Detection Of Peritoneal Carcinomatosis Research Articles

Utilizing 99mTc-FAPI-46 SPECT/CT in Detection of Peritoneal Carcinomatosis in Gastric Poorly Differentiated Adenocarcinoma: A Case Report.

We introduce a 61-year-old man with poorly differentiated gastric adenocarcinoma, who previously underwent surgical treatment. In this presentation, he complained of a newly appeared midabdominal mass after the latest chemotherapy session. He was a candidate for diagnostic laparotomy, but in the setting of trial, 99mTc-FAPI-46 SPECT/CT was performed revealing 2 peritoneal masses, which were the only findings of diagnostic surgery subsequent to the scan. This report presents the first case of 99mTc-FAPI-46 SPECT/CT in metastasis workup of gastric adenocarcinoma.

Long Axial Field-of-View PET/CT Could Answer Unmet Needs in Gynecological Cancers.

Gynecological malignancies currently affect about 3.5 million women all over the world. Imaging of uterine, cervical, vaginal, ovarian, and vulvar cancer still presents several unmet needs when using conventional modalities such as ultrasound, computed tomography (CT), magnetic resonance, and standard positron emission tomography (PET)/CT. Some of the current diagnostic limitations are represented by differential diagnosis between inflammatory and cancerous findings, detection of peritoneal carcinomatosis and metastases <1 cm, detection of cancer-associated vascular complications, effective assessment of post-therapy changes, as well as bone metabolism and osteoporosis assessment. As a result of recent advances in PET/CT instrumentation, new systems now offer a long-axial field-of-view (LAFOV) to image between 106 cm and 194 cm (i.e., total-body PET) of the patient's body simultaneously and feature higher physical sensitivity and spatial resolution compared to standard PET/CT systems. LAFOV PET could overcome the forementioned limitations of conventional imaging and provide valuable global disease assessment, allowing for improved patient-tailored care. This article provides a comprehensive overview of these and other potential applications of LAFOV PET/CT imaging for patients with gynecological malignancies.

Diagnostic value of positron emission tomography/computed tomography (PET/CT) in detection of peritoneal carcinomatosis

BackgroundThe diagnosis of peritoneal carcinomatosis is challenging and can be difficult to detect with imaging, especially the detection of small-sized peritoneal lesions. The presence of peritoneal neoplastic spread alters tumour staging and is one of the most significant prognostic indicators in several malignancies, and the purpose of this study was to highlight the diagnostic value of PET/CT in detection of peritoneal carcinomatosis in patients with malignant neoplastic disease.ResultsPET/CT has 76.2% sensitivity, 88.9% specificity, 94.1% PPV, 61.5% NPV and 80% accuracy in detection of peritoneal carcinomatosis. Different patterns of FDG uptake of peritoneal carcinomatosis were found such as focal nodular uptake, diffuse abdominal uptake and liver surface focal or diffuse uptake. From all these different patterns, focal nodular uptake was the most frequent pattern. The best cut-off value of SUVmax was 5 for diagnosis.ConclusionsThe study affirms the significant role of PET/CT in the diagnosis of peritoneal carcinomatosis and its important value in the staging, management and follow-up of patients with secondary peritoneal malignancies, especially in case of unavailable or inappropriate peritoneal biopsy. Therefore, PET/CT could help reduce the number of laparotomies and a better selection of patients who are candidates for adjuvant chemotherapy.

Prospective Multicentric Assessment of 68Ga-DOTANOC PET/CT in Grade 1-2 GEP-NET.

