Comparison and evaluation of methods for liver segmentation from CT datasets

This paper presents a comparison study between 10 automatic and six interactive methods for liver segmentation from contrast-enhanced CT images. It is based on results from the "MICCAI 2007 Grand Challenge" workshop, where 16 teams evaluated their algorithms on a common database. A collection of 20 clinical images with reference segmentations was provided to train and tune algorithms in advance. Participants were also allowed to use additional proprietary training data for that purpose. All teams then had to apply their methods to 10 test datasets and submit the obtained results. Employed algorithms include statistical shape models, atlas registration, level-sets, graph-cuts and rule-based systems. All results were compared to reference segmentations five error measures that highlight different aspects of segmentation accuracy. All measures were combined according to a specific scoring system relating the obtained values to human expert variability. In general, interactive methods reached higher average scores than automatic approaches and featured a better consistency of segmentation quality. However, the best automatic methods (mainly based on statistical shape models with some additional free deformation) could compete well on the majority of test images. The study provides an insight in performance of different segmentation approaches under real-world conditions and highlights achievements and limitations of current image analysis techniques.

CT diagnosis of recurrence after pancreatic cancer: Is there a pattern?

AIM: To investigate predilection sites of recurrence of pancreatic cancer by computed tomography (CT) in follow-up after surgery.

METHODS: Seventy seven patients with recurrence after pancreatic cancer surgery were retrospectively identified. The operative technique, R-status, T-stage and development of tumor markers were evaluated. Two radiologists analyzed CT scans with consensus readings. Location of local recurrence, lymph node recurrence and organ metastases were noted. Surgery and progression of findings on follow-up CT were considered as reference standard.

RESULTS: The mean follow-up interval was 3.9 ± 1.8 mo, with a mean relapse-free interval of 12.9 ± 10.4 mo. The predominant site of recurrence was local (65%), followed by lymph node (17%), liver metastasis (11%) and peritoneal carcinosis (7%). Local recurrence emerged at the superior mesenteric artery (n = 28), the hepatic artery (n = 8), in an area defined by the surrounding vessels: celiac trunk, portal vein, inferior vena cava (n = 22), and in a space limited by the mesenteric artery, portal vein and inferior vena cava (n = 17). Lymph node recurrence occurred in the mesenteric root and left lateral to the aorta. Recurrence was confirmed by surgery (n = 22) and follow-up CT (n = 55). Tumor markers [carbohydrate antigen 19-9 (CA19-9), carcinoembryonic antigen (CEA)] increased in accordance with signs of recurrence in most cases (86% CA19-9; 79.2% CEA).

CONCLUSION: Specific changes of local and lymph node recurrence can be found in the course of the cardinal peripancreatic vessels. The superior mesenteric artery is the leading structure for recurrence.

The impact of 3-dimensional reconstructions on operation planning in liver surgery

BACKGROUND

Operation planning in liver surgery depends on the precise understanding of the 3-dimensional (D) relation of the tumor to the intrahepatic vascular trees. To our knowledge, the impact of anatomical 3-D reconstructions on precision in operation planning has not yet been studied.

HYPOTHESIS

Three-dimensional reconstruction leads to an improvement of the ability to localize the tumor and an increased precision in operation planning in liver surgery.

DESIGN

We developed a new interactive computer-based quantitative 3-D operation planning system for liver surgery, which is being introduced to the clinical routine. To evaluate whether 3-D reconstruction leads to improved operation planning, we conducted a clinical trial. The data sets of 7 virtual patients were presented to a total of 81 surgeons in different levels of training. The tumors had to be assigned to a liver segment and subsequently drawn together with the operation proposal into a given liver model. The precision of the assignment to a liver segment according to Couinaud classification and the operation proposal were measured quantitatively for each surgeon and stratified concerning 2-D and different types of 3-D presentations.

RESULTS

The ability of correct tumor assignment to a liver segment was significantly correlated to the level of training (P<.05). Compared with 2-D computed tomography scans, 3-D reconstruction leads to a significant increase of precision in tumor localization by 37%. The target area of the resection proposal was improved by up to 31%.

CONCLUSION

Three-dimensional reconstruction leads to a significant improvement of tumor localization ability and to an increased precision of operation planning in liver surgery.

