tumors and demonstrate subtle degrees of vascular involvement by tumor. However, magnetic resonance imaging and positron emission tomography are now playing an increasing role in pancreatic cancer imaging. These 3 imaging modalities each have specific strengths and benefits and should be used in a complementary fashion.

Multimodality imaging of pancreatic ductal adenocarcinoma: a review of the literature

BACKGROUND

Accurate pre-operative imaging in pancreatic cancer helps avoid unsuccessful surgical explorations and forewarns surgeons regarding aberrant anatomy. This review aimed to determine the role of current imaging modalities in the diagnosis and determination of resectability of pancreatic and peri-ampullary adenocarcinomas.

METHODS

A systematic search of the scientific literature was carried out using EMBASE, PubMed/MEDLINE and the Cochrane Central Register of Controlled Trials for the years 1990 to 2011 to obtain access to all publications, especially randomized controlled trials, reporting on the diagnostic accuracy of ultrasonography, multi-detector computed tomography (MDCT), magnetic resonance imaging (MRI), endoscopic ultrasonography (EUS) or positron emission tomography (PET)-computed tomography (CT) and the evaluation of resectability of pancreatic and peri-ampullary adenocarcinomas.

RESULTS

Based on 66 articles analysed in the review, MDCT and MRI/MRCP have comparable sensitivity and specificity rates for diagnosis and staging of pancreatic cancers. EUS offers the best sensitivity and specificity rates for lesions <2 cm. Improved staging has been noted when PET-CT scans are added to pre-operative evaluation.

CONCLUSIONS

MDCT with angiography or MRI/MRCP should constitute the first imaging modality in suspected pancreatic adenocarcinomas. EUS is recommended for assessing lesions not clearly detected, but suspected, on CT/MRI and in tumours considered 'borderline resectable' on MDCT to assess vascular involvement. PET-CT in locally advanced lesions will help rule out distant metastases.

[Diffusion-weighted MR imaging; the significance of ADC and perfusion values in the differential diagnosis of pancreatic adenocarcinoma and mass forming pancreatitis]

Despite the increasing diagnostic accuracy of cross sectional imaging modalities, the correct differentiation between pancreatic adenocarcinoma and mass forming pancreatitis has remained a challenge.

AIM

Based on their 2 and ½ -year experience, the aim of the authors was to assess the clinical utility of diffusion-weighted magnetic resonance imaging in the diagnosis and discernment of pancreatic adenocarcinoma and mass forming pancreatitis.

METHODS

3 b-values diffusion-weighted magnetic resonance examinations were performed in 19 patients suffering from adenocarcinoma and in 8 patients with pancreatitis. 12 healthy patients were examined as reference. Apparent diffusion coefficient and perfusion values were calculated. Malignancy was verified by pathology in all cases. An inflammatory disease was diagnosed on the basis of previous medical history, changes in laboratory values, follow-up computer tomographic examinations and improvement in the patients' condition.

RESULTS

Comparison of the apparent diffusion coefficient and perfusion values revealed significant differences between healthy pancreatic tissues and those affected by inflammation or tumor. The highest apparent diffusion coefficient and perfusion values were detected in the normal pancreas. Mass forming pancreatitis had diminished the apparent diffusion coefficient and perfusion values, whereas these values were the lowest in tumorous tissues.

CONCLUSION

In agreement with literature data, the authors conclude that diffusion-weighted magnetic resonance imaging is a promising differential-diagnostic imaging tool in the distinction of circumscribed pancreatic lesions.

Low tube voltage CT for improved detection of pancreatic cancer: detection threshold for small, simulated lesions

BACKGROUND

Pancreatic ductal adenocarcinoma is associated with dismal prognosis. The detection of small pancreatic tumors which are still resectable is still a challenging problem.The aim of this study was to investigate the effect of decreasing the tube voltage from 120 to 80 kV on the detection of pancreatic tumors.