The aim of this multicentric study was to prospectively compare 68Ga-DOTANOC PET/CT versus somatostatin receptor scintigraphy (SRS) with SPECT/CT, combined with multiphasic CT scan and MRI in patients with grade 1 or 2 gastroenteropancreatic neuroendocrine tumors (GEP-NET). Patients with histologically proven grade 1 or 2 GEP-NET with suspicion of recurrence or progression, or with typical aspects of GEP-NET on morphological imaging, were explored with conventional imaging (CI): SRS with SPECT/CT, multiphasic CT scan and/or liver MRI followed by 68Ga-DOTANOC PET/CT. The gold standard was based on histology and imaging follow-up. The data of 105 patients (45 woman and 60 men; median age) were analyzed. 68Ga-DOTANOC PET/CT sensitivity was significantly higher than CI sensitivity in per-patient (98.9% vs. 88.6%, p = 0.016) and per-region (97.6% vs. 75.6%, p &lt; 0.001) analyses, in the detection of the primary (97.9% vs. 78.7%; p = 0.016), peritoneal carcinomatosis (95% vs. 30%, p &lt; 0.001), and bone metastases (100% vs. 33.3%, p = 0.041). 68Ga-DOTANOC PET/CT had an impact on the therapeutic management of 41.9% (44/105) patients compared to decisions based on CI explorations. Our data confirm the superiority of 68Ga-DOTANOC PET/CT over CI in the detection of peritoneal carcinomatosis and bone metastasis, as well as its strong therapeutic impact on the management of patients with grade 1-2 GEP-NETs.

Usefulness of [68Ga]FAPI-04 and [18F]FDG PET/CT for the detection of primary tumour and metastatic lesions in gastrointestinal carcinoma: a comparative study.

To assess and compare the diagnostic performance of gallium-68-labelled fibroblast activation protein inhibitor ([68Ga]FAPI-04) and fluorine-18 fluorodeoxyglucose ([18F]FDG) positron emission tomography/computed tomography (PET/CT) in gastrointestinal cancer. Fifty-one patients who underwent both [18F]FDG and [68Ga]FAPI-04 PET/CT for initial staging or restaging were enrolled. Histopathological findings, typical radiological appearances, and clinical imaging follow-up were used as the reference standard. The diagnostic performance of the two tracers was calculated and compared. The maximum standardised uptake value (SUVmax), mean SUV (SUVmean), tumour-to-mediastinal blood pool ratio (TBR), and tumour-to-liver ratio (TLR) of primary and metastatic lesions were measured and compared between two imaging modalities. In patient-based analysis, [68Ga]FAPI-04 showed much better diagnostic sensitivity than [18F]FDG in detecting primary tumour (94.44% [17/18] vs. 61.11% [11/18]), postoperative recurrence and metastases (95.65% [22/23] vs. 69.57% [16/23]), and peritoneal carcinomatosis (100% [28/28] vs. 60.71% [17/28]) (all p < 0.05). In lesion-based analysis, [68Ga]FAPI-04 showed higher sensitivity than [18F]FDG for detecting lymph node metastases. In peritoneal carcinomatosis, the median SUVmax (12.12 vs. 7.18) and SUVmean (6.84 vs. 4.11) with [68Ga]FAPI-04 were significantly higher than those with [18F]FDG (all p < 0.005). The TBR and TLR of [68Ga]FAPI-04 were significantly higher than those of [18F]FDG for detecting primary tumour, lymph node, liver, and peritoneal metastases (all p < 0.005). Therapeutic management changed in 13 patients according to [68Ga]FAPI-04 PET/CT compared with conventional imaging. [68Ga]FAPI-04 is superior to [18F]FDG PET/CT for detecting primary tumour, postoperative recurrence and metastasis, and peritoneal carcinomatosis in gastrointestinal cancer. • [68Ga]FAPI-04 PET/CT showed significantly higher sensitivity than [18F]FDG PET/CT in the detection of primary tumour and postoperative recurrence and metastasis in patients with gastrointestinal carcinoma. • [68Ga]FAPI-04 PET/CT had obvious advantages over [18F]FDG PET/CT in the detection of peritoneal carcinomatosis from gastrointestinal carcinoma with a much higher FAPI uptake value, TBR, and TLR. • Although the median SUVmax and SUVmean of [68Ga]FAPI-04 were similar to those of [18F]FDG for the primary tumour, lymph node metastases, and liver metastases in gastrointestinal carcinoma, the TBR and TLR of the SUVmax and SUVmean were significantly higher on [68Ga]FAPI-04 PET/CT, causing the lesions to be displayed more clearly.

FDG-PET/MRI for the preoperative diagnosis and staging of peritoneal carcinomatosis: a prospective multireader pilot study.

To assess the diagnostic performance of FDG-PET/MRI for the preoperative diagnosis and staging of peritoneal carcinomatosis (PC) using surgical Sugarbaker's PC index (PCI) as the reference in a multireader pilot study. Fourteen adult patients (M/F: 3/11, mean age: 57 ± 12year) with PC were prospectively included in this single-center study. Patients underwent FDG-PET/MRI prior to surgery (mean delay: 14d, range: 1-63d). Images were reviewed independently by 2 abdominal radiologists and 2 nuclear medicine physicians. The radiologists assessed contrast-enhanced abdominal MR images, while the nuclear medicine physicians assessed PET images fused with T2-weighted images. The abdomen was divided in 13 regions, scored from 0 to 3. A hybrid FDG-PET/MRI radiological PCI was created by combining the study data. Radiological PCI was compared to the surgical PCI on a per-patient and per-region basis. Inter-reader agreement was evaluated. Mean surgical PCI was 10 ± 8 (range: 0-24). Inter-reader agreement was almost perfect for all sets for radiologic PCI (Kappa: 0.81-0.98). PCI scores for all reading sets significantly correlated with the surgical PCI score (r range: 0.57-0.74, p range: < 0.001-0.003). Pooled per-patient sensitivity, specificity, and accuracy were 75%/50%/71.4% for MRI, 66.7%/50%/64.3% for FDG-PET, and 91.7%/50%/85.7% for FDG-PET/MRI, without significant difference (p value range 0.13-1). FDG-PET/MRI achieved 100% sensitivity and 100% specificity for a cutoff PCI of 20. Per-region sensitivity and accuracy were lower: 37%/61.8% for MRI, 17.8%/64.3% for FDG-PET, and 52.7%/60.4% for FDG-PET/MRI, with significantly higher sensitivity for FDG-PET/MRI. Per-region specificity was higher for FDG-PET (95%) compared to MRI (78.4%) and FDG-PET/MRI (66.5%). FDG-PET/MRI achieved an excellent diagnostic accuracy per-patient and weaker performance per-region for detection of PC. The added value of PET/MRI compared to MRI and FDG-PET remains to be determined.

Spectral CT in peritoneal carcinomatosis from ovarian cancer: a tool for differential diagnosis of small nodules?

The detection of peritoneal carcinomatosis in patients with ovarian cancer is crucial to establish the correct therapeutic planning (debulking surgery versus neoadjuvant chemotherapy).Often, however, the nodules of peritoneal carcinomatosis are very small in size or have a reticular appearance that can mimic the fat stranding that is typical of acute inflammation conditions. Our hypothesis is that the use of dual-layer spectral computed tomography with its applications, such as virtual monoenergetic imaging and Z-effective imaging, might improve the detection and the characterisation of peritoneal nodules, increasing sensitivity and diagnostic accuracy, as recently described for other oncological diseases.

Imaging Cancer-Associated Fibroblasts (CAFs) with FAPi PET.

The tumor microenvironment (TME) surrounding tumor cells is a complex and highly dynamic system that promotes tumorigenesis. Cancer-associated fibroblasts (CAFs) are key elements in TME playing a pivotal role in cancer cells’ proliferation and metastatic spreading. Considering the high expression of the fibroblast activation protein (FAP) on the cell membrane, CAFs emerged as appealing TME targets, namely for molecular imaging, leading to a pan-tumoral approach. Therefore, FAP inhibitors (FAPis) have recently been developed for PET imaging and radioligand therapy, exploring the clinical application in different tumor sub-types. The present review aimed to describe recent developments regarding radiolabeled FAP inhibitors and evaluate the possible translation of this pan-tumoral approach in clinical practice. At present, the application of FAPi-PET has been explored mainly in single-center studies, generally performed in small and heterogeneous cohorts of oncological patients. However, preliminary results were promising, in particular in low FDG-avid tumors, such as primary liver and gastro-entero-pancreatic cancer, or in regions with an unfavorable tumor-to-background ratio at FDG-PET/CT (i.e., brain), and in radