Comparison of helical CT and MR imaging in detecting and staging small pancreatic adenocarcinoma

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.

Pancreatic adenocarcinoma: imaging techniques for diagnosis and management

Pancreatic cancer is a leading cause of death from cancer but only a minority of patients with pancreatic ductal adenocarcinomas are eligible for curative resection. The increasing role of neoadjuvant therapy provides hope of improving outcomes. However, progress is also reliant on advances in imaging that can identify disease earlier and accurately assess treatment response. Computed tomography remains the cornerstone in evaluation of resectability, offering excellent spatial resolution. However, in high-risk patients, additional magnetic resonance imaging and positron emission tomography-computed tomography may further guide treatment decisions. Conventional computed tomography can be limited in its ability to determine disease response after neoadjuvant therapy. Dual-energy computed tomography and computed tomography or magnetic resonance imaging perfusion studies emerging as potentially better alternatives. Combined with pioneering advances in radiomic analysis, these modalities also show promise in analysing tumour heterogeneity and thereby more accurately predicting outcomes. This article reviews these imaging techniques.

Abnormal Findings on "T1WI or DWI or MRCP:" An Effective Boolean Interpretation Model in Discriminating Small Pancreatic Ductal Adenocarcinoma from Control Group

Objectives

The objectives of the study was to evaluate the diagnostic performance of findings on T1-weighted imaging (T1WI), T2-weighted imaging (T2WI), diffusion-weighted imaging (DWI), and magnetic resonance cholangiopancreatography (MRCP) separately and to identify an optimal Boolean interpretation model for discriminating patients with small pancreatic ductal adenocarcinoma (PDAC) from control groups in clinical practice.

Material and Methods

We retrospectively enrolled 30 patients with surgery confirmed small PDAC (≤20 mm) and 302 patients without pancreatic abnormality between April 2008 and February 2020. The presence of masses was evaluated by T1WI, T2WI, and DWI. Abnormality of the main pancreatic duct (MPD) was evaluated by T2WI and MRCP. Multivariate logistic regression analysis was performed to select significant sequences for discriminating the small PDAC and control groups. Boolean operators "OR" or "AND" were used to construct sequence combinations. Diagnostic performances of these sequences and combinations were evaluated by X ² tests.

Results

The sensitivity of T2WI was lowest (20%) for detecting masses. For evaluating MPD abnormality, sensitivity was higher for MRCP than for T2WI (86.7% vs. 53.3%). Multivariate logistic regression analysis showed that T1WI and DWI for detecting the presence of masses and MRCP for evaluating MPD abnormality were significantly associated with differentiation between the two groups (P = 0.0002, P = 0.0484, and P < 0.0001, respectively). Seven combinations were constructed with T1WI, DWI, and MRCP. The combination of findings on "T1WI or DWI or MRCP" achieved the highest sensitivity of 96.7% and negative predictive value of 99.6%.

Conclusion

The combination of findings on "T1WI or DWI or MRCP" might be an optimal interpretation model for discriminating small PDAC from control groups in clinical practice.

Current controversies and advances in the management of pancreatic adenocarcinoma

Pancreatic adenocarcinoma is a lethal disease with a mortality rate that has not significantly improved over decades. This is likely due to several challenges unique to pancreatic cancer. Most patients with pancreatic cancer are diagnosed at a late stage of disease due to the lack of specific symptoms prompting an early investigation. A small subset of patients who are diagnosed at an early stage have a better chance at survival with curative surgical resection, but most patients still succumb to the disease in a few years. The dismal overall prognosis is due to suspected micro-metastasis at an early stage. Due to this reason, there is a recent interest in treating all patients with pancreatic cancers with systemic therapy upfront (including the ones that are surgically resectable). This approach is still not the standard of care due to the lack of robust prospective data available. Recent advancements in treatment regimens of chemotherapy, radiation and immunotherapy have improved the overall short-term survival but the long-term survival still remains poor. Novel approaches in diagnosis and treatment have shown promise in clinical studies but long-term clinical data is lacking. The following manuscript presents an overview of the epidemiology, diagnosis, staging, recent advances, novel approaches and controversies in the management of pancreatic adenocarcinoma.

A review of response in neoadjuvant therapy for exocrine pancreatic cancer

Despite overall advances in cancer therapy, patients with pancreatic ductal adenocarcinoma continue to have a poor prognosis. While adjuvant therapy is still considered standard, there is mounting evidence that neoadjuvant therapy confers similar benefits in patients with locally advanced disease. The primary measures of response are radiographic, biochemical, margin status, and pathologic. Given overall low response rates and the need for new treatment strategies, standard metrics remain important to the investigation of new systemic agents.

Guidelines for the Diagnostic Cross Sectional Imaging and Severity Scoring of Chronic Pancreatitis

The paper presents the international guidelines for imaging evaluation of chronic pancreatitis. The following consensus was obtained: Computed tomography (CT) is often the most appropriate initial imaging modality for evaluation of patients with suspected chronic pancreatitis (CP) depicting most changes in pancreatic morphology. CT is also indicated to exclude other potential intraabdominal pathologies presenting with symptoms similar to CP. However, CT cannot exclude a diagnosis of CP nor can it be used to exclusively diagnose early or mild disease. Here magnetic resonance imaging (MRI) and MR cholangiopancreatography (MRCP) is superior and is indicated especially in patients where no specific pathological changes are seen on CT. Secretin-stimulated MRCP is more accurate than standard MRCP in the depiction of subtle ductal changes. It should be performed after a negative MRCP, when there is still clinical suspicion of CP. Endoscopic ultrasound (EUS) can also be used to diagnose parenchymal and ductal changes mainly during the early stage of the disease. No validated radiological severity scoring systems for CP are available, although a modified Cambridge Classification has been used for MRCP. There is an unmet need for development of a new and validated radiological CP severity scoring system based on imaging criteria including glandular volume loss, ductal changes, parenchymal calcifications and parenchymal fibrosis based on CT and/or MRI. Secretin-stimulated MRCP in addition, can provide assessment of exocrine function and ductal compliance. An algorithm is presented, where these imaging parameters can be incorporated together with clinical findings in the classification and severity grading of CP.

Diagnosis and Detection of Pancreatic Cancer

Computed tomography is the first-line imaging modality for suspected pancreatic cancer. Magnetic resonance cholangiopancreatography is a second-line modality for suspected pancreatic cancer and is usually reserved for equivocal cases. Both computed tomography and MR are highly sensitive in the detection of pancreatic cancer, with up to 96% and 93.5% sensitivity, respectively. Computed tomography is superior to MR in the assessment of tumor resectability, with accuracy rates of up to 86.8% and 78.9%, respectively. Close attention to secondary signs of pancreatic cancer, such as pancreatic duct dilatation, abrupt pancreatic duct caliber change, and parenchymal atrophy, are critical in the diagnosis of pancreatic cancer. Emerging techniques such as radiomics and molecular imaging have the potential of identifying malignant precursors and lead to earlier disease diagnosis. The results of these promising techniques need to be validated in larger clinical studies.

Does Second Reader Opinion Affect Patient Management in Pancreatic Ductal Adenocarcinoma?

RATIONALE AND OBJECTIVES

To determine the impact of second-opinion assessment on cancer staging and patient management in patients with pancreatic ductal adenocarcinoma.

METHODS AND MATERIALS

This retrospective study was approved by our institutional review board with a waiver of informed consent. Second-opinion reports between January 1, 2009 and December 31, 2013, alongside outside reports for 65 consecutive cases of biopsy-proven pancreatic adenocarcinomas, were presented in random order to two experienced abdominal surgeons who independently reviewed them blinded to the origin of the report, images of the examinations, and patient identifier. Each surgeon filled in a questionnaire for each report recommending cancer staging and patient management. Recommended patient management and staging were evaluated against reference standards (actual patient management at 6 months following second-opinion assessment, and pathology or other clinical and imaging reference standards at 6 months or longer, respectively) using Cohen kappa.

RESULTS

Cancer staging differed in 13% (9 of 65) of cases for surgeon 1 and in 18.4% (12 of 65) for surgeon 2. Patient management changed in 38.4% (25 of 65) of cases for surgeon 1 and in 20% (13 of 65) for surgeon 2. When compared to the pathologic staging gold standard, second opinion was correct in 85.7% (six of seven) of the time for both surgeons. Recommended patient management from second-opinion reports showed good agreement with the reference standard (weighted k = 0.6467 [0.4014-0.892] and weighted k = 0.6262 [0.3954-0.857] for surgeon 2).

CONCLUSION

Second-opinion review by subspecialized oncologic radiologists can impact patient care, specifically in terms of management decision.

Pancreatic cancer in patients with chronic calcifying pancreatitis: Computed tomography findings - a retrospective analysis of 48 patients

OBJECTIVE

Chronic calcifying pancreatitis (CCP) is a risk factor for pancreatic cancer (PC). Symptoms of PC are non-specific in patients with CCP, and diagnostic imaging can be difficult. Some studies have shown that diagnosis may take several months, leading to delays in treatment (Lin et al., 2015; Lennon et al., 2014) [2,3]. The aim of this study was to describe the radiological signs of PC in patients with CCP.

METHODS

This retrospective, single-center study was conducted between January 2004 and December 2014. Patients with CCP who were being monitored for PC were included. Each patient diagnosed with PC was matched with two CCP controls who did not develop PC.

RESULTS

We studied 48 patients with CCP (30 men (62%) and 18 women (38%), mean age 69.4 years). Sixteen patients (with 18 tumor sites) who developed PC (1.52%) were compared with 32 controls who did not develop PC. A hypodense mass was observed in all of the patients with PC, predominantly in the pancreatic head (61.2%). No such masses were observed in the controls (p<0.001). The average mass size was 36.3mm, and the masses were observed to push aside the calcifications in all patients (p<0.001). Calcifications were very abundant (>10) in 33.3% of the patients with PC and in 71.9% of the controls (p=0.0076). The main pancreatic duct (MPD) was dilated in all of the patients with PC (average diameter 8.6mm; homogeneous in 83.3%) and in only 46.9% of the controls (average 7.4mm; homogeneous in 37.5%) (p>0.05). Dilation of the intrahepatic bile ducts and common bile duct was observed in 15 (94.4%) of the patients with PC and in none of the controls (p<0.0001). The average alcohol consumption was 1g/day (0-5g/day) in the PC group and 4.6g/day (0-20g/day) in the control group. In addition, the average smoking history was 14.25 pack-years (0-40 PY) in the PC group and 27.70 PY (0-60 PY) in the control group.

CONCLUSION

The presence of a pancreatic mass in a patient with CCP is suggestive of malignancy, especially when few pancreatic calcifications are observed (that are pushed aside by the tumor) and when the tumor causes dilation of the common bile duct and main pancreatic duct.

Molecular Imaging of Pancreatic Cancer with Antibodies

Development of novel imaging probes for cancer diagnostics remains critical for early detection of disease, yet most imaging agents are hindered by suboptimal tumor accumulation. To overcome these limitations, researchers have adapted antibodies for imaging purposes. As cancerous malignancies express atypical patterns of cell surface proteins in comparison to noncancerous tissues, novel antibody-based imaging agents can be constructed to target individual cancer cells or surrounding vasculature. Using molecular imaging techniques, these agents may be utilized for detection of malignancies and monitoring of therapeutic response. Currently, there are several imaging modalities commonly employed for molecular imaging. These imaging modalities include positron emission tomography (PET), single-photon emission computed tomography (SPECT), magnetic resonance (MR) imaging, optical imaging (fluorescence and bioluminescence), and photoacoustic (PA) imaging. While antibody-based imaging agents may be employed for a broad range of diseases, this review focuses on the molecular imaging of pancreatic cancer, as there are limited resources for imaging and treatment of pancreatic malignancies. Additionally, pancreatic cancer remains the most lethal cancer with an overall 5-year survival rate of approximately 7%, despite significant advances in the imaging and treatment of many other cancers. In this review, we discuss recent advances in molecular imaging of pancreatic cancer using antibody-based imaging agents. This task is accomplished by summarizing the current progress in each type of molecular imaging modality described above. Also, several considerations for designing and synthesizing novel antibody-based imaging agents are discussed. Lastly, the future directions of antibody-based imaging agents are discussed, emphasizing the potential applications for personalized medicine.

Missed pancreatic ductal adenocarcinoma: Assessment of early imaging findings on prediagnostic magnetic resonance imaging

OBJECTIVE

To investigate the early imaging findings and growth rate of pancreatic ductal adenocarcinoma (PDAC), and to assess whether MR imaging detects early PDAC better than CT.

MATERIALS AND METHODS

The institutional review board approved this retrospective study and waived the requirement for informed consent. Twenty-two patients were included, and two radiologists, by consensus, assessed the presence of focal lesions, interruption of the main pancreatic duct (MPD), MPD dilatation, and pancreatitis, volume doubling time (VDT) of PDAC on prediagnostic MR imaging. Two other observers independently reviewed three image sets (CT images, unenhanced MR images, and unenhanced and contrast-enhanced MR images) for the detection of early PDAC. Paired Wilcoxon signed rank test and receiver operating characteristic (ROC) curve analysis were used for statistical analyses.

RESULTS

In 20 (90.9%) patients, prediagnostic MR exams showed abnormality, and all of them showed focal lesions on the first abnormal prediagnostic MR exams. Thirteen lesions (65%) showed no MPD interruption and one lesion (5%) was accompanied by pancreatitis. The mean VDT of PDAC was 151.7 days (range, 18.3-417.8 days). Diagnostic performance of unenhanced MR images (Az, 0.971-0.989) and combined unenhanced and contrast-enhanced MR images (Az, 0.956-0.963) was significantly better than that of CT images (Az, 0.565-0.583; p<0.01) for both observers,

CONCLUSION

The most common early imaging finding of PDAC on prediagnostic MR exams was a focal lesion with no MPD interruption with a mean volume doubling time of five months. MR imaging was superior to CT for the detection of early PDAC.

