Helical CT with CT angiography in assessing periampullary neoplasms: identification of vascular invasion

Imaging Techniques and Biochemical Biomarkers: New Insights into Diagnosis of Pancreatic Cancer

Pancreatic cancer (PaC) incidence is increasing, but our current screening and diagnostic strategies are not very effective. However, screening could be helpful in the case of PaC, as recent evidence shows that the disease progresses gradually. Unfortunately, there is no ideal screening method or program for detecting PaC in its early stages. Conventional imaging techniques, such as abdominal ultrasound, CT, MRI, and EUS, have not been successful in detecting early-stage PaC. On the other hand, biomarkers may be a more effective screening tool for PaC and have greater potential for further evaluation compared to imaging. Recent studies on biomarkers and artificial intelligence (AI)-enhanced imaging have shown promising results in the early diagnosis of PaC. In addition to proteins, non-coding RNAs are also being studied as potential biomarkers for PaC. This review consolidates the current literature on PaC screening modalities to provide an organized framework for future studies. While conventional imaging techniques have not been effective in detecting early-stage PaC, biomarkers and AI-enhanced imaging are promising avenues of research. Further studies on the use of biomarkers, particularly non-coding RNAs, in combination with imaging modalities may improve the accuracy of PaC screening and lead to earlier detection of this deadly disease.

The exploration of quantitative intra-tumoral metabolic heterogeneity in dual-time 18F-FDG PET/CT of pancreatic cancer

PURPOSE

We aimed to analyze the change of quantitative intra-tumoral metabolic heterogeneity consisting of texture features and conventional metabolic parameters of pancreatic cancer (PC) in dual-time 2-deoxy-2(18F) fluoro-D-glucose (18F-FDG) positron emission tomography-computed tomography (PET/CT).

METHODS

A retrospective analysis was conducted considering the texture features and conventional metabolic parameters in dual-time 18F-FDG PET/CT scans of PC patients. Features were extracted based on spatial distribution of 18F-FDG uptake in image. Firstly, the texture features and the conventional metabolic parameters of the delayed scan were both compared with that of the early scan. Statistically different data was defined among them. Secondly, the study evaluated the correlations between retention index (RI) of the texture features and the conventional metabolic parameters. Finally, the variation of texture features in dual-time PET/CT of resectable PC patients and unresectable PC patients was calculated separately.

RESULTS

In total, 183 PC patients were analyzed retrospectively in this research. The conventional metabolic parameters were all statistically different between the early and delayed scans except for metabolic tumor volume (MTV). In the radiomics, there were 59 textural features. Nineteen of 59 texture features were statistically different between the early and delayed scans. Features that were more than 10% different during two scans were observed in a substantial percentage of patients. Weak correlations were only found between MTV, TLG (Total lesion glycolysis), SUVpeak and the RI of some texture features in early or delayed scans. There were obviously fewer features with significant difference in resectable PC group than in unresectable PC group. Most features showing the difference in unresectable group while no significant difference in resectable group.

CONCLUSIONS

This study investigated the change and inner correlations of quantitative tumoral metabolic heterogeneity in the dual-time 18F-FDG-PET/CT scan of PC patients. Some features displayed the difference between dual-time scans. Conventional metabolic parameters were weakly related to the change of texture feature. The change of texture feature in resectable PC group was different from that in unresectable PC group. This result is potential to provide more information for the image evaluation of PC.

Review of radiological classifications of pancreatic cancer with peripancreatic vessel invasion: are new grading criteria required?

Pancreatic cancer is mainly diagnosed at an advanced stage when adjacent vessel invasion is present; however, radical resection is potentially curative for selected patients with adjacent vessel invasion. Therefore, accurately judging the resectability of patients with adjacent vessel invasion represents a crucially important step in diagnosis and treatment. Currently, decisions regarding resectability are based on imaging studies, commonly contrast computed tomography (CT). Several radiological classifications have been published for vascular infiltration in pancreatic cancer. However, radiologists always formulate these CT grading systems according to their own experience, resulting in different judgment methods and parameters. And it is controversial in evaluating performance and clinical application. Besides, the conventional CT grading systems mainly focus on the evaluation of vessel invasion so as to less on the outcome of patient evaluation. In this review, we summarize the mainstream CT grading systems for vascular invasion in pancreatic cancer, with the aim of improving the clinical value of CT grading systems for predicting resectability and survival.

Comparison of preoperative evaluation of malignant low-level biliary obstruction using plain magnetic resonance and coronal liver acquisition with volume acceleration technique alone and in combination

Background

To evaluate the clinical value of plain magnetic resonance (MR) imaging (including magnetic resonance cholangiopancreatography, MRCP) and coronal liver acquisition with volume acceleration (LAVA) technique in the diagnosis and preoperative assessment of malignant low-level biliary obstruction.

Methods

Forty-one patients with confirmed malignant low-level biliary obstruction were examined by plain MR, MRCP and coronal LAVA techniques. Group 1, plain MR (including MRCP); group 2, coronal LAVA; group 3, plain MR and coronal LAVA. Assessments included positioning, qualitative diagnosis and preoperative evaluation. The results were compared with pathological, endoscopic retrograde cholangiopancreatography or percutaneous transhepatic cholangiography results.

Results

There were 14 pancreatic adenocarcinoma, 12 distal common bile duct carcinoma, 10 ampullary carcinoma, and 5 duodenal carcinoma cases. There was no significant difference in accuracy of the three groups’ positioning diagnoses, 87.8, 90.2, and 92.7 %, respectively. The accuracy of the qualitative diagnoses was lower in group 1 at 78.0 %, but not significantly different in groups 2 and 3 at 92.7 and 95.1 %, respectively (P = 0.031, and 0.039, group 1 vs groups 2 and 3, respectively). Thirty-three patients underwent open surgery. There were 19 adjacent organ involvements, 9 vascular involvements, 13 lymph node metastases and 6 liver metastases. 22 patients were verified surgically and histologically for resectable lesions. Plain MR with coronal LAVA imaging showed 85.4 % accuracy, 90.9 % sensitivity, 78.9 % specificity, 83.3 % positive and 88.2 % negative predictive value for resectability.

Conclusions

Plain MR and coronal LAVA techniques are potential noninvasive tools for diagnosis and preoperative assessment of malignant low-level biliary obstruction.

Electronic supplementary material

The online version of this article (doi:10.1186/s40001-015-0188-3) contains supplementary material, which is available to authorized users.

Diagnostic accuracy of EUS and CT of vascular invasion in pancreatic cancer: a systematic review

OBJECTIVE

The objective of this study was to summarize the accuracy of preoperative vascular invasion with endoscopic ultrasound (EUS) and computed tomography (CT) test performance in pancreatic cancer with meta-analysis

METHOD

Two reviewers searched MEDLINE database to identify relevant studies. The reference lists of the trials were manually searched. Included studies used surgical and/or histological findings as the "gold standard," and provided sufficient data to construct a diagnostic 2 × 2 table. A statistical program of Meta-Disc was used to calculate the pooled sensitivity, specificity, positive LR, negative LR, DOR, and the SROC curve. Publication bias was assessed by Deeks' asymmetry test. Sensitivity analysis and subgroup analysis were calculated to down the heterogeneity. Meta-regression was calculated to evaluate potential sources of heterogeneity

RESULT

A total of 30 studies with 1,554 patients were included for the analysis, nine of these studies compared EUS with CT to assess the diagnostic efficiency The pooled sensitivity of EUS and CT was 72 % (95 % CI 67-77 %) and 63 % (95 % CI 58-67 %), and the pooled specificity of EUS and CT was 89 % (95 % CI 86-92 %) and 92 % (95 % CI 90-94 %), respectively. The positive LR of EUS and CT was 5.14 (95 % CI 3.14-8.40) and 6.21 (95 % CI 3.96-9.71), and the negative LR was 0.36 (95 % CI 0.25-0.52) and 0.41 (95 % CI 0.31-0.55), respectively. The AUCs of EUS and CT were 0.9037 and 0.8948. The subgroup analysis of nine studies performed both EUS and CT showed CT scan with a lower sensitivity of 48 % (95 % CI 0.40-0.56), when compared to EUS of 69 % (95 % CI 0.61-0.77). The overall AUCs of CT scan appear to be lower (AUCs = 0.8589), compared with EUS (AUCs = 0.9379) CONCLUSION: EUS performed better than CT in differentiating vascular invasion preoperative on pancreatic cancer. EUS could provide other additional information when compared with CT.

The presence of a cytopathologist increases the diagnostic accuracy of endoscopic ultrasound-guided fine needle aspiration cytology for pancreatic adenocarcinoma: a meta-analysis

OBJECTIVE

A meta-analysis has not been previously performed to evaluate critically the diagnostic accuracy of endoscopic ultrasound-guided fine needle aspiration (EUS-FNA) of solely pancreatic ductal adenocarcinoma and address factors that have an impact on variability of accuracy. The aim of this study was to determine whether the presence of a cytopathologist, variability of the reference standard and other sources of heterogeneity significantly impacts diagnostic accuracy.

METHODS

We conducted a comprehensive search to identify studies, in which the pooled sensitivity, specificity, likelihood ratios for a positive or negative test (LR+, LR-) and summary receiver-operating curves (SROC) could be determined for EUS-FNA of the pancreas for ductal adenocarcinoma using clinical follow-up, and/or surgical biopsy or excision as the reference standard.

RESULTS

We included 34 distinct studies (3644 patients) in which EUS-FNA for a solid pancreatic mass was evaluated. The pooled sensitivity and specificity for EUS-FNA for pancreatic ductal adenocarcinoma was 88.6% [95% confidence interval (CI): 87.2-89.9] and 99.3% (95% CI: 98.7-99.7), respectively. The LR+ and LR- were 33.46 (95% CI: 20.76-53.91) and 0.11 (95% CI: 0.08-0.16), respectively. The meta-regression model showed rapid on-site evaluation (ROSE) (P = 0.001) remained a significant determinant of EUS-FNA accuracy after correcting for study population number and reference standard.

CONCLUSION

EUS-FNA is an effective modality for diagnosing pancreatic ductal adencarcinoma in solid pancreatic lesions, with an increased diagnostic accuracy when using on-site cytopathology evaluation.

Computed tomography-based diagnostics might be insufficient in the determination of pancreatic cancer unresectability

AIM

To inquire into a question of an overestimation of arterial involvement in patients with pancreatic cancer (PC).

METHODS

Radiology data were compared with the findings from 51 standard, 58 extended and 17 total pancreaticoduodenectomies; 9 distal resections with celiac artery (CA) excision; and 28 palliations for PC. The survival of 11 patients with controversial computed tomography (CT) and endoscopic ultrasound data with regard to arterial invasion, after R0/R1 procedures (false-positive CT results, Group A), was compared to survival after eight R2 resections (false-negative CT results, Group B) and after 12 bypass procedures for locally advanced cancer (true-positive CT results, Group C).

RESULTS

In all of the cases in group A, operative exploration revealed no arterial invasion, which was predicted by CT. The one-year survival in Group A was 88.9%, and the two-year survival was 26.7%, with a median follow-up of 22 mo. One-year survival was not attained in groups B and C, with a significant difference in survival (P a-b = 0.0029, P b-c = 0.003).

CONCLUSION

Arterial encasement on CT does not necessarily indicate arterial invasion. Whenever PC is considered unresectable, endoUS should be used. In patients with controversial CT an EUS data for peripancreatic arteries involvement radical resection might be possible, providing survival benefits as compared to R2- resections or palliative surgery.

Pancreatic adenocarcinoma: Outstanding problems

Pancreatic adenocarcinoma remains the fourth leading cause of cancer-related death and is one of the most aggressive malignant tumors with an overall 5-year survival rate of less than 4%. Surgical resection remains the only potentially curative treatment but is only possible for 15%-20% of patients with pancreatic adenocarcinoma. About 40% of patients have locally advanced nonresectable disease. In the past, determination of pancreatic cancer resectability was made at surgical exploration. The development of modern imaging techniques has allowed preoperative staging of patients. Institutions disagree about the criteria used to classify patients. Vascular invasion in pancreatic cancers plays a very important role in determining treatment and prognosis. There is no evidence-based consensus on the optimal preoperative imaging assessment of patients with suspected pancreatic cancer and a unified definition of borderline resectable pancreatic cancer is also lacking. Thus, there is much room for improvement in all aspects of treatment for pancreatic cancer. Multi-detector computed tomography has been widely accepted as the imaging technique of choice for diagnosing and staging pancreatic cancer. With improved surgical techniques and advanced perioperative management, vascular resection and reconstruction are performed more frequently; patients thought once to be unresectable are undergoing radical surgery. However, when attempting heroic surgery, a realistic approach concerning the patient’s age and health status, probability of recovery after surgery, perioperative morbidity and mortality and life quality after tumor resection is necessary.