Intravoxel incoherent motion MRI for the differentiation between mass forming chronic pancreatitis and pancreatic carcinoma

PURPOSE

To determine which of the quantitative parameters obtained from intravoxel incoherent motion diffusion weighted imaging (DWI) is the most significant for the differentiation between pancreatic carcinoma and mass-forming chronic pancreatitis.

MATERIALS AND METHODS

Twenty-nine patients with pancreatic masses were included, 9 proved to have a mass-forming pancreatitis and 20 had a pancreatic carcinoma. The patients were studied using intravoxel incoherent motion DWI with 11 b-values and the apparent diffusion coefficient (ADC), the true diffusion constant (D) and the perfusion fraction (f) were calculated. The diagnostic strength of the parameters was evaluated using receiver operating characteristic analysis.

RESULTS

The ADC in chronic pancreatitis was higher than in pancreatic carcinoma with significant differences at b = 50, 75, 100, 150, 200, 300 s/mm (ADC50 = 3.17 ± 0.67 vs. 2.55 ± 1.09, ADC75 = 2.46 ± 0.4 vs. 1.93 ± 0.52, ADC100 = 2.28 ± 0.48 vs. 1.73 ± 0.45, ADC150 = 1.97 ± 0.26 vs. 1.63 ± 0.40, ADC200 = 1.98 ± 0.24 vs. 1.53 ± 0.28, and ADC300 = 1.76 ± 0.19 vs. 1.46 ± 0.31 × 10(-3) mm2/s). No significant differences were found at b = 25, 400, 600, and 800 s/mm (ADC25 = 4.69 ± 0.65 vs. 4.04 ± 1.35, ADC400 = 1.57 ± 0.21 vs. 1.37 ± 0.30, ADC600 = 1.38 ± 0.18 vs. 1.24 ± 0.25, and ADC800 = 1.27 ± 0.10 vs. 1.18 ± 0.19 × 10(-3) mm2/s) nor using ADCtot (1.42 ± 0.23 vs. 1.28 ± 0.12 × 10(-3) mm2/s). The perfusion fraction f was significantly higher in pancreatitis compared with pancreatic carcinoma (16.3% ± 5.30% vs. 8.2% ± 4.00%, P = 0.0001). There was no significant difference between groups for D (1.07 ± 0.224 × 10(-3) mm2/s for chronic pancreatitis and 1.09 ± 0.3 × 10(-3) mm2/s for pancreatic carcinoma, P = 0.66). For f, the highest area under the curve (0.894) and combined sensitivity (80%) and specificity (89.9%) were found.

CONCLUSIONS

There were significant differences in ADC50-300 between chronic pancreatitis and pancreatic carcinoma. Because D is not significantly different between groups, differences in ADC can be attributed mainly to differences in perfusion. The perfusion fraction f proved to be the superior DWI-derived parameter for differentiation of mass-forming pancreatitis and pancreatic carcinoma.

Re-resection for isolated local recurrence of pancreatic cancer is feasible, safe, and associated with encouraging survival

BACKGROUND

Local recurrence of pancreatic cancer occurs in 80% of patients within 2 years after potentially curative resections. Around 30% of patients have isolated local recurrence (ILR) without evidence of metastases. In spite of localized disease these patients usually only receive palliative chemotherapy and have a short survival.

PURPOSE

To evaluate the outcome of surgery as part of a multimodal treatment for ILR of pancreatic cancer.

METHODS

All consecutive operations performed for suspected ILR in our institution between October 2001 and October 2009 were identified from a prospective database. Perioperative outcome, survival, and prognostic parameters were assessed.

RESULTS

Of 97 patients with histologically proven recurrence, 57 (59%) had ILR. In 40 (41%) patients surgical exploration revealed metastases distant to the local recurrence. Resection was performed in 41 (72%) patients with ILR, while 16 (28%) ILR were locally unresectable. Morbidity and mortality were 25 and 1.8% after resections and 10 and 0% after explorations, respectively. Median postoperative survival was 16.4 months in ILR versus 9.4 months in metastatic disease (p < 0.0001). In ILR median survival was significantly longer after resection (26.0 months) compared with exploration without resection (10.8 months, p = 0.0104). R0 resection was achieved in 18 patients and resulted in 30.5 months median survival. Presence of metastases, incomplete resection, and high preoperative CA 19-9 serum values were associated with lesser survival.

CONCLUSIONS

Resection for isolated local recurrence of pancreatic cancer is feasible, safe, and associated with favorable survival outcome. This concept warrants further evaluation in other institutions and in randomized controlled trials.

Is preoperative chemotherapy followed by surgery the appropriate treatment for signet ring cell containing adenocarcinomas of the esophagogastric junction and stomach?

BACKGROUND

Recent data suggest primary resection as the preferable approach in patients with signet ring cell gastric cancer (SRC). The aim of our retrospective exploratory study was to evaluate the influence of SRC on prognosis and response in esophagogastric adenocarcinoma treated with neoadjuvant chemotherapy.

METHODS

A total of 723 locally advanced esophagogastric adenocarcinomas (cT3/4 N any) documented in a prospective database from two academic centers were classified according to the WHO definition for SRC (more than 50 % SRC) and analyzed for their association with response and prognosis after neoadjuvant treatment.

RESULTS

A total of 235 tumors (32.5 %) contained SRC. Median survival of SRC was 26.3 compared with 46.6 months (p < 0.001) for non-SRC. SRC were significantly associated with female gender, gastric localization, advanced ypT and R1/2 categories, and lower risk of surgical complications and anastomotic leakage (each p < 0.001). Clinical (21.1 vs. 33.7 %, p = 0.001) and histopathological response (less than 10 % residual tumor: 16.3 vs. 28.9 %, p < 0.001) were significantly less frequent in SRC. Clinical response (p = 0.003) and complete histopathological response (pCR) (3.4 %) (p = 0.003) were associated with improved prognosis in SRC. Clinical response, surgical complications, ypTN categories, but not SRC were independent prognostic factors in forward Cox regression analysis in R0 resected patients. Risk of peritoneal carcinomatosis was increased (p < 0.001), while local (p = 0.015) and distant metastases (p = 0.02) were less frequent than in non-SRC.

CONCLUSIONS

Prognosis of SRC is unfavorable. Although response to neoadjuvant chemotherapy is rare in SRC, it is associated with improved outcome. Thus, chemotherapy might not generally be abandoned in SRC. A stratification based on SRC should be included in clinical trials.

International comparison of the German evidence-based S3-guidelines on the diagnosis and multimodal treatment of early and locally advanced gastric cancer, including adenocarcinoma of the lower esophagus

BACKGROUND

Clinical guidelines are essential in implementing and maintaining nationwide stage-specific diagnostic and therapeutic standards. In 2011, the first German expert consensus guideline defined the evidence for diagnosis and treatment of early and locally advanced esophagogastric cancers. Here, we compare this guideline with other national guidelines as well as current literature.

METHODS

The German S3-guideline used an approved development process with de novo literature research, international guideline adaptation, or good clinical practice. Other recent evidence-based national guidelines and current references were compared with German recommendations.

RESULTS

In the German S3 and other Western guidelines, adenocarcinomas of the esophagogastric junction (AEG) are classified according to formerly defined AEG I-III subgroups due to the high surgical impact. To stage local disease, computed tomography of the chest and abdomen and endosonography are reinforced. In contrast, laparoscopy is optional for staging. Mucosal cancers (T1a) should be endoscopically resected "en-bloc" to allow complete histological evaluation of lateral and basal margins. For locally advanced cancers of the stomach or esophagogastric junction (≥T3N+), preferred treatment is preoperative and postoperative chemotherapy. Preoperative radiochemotherapy is an evidence-based alternative for large AEG type I-II tumors (≥T3N+). Additionally, some experts recommend treating T2 tumors with a similar approach, mainly because pretherapeutic staging is often considered to be unreliable.

CONCLUSIONS

The German S3 guideline represents an up-to-date European position with regard to diagnosis, staging, and treatment recommendations for patients with locally advanced esophagogastric cancer. Effects of perioperative chemotherapy versus chemoradiotherapy are still to be investigated for adenocarcinoma of the cardia and the lower esophagus.

Limits of Couinaud's liver segment classification: a quantitative computer-based three-dimensional analysis

PURPOSE

Traditionally, liver surgery relies on Couinaud's liver segment classification. As the position and shape of these segments are variable and their borders are hidden within the homogeneous liver mass, the accuracy of segment identification methods needs computer-aided reevaluation.

METHOD

The segmental liver anatomy of 23 patients receiving diagnostic helical CT scans because of suspected intrahepatic lesion was analyzed with the aid of a computer-based operation-planning system. We compared the standard Couinaud classification, which depends particularly on the main stems of portal and hepatic veins, with a method that calculates the segment borders by analyzing the complete portal venous tree. Volume, shape, and position of the liver segments found by each method were compared.

RESULTS

With reference to the portal vein-based method, segmental volumes were overestimated by the classic Couinaud method by up to 24% and underestimated to 13%. Volumes of Couinaud segments 4a, 7, and 8 were generally larger compared with those obtained by the portal vein-based method, whereas segments 3 and 6 were smaller. Gross variations were found in segments 5, 7, and 8. When shape and position were considered, poor correlation was found for five segments (median kappa = 0.35-0.45). Only segments 2, 7, and 8 had kappa values clearly above 0.45 in the majority of cases. The plane that divides the two hemilivers along the middle hepatic vein and the border between the left sector (segments 2 and 3) and the medial sector (4a and 4b) were found in both methods with very good conformity (kappa > 0.75).

CONCLUSION

Couinaud's method of dividing the liver into eight autonomous liver segments has to be accepted as a good approximation. Nevertheless, the volume, position, and shape of these segments and their segmental borders show significant variability.

Pharmacodynamics of streptavidin-coated cyanoacrylate microbubbles designed for molecular ultrasound imaging

OBJECTIVES

To assess the pharmacodynamic behavior of cyanoacrylate, streptavidin-coated microbubbles (MBs) and to investigate their suitability for molecular ultrasound imaging.

MATERIALS AND METHODS

Biodistribution of MBs was analyzed in tumor-bearing mice using gamma-counting, immunohistochemistry, flow cytometry, and ultrasound. Further, vascular endothelial growth factor receptor 2-antibody coupled MBs were used to image tumor neovasculature.

RESULTS

After 1 minute >90% of MBs were cleared from the blood and pooled in the lungs, liver, and spleen. Subsequently, within 1 hour a decent reincrease of MB-concentration was observed in the blood. The remaining MBs were removed by liver and spleen macrophages. About 30% of the phagocytosed MBs were intact after 48 hours. Shell fragments were found in the kidneys only. No relevant MB-accumulation was observed in tumors. In contrast, vascular endothelial growth factor receptor 2-specific MBs accumulated significantly within the tumor vasculature (P < 0.05).

CONCLUSIONS

The pharmacokinetic behavior of streptavidin-coated cyanoacrylate MBs has been studied. In this context, the low amount of MBs in tumors after >5 minutes is beneficial for specific targeting of angiogenesis.

Anti-angiogenic activity of VXM01, an oral T-cell vaccine against VEGF receptor 2, in patients with advanced pancreatic cancer: A randomized, placebo-controlled, phase 1 trial

VEGFR-2 is expressed on tumor vasculature and a target for anti-angiogenic intervention. VXM01 is a first in kind orally applied tumor vaccine based on live, attenuated Salmonella bacteria carrying an expression plasmid, encoding VEGFR-2. We here studied the safety, tolerability, T effector (Teff), T regulatory (Treg) and humoral responses to VEGFR2 and anti-angiogenic effects in advanced pancreatic cancer patients in a randomized, dose escalation phase I clinical trial. Results of the first 3 mo observation period are reported. Locally advanced or metastatic, pancreatic cancer patients were enrolled. In five escalating dose groups, 30 patients received VXM01 and 15 placebo on days 1, 3, 5, and 7. Treatment was well tolerated at all dose levels. No dose-limiting toxicities were observed. Salmonella excretion and salmonella-specific humoral immune responses occurred in the two highest dose groups. VEGFR2 specific Teff, but not Treg responses were overall increased in vaccinated patients. We furthermore observed a significant reduction of tumor perfusion after 38 d in vaccinated patients together with increased levels of serum biomarkers indicative of anti-angiogenic activity, VEGF-A, and collagen IV. Vaccine specific Teff responses significantly correlated with reductions of tumor perfusion and high levels of preexisting VEGFR2-specific Teff while those showing no antiangiogenic activity had low levels of preexisting VEGFR2 specific Teff, showed a transient early increase of VEGFR2-specific Treg and reduced levels of VEGFR2-specific Teff at later time points - pointing to the possibility that early anti-angiogenic activity might be based at least in part on specific reactivation of preexisting memory T cells.

Anaplastic pancreatic cancer: Presentation, surgical management, and outcome

BACKGROUND

Anaplastic pancreatic cancers are rare neoplasms. The available data are focused on pathologic and molecular features, and little is known about the clinical presentation and management. The outcome of operative exploration and resection is unknown.

METHODS

From a prospective database, all consecutive operations for anaplastic pancreatic cancer performed at our institution were identified. The clinicopathologic details were analyzed and the outcome was compared with a matched group of typical pancreatic ductal adenocarcinomas (nested case-control study).

RESULTS

Eighteen patients with anaplastic pancreatic cancer were identified. The patients had a median age of 64 years. The tumors were large (median diameter, 4 cm) and showed peripheral contrast enhancement in radiologic imaging. Fifteen (83%) patients underwent resection, a palliative bypass procedure was performed in 1 (6%) patient, and 2 patients underwent exploration with biopsy only. Perioperative morbidity was 39% and mortality was 6%. The median survival rate in patients with anaplastic pancreatic cancer was 5.7 months and was less than in the control group of patients with pancreatic ductal adenocarcinoma (15.7 months). In anaplastic pancreatic cancer, the median duration of survival was significantly greater after R0/R1 resection, as compared with palliative surgery (7.1 vs 2.3 months). The duration of survival was significantly greater in neoplasms with osteoclast-like giant cells. In 3 (17%) patients, long-term survival of 33, 49, and 161 months was observed.

CONCLUSION

Anaplastic pancreatic cancer is an aggressive type of pancreatic cancer with a short median survival; however, because of the observation of prolonged survival after resection, resection should be performed whenever possible. The presence of osteoclast-like giant cells is associated with a favorable prognosis.

Retained surgical sponge with migration into the duodenum and persistent duodenal fistula

Migration of a retained surgical sponge into the bowel is a rare cause of bowel obstruction. Thus far, there have not been any reports that the site of initial migration of the sponge was identified by imaging studies or surgical exploration because the onset of symptoms is usually delayed. Unique about the case presented herein is that a barium meal follow-through study revealed a duodenal fistula that had developed after uneventful cholecystectomy due to a retained surgical sponge that had migrated into the duodenum and obstructed the distal jejunum. Imaging findings are presented and discussed.

Fluid collection after distal pancreatectomy: a frequent finding

BACKGROUND

Fluid collections (FC) at the resection margin of the pancreatic stump after distal pancreatectomy (DP) are common radiological findings in follow-up scans. No recommendations exist regarding the management of such findings. The aim was to characterise incidence, risk factors, clinical impact and therapy of FC.

METHOD

Data of 209 patients who underwent DP between 07/2009 and 06/2011 were prospectively collected and analysed, regarding follow-up CT or MRI scan findings of FC at the resection margin. FC was defined as a cyst-like lesion >1 cm in diameter.

RESULTS

A follow-up with at least two cross-sectional images was available in 159/209 patients. In the first postoperative control, 68 patients showed an FC (43%). FC size was classified as <5 cm (n = 38 pat.), 5-10 cm (n = 24 pat.) and >10 cm (n = 6 pat.). 20 patients (30%) showed clinical symptoms. Six patients (9%) required specific treatment, all other FC showed spontaneous regression. No correlation with stump closure techniques or preceding postoperative pancreatic fistula was found (4/68 patients, 6%). Multivariate analysis revealed standard resections as the only significant factor for FC.

CONCLUSIONS

FCs at the resection margin after DP are frequent and harmless findings. Therapeutic interventions are required in only 9% of all FC patients.