METHODS

Three scanning protocols was used; one using the standard tube voltage (120 kV) and current (160 mA) and two using 80 kV but with different tube currents (500 and 675 mA) to achieve equivalent dose (15 mGy) and noise (15 HU) as that of the standard protocol.Tumors were simulated into collected CT phantom images. The attenuation in normal parenchyma at 120 kV was set at 130 HU, as measured previously in clinical examinations, and the tumor attenuation was assumed to differ 20 HU and was set at 110HU. By scanning and measuring of iodine solution with different concentrations the corresponding tumor and parenchyma attenuation at 80 kV was found to be 185 and 219 HU, respectively.To objectively evaluate the differences between the three protocols, a multi-reader multi-case receiver operating characteristic study was conducted, using three readers and 100 cases, each containing 0-3 lesions.

RESULTS

The highest reader averaged figure-of-merit (FOM) was achieved for 80 kV and 675 mA (FOM=0,850), and the lowest for 120 kV (FOM=0,709). There was a significant difference between the three protocols (p<0,0001), when making an analysis of variance (ANOVA). Post-hoc analysis (students t-test) shows that there was a significant difference between 120 and 80 kV, but not between the two levels of tube currents at 80 kV.

CONCLUSION

We conclude that when decreasing the tube voltage there is a significant improvement in tumor conspicuity.

Malignant pancreatic tumors in children: a single-institution series

BACKGROUND

Pancreatic tumors in children represent a very rare entity. We reviewed the clinical and pathologic features of pediatric patients with pancreatic tumors at a single institution.

METHODS

We conducted a retrospective review of cases diagnosed at the Hospital for Sick Children between 1986 and 2010.

RESULTS

Twenty-seven patients were diagnosed during the study period: 18 with solid pseudopapillary neoplasm (SPN), 6 with pancreatic endocrine neoplasia, and 3 with other tumors. Of the 27 children, 3 had associated syndromes, in specific tuberous sclerosis, von Hippel-Lindau, and polycystic ovarian syndrome. The most common symptoms were pain and vomiting in SPN and hypoglycemia and seizures in insulinomas. Magnetic resonance imaging and computed tomographic scan were equally accurate in determining size and site of origin of the tumor, and both were better than ultrasound. All patients underwent surgery (distal pancreatectomy in 14 cases, Whipple procedure in 8, other procedures in 5), which represented the only treatment for all but 3 cases. Seventeen patients (94%) with SPN are alive (median follow-up, 32 months), 3 of whom had positive margins. Two patients died: 1 male with SPN with malignant transformation and 1 with fibrosarcoma.

CONCLUSIONS

We describe the largest single-institution study of pediatric pancreatic tumors. Females with SPN have an excellent outcome, even in presence of positive margins, suggesting that limited surgical resection may be appropriate for these patients.

Value of diffusion-weighted imaging for the discrimination of pancreatic lesions: a meta-analysis

OBJECTIVE

We aimed to explore the role of diffusion-weighted imaging (DWI) in the discrimination of pancreatic lesions through meta-analysis.

METHODS

The MEDLINE, EMBASE, Cancerlit, and Cochrane Library databases, from January 2001 to August 2011, were searched for studies evaluating the diagnostic performance of DWI in the discrimination of pancreatic lesions. We determined sensitivities and specificities across studies, calculated positive and negative likelihood ratios (LR+ and LR-), and constructed summary receiver operating characteristic curves.

RESULTS

A total of 11 studies with 586 patients, who fulfilled all of the inclusion criteria, were considered for the analysis. No publication bias was found. The pooled sensitivity of DWI was 0.86 [95% (confidence interval (CI), 0.78, 0.91] and the pooled specificity was 0.91 (95% CI, 0.81, 0.96). Overall, LR+ was 9.8 (95% CI, 4.1, 23.3) and LR- was 0.15 (95% CI, 0.09, 0.26). The area under the curve of the summary receiver operating characteristic was 0.94 (95% CI, 0.91-0.96). In subgroup analysis, prospectively designed studies had the highest pooled sensitivity (0.87, 95% CI 0.75, 0.94) and specificity (0.96, 95% CI 0.91, 0.99) (P<0.05). Study sensitivity was not correlated with the prevalence of pancreatic lesions (R=0.1076, P=0.3247).

CONCLUSION

A limited number of small studies suggest that DWI is a potentially technically feasible measure to differentiate malignant from benign pancreatic lesions. However, it is still controversial and is limited in that it can only distinguish certain lesions. High-quality prospective studies on DWI for the discrimination of pancreatic lesions still need to be conducted.