Staging cancer of the pancreas

Pancreatic carcinoma is the fourth cause of death from cancer in the United States, with a survival rate at 5 years of less than 5%. About 60% of tumors originate at the head of the pancreas, 15% in the body, 5% in the tail; 20% are diffuse within the pancreas. This article discusses the imaging and staging of pancreatic cancer.

Resectability of pancreatic adenocarcinoma in patients with locally advanced disease downstaged by preoperative therapy: a challenge for MDCT

OBJECTIVE

The purpose of this study was to determine whether preoperative neoadjuvant therapy in patients with locally advanced pancreatic cancer affects the ability of multiphasic MDCT to predict successful surgical resection.

MATERIALS AND METHODS

From 2000 to 2006, there were 12 patients with prior neoadjuvant therapy successfully downstaged by CT and 31 age-matched pancreatic cancer patients without preoperative therapy who underwent pancreatic MDCT followed by attempted pancreaticoduodenectomy. Three readers blinded to surgical findings independently analyzed immediate preoperative MDCT scans of 43 patients comprising the retrospective data set in random order for vascular involvement (degree of contact and narrowing) and distant metastases. Individual reader sensitivity and specificity for resectability prediction were compared for study and control groups using the Fisher's exact test. Interobserver agreement was assessed using the kappa statistic.

RESULTS

Seven (58%) of 12 neoadjuvant-treated adenocarcinomas and 10 (32%) of 31 control pancreatic carcinomas were resectable (p > 0.05). For resectable disease, sensitivities were 86%, 71%, and 14% for the neoadjuvant group and 90%, 90%, and 60% for the control group (p > 0.05). Specificities were 80%, 100%, and 100% for the neoadjuvant group and 57%, 43%, and 76% for the control group (reader 2 specificity difference, p = 0.04). The multi rater kappa value of resectability prediction for neoadjuvant patients was 0.28, and that for control subjects was 0.63 (p < 0.001). In the neoadjuvant group, the majority of individual reader errors were false-negative resectability interpretations resulting from overestimation of vascular involvement. Consideration of degrees of venous abutment did not improve estimation of resectability in patients with neoadjuvant therapy.

CONCLUSION

Sensitivity for prediction of resectability tends to be lower for patients with locally advanced pancreatic cancer that has been downstaged by neoadjuvant therapy, but this trend is not statistically significant. Interobserver variability for determination of resectability is statistically higher than for controls who did not receive preoperative therapy.

Vascular invasion in pancreatic cancer: Imaging modalities, preoperative diagnosis and surgical management

Pancreatic cancer is associated with a poor prognosis, and surgical resection remains the only chance for curative therapy. In the absence of metastatic disease, which would preclude resection, assessment of vascular invasion is an important parameter for determining resectability of pancreatic cancer. A frequent error is to misdiagnose an involved major vessel. Obviously, surgical exploration with pathological examination remains the “gold standard” in terms of evaluation of resectability, especially from the point of view of vascular involvement. However, current imaging modalities have improved and allow detection of vascular invasion with more accuracy. A venous resection in pancreatic cancer is a feasible technique and relatively reliable. Nevertheless, a survival benefit is not achieved by curative resection in patients with pancreatic cancer and vascular invasion. Although the discovery of an arterial invasion during the operation might require an aggressive management, discovery before the operation should be considered as a contraindication. Detection of vascular invasion remains one of the most important challenges in pancreatic surgery. The aim of this article is to provide a complete review of the different imaging modalities in the detection of vascular invasion in pancreatic cancer.

Vascular involvement in periampullary tumors: MDCT, EUS, and CDU

In patients affected by periampullary tumors, surgical resection represents the only treatment with curative intent. Preoperative evaluation of vascular involvement is necessary to avoid surgical treatments unable of curative intent resection. The aim of our update article is to assess the performance of multidetector computed tomography (MDCT), endoscopic ultrasonography (EUS), and color Doppler ultrasonography (CDU) in the evaluation of vascular involvement of major peripancreatic vessels, in periampullary tumors, analyzing the current and past literature.

