Differentiation of noncalculous periampullary obstruction: comparison of CT with negative-contrast CT cholangiopancreatography versus MRI with MR cholangiopancreatography

Application of imaging technology for the diagnosis of malignancy in the pancreaticobiliary duodenal junction (Review)

The pancreaticobiliary duodenal junction (PBDJ) is the connecting area of the pancreatic duct, bile duct and duodenum. In a broad sense, it refers to a region formed by the head of the pancreas, the pancreatic segment of the common bile duct and the intraduodenal segment, the descending and the horizontal part of the duodenum, and the soft tissue around the pancreatic head. In a narrow sense, it refers to the anatomical Vater ampulla. Due to its complex and variable anatomical features, and the diversity of pathological changes, it is challenging to make an early diagnosis of malignancy at the PBDJ and define the histological type. The unique anatomical structure of this area may be the basis for the occurrence of malignant tumors. Therefore, understanding and subclassifying the anatomical configuration of the PBDJ is of great significance for the prevention and treatment of malignant tumors at their source. The present review comprehensively discusses commonly used imaging techniques and other new technologies for diagnosing malignancy at the PBDJ, offering evidence for physicians and patients to select appropriate examination methods.

Evaluation of three-dimensional dual-energy CT cholangiopancreatography image quality in patients with pancreatobiliary dilatation: Comparison with conventional single-energy CT

Objective

This study aimed to evaluate three-dimensional (3D) negative-contrast CT cholangiopancreatography (nCTCP) image quality using dual-energy CT (DECT) with iterative reconstruction (IR) technique in patients with pancreatobiliary dilatation compared with single-energy CT (SECT).

Methods

Of the patients, 67 and 56 underwent conventional SECT (SECT set) and DECT with IR technique (DECT set), respectively. All patients were retrospectively analyzed during the portal phase to compare objective image quality and other data including patient demographics, hepatic and pancreatic parenchymal enhancement, noise, and attenuation difference (AD) between dilated ducts and enhanced hepatic parenchyma, signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), and CT volume dose index (CTDIvol). Two radiologists used the five-point Likert scale to evaluate the subjective image quality of 3D nCTCP regarding image noise, sharpness of dilated ducts, and overall image quality. Statistical analyses used the Mann-Whitney U test.

Results

No significant difference in patient demographics in either CT set was showed during objective evaluation (p > 0.05). However, higher hepatic and pancreatic parenchymal enhancement, AD, SNR, and CNR and lower hepatic and pancreatic noise (p < 0.005) as well as CTDIvol (p = 0.005) on DECT than on SECT were observed. Higher mean grades on DECT than on SECT were showed for image noise (4.65 vs 3.92), sharpness of dilated ducts (4.52 vs 3.94), and overall image quality (4.45 vs 3.91; p < 0.001), respectively during subjective evaluation.

Conclusion

A higher overall image quality and lower radiation dose on 3D nCTCP can be obtained by DECT with IR technique than with conventional SECT in patients with pancreatobiliary dilatation.

Role of endoscopic ultrasound in the evaluation of unexplained extrahepatic bile duct dilatation

OBJECTIVE

This study was performed to assess the diagnostic performance of endoscopic ultrasonography (EUS) in patients with extrahepatic bile duct (EBD) dilatation and develop a novel model incorporating EUS-based signature with clinical parameters for distinguishing the malignant dilation of EBD.

METHODS

The EUS data and clinical parameters of the patients were collected and analyzed retrospectively. First, we evaluated the diagnostic performance of EUS in detecting the cause of EBD dilatation. Then, we performed univariate and multivariate binary logistic regression analyses based on clinical and EUS features. Finally, a nomogram was established to aid in distinguishing between malignant dilation and noncalculous benign dilatation of EBD in patients.

RESULTS

A total of 184 patients were enrolled. For the diagnosis of malignant dilation, EUS achieved an accuracy of 90.76%, sensitivity of 85.96%, and specificity of 92.91%. For the diagnosis of calculous dilation, EUS achieved an accuracy of 100%, sensitivity of 100%, and specificity of 100%. For the diagnosis of noncalculous benign dilatation, EUS achieved an accuracy of 90.76%, sensitivity of 90.90%, and specificity of 90.58%. Multivariable logistic regression analyses indicated that abnormal liver function test, elevated tumor markers, and EUS findings were the well-diagnostic factors of malignant EBD dilation. The nomogram established by these factors showed good calibration and discrimination.

CONCLUSION

EUS is a useful examinational modality in the work-up of EBD dilatation. In combination with abnormal liver function test and elevated tumor markers, EUS may provide additional information for the detection of malignant dilation of EBD and should be further investigated.

Preoperative evaluation of malignant pancreatobiliary obstruction: A novel technique for multiphase fusion 3D CT images

The purpose of this article is to describe a novel technique of multiphase fusion three-dimensional (3D) images in patients with malignant pancreatobiliary obstruction. Multiphase fusion 3D images of CT arteriography, portovenography and hepatic venography combined with negative-contrast CT cholangiopancreatography can be done with enhanced multiphase CT scan using intravenous contrast agent at once. This technique may be feasible for one-stop evaluation of malignant pancreatobiliary obstruction.

Diffusion-weighted image improves detectability of magnetic resonance cholangiopancreatography for pancreatic ductal adenocarcinoma concomitant with intraductal papillary mucinous neoplasm

The present study is aimed to clarify the utility of magnetic resonance cholangiopancreatography (MRCP) and the additional value of diffusion-weighted imaging (DWI) in diagnosing pancreatic ductal adenocarcinoma (PDAC) concomitant with intraductal papillary mucinous neoplasm (IPMN).This retrospective study involved 38 patients with PDAC concomitant with IPMN and 114 patients (control) who were randomly selected from 320 patients with IPMN without PDAC and were matched with cases for magnetic resonance imaging (MRI) strength (1.5 T/3.0 T). Two radiologists reviewed the 2 MR image sets with relevant clinical information blinded, first MRCP alone and then combined MRI set including DWI. Diagnostic capability and interobserver agreement were assessed by using receiver operating characteristics curve (Az) analysis and weighted κ statistics.Az values for the 2 observers were 0.834 and 0.821 for MRCP alone and 0.964 and 0.926 for the combined MRI (P < .001 and P < .001), respectively. The sensitivity of MRCP alone was 61% (23/38), with both observers failing to diagnose PDACs located at the end of tail or away from the pancreatic duct. Meanwhile, with combined MRI, sensitivity was significantly increased for both observers (61% to 92%, P = .002; 61% to 87%, P = .004). Moreover, the interobserver agreement was higher with combined MRI (κ = 0.85) than MRCP alone (κ = 0.59).MRCP and DWI might be a superior option with a higher diagnostic capability of PDAC concomitant with IPMN than MRCP alone, especially for tumors away from the pancreatic duct.

Combination of CEUS and MRI for the diagnosis of periampullary space-occupying lesions: a retrospective analysis

Background

The value of magnetic resonance imaging (MRI), contrast-enhanced ultrasound (CEUS), and the combination of CEUS and MRI (CCWM) for the diagnosis of periampullary space-occupying lesions (PSOL) was investigated.

Methods

A total of 102 patients diagnosed with PSOLs by surgery or biopsy were recruited retrospectively. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy of MRI, CEUS, and CCWM were analyzed.

Results

MRI, CEUS, and CCWM allowed for the accurate detection of 91.17, 92.15, and 99.01% of PSOLs, respectively. The specificity, PPV, and accuracy of CCWM were significantly different from MRI and CEUS (p < 0.05). However, there the sensitivity and NPV were not significantly different among the three diagnostic technologies. In addition, the specificity, PPV, and accuracy were not significantly different between MRI and CEUS (all p > 0.05).

Conclusions

CCWM is valuable for differentiating benign and malignant PSOL, which provides important guiding significances for the clinic.

Prediction of Vascular Invasion Using a 3-Point Scale Computed Tomography Grading System in Pancreatic Ductal Adenocarcinoma: Correlation With Surgery

OBJECTIVE

The aim of this study was to evaluate the correlation between a 3-point scale multidetector computed tomography (MDCT) grading system and surgical exploration in predicting vascular invasion and resectability in patients with pancreatic ductal adenocarcinoma (PDA).

METHODS

Fifty-five patients with surgical and pathologic confirmation of PDA were retrospectively analyzed by 3 radiologists independently. All patients had MDCT examination with multiplanar reformatted images, computed tomography (CT) angiography, and negative-contrast CT cholangiopancreatography (nCTCP). A 3-point scale CT grading system and criteria for unresectability adopting the latest guidelines were used in predicting the correlation between the invasion and resectability of 5 peripancreatic vessels and surgical grade and pathology.

RESULTS

Tumor location was correctly identified in all patients including 2 isodense lesions by means of nCTCP. The mean sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of MDCT were 92%, 83%, 95%, 78%, and 90%, respectively, in predicting tumor resectability compared with surgery and pathology and with good agreement (κ = 0.72-0.77). A correlation was observed between CT and surgical grade in predicting vascular invasion on a per-vessel basis, and the agreement presented as good to excellent (κ = 0.66-1.00).

CONCLUSIONS

A 3-point scale CT grading system is a simple and practical method in predicting peripancreatic vessel invasion and, importantly, correlates with surgical grade and pathology. Axial images combined with multiplanar reformation, nCTCP, and CT angiography can strengthen the comprehensive evaluation of PDA for resectability.

Presurgical Evaluation of Pancreatic Cancer: A Comprehensive Imaging Comparison of CT Versus MRI

OBJECTIVE

The purpose of this study was to compare comprehensive CT and MRI in the presurgical evaluation of pancreatic cancer.

MATERIALS AND METHODS

Thirty-eight patients with pathologically proven pancreatic cancer were included in a retrospective study. CT with negative-contrast CT cholangiopancreatography and CT angiography (CTA) (CT image set) versus MRI with MRCP and MR angiography (MRI image set) were analyzed independently by two reviewers for tumor detection, extension, metastasis, vascular invasion, and resectability. These results were compared with the surgical and pathologic findings.

RESULTS

The rate of detection of tumors was higher with MRI than with CT but not significantly so (reviewer 1, p = 1.000; reviewer 2, p = 0.500). In the evaluation of vessel involvement, nodal status, and resectability, although CT had higher ROC AUC values than did MRI (reviewer 1, 0.913 vs 0.858, 0.613 vs 0.503, and 0.866 vs 0.774; reviewer 2, 0.879 vs 0.849, 0.640 vs 0.583, and 0.830 vs 0.815), the differences were not statistically significant (p = 0.189 vs 0.494, 0.328 vs 0.244, and 0.193 vs 0.813 for reviewers 1 and 2). In the evaluation of tumor extension and organ metastases in the 38 patients, correct diagnosis of one of two liver metastases was achieved with both image sets, one case of omental and one case of peritoneal seeding were underestimated, and one case of stomach invasion was overestimated.

CONCLUSION

MRI and CT had similar performance in the presurgical evaluation of pancreatic cancer.

Differentiation of pancreatobiliary-type from intestinal-type periampullary carcinomas using 3.0T MRI

PURPOSE

To differentiate pancreatobiliary-type from intestinal-type periampullary carcinomas using combined magnetic resonance cholangiopancreatography (MRCP), contrast-enhanced MRI, and diffusion-weighted imaging (DWI).

MATERIALS AND METHODS

MRI (3.0T) results of 41 patients with pathologically confirmed periampullary carcinoma were retrospectively assessed. Two radiologists, blinded to histologic type of each tumor, evaluated image findings independently. MRCP image features, enhancement pattern, and apparent diffusion coefficient (ADC) values were analyzed. Independent-sample t-test, chi-square, or Fisher's exact test were used to determine differential image findings between the pancreatobiliary-type and the intestinal-type group. Cohen's κ statistic or interclass correlation coefficient (ICC) were used to evaluate interobserver agreement between two observers. Univariate and multiple logistic regression analysis were performed to identify MRI features with predictive values.

RESULTS

On the basis of hematoxylin-eosin staining, 27 patients were classified as having pancreatobiliary-type carcinomas, and 14 patients the intestinal type. The pancreatobiliary-type carcinomas more commonly showed progressive enhancement than the intestinal type (P = 0.003). The minimum ADC (ADCmin ) value of the pancreatobiliary-type group ([0.95 ± 0.21] × 10(-3) mm(2) /s) was significantly lower than the intestinal-type group ([1.10 ± 0.25] × 10(-3) mm(2) /s) (P = 0.047). For interobserver agreement, the κ values and ICCs for all parameters exceeded 0.8, indicating almost perfect agreement. At multiple logistic regression analysis, the enhancement pattern was the only significant independent predictor (P = 0.011, odds ratio [OR] = 0.105). When the enhancement pattern and ADCmin were used in combination, we could identify 70.4% of pancreatobiliary-type and 78.6% of intestinal-type carcinomas.

CONCLUSION

Progressive enhancement and low ADCmin values suggest a pancreatobiliary-type periampullary carcinoma.

State-of-the-art cross-sectional liver imaging: beyond lesion detection and characterization

Cross-sectional imaging with computed tomography or magnetic resonance imaging is routinely used to detect and diagnose liver lesions; however, these examinations can provide additional important information. The improvement of equipment and techniques has allowed outstanding evaluation of the vascular and biliary anatomy, which is practicable in most routine examinations. Anatomical variants may exclude patients from certain therapeutic options and may be the cause of morbidity or mortality after surgery or interventional procedures. Diffuse liver disease, such as steatosis, hemochromatosis, or fibrosis, must be diagnosed and quantified. Usually these conditions are silent until the late stages, and imaging plays an important role in detecting them early. Additionally, a background of diffuse disease may interfere in a focal lesion systematic reasoning. The diagnostic probability of a particular nodule varies according to the background liver disease. Nowadays, most diffuse liver diseases can be easily and accurately quantified by imaging, which has allowed better understanding of these diseases and improved patient management. Finally, cross-sectional imaging can calculate total and partial liver volumes and estimate the future liver remnant after hepatectomy. This information helps to select patients for portal vein embolization and reduces postoperative complications. Use of a specific hepatic contrast agent on magnetic resonance imaging, in addition to improving detection and characterization of focal lesions, provides functional global and segmental information about the liver parenchyma.