Phase-contrast X-ray CT imaging of esophagus and esophageal carcinoma

The electron density resolution is 1000 times higher for synchrotron-radiation phase-contrast CT imaging than conventional X-ray absorption imaging in light elements, with which high-resolution X-ray imaging of biological soft tissue can be achieved. In the present study, we used phase-contrast X-ray CT to investigate human resected esophagus and esophageal carcinoma specimens. This technology revealed the three-layer structure of the esophageal wall-- mucous, submucosa and muscular layers. The mucous and muscular layers were clearly separated by a loose submucosa layer with a honeycomb appearance. The surface of the mucous layer was smooth. In esophageal carcinoma, because of tumor tissue infiltration, the submucosa layer was absent, which indicated destruction of the submucosa. The boundary between normal tissue and tumor was comparatively fuzzy, the three-layer structure of the esophageal wall was indistinct. The surface of the mucous layer was rugose. The technology might be helpful in tumor staging of esophageal carcinoma.

CT and MR imaging patterns for pancreatic carcinoma invading the extrapancreatic neural plexus (Part II): Imaging of pancreatic carcinoma nerve invasion

Computed tomography (CT) and magnetic resonance imaging (MRI) are excellent modalities which have the ability to detect, depict and stage the nerve invasion associated with pancreatic carcinoma. The aim of this article is to review the CT and MR patterns of pancreatic carcinoma invading the extrapancreatic neural plexus and thus provide useful information which could help the choice of treatment methods. Pancreatic carcinoma is a common malignant neoplasm with a high mortality rate. There are many factors influencing the prognosis and treatment options for those patients suffering from pancreatic carcinoma, such as lymphatic metastasis, adjacent organs or tissue invasion, etc. Among these factors, extrapancreatic neural plexus invasion is recognized as an important factor when considering the management of the patients.

Pancreas-protocol imaging at a high-volume center leads to improved preoperative staging of pancreatic ductal adenocarcinoma

BACKGROUND

High-quality preoperative cross-sectional imaging is vital to accurately stage patients with pancreatic ductal adenocarcinoma (PDAC). We hypothesized that imaging performed at a high-volume pancreatic cancer center with pancreatic imaging protocols more accurately stages patients compared with pre-referral imaging.

METHODS

We retrospectively reviewed data from all patients with PDAC who presented to the surgical oncology clinic at our institution between June 2005 and August 2009. Detailed preoperative imaging, staging, and operative data were collected for each patient.

RESULTS

A total of 230 patients with PDAC were identified, of which 169 had pre-referral imaging. Patients were selectively reimaged at our institution based on the quality and timing of imaging at the outside facility: 108 (47%) patients were deemed resectable, 54 (23.5%) were deemed borderline-resectable, and 68 (29.5%) were deemed unresectable. Of the resectable patients, 99 opted for resection. Eighty-two of those 99 patients underwent preoperative imaging at our institution, and of these 27% had unresectable disease at the time of surgery compared with 47% of patients who only had pre-referral imaging (p = 0.14). Reimaging altered staging and changed management in 56% of patients. Among that group were 55 patients, categorized as resectable on pre-referral imaging, who on repeat imaging were deemed to be borderline resectable (n = 27) or unresectable (n = 28).

CONCLUSIONS

Pancreas-protocol imaging at a high-volume center improves preoperative staging and alters management in a significant proportion of patients with PDAC who undergo pre-referral imaging. Thus, repeat imaging with pancreas protocols and dedicated radiologists is justified at high-volume centers.

Gadobenate dimeglumine-enhanced 3.0-T MR imaging versus multiphasic 64-detector row CT: prospective evaluation in patients suspected of having pancreatic cancer

PURPOSE

To compare the diagnostic performance (detection, local staging) of multiphasic 64-detector row computed tomography (CT) with that of gadobenate dimeglumine-enhanced 3.0-T magnetic resonance (MR) imaging in patients suspected of having pancreatic cancer.

MATERIALS AND METHODS

The institutional review board approved this prospective study, and all patients provided written informed consent. Multidetector CT and MR imaging were performed in 89 patients (48 women aged 46-89 years [mean, 65.6 years] and 41 men aged 46-86 years [mean, 65.3 years]) suspected of having pancreatic cancer on the basis of findings from clinical examination or previous imaging studies. Two readers independently assessed the images to characterize lesions and determine the presence of focal masses, vascular invasion, distant metastases, and resectability. Findings from surgery, biopsy, endosonography, or follow-up imaging were used as the standard of reference. Logistic regression, the McNemar test, and κ values were used for statistical analysis.

RESULTS

Focal pancreatic masses were present in 63 patients; 43 patients had adenocarcinoma. For reader 1, the sensitivities and specificities in the detection of pancreatic adenocarcinoma were 98% (42 of 43 patients) and 96% (44 of 46 patients), respectively, for CT and 98% (42 of 43 patients) and 96% (44 of 46 patients) for MR imaging. For reader 2, the sensitivities and specificities were 93% (40 of 43 patients) and 96% (44 of 46 patients), respectively, for CT and 95% (41 of 43 patients) and 96% (44 of 46 patients) for MR imaging. Vessel infiltration was determined in 22 patients who underwent surgery, and reader 1 obtained sensitivities and specificities of 90% (nine of 10 vessels) and 98% (119 of 122 vessels), respectively, for CT and 80% (eight of 10 vessels) and 96% (117 of 122 vessels) for MR imaging; for reader 2, those values were 70% (seven of 10 vessels) and 98% (120 of 122 vessels) for CT and 50% (five of 10 vessels) and 98% (120 of 122 vessels) for MR imaging. Both readers correctly assessed resectability in 87% (13 of 15 patients) of cases with CT and 93% (14 of 15 patients) of cases with MR imaging. Nonresectability was assessed correctly with CT in 75% (six of eight patients) of cases by reader 1 and 63% (five of eight patients) of cases by reader 2; nonresectability was correctly assessed with MR imaging in 75% (six of eight patients) of cases by reader 1 and 50% (four of eight patients) of cases by reader 2. None of the differences between modalities and readers were statistically significant (P > .05).

CONCLUSION

Both CT and MR imaging are equally suited for detecting and staging pancreatic cancer.

SUPPLEMENTAL MATERIAL

http://radiology.rsna.org/lookup/suppl/doi:10.1148/radiol.11101189/-/DC1.

Peripancreatic fat invasion is an independent predictor of poor outcome following pancreaticoduodenectomy for pancreatic ductal adenocarcinoma

BACKGROUND

Following pancreaticoduodenectomy for pancreatic ductal adenocarcinoma (PDAC), identification of peripancreatic fat tumor invasion promotes a tumor to stage T3. We sought to understand better the impact of histological peripancreatic fat invasion on prognosis and site of recurrence in a cohort of patients with PDAC.

METHODS

We analyzed the patient demographics, outcome, and recurrence data that had been prospectively collected in 189 consecutive PDAC undergoing potentially curative pancreaticoduodenectomy between 1996 and 2009. Pathological features were reassessed for all patients. Survival outcome was compared using Kaplan-Meier/Cox proportional hazards analysis. The primary site of recurrence was defined as either locoregional or distant metastases.

RESULTS

The median survival of this PDAC cohort was 18.9 months (95% confidence interval (CI) 15.7-22.2). Histological peripancreatic fat invasion was evident in 51 (27%) patients and was associated with lymph node metastases (p = 0.004) and larger tumor size (p = 0.015). The presence of peripancreatic fat invasion was associated with reduced overall survival following resection (12.4 months [95% CI 9.9-15.0]) when compared to those patients with no evidence of fat invasion (22.6 months [95% CI 18.5-26.7]; p < 0.0001). By multivariate survival analysis, independent predictors of overall survival included tumor grade (p = 0.002), lymph node involvement (p = 0.025), resection margin status (p = 0.003), venous invasion (p = 0.045), and peripancreatic fat invasion (p = 0.007). Invasion into the pancreatic fat was significantly associated with the primary site of recurrence being locoregional failure (p = 0.002).

CONCLUSIONS

Peripancreatic fat invasion was identified as being an independent predictor of poor outcome following pancreaticoduodenectomy for PDAC. Additionally, the presence of peripancreatic fat invasion was associated with locoregional disease as the primary site of recurrence. This may have implications for the staging of PDAC and potentially require incorporation into future staging systems to improve outcome stratification.

Advances in diagnosis, treatment and palliation of pancreatic carcinoma: 1990-2010

Several advances in genetics, diagnosis and palliation of pancreatic cancer (PC) have occurred in the last decades. A multidisciplinary approach to this disease is therefore recommended. PC is relatively common as it is the fourth leading cause of cancer related mortality. Most patients present with obstructive jaundice, epigastric or back pain, weight loss and anorexia. Despite improvements in diagnostic modalities, the majority of cases are still detected in advanced stages. The only curative treatment for PC remains surgical resection. No more than 20% of patients are candidates for surgery at the time of diagnosis and survival remains quite poor as adjuvant therapies are not very effective. A small percentage of patients with borderline non-resectable PC might benefit from neo-adjuvant chemoradiation therapy enabling them to undergo resection; however, randomized controlled studies are needed to prove the benefits of this strategy. Patients with unresectable PC benefit from palliative interventions such as biliary decompression and celiac plexus block. Further clinical trials to evaluate new chemo and radiation protocols as well as identification of genetic markers for PC are needed to improve the overall survival of patients affected by PC, as the current overall 5-year survival rate of patients affected by PC is still less than 5%. The aim of this article is to review the most recent high quality literature on this topic.

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

PURPOSE

This study compared the results of multislice computed tomography (MSCT) and high-field magnetic resonance imaging (MRI) in the diagnostic evaluation of pancreatic masses.

MATERIALS AND METHODS

Forty patients with clinical and ultrasonographic evidence of pancreatic masses underwent MSCT and MRI. The majority of patients (31/40, 78%) had proven malignant pancreatic tumours (24 ductal adenocarcinoma, six mucinous cystadenocarcinoma, one intraductal papillary mucinous carcinoma), whereas the remaining patients (9/40, 22%) were found to have benign lesions (eight chronic pancreatitis, one serous cystadenoma). Results of the imaging studies were compared with biopsy (n=33) and/or histology (n=7) findings to calculate sensitivity, specificity, accuracy and positive (PPV) and negative (NPV) predictive value for correct identification of tumours and evaluation of resectability of malignancies.

RESULTS

Both for tumour identification and resectability, MSCT and MRI had comparable diagnostic accuracy, with no statistically significant differences between them. Tumour identification CT/MRI: accuracy 98/98%, sensitivity 100/100%, specificity 88/88%, PPV 97/97%, NPV 100/100%; tumour resectability CT/MRI: accuracy 94/90%, sensitivity 92/88%, specificity 100/100%, PPV 100/100%, NPV 78/70%.

CONCLUSIONS

MRI represents a valid diagnostic alternative to CT in the evaluation of patients with pancreatic masses, both for correct identification and characterisation of primary lesions and to establish resectability in the case of malignancies. New high-field MRI equipment allows optimal imaging quality with good contrast resolution in evaluating the upper abdomen.

Extrapancreatic neural plexus invasion by pancreatic carcinoma: characteristics on magnetic resonance imaging

BACKGROUND

Our objective is to study the characteristics of extrapancreatic neural plexus invasion by pancreatic carcinoma on MR imaging.

METHODS

20 patients with both pancreatic carcinoma and extrapancreatic neural plexus invasion confirmed by pathology were recruited in this study. MR imaging was performed within 1 month before surgery. On MR images, signal intensity at the site of potential extrapancreatic neural plexus invasion, lymph nodes and tumor size were noted. The relationship of extrapancreatic neural plexus invasion to these findings was analyzed.

RESULTS

Signs of extrapancreatic neural plexus invasion were depicted on MR imaging in 80% of patients, which included streaky and strand-like signal intensity structure in fat tissue in 50% of patients and irregular masses adjacent to tumor in 30%. Signal intensity at invasion site was similar to that of pancreatic carcinoma. The frequencies of patients with vascular invasion and with lymph nodes larger than 5 mm were, respectively, 50% and 55%. Tumor diameter was 24 +/- 7 mm on MR imaging. Extrapancreatic neural plexus invasion was correlated with vascular invasion (r = 0.58, P < 0.005), slightly related with lymphadenopathy (r = 0.35, 0.1 > P > 0.05), but not related with tumor size.

CONCLUSION

MR imaging is useful to depict extrapancreatic neural plexus invasion by pancreatic carcinoma.

Preoperative evaluation of pancreatic cancer: comparison of gadolinium-enhanced dynamic MRI with MR cholangiopancreatography versus MDCT

PURPOSE

To determine the accuracy of magnetic resonance imaging (MRI) including dynamic imaging using three-dimensional gradient-echo (3D-GRE) sequences and MR cholangiopancreatograpy (MRCP) compared with that of multidetector row CT (MDCT) with regard to resectability in pancreas cancer.

MATERIALS AND METHODS

From February 2004 to July 2008, 54 patients (32 men, 22 women: age range, 28-83 years; mean age, 63.1 years old) with surgically proven pancreatic carcinoma, who had undergone preoperative gadolinium-enhanced 3D-GRE MRI with MRCP and triple-phase MDCT, were included in this retrospective study. Two, clinically experienced attending radiologists independently reviewed the two image sets. These readers evaluated the tumor conspicuity, presence of vascular invasion, choledochal and duodenal invasion, lymph node metastases, distant metastasis, and tumor resectability. The results were compared with the surgical and histopathologic findings using receiver operating characteristic analysis (Az) and kappa statistics.

RESULTS

Curative resections were performed on 42 patients. Regarding the tumor conspicuity, MRI had a significantly higher Az value compared with MDCT according to both reviewers (P < 0.05). The accuracy of resectability was Az = 0.753 and 0.768 on MRI and Az = 0.829 and 0.762 on MDCT for each reviewer, and the difference in the accuracy of resectability was not significant between MRI and MDCT for either reviewer (P > 0.05). Two imaging sets showed a similar diagnostic performance in the evaluation of vascular involvement, lymph node metastasis, and distant metastasis.

CONCLUSION

Dynamic 3D-GRE MRI with MRCP shows superior tumor conspicuity and similar diagnostic performance compared with MDCT in evaluating the resectability of pancreatic cancer.