Evaluation of vascular infiltration in resected patients for pancreatic cancer: comparison among multidetector CT, intraoperative findings and histopathology

BACKGROUND

To assess vascular infiltration is crucial in surgical planning of pancreatic cancer. Our aim was to assess the capability of multidetector CT in detecting vascular infiltration.

METHODS

We evaluated 37 patients with pancreatic tumors. The relation between tumor and vessels was classified: grade 0: no contact between lesion and vessel; grade I: focal contiguity without modification of the vessel caliber; grade II: lesion surrounding the vessel, without reduction of its lumen; grade III: cancer surrounding the vessel with reduction or obstruction of its lumen. CT grades were compared to intraoperative findings and histopathology.

RESULTS

We evaluated 52 critical vessels with the following CT grades: grade 0 (4 cases), grade I (13 cases), grade II (17 cases), grade III (18 cases). Vascular resection was performed in 26 patients, with a total of 31 resected vessels (3 of grade 0, 5 of grade I, 8 of grade II, 15 of grade III). Histopathology excluded vascular infiltration in 4/4 cases with grade 0 and in 10/13 cases with grade I and confirmed it in 14/17 cases with grade II and 14/18 cases with grade III.

CONCLUSIONS

Multidetector CT is accurate in detecting vascular involvement and provides pre-operative information to effectively plan resection.

Arterial vs pancreatic phase: which is the best choice in the evaluation of pancreatic endocrine tumours with multidetector computed tomography (MDCT)?

PURPOSE

The aim of this study was to assess whether the pancreatic phase may replace the arterial phase in the evaluation of endocrine pancreatic tumours.

MATERIALS AND METHODS

Twenty-nine endocrine pancreatic lesions with definitive morphological and immunohistochemical characterisation after surgical treatment (n=24) or fine-needle-aspiration cytology under endoscopic ultrasonography guidance (n=5) were retrospectively evaluated. All lesions were studied with triple-phase 16-row multidetector computed tomography (MDCT). Images obtained during each phase were separately interpreted by two senior radiologists experienced in pancreatic pathology and who were blinded to surgical results. Endocrine tumour and normal pancreas attenuation and the mean absolute tumour-to-gland attenuation difference were measured in each phase, and data were analysed with Student's t test. Visualisation of arterial vascular abnormalities and hypervascular liver metastases in the arterial and pancreatic phases and the diagnostic contribution of the two phases were compared.

RESULTS

For both radiologists, the mean absolute tumour-to-gland attenuation difference was significantly higher (p<0.05) in the pancreatic phase (40+/-53 HU and 34+/-56 HU) than in the arterial phase (31+/-38 HU and 26+/-43 HU). There were no differences in the detection of arterial vascular abnormalities or hypervascular liver metastases in the two phases. The diagnostic contribution was higher in the pancreatic phase.

CONCLUSIONS

In our experience, the pancreatic phase can replace the arterial phase in the evaluation of pancreatic endocrine tumours.

Usefulness of the long-axis and short-axis reformatted images of multidetector-row CT in evaluating T-factor of the surgically resected pancreaticobiliary malignancies

PURPOSE

To evaluate the diagnostic efficacy of curved planar reformations along the duct (long-axis CPR) and series of reformations perpendicular to the duct (short-axis MPR) in evaluating T-factors of pancreaticobiliary malignancy.

MATERIALS AND METHODS

Twenty-five patients with surgically proven pancreaticobiliary malignancy (12 bile duct cancers and 13 pancreas cancers) were evaluated. A dynamic study was performed with multidetector-row CT with four detectors, and reconstructed with 1mm thickness and intervals. Tracing the center of the duct system on axial images, long-axis CPR images and serial short-axis MPR images were obtained. Two radiologists interpreted the T factor of the diseases three times: session (1), axial images only; session (2), axial, coronal and sagittal multiplanar reformation images; and session (3), axial, long-axis CPR, and short-axis MPR images. Receiver operating characteristic curves were analyzed.

RESULTS

In evaluations of bile duct cancer, Az values of (3) (0.95, 0.92) were higher than those of (1) (0.89, 0.88) and (2) (0.92, 0.89), with some significant differences. In evaluations of pancreas cancer, Az values of all interpretations were almost equal.

CONCLUSION

Long-axis CPR and short-axis MPR images were suggested to be useful as additional images to the original axial images in evaluating the local extension of bile duct carcinomas.

Pancreatic adenocarcinoma: signs of vascular invasion determined by multi-detector row CT

The purpose of this study was to analyse multi-detector row CT (MDCT) signs of peripancreatic arterial and venous invasion in pancreatic carcinoma. Among 101 patients with pancreatic carcinoma examined by MDCT, 54 candidates for surgery were pre-operatively evaluated for vascular invasion based on MDCT signs. The peripancreatic major vessels (including superior mesenteric artery, coeliac artery, common hepatic artery, superior mesenteric vein and portal vein) were examined carefully by surgeons during the operation. At surgical exploration, 78 of 224 vessels were invaded by tumour. The invaded peripancreatic major arteries (n = 29) and veins (n = 49) presented different MDCT signs: 43% of invaded veins (18/42, except for 7 occluded veins) were surrounded by tumour less than 50% of the vessel circumference compared with 97% (28/29) of the invaded arteries, which were surrounded by tumour more than 50% of the vessel circumference or were embedded in tumour (p<0.001). 69% (34/49) of the invaded veins had vascular stenosis or obliteration, compared with 41% (12/29) of the invaded arteries (p<0.05). Irregularity of the vein wall, 74% (31/42, except for 7 occluded veins); occurred more often than that of the artery wall, 45% (13/29) (p<0.05). In conclusion, the MDCT signs of peripancreatic arterial and venous invasion have different characteristics, which should be considered in pre-operative evaluation.

Multidetector CT of the pancreas

CT is the primary imaging modality of the pancreas. This article reviews the multidector CT technique and its current status in the diagnosis of various pancreatic diseases. Special emphasis is given to the impact of multidetector CT and postprocessing imaging techniques on the staging of pancreatic adenocarcinoma.

Pancreatic adenocarcinoma: the different CT criteria for peripancreatic major arterial and venous invasion

OBJECTIVE

To establish preliminarily the different diagnostic criteria for peripancreatic arterial and venous invasion in pancreatic carcinoma by comparing their multidetector-row computed tomography (MDCT) appearances with surgical exploration.

METHODS

Among 101 patients with pancreatic carcinoma examined by MDCT, 54 candidates accepting surgery were preoperatively evaluated for vascular invasion based on CT signs (A-E): arterial embedment in tumor or venous obliteration; tumor involvement exceeding one-half of the circumference of the vessel; vessel wall irregularity; vessel caliber stenosis; teardrop superior mesenteric vein (SMV). The peripancreatic major vessels (n = 224) were examined carefully by surgeons during the operation.

RESULTS

During surgical exploration, 78 vessels were found to be invaded. With sign A (B, C, or D) as the CT criterion for peripancreatic vascular invasion, the sensitivity of arterial and venous invasion was 66% (97%, 45%, or 41%) and 14% (49%, 63%, or 55%), respectively; the specificity of absence of arterial and venous invasion was 100% (91%, 99%, or 100%) and 100% (all 100%). In this study, there were 3 SMVs appearing teardrop (sign E), which were all confirmed to be invaded.

CONCLUSIONS

It is recommended that the CT diagnostic criteria for arterial and venous invasion should be dealt with differently. The criteria of arterial invasion are the presence of sign A or the combination of sign B with one of signs C and D. The criteria of venous invasion are the presence of one of the following signs: sign A, sign B, sign C, sign D, and sign E.

Multidetector row CT of the pancreas

Multidetector CT (MDCT) has gained a great role in clinical imaging practice in a short time. Its major advantages are faster image acquisition and improved z-axis resolution. In spite of the advent of other imaging modalities CT is still the gold standard for the evaluation of pancreatic pathology. In this article, a review of the utility of MDCT in pancreatic applications is given with emphasis on acquisition techniques tailored to contrast material pharmacokinetics to improve lesion detection and characterization.

Periampullary Tumors: High-Spatial-Resolution MR Imaging and Histopathologic Findings in Ampullary Region Specimens

PURPOSE

To prospectively determine the magnetic resonance (MR) signal intensity characteristics of structures of the ampullary region and to assess the potential use of MR imaging in evaluation of the extent of periampullary tumors in resected specimens.