Pancreatic cancer: an endoscopic perspective

Pancreatic cancer continues to be a diagnostic and therapeutic challenge. The advent of endoscopic ultrasound-guided interventions have brought about a paradigm shift in the endoscopic approach to diagnosis, treatment and palliation of this common malignancy. The last decade has witnessed significant advances in techniques of endoscopic biliary drainage, endoluminal stenting, celiac plexus neurolysis and image-guided radiation therapy, which have transformed the scope of palliation in pancreatic cancer. Moreover, endoscopic ultrasound-aided intratumoral delivery of fiducials, radioisotopes and chemotherapeutic agents have shown promising results and warrant further investigation. This review summarizes the recent advances in endoscopic applications for the management of pancreatic neoplasms.

Surgery for pancreatic carcinoma: state of the art

Carcinoma of the pancreas remains a malignancy with a generally dismal outcome owing to the delayed presentation of the disease. To date, surgery affords the best outcomes when a complete resection can be achieved. Improvements in imaging, surgical techniques and adjuvant therapies are perceived advancements in the management of this cancer. This article reviews the latest evidence in terms of the diagnosis and management of pancreatic cancer.

Clinical usefulness of diffusion-weighted MR imaging for detection of pancreatic cancer: comparison with enhanced multidetector-row CT

PURPOSE

The aim of this study was to compare diffusion-weighted magnetic resonance imaging (DWI) and multidetector-row computed tomography (MDCT) for detection of primary pancreatic cancer by reviewing images of patients at high risk for pancreatic cancer with main pancreatic duct (MPD) dilatation shown by magnetic resonance cholangiopancreatography (MRCP).

METHODS

From October 2007 to September 2009, 83 patients who had undergone both DWI and MDCT with MPD dilatation were identified and were reviewed by four readers (2 radiologists and 2 gastroenterology fellows). Diagnostic performance in pancreatic cancer detection was evaluated with 95% confidence intervals. Statistically significant differences in the detection of pancreatic cancer between DWI and MDCT were compared by receiver operating characteristics and the confidence of the diagnosis by the paired t test.

RESULTS

Thirty-two of 83 patients were diagnosed with primary pancreatic cancer by histological evaluation of 15 surgical and 2 endoscopic ultrasound-guided fine needle aspiration samples, and by the clinical course for 15 lesions. Overall average accuracies of pancreatic cancer detection by the four readers were 84% with DWI and 86% with MDCT.

CONCLUSION

Performance of DWI and MDCT was equivocal for detection of pancreatic cancer in a high-risk population with MPD dilatation. The combination of MRCP and DWI for detection of pancreatic cancer allowed identification of a high-risk population and tumor detection with a single imaging modality with no need for contrast medium.

Differentiation between pancreatic carcinoma and mass-forming chronic pancreatitis: usefulness of high b value diffusion-weighted imaging

OBJECTIVE

To investigate the value of high b value diffusion-weighted (DW) imaging in differentiating between pancreatic carcinoma and mass-forming chronic pancreatitis (MFCP).

METHODS

Fifty-one consecutive patients with pathology-proven pancreatic carcinoma (n = 37) or MFCP (n = 14) were evaluated with DW imaging (b value, 0 and 1000 s/mm(2)) at a 3-T MR system. Overall 20 healthy volunteers were evaluated as the control group. The apparent diffusion coefficient (ADC) values of normal pancreas, pancreatic carcinoma, MFCP, and mass-associated obstructive pancreatitis were measured.

RESULTS

On high b value (1000 s/mm(2) ) DW images, both pancreatic carcinoma and MFCP were hyperintense focal lesions; mass-associated obstructive pancreatitis occurred in 17 of 37 (45.9%) pancreatic carcinoma and 8 of 14 (57.1%) MFCP. The ADC (×10(-3) mm(2) /s) of the pancreatic carcinomas (1.06 ± 0.15) was significantly lower than that of normal pancreas (1.47 ± 0.18; P < 0.01), MFCP (1.35 ± 0.14; P < 0.01) and mass-associated chronic pancreatitis (1.44 ± 0.17; P < 0.01). The ADC of MFCP was also lower than that in the normal pancreas (P = 0.025), whereas the ADC of mass-associated obstructive pancreatitis was not different from those of the MFCP (P = 0.113) and normal pancreas (P = 0.544). When 1.195 was used as the optimal cut-off value, ADC quantification obtained a sensitivity of 85.7% and a specificity of 86.5% for differentiating pancreatic carcinomas from MFCP.