Mass-forming pancreatitis with positive fluoro-2-deoxy-D: -glucose positron emission tomography and positive diffusion-weighted imaging-magnetic resonance imaging: Report of a case

It is difficult to make an accurate radiological diagnosis of a pancreatic tumor because of its location and anatomical characteristics. Mass-forming pancreatitis and pancreatic cancer are particularly difficult to differentiate. New diagnostic technology, which includes diffusion-weighted imaging-magnetic resonance imaging (DWI-MRI) and 2-[(18)F]-fluoro-2-deoxy-Dglucose positron emission tomography (FDG-PET), offers hope for the detection of classical pancreatic cancer. Few studies have been conducted on FDG-PET and DWI-MRI as tools used to distinguish between mass-forming pancreatitis and pancreatic cancers. Furthermore, positive findings of mass-forming pancreatitis on DWI-MRI and FDG-PET have yet to be documented. We report a case of a pancreatic head tumor, present on FDG-PET and DWI-MRI which, on closer examination, revealed benign mass-forming pancreatitis. We discuss the utility of FDG-PET and DWI-MRI as preoperative diagnostic tools.

Magnetic resonance imaging of adenocarcinoma of the pancreas

Magnetic resonance imaging (MRI) is a valuable tool in the assessment of the full spectrum of pancreatic disease. A standard MR protocol including noncontrast T1-weighted fat-suppressed and dynamic gadolinium-enhanced gradient-echo imagings is sensitive for the evaluation of pancreatic cancer. Optimal use of MRI in the investigation of pancreatic cancer occurs in the following circumstances: (1) detection of small non-contour-deforming tumors, (2) evaluation of local extension and vascular encasement, (3) determination of the presence of lymph node and peritoneal metastases, and (4) determination and characterization of associated liver lesions and liver metastases. The objective of this study was to describe the attribute of MRI for evaluating pancreatic cancer.

MR imaging for predicting the recurrence of pancreatic carcinoma after surgical resection

OBJECTIVE

To study the relationship of characteristics of pancreatic carcinoma on MR imaging to tumor recurrence time after surgical resection.

MATERIALS AND METHODS

Twenty-seven patients with pancreatic carcinoma were followed up at least 2 years after surgical resection of the tumor. All patients had MR imaging within 1 month before surgery. The tumor's size, signal intensity, local and vascular invasion, abdominal lymphadenopathy on MR imaging and the positive surgical margin were noted. The results from MR imaging were compared with the duration after surgery until tumor recurrence and with the positive surgical margin.

RESULTS

59% of patients had various degree of extrapancreatic invasion. The tumor recurrence times were, respectively, 24+/-21 months and 26+/-29 months in patients with and without vascular invasion (P=0.79). The combination of vascular with local invasion showed a correlation to the time of tumor recurrence (r=-0.34; P<0.05). Patients with positive surgical margins had a higher local invasion score on MR imaging and a shorter recurrence time than those with negative surgical margins. The number and size of lymph nodes were not related with tumor recurrence time.

CONCLUSION

MR imaging was useful for predicting the recurrence of pancreatic carcinoma after surgical resection. Local invasion associated with and without vascular invasion on MR imaging was the indicator for the tumor recurrence.

State-of-the-art magnetic resonance imaging of pancreatic cancer

Technical advances of magnetic resonance imaging (MRI), including ultrahigh-field magnetic resonance at 3.0 T, parallel imaging techniques, and multichannel receive coils of the abdomen, have promoted MRI of the pancreas. For adenocarcinoma, which is the most common malignant pancreatic tumor, helical CT has been most often used for detection and staging, but it has limitations in the detection of small cancers 2 cm in diameter or less (sensitivity, 63%). Moreover, it is not very accurate in determining nonresectability, because small liver metastases, peritoneal carcinomatosis, and subtle signs of vascular infiltration may be missed. At ultrahigh field at 3.0 T, gadolinium-enhanced MRI using volume-interpolated 3-dimensional gradient-recalled echo pulse sequences with near-isotropic voxels are very useful for detection of subtle abnormalities. Mangafodipir-enhanced MRI reveals a very high tumor-pancreas contrast, which helps to diagnose small cancers. Contrast-enhanced MRI is a problem-solving tool in case of equivocal CT: it helps to differentiate between cancer and focal pancreatitis. Neuroendocrine carcinoma may present with a spectrum of appearances at MRI, but the primary tumor and liver metastases are hypervascular in approximately 70%. In this article, pancreas imaging protocols for 1.5 and 3.0 T are explained. We present the imaging features of pancreatic cancer and the important questions in staging, which should be addressed by the radiologist.

[Pancreas. Part II: Tumors]

Adenocarcinoma is the most common malignant pancreatic tumor, affecting the head in 60-70% of cases. By the time of diagnosis, approximately 80% of tumors are unresectable. Helical CT is very effective in detection and staging of adenocarcinoma, with a sensitivity of 76-92% for detection and an accuracy of 80-90% for staging, but it has limitations in the detection of small cancers (< or =2 cm). Multidetector CT (MDCT) has brought substantial improvements with its inherent 3D imaging capability. Mangafodipir-enhanced MRI is a problem-solving tool in the depiction of small cancers following an equivocal CT imaging result. Gadolinium-enhanced 3D gradient-echo MRI is helpful in the assessment of vascular invasion of cancer and in determining the etiology of cystic lesions. Serous cystadenoma is benign, has a lobulated contour and contains innumerable small cysts of 0.1-2 cm in diameter. Mucinous cystic neoplasms are unilocular or multilocular (fewer than six cysts), and the cyst diameter exceeds 2 cm. The presence of solid nodular components should alert the radiologist to suspect cystadenocarcinoma. Neuroendocrine tumors are mostly hypervascular. Diagnosis of insulinoma is a challenge: they are <2 cm in 90% of cases and mostly hypervascular at CT or MRI. A combination of contrast-enhanced MDCT, MRI, endosonography, and/or somatostatin receptor scintigraphy is used to detect these small tumors. This review summarizes the imaging features of the most common pancreatic tumors and discusses the limitations of CT, MRI and endosonography.

Pancreatic adenocarcinoma

Adenocarcinoma is the most common malignant pancreatic tumor, affecting the head of the pancreas in 60-70% of cases. By the time of diagnosis, at least 80% of tumors are unresectable. Helical computed tomography (CT) is very effective in detecting and staging adenocarcinoma, with a sensitivity of up to 90% for detection and an accuracy of 80-90% for staging, but it has limitations in detecting small cancers. Moreover, it is not very accurate for determining nonresectability because small liver metastases, peritoneal carcinomatosis, and subtle signs of vascular infiltration may be missed. Multidetector-row CT (MDCT) has brought substantial improvements with its inherent ability to visualize vascular involvement in three dimensions. MDCT has been found to be at least equivalent to contrast-enhanced magnetic resonance imaging (MRI) for detecting adenocarcinoma. MRI can be used as a problem-solving tool in equivocal CT: MRI may help rule out pitfalls, such as inflammatory pseudotumor, focal lipomatosis, abscess, or cystic tumors. Mangafodipir-enhanced MRI reveals a very high tumor-pancreas contrast, which helps in diagnosing small cancers. Endosonography is, if available, also a very accurate tool for detecting small cancers, with a sensitivity of up to 98%. It is the technique of choice for image-guided biopsy if a histologic diagnosis is required for further therapy.

Diagnóstico y estadificación del carcinoma de páncreas (I)

Carcinoma of the pancreas is a neoplasm with a poor prognosis that is diagnosed in the advanced stages in most patients. Given that surgical resection is the only potentially curative treatment for this disease, it is of the utmost importance to appropriately select the group of patients with initial stage pancreatic tumors that have not extended and can therefore be resected. Several different imaging techniques can be used for this purpose: ultrasonography (US), computed tomography (CT), magnetic resonance (MR), as well as the recent additions of endoscopic ultrasonography (EUS) and positron emission tomography (PET). Other techniques, such as laparoscopy and laparoscopic ultrasonography, also play a role in the diagnosis and staging of these patients. Continual technological developments in each of the above-mentioned techniques have led to reiterated updates in the scientific literature throughout the last two decades. This review aims to evaluate each of these techniques and present diagnostic algorithms reflected in the literature in order to achieve the greatest diagnostic accuracy in determining the extent of the disease so that unnecessary surgery can be avoided in cases not susceptible to resection.

Pancreatic adenocarcinoma: MDCT versus MRI in the detection and assessment of locoregional extension

PURPOSE

To compare dynamic-contrast enhanced multirow detector computed tomography (MDCT) including multiplanar reformatted images (MPR) and magnetic resonance imaging (MRI) including magnetic resonance cholangiopancreatography images for the detection and assessment of locoregional extension of pancreatic adenocarcinoma.

MATERIALS AND METHODS

Twenty-four patients with and 21 patients without pancreatic adenocarcinoma underwent triple-phase MDCT and MRI. Three radiologists independently attempted to detect pancreatic adenocarcinoma and assess locoregional extension in 3 sessions. First session involved MDCT images. In the second session, radiologists had access to coronal and sagittal MPR images together with the axial images (MDCT + MPR). Third session involved MR images. Results were compared with surgical findings using receiver operating characteristic analysis and kappa statistics.

RESULTS

Regarding tumor detection, MDCT + MPR had a significantly higher value for areas under the curve (0.96 +/- 0.02) at receiver operating characteristic analysis compared with those of MRI (0.90 +/- 0.03) and MDCT (0.85 +/- 0.04). MDCT + MPR had the highest mean sensitivity (96%), and MRI had the highest mean specificity (98%). For locoregional extension, MDCT + MPR showed the highest kappa values of the study for all factors evaluated (range, 0.63-0.86).

CONCLUSIONS

In conclusion, multiphasic MDCT imaging with MPR images was superior to multiphasic MDCT imaging without MPR images and to comprehensive MRI employing 2-D sequences and magnetic resonance cholangiopancreatography for both the detection and assessment of locoregional extension of pancreatic adenocarcinomas. MRI might be used for further lesion characterization regarding its high specificity.

Pancreatic head cancer: accuracy of CT in determination of resectability

BACKGROUND

Pancreatic cancer is a devastating disease whose early detection remains difficult. There is no 100% reliable imaging test to diagnose and stage pancreatic cancer. We assessed the surgical value of contrast-enhanced spiral computed tomography (CT) in predicting the resectability and survival rates of patients who had pancreatic head cancer.

METHODS

Eighty-nine patients who had pancreatic head cancer were investigated with spiral CT. Based on the preoperative CT results, we assigned patients to one of three CT groups based on resectability.

RESULTS

A correlation between classification of CT resectability and intraoperative finding was found in 83% of patients. The sensitivity, specificity, negative predictive value, positive predictive value, and accuracy of spiral CT in identifying predictive unresectability were 79%, 82%, 91%, 62%, and 81%, respectively. Sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of CT in diagnosis of vascular invasion were 94%, 84.2%, 94%, 84%, and 91.3%, respectively.

CONCLUSION

The use of CT in the evaluation of pancreatic tumors provides valuable preoperative assessment of surgical resectability and should be performed for clinical examination. Classifying patients by tumor resectability on CT helps to estimate more precisely the tumor stage and to prognosticate survival rates of these patients.

[Imaging of pancreatic adenocarcinoma]

Pancreatic cancer remains the fourth most common cause of cancer death. Surgery remains the only option for cure. Accurate diagnosis and staging are essential for appropriate management of patients with pancreatic cancer. This paper reviews the state of the art for imaging modalities in the diagnosis and staging of pancreatic adenocarcinoma. The crucial role of CT has increased with the new generation of multidetector CT.

Preoperative assessment of pancreatic tumors using magnetic resonance imaging, endoscopic ultrasonography, positron emission tomography and laparoscopy

BACKGROUND

The appropriate preoperative evaluation of a pancreatic tumor remains a matter of debate.

METHODS

We retrospectively evaluated an institutional strategy including magnetic resonance imaging (MRI), endoscopic ultrasonography (EUS), positron emission tomography (PET) and laparoscopy (LAP) for detection and staging of pancreatic tumors suspected to be malignant.

RESULTS

In a consecutive series of 59 patients screened by MRI, PET, EUS and LAP between July 1998 and November 2002, 48 patients were found to bear pancreatic adenocarcinoma and surgery was performed in 27 of them. For tumor detection, the sensitivity of EUS was superior to MRI and PET (98 vs. 87.5 and 87.5%, respectively, p = 0.13). MRI best assessed loco-regional staging, i.e. arterial involvement. For the detection of distant metastases, the sensitivity of all preoperative examinations taken separately was low. When laparotomy was performed with a curative intent according to all four examinations, occult metastasis or carcinomatosis was discovered in 7/27 patients and the overall predictive value of resectability was thus 74%. Five-year and median survival were significantly better in resected vs. non-resected patients (39% and 26 months vs. 0% and 8 months, p = 0.0006).

CONCLUSIONS

MRI can be recommended has the first examination in patients bearing pancreatic tumors, complemented by EUS if the findings of MRI are non-conclusive. For detection of distant metastasis, only the combination of all preoperative examination was proved to be more accurate than a single technique.

Assessment of publication bias in the reporting of EUS performance in staging rectal cancer

INTRODUCTION

Endoscopic ultrasound (EUS) has emerged as a promising diagnostic modality for locoregional staging of rectal cancer. However, as with any new technology, publication bias, the selective reporting of studies featuring positive results, may result in overestimation of the capability of EUS. The aim of this study was to systematically assess for publication bias in the reporting of the accuracy of EUS in staging rectal cancer.

METHODS

A MEDLINE search for all published estimates of EUS accuracy in staging rectal cancer between 1985 and 2003 was performed. All retrieved studies were fully published in the English literature. Published studies were analyzed and the following information was abstracted: accuracy of EUS, year of publication, number of subjects studied, impact factor of journal, and type of journal (gastroenterology, surgery, radiology, other).

RESULTS

Two hundred and two abstracts were reviewed; 41 publications met the stated criteria for inclusion. EUS T-staging accuracy was reported in 40 studies while EUS N-staging accuracy was reported in 27 studies. The experience of 4, 118 subjects was reported with an overall mean T-staging accuracy of 85.2% (median, 87.5%) and N-staging accuracy of 75.0% (median, 76.0%). There was a paucity of smaller studies expressing low EUS accuracy rates. Both T-staging and N-staging accuracy rates also declined over time with the lowest rates reported in more recent literature.

CONCLUSION

The performance of EUS in staging rectal cancer may be overestimated in the literature due to publication bias. This inflated estimate of the capability of EUS may lead to unrealistic expectations of this technology.

MRI combined with MR cholangiopancreatography versus helical CT in the evaluation of patients with suspected periampullary tumors: a prospective comparative study

PURPOSE

To establish the diagnostic accuracy of MRI including MR cholangiopancreatography (MRCP) compared with helical CT in the differentiation of malignant and benign lesions in the periampullary region.

MATERIAL AND METHODS

Fifty-one patients (27 M, 24 F, mean age 66 years, range 39-86 years) with obstructive jaundice and sonographic evidence of intra- and extrahepatic bile duct dilatation (n=31) or suspicion of periampullary tumor, based on previously performed ultrasound and/or CT examination (n=20), were studied. MRI with MRCP and helical CT were reviewed blindly under standardized conditions. Lesion status (differentiation of malignant versus benign) was rated on a 5-point diagnostic confidence scale. Reference standards for comparison were findings at surgery or laparoscopy and/ or the clinical outcome. The predictive value of imaging findings was determined with multivariate logistic regression analysis.

RESULTS

The areas under the receiver operating characteristic curve were 0.96 for MRI with MRCP and 0.81 for CT (P <0.05). Multivariate analysis of eight imaging variables at MRI indicated that a stricture with malignant characteristics at MRCP was the best predictor of malignancy.

CONCLUSION

MRI with MRCP was significantly more accurate than CT in differentiating between malignant and benign lesions in patients with suspected periampullary tumors, mainly due to the information obtained on the MRCP images of the biliary and pancreatic duct anatomy.

Improved targeting of pancreatic cancer: experimental studies of a new bispecific antibody, pretargeting enhancement system for immunoscintigraphy

PURPOSE

The early detection and diagnosis of pancreatic cancer remains a major clinical challenge in which imaging procedures have a central role. The purpose of this study was to evaluate a pretargeting method with a bispecific PAM4 (bsPAM4; anti-MUC1) antibody for radioimmunoscintigraphy of experimental human pancreatic cancer.

EXPERIMENTAL DESIGN

A bispecific F(ab')(2) antibody was generated from chimeric PAM4 Fab' and murine 734 (anti-indium-diethylenetriaminepentaacetic acid) Fab' fragments and then used in conjunction with 2 peptide haptens ((111)In-IMP-156 and (99m)Tc-IMP-192). Biodistribution studies and radioimmunoscintigraphic imaging properties of the radiolabeled bsPAM4, and pretargeted, radiolabeled peptides were examined in the CaPan1 human pancreatic tumor grown as s.c. xenografts in athymic nude mice. Tumor uptake and tumor:nontumor ratios were compared with a nontargeting irrelevant anti-CD20, bispecific rituximab, radiolabeled peptides alone, and with directly labeled PAM4.

RESULTS

Biodistribution results indicated significantly greater tumor uptake of radiolabeled peptides at 3 h after injection when pretargeting was performed with bsPAM4 as compared with the bispecific rituximab [20.2 +/- 5.5 percentage of injected dose per gram of tissue (%ID/g) versus 0.9 +/- 0.1%ID/g, respectively, for (111)In-IMP-156, and 16.8 +/- 4.8%ID/g versus 1.1 +/- 0.2%ID/g, respectively, for (99m)Tc-IMP-192]. Similar results were obtained at the 24-h time point. Tumor:nontumor ratios were >30 for all of the tissues except the kidneys, where a ratio of 7.8 +/- 2.8 was observed. By immunoscintigraphy, tumors could be visualized as early as 30 min after injection of the radiolabeled peptide.

CONCLUSIONS

These studies demonstrate the feasibility of using the pretargeted, bispecific antibody technology for nuclear imaging of pancreatic cancer. The advantage of pretargeted bsPAM4 antibody as an imaging platform is the high specificity for pancreatic cancer as compared with the physicochemical parameters identified by current imaging technologies.

Endoscopic retrograde cholangiopancreatography, intraductal ultrasonography, and magnetic resonance cholangiopancreatography in bile duct strictures: a prospective comparison of imaging diagnostics with histopathological correlation

OBJECTIVES

A variety of imaging techniques are available to diagnose bile duct strictures; the most effective imaging technique, however, has not been established yet. In the present study, we compared the impact of endoscopic retrograde cholangiopancreatography (ERCP), intraductal ultrasonography (IDUS), and magnetic resonance cholangiopancreatography (MRCP) with regard to diagnosing bile duct strictures.

METHODS

We prospectively examined 33 patients with jaundice due to bile duct strictures by ERCP plus IDUS and MRCP. The objectives were to assess diagnostic quality of imaging, complete presentation of the bile duct, and differentiation of malignant from benign lesions. Surgical and histopathological correlations, which were used as the gold standard, were available in all cases since all included patients underwent laparotomy.

RESULTS

Diagnostic image quality for ERCP was 88% and 76% for MRCP (p > 0.05). Comparing ERCP and MRCP, complete presentation of the biliary tract was achieved in 94% and 82%, respectively (p > 0.05). ERCP and MRCP allowed correct differentiation of malignant from benign lesions in 76% and 58% (p= 0.057), respectively. By supplementing ERCP with IDUS, the accuracy of correct differentiation of malignant from benign lesions increased significantly to 88% (p= 0.0047).

CONCLUSIONS

Comparing ERCP with MRCP, we found adequate presentation of bile duct strictures in high imaging quality for both techniques. ERCP supplemented by IDUS gives more reliable and precise information about differentiation of malignant and benign lesions than MRCP alone without additional imaging sequences.

Role of CT and MR in detection and staging of pancreatic adenocarcinoma

In this review article, the roles of imaging with CT and MRI in the detection and staging of pancreatic carcinoma will be discussed. The frequently employed techniques using these modalities, the common imaging appearances of this tumor, and the limitations of imaging will be addressed.

Preoperative TN staging of esophageal cancer: Comparison of miniprobe ultrasonography, spiral CT and MRI

AIM: To evaluate the value of miniprobe sonography (MPS), spiral CT and MR imaging (MRI) in the tumor and regional lymph node staging of esophageal cancer.

METHODS: Eight-six patients (56 men and 30 women; age range of 39-73 years, mean 62 years) with esophageal carcinoma were staged preoperatively with imaging modalities. Of them, 81 (94%) had squamous cell carcinoma, 4 (5%) adenocarcinoma, and 1 (1%) adenoacanthoma. Eleven patients (12%) had malignancy of the upper one third, 41 (48%) of the mid-esophagus and 34 (40%) of the distal one third. Forty-one were examined by spiral CT in whom 13 were co-examined by MPS, and forty-five by MRI in whom 18 were also co-examined by MPS. These imaging results were compared with the findings of the histopathologic examination for resected specimens.

RESULTS: In staging the depth of tumor growth, MPS was significantly more accurate (84%) than spiral CT and MRI (68% and 60%, respectively, P < 0.05). The specificity and sensitivity were 82% and 85% for MPS; 60% and 69% for spiral CT; and 40% and 63% for MRI, respectively. In staging regional lymph nodes, spiral CT was more accurate (78%) than MPS and MRI (71% and 64%, respectively), but the difference was not statistically significant. The specificity and sensitivity were 79% and 77% for spiral CT; 75% and 68% for MPS; and 68% and 62% for MRI, respectively.

CONCLUSION: MPS is superior to spiral CT or MRI for T staging, especially in early esophageal cancer. However, the three modalities have the similar accuracy in N staging. Spiral CT or MRI is helpful for the detection of far-distance metastasis in esophageal cancer.

Diagnosis and staging of pancreatic cancer: comparison of mangafodipir trisodium-enhanced MR imaging and contrast-enhanced helical hydro-CT

OBJECTIVE

The purpose of this study was to compare mangafodipir trisodium-enhanced MR imaging performed with a phased array coil and contrast-enhanced single-detector helical CT for accuracy in the detection and local staging of pancreatic adenocarcinoma and in the differentiation between cancer and focal pancreatitis.

SUBJECTS AND METHODS

Forty-two patients with suspected pancreatic masses underwent contrast-enhanced helical CT and mangafodipir trisodium-enhanced MR imaging at 1.5 T. The images were assessed for the presence or absence of tumors; characterization of masses; and presence of vascular invasion, lymph node metastases, or liver metastases. Imaging findings were correlated with findings at laparotomy, laparoscopy, biopsy, or follow-up.

RESULTS

Focal masses were present in 36 patients (cancer, n = 26; focal pancreatitis, n = 7; other, n = 3). The sensitivity for lesion detection of MR imaging was 100% and of CT, 94%. Two small malignant lesions were missed on CT. For the diagnosis of tumor nonresectability, the sensitivity of MR imaging and CT was 90% and 80%, respectively. Liver metastases were missed on MR imaging in one of the eight patients and on CT in four. For differentiation between adenocarcinoma and nonadenocarcinoma, the sensitivity of MR imaging was 100% (positive predictive value, 90%; negative predictive value, 100%), and the sensitivity of CT was 92% (positive predictive value, 80%; negative predictive value, 67%). Receiver operating characteristic analysis revealed that the mean area under the curve for MR imaging was 0.920 and for CT, 0.832 (not significant).

CONCLUSION

Mangafodipir trisodium-enhanced MR imaging is as accurate as contrast-enhanced helical CT for the detection and staging of pancreatic cancer but offers improved detection of small pancreatic metastases and of liver metastases compared with CT.

MR imaging of ampullary carcinomas

OBJECTIVE

The purpose of this study was to demonstrate the appearance of ampullary carcinomas on MR images.

METHODS

Sixteen patients with ampullary carcinomas underwent MR imaging. Tumor detectability, signal intensity of the tumor, and enhancement pattern on dynamic study were analyzed. MR cholangiopancreatography (MRCP) findings were assessed and were compared with the endoscopic retrograde cholangiopancreatography (ERCP) findings.

RESULTS

Signal intensities of the tumor on each image were various. Dynamic study detected all tumors except one, and all detected tumors showed delayed enhancement. MRCP delineated more than half of the tumors as a filling defect within the duodenal fluid and clearly demonstrated pancreaticobiliary ductal.

CONCLUSIONS

Dynamic study is mandatory in diagnosing ampullary carcinoma, because it can depict most of the tumors, and delayed enhancement of such tumors is characteristic in case of ampullary carcinoma. MRCP can provide reliable information about pancreaticobiliary duct and it can replace diagnostic ERCP.

Imaging pancreatic cancer: the role of multidetector CT with three-dimensional CT angiography

Over the past two decades, there have been significant technical advancements in computed tomography (CT). This has allowed CT to remain the gold standard for the evaluation of pancreatic pathology despite the advent of other imaging modalities, including MRI, PET and endoscopic ultrasound. Initially, CT scanners could only obtain 10-mm-thick slices at a rate of 4 slices per minute. Today, the current state of the art is multidetector CT (MDCT) technology, which allows the entire pancreas to be imaged by 1-mm slices in under 20 s. In addition, these new scanners allow true volume acquisition. The resultant data sets can be displayed not only as axial slices but also as a three-dimensional (3D) volume. The detail of these reconstructions when performed with volume rendering and maximum intensity projection techniques allows a detailed vascular mapping with accuracy that may exceed classic angiography. The use of thin collimation and dual-phase acquisition also improves the detection of hepatic metastasis as well as other sites of extrapancreatic disease. This article reviews the current state of the art of pancreatic imaging with specific emphasis on the use of MDCT, volume acquisitions and 3D arterial- and venous-phase vascular mapping. The advantages of these techniques and their impact on diagnosis and patient management are also addressed.

Endoscopic retrograde cholangiopancreatography should no longer be used as a diagnostic test: the case in favour

The requirement for diagnostic endoscopic retrograde cholangiopancreatography has decreased considerably in the past 10 years. Alternative imaging techniques are now available for the diagnosis of bile duct stones, pancreatic and biliary tract malignancy and inflammatory diseases such as sclerosing cholangitis and chronic pancreatitis. The imaging techniques include endoscopic ultrasonography, magnetic resonance cholangiopancreatography and helical computed tomography. There is good evidence that these techniques have an accuracy comparable to endoscopic retrograde cholangiopancreatography in the diagnosis of diseases of the bile and pancreatic ducts. All of these methods are less invasive than endoscopic retrograde cholangiopancreatography and have extremely low or negligible complication rates. The choice of technique used depends on local availability and expertise. In future, endoscopic retrograde cholangiopancreatography will be reserved exclusively for therapeutic applications.

Pancreatic carcinoma: MR, MR angiography and dynamic helical CT in the evaluation of vascular invasion

OBJECTIVE

To assess the value of MR angiography in combination with contrast-enhanced MR imaging, and to compare MR imaging including MR angiography with dynamic contrast-enhanced dual phase helical CT in the preoperative assessment of vascular invasion in patients with suspected pancreatic carcinoma.

METHODS AND MATERIAL

MR imaging only, MR imaging including MR angiography and dynamic contrast-enhanced dual phase helical CT images of 48 patients who were operated due to suspicion of pancreas cancer were correlated with the surgery results in terms of vascular invasion. Pathologic diagnosis were pancreatic adenocarcinoma in 31 patients of which nine had surgically confirmed vascular invasion. Sensitivity, specificity, predictive values (including 95% confidence intervals) and accuracy of MR imaging only, MR imaging including MR angiography and helical CT were calculated.

RESULTS

Sensitivity, specificity, positive and negative predictive values and accuracy were 56, 100, 100, 85, 87%; 67, 100, 100, 88, 90% and 67, 100, 100, 88, 90%, respectively, for MR imaging only, MR imaging including MR angiography and helical CT in the adenocarcinoma group. The corresponding figures in the overall study group were 56, 97, 83, 90, 90%; 67, 97, 86, 93, 92% and 67, 97, 86, 93, 92%. Confidence intervals (95%) showed that the differences in the diagnostic efficacy of the techniques were not statistically significant in the overall study group, but the confidence intervals were undefined in the adenocarcinoma group due to the small sample size.

CONCLUSION

Diagnostic efficacy of MR imaging when combined with MR angiography is equal to that of dynamic contrast-enhanced dual phase helical CT in the assessment of vascular invasion of pancreatic tumors.