MATERIALS AND METHODS

Twenty-five specimens from the ampullary region obtained in four autopsy cases without periampullary tumors and in 21 patients with periampullary tumors were examined with a 1.5-T MR system and a circular surface coil with 5-inch (12.7-cm) diameter. High-spatial-resolution MR images were obtained with field of view of 100 x 100 mm, matrix of 256 x 256 or 512 x 256, and section thickness of 2 mm. MR imaging findings were compared with histopathologic findings. Sensitivity, specificity, accuracy, positive predictive value, and negative predictive value of high-spatial-resolution MR imaging for assessment of tumor invasion into surrounding tissues were evaluated by two radiologists.

RESULTS

T1- and T2-weighted MR images clearly depicted normal structures in the ampullary region that included Oddi muscle, duodenal wall, common bile duct, and pancreas; these findings corresponded well with histologic findings. In 20 (95%) of 21 tumors, high-spatial-resolution MR imaging depicted location and extension of periampullary tumors precisely. Sensitivity, specificity, accuracy, positive predictive value, and negative predictive value of high-spatial-resolution MR imaging for assessment of tumor invasion into surrounding tissue were 88%, 100%, 96%, 100%, and 94%, respectively.

CONCLUSION

In this study, MR imaging correctly depicted location, extension, and origin of tumor. High-spatial-resolution MR imaging has potential for presurgical staging of tumors in this region.

MDCT in Pancreatic adenocarcinoma: prediction of vascular invasion and resectability using a multiphasic technique with curved planar reformations

OBJECTIVE

The objective of our study was to determine the negative predictive value of MDCT with curved planar reformations for detecting vascular invasion and predicting overall resectability in patients with pancreatic adenocarcinoma.

MATERIALS AND METHODS

Imaging findings related to vascular invasion and overall tumor resectability in 25 patients who underwent contrast-enhanced biphasic MDCT evaluation were correlated with actual vessel invasion and overall resectability determined at surgery and pathologic examination. The presence of vascular invasion was assessed in 110 major peripancreatic vessels in 22 patients who underwent resection.

RESULTS

On MDCT, 23 (92%) of 25 patients were deemed to have resectable pancreatic adenocarcinoma. The tumors in the remaining two (8%) were considered not resectable because of the presence of vascular invasion (which was confirmed in only one patient at surgery). Of those 23 patients deemed to be candidates for curative resection on the basis of MDCT results, 20 were found to have resectable adenocarcinoma at time of surgery, yielding a negative predictive value for MDCT of 87% (20/23 patients) for overall resectability. In the other three patients, adenocarcinoma was deemed to be unresectable because of small metastases to the liver (two patients) or to the peritoneum (one patient) discovered at surgery. For detection of vascular invasion, MDCT yielded a negative predictive value of 100% (108/108 vessels) with no false-negative findings and an accuracy of 99% (109/110 vessels) with 108 true-negative findings, one true-positive finding, and one false-positive finding.

CONCLUSION

Our preliminary data on MDCT show that the technique has excellent negative predictive value for vascular invasion and good negative predictive value for overall tumor resectability in patients with pancreatic adenocarcinoma, suggesting an improvement over previous results reported using single-detector CT. The problem of undetected micrometastases to the liver and peritoneum remains.

Vascular involvement in pancreatic neoplasm: a comparison between spiral CT and DSA

The principal criterion for resectability of pancreatic carcinoma is the assessment of vascular involvement. In a prospective evaluation the ability of Spiral CT Angiography (CTA) to detect vascular involvement in 50 patients with pancreatic carcinoma, was proved; DSA was performed later in all patients. In 20 patients, without vascular involvement, a complete concordance was obtained. Of 30 patients with vascular involvement, there was complete concordance between CTA and angiography in 22 patients and discordance in 8 patients. CTA was superior in 2 cases with periadventitial infiltration and in 5 patients with splenoportal confluence thrombosis. DSA was superior in 1 case with infiltration of the superior mesenteric vein. After surgical evaluation, sensitivity of CTA and DSA was 97% and 77%, respectively, and the negative predictive values were 95% and 74%. As compared to DSA, CTA is more rapid and less invasive and can be considered the modality of choice for preoperative work-up of pancreatic neoplasm.