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

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

A phase 1 trial extension to assess immunologic efficacy and safety of prime-boost vaccination with VXM01, an oral T cell vaccine against VEGFR2, in patients with advanced pancreatic cancer

VXM01 is a first-in-kind orally applied tumor vaccine based on live attenuated Salmonella typhi carrying an expression plasmid encoding VEGFR2, an antigen expressed on tumor vasculature and a stable and accessible target for anti-angiogenic intervention. A recent randomized, placebo-controlled, phase I dose-escalation trial in advanced pancreatic cancer patients demonstrated safety, immunogenicity and transient, T-cell response-related anti-angiogenic activity of four priming vaccinations applied within one week. We here evaluated whether monthly boost vaccinations are safe and can sustain increased frequencies of vaccine-specific T cells. Patients with advanced pancreatic cancer were randomly assigned at a ratio of 2:1 to priming with VXM01 followed by up to six monthly boost vaccinations, or placebo treatment. Vaccinations were applied orally at two alternative doses of either 10⁶ colony-forming units (CFU) or 10⁷ CFU, and concomitant treatment with standard-of-care gemcitabine during the priming phase, and any treatment thereafter, was allowed in the study. Immunomonitoring involved interferon-gamma (IFNγ) ELIspot analysis with long overlapping peptides spanning the entire VEGFR2 sequence. A total of 26 patients were treated. Treatment-related adverse events preferentially associated with VXM01 were decreases in lymphocyte numbers in the blood, increased frequencies of neutrophils and diarrhea. Eight out of 16 patients who received at least one boosting vaccination responded with pronounced, i.e. at least 3-fold, increase in VEGFR2-specific T cell response over baseline levels. In the VXM01 vaccination group, VEGFR2-specific T cells peaked preferentially during the boosting phase with an average 4-fold increase over baseline levels. In conclusion, prime/boost vaccination with VXM01 was safe and immunogenic and increased vaccine specific T cell responses compared with placebo treatment.

Double-blind, placebo-controlled first in human study to investigate an oral vaccine aimed to elicit an immune reaction against the VEGF-Receptor 2 in patients with stage IV and locally advanced pancreatic cancer

Background

The investigational oral DNA vaccine VXM01 targets the vascular endothelial growth factor receptor 2 (VEGFR-2) and uses Salmonella typhi Ty21a as a vector. The immune reaction elicited by VXM01 is expected to disrupt the tumor neovasculature and, consequently, inhibit tumor growth. VXM01 potentially combines the advantages of anti-angiogenic therapy and active immunotherapy.

Methods/Design

This phase I trial examines the safety, tolerability, and immunological and clinical responses to VXM01. The randomized, placebo-controlled, double blind dose-escalation study includes up to 45 patients with locally advanced and stage IV pancreatic cancer. The patients will receive four doses of VXM01 or placebo in addition to gemcitabine as standard of care. Doses from 10⁶ cfu up to 10¹⁰ cfu of VXM01 will be evaluated in the study. An independent data safety monitoring board (DSMB) will be involved in the dose-escalation decisions. In addition to safety as primary endpoint, the VXM01-specific immune reaction, as well as clinical response parameters will be evaluated.

Discussion

The results of this study shall provide the first data regarding the safety and immunogenicity of the oral anti-VEGFR-2 vaccine VXM01 in cancer patients. They will also define the recommended dose for phase II and provide the basis for further clinical evaluation, which may also include additional cancer indications.

Trial registration

EudraCT No.: 2011-000222-29, NCT01486329, ISRCTN68809279

Morphologic patterns of autoimmune pancreatitis in CT and MRI

BACKGROUND/AIMS

To retrospectively evaluate the morphologic characteristics of autoimmune pancreatitis (AIP) using MRI and CT.

METHODS

86 dynamic contrast-enhanced CT and MRI scans in 36 AIP patients were evaluated regarding: different enlargement types, abnormalities of the main pancreatic duct (MPD), morphology of the parenchyma and other associated findings.