CONCLUSION

High b value DW imaging in combination with ADC quantification at a 3-T MR system is useful in differentiating between pancreatic carcinoma and MFCP.

Endoscopic ultrasound staging and guided fine needle aspiration biopsy in patients with resectable pancreatic malignancies: a single-center prospective experience

BACKGROUND

Endoscopic ultrasound staging and guided fine needle aspiration biopsy (EUS-FNA) is a highly accurate diagnostic method, useful in characterizing pancreatic lesions, obtaining definitive tissue diagnosis in patients with suspected pancreatic lesions, and providing accurate locoregional staging that enhances diagnostic certainty and evaluation of appropriateness of surgical intervention. The aims of this study were to evaluate the preoperative contribution of EUS staging and EUS-FNA in patients with suspected resectable pancreatic malignancies.

PATIENTS AND METHODS

A prospective study was conducted in a tertiary referral center. During a 54-month period, a total of 103 consecutive patients were prospectively evaluated with EUS and EUS-FNA. Enrolled in the study were patients with resectable pancreatic lesions, who underwent surgery.

RESULTS

The overall operating characteristics of EUSFNA were sensitivity 96.7%, specificity 90.0%, positive predictive value 98.9%, negative predictive value 75.0%, and diagnostic accuracy 96.1%.

CONCLUSION

EUS and EUS-FNA have a high accuracy and positive predictive value in the preoperative determination of resectability in pancreatic cancer.

Enhancing pancreatic adenocarcinoma delineation in diffusion derived intravoxel incoherent motion f-maps through automatic vessel and duct segmentation

Diffusion-based intravoxel incoherent motion imaging has recently gained interest as a method to detect and characterize pancreatic lesions, especially as it could provide a radiation- and contrast agent-free alternative to existing diagnostic methods. However, tumor delineation on intravoxel incoherent motion-derived parameter maps is impeded by poor lesion-to-pancreatic duct contrast in the f-maps and poor lesion-to-vessel contrast in the D-maps. The distribution of the diffusion and perfusion parameters within vessels, ducts, and tumors were extracted from a group of 42 patients with pancreatic adenocarcinoma. Clearly separable combinations of f and D were observed, and receiver operating characteristic analysis was used to determine the optimal cutoff values for an automated segmentation of vessels and ducts to improve lesion detection and delineation on the individual intravoxel incoherent motion-derived maps. Receiver operating characteristic analysis identified f = 0.28 as the cutoff for vessels (Area under the curve (AUC) = 0.901) versus tumor/duct and D = 1.85 μm(2) /ms for separating duct from tumor tissue (AUC = 0.988). These values were incorporated in an automatic segmentation algorithm and then applied to 42 patients. This yielded clearly improved tumor delineation compared to individual intravoxel incoherent motion-derived maps. Furthermore, previous findings that indicated that the f value in pancreatic cancer is strongly reduced compared to healthy pancreatic tissue were reconfirmed.

Diagnostic management of pancreatic cancer

Pancreatic cancer is one of the most deadly solid tumors, with an overall 5-year survival rate of less than 5%. Due to a non-specific clinical presentation, it is often diagnosed at an advanced stage and is rarely amenable for curative treatment. Therefore early diagnosis and appropriate staging are still essential to define the best care and to improve patient survival. Several imaging modalities are currently available for the evaluation of pancreatic cancer. This review focuses on different techniques and discusses the diagnostic management of patients with pancreatic cancer. This review was conducted utilizing Pubmed and was limited to papers published within the last 5 years. The search key words pancreatic cancer, pancreatic adenocarcinoma, pancreatic tumors, diagnosis, radiology, imaging, nuclear imaging, endoscopy, endoscopic ultrasound and biochemical markers were used.