RESULTS

3 types of enlargement were found: (1) a focal type (28%), (2) a diffuse type (involving the entire pancreas, 11%) and (3) a combined type (56%). The MPD was usually dilated together with focal or diffuse narrowing in 67% (24/36). Unenhanced MRI showed AIP area in 56% (mostly T(1) hypo- and T(2) hyperattenuating), and CT in 10% (hypoattenuating). The arterial phase depicted similar patterns for CT and MRI (hypoattenuating in 58 and 52%, respectively). Venous and late venous phase patterns were usually hyperattenuating in MRI (65 and 74%, late enhancement), while CT mostly showed no signal differences (isoattenuating in 57 and 75%), yielding significant differences between CT and MRI for the venous (p < 0.0001) and the late phase (p = 0.025). Miscellaneous findings were: rim sign (25%), pseudocysts (8%) and infiltration of large vessels (11%).

CONCLUSIONS

The 'late-enhancement' sign seems to be a key feature and is best detectable with MRI. MRI may be recommended in the diagnostic workup of AIP patients. and IAP.

A new invasion score for determining the resectability of pancreatic carcinomas with contrast-enhanced multidetector computed tomography

OBJECTIVE

It was the aim of this study to evaluate a new infiltration score to determine the resectability of pancreatic carcinomas in preoperative planning.

MATERIALS AND METHODS

Eighty patients with suspected pancreatic tumor were examined prospectively using 16-row spiral CT. The scans were evaluated for the presence of pancreatic carcinoma, peripancreatic tumor extension and vascular invasion using a standardized questionnaire. Invasion of the surgically relevant vessels was evaluated using a new invasion score. The operative and histological findings and the clinical follow-up served as the gold standard.

RESULTS

Forty patients had a pancreatic carcinoma, 5 had metastasis of a different primary tumor, and in 35 patients, there was no malignant pancreatic disease. The sensitivity for tumor detection was 100%, with a specificity of 88% for differentiating between malignant and benign pancreatic tumors. Invasion of the surrounding vessels was evaluated correctly using the invasion score, with a sensitivity of 89% and a specificity of 99%. In evaluation of resectability, a sensitivity of 94% and a specificity of 89% were achieved.

CONCLUSION

Using 16-row spiral CT, the invasion score is a valid tool for correctly assessing invasion in relevant vessels in cases of pancreatic carcinoma and for determining resectability.

Targeted diagnostic magnetic nanoparticles for medical imaging of pancreatic cancer

Highly aggressive cancer types such as pancreatic cancer possess a mortality rate of up to 80% within the first 6months after diagnosis. To reduce this high mortality rate, more sensitive diagnostic tools allowing an early stage medical imaging of even very small tumours are needed. For this purpose, magnetic, biodegradable nanoparticles prepared using recombinant human serum albumin (rHSA) and incorporated iron oxide (maghemite, γ-Fe2O3) nanoparticles were developed. Galectin-1 has been chosen as target receptor as this protein is upregulated in pancreatic cancer and its precursor lesions but not in healthy pancreatic tissue nor in pancreatitis. Tissue plasminogen activator derived peptides (t-PA-ligands), that have a high affinity to galectin-1 have been chosen as target moieties and were covalently attached onto the nanoparticle surface. Improved targeting and imaging properties were shown in mice using single photon emission computed tomography-computer tomography (SPECT-CT), a handheld gamma camera, and magnetic resonance imaging (MRI).

Value of three-dimensional reconstructions in pancreatic carcinoma using multidetector CT: Initial results

AIM: To evaluate the use of three-dimensional imaging of pancreatic carcinoma using multidetector computed tomography (CT) in a prospective study.

METHODS: Ten patients with suspected pancreatic tumors were examined prospectively using multidetector CT (Somatom Sensation 16, Siemens, Erlangen, Germany). The images were evaluated for the presence of a pancreatic carcinoma and invasion of the peripancreatic vessels and surrounding organs. Using the isotropic CT data sets, a three-dimensional image was created with automatic vascular analysis and semi-automatic segmentation of the organs and pancreatic tumor by a radiologist. The CT examinations and the three-dimensional images were presented to the surgeon directly before and during the patient’s operation using the Medical Imaging Interaction Toolkit-based software “ReLiver”. Immediately after surgery, the value of the two images was judged by the surgeon. The operation and the histological results served as the gold standard.

RESULTS: Nine patients had a pancreatic carcinoma (all pT3), and one patient had a serous cystadenoma. One tumor infiltrated the superior mesenteric vein. The infiltration was correctly evaluated. All carcinomas were resectable. In comparison to the CT image with axial and coronal reconstructions, the three-dimensional image was judged by the surgeons as better for operation planning and consistently described as useful.

CONCLUSION: A 3D-image of the pancreas represents an invaluable aid to the surgeon. However, the 3D-software must be further developed in order to be integrated into daily clinical routine.

Persistent left superior vena cava with absent right superior vena cava: Morphological CT features and clinical implications

Here we report a rare case of the persisting left superior vena cava with simultaneous absence of the right superior vena cava. This central venous variation has been identified during a routine chest CT scan as follow-up after colonic cancer in an asymptomatic patient with no previous history of heart diseases. Morphological features of this variation are illustrated on axial CT images and 3D image reconstructions. This anomaly occurs in 0.1% of the general population. In presence with the right superior vena cava it is the most common anatomical variation in the central venous system with a reported occurrence of 0.2-8%. Such condition can be associated with additional congenital cardiovascular malformations and heart diseases or rhythm abnormalities. Diagnosis can be difficult and is often achieved incidentally since hemodynamics in these patients can be normal and clinical symptoms are mostly absent. Important clinical implications include difficulties in central venous access or cardiac pacemaker placement as well as management consequences in cardiothoracic surgery. In conclusion clinicians should be aware of this anomaly and their clinical relevance to avoid possible complications.

Clinicopathologic characteristics of patients with resected multifocal intraductal papillary mucinous neoplasm of the pancreas

BACKGROUND

Intraductal papillary mucinous neoplasms of the pancreas are defined as mucin-producing neoplasms arising in the main pancreatic duct (main duct type), its major branches (branch duct type), or in both (mixed type). Intraductal papillary mucinous neoplasms of the pancreas can occur as a single collection of cysts or as multifocal lesions. While subtypes of intraductal papillary mucinous neoplasms of the pancreas are well described in literature, little is known about the importance of multifocal intraductal papillary mucinous neoplasms of the pancreas. This study evaluated the clinicopathologic characteristics of patients with surgically resected, multifocal intraductal papillary mucinous neoplasm of the pancreas.

METHODS

Clinicopathologic features and preoperative imaging of patients resected for multifocal intraductal papillary mucinous neoplasm of the pancreas defined as intraductal papillary mucinous neoplasm of the pancreas occurring in more than just 1 area, from January 2004 to July 2010 at the Department of Surgery, University of Heidelberg were analyzed. Preoperative parameters, including number of cysts, cyst size, presence of nodules, and epidemiologic data, were assessed and compared to patients with unifocal intraductal papillary mucinous neoplasms of the pancreas.

RESULTS

Among 287 patients with resected intraductal papillary mucinous neoplasms of the pancreas, 51 patients (17.8%) with multifocal cystic pancreatic lesions were identified by preoperative imaging. The median age of patients with multifocal intraductal papillary mucinous neoplasms of the pancreas was ≥ 68 years (P = .002) compared to patients with unifocal intraductal papillary mucinous neoplasm of the pancreas (median age, 64 years). Thirty-one multifocal intraductal papillary mucinous neoplasms of the pancreas were of mixed type (60.8%), 15 of branch duct type (29.4%), and 5 of main duct type (9.8%). Histologically, 10 multifocal intraductal papillary mucinous neoplasms of the pancreas had low-grade dysplasia (19.6%), 11 had moderate dysplasia (21.6%), 6 had high-grade dysplasia (11.8%), and 24 had invasive carcinoma (47.1%).

CONCLUSION

Most multifocal intraductal papillary mucinous neoplasms of the pancreas involve the main pancreatic duct and synchronously its major side branches (mixed type). Patients with multifocal intraductal papillary mucinous neoplasm of the pancreas present at an older age compared to patients with single cystic pancreatic neoplasm. The risk of harboring malignancy-nearly 60% in the present study-seems to be increased in patients with multifocal intraductal papillary mucinous neoplasms of the pancreas compared to single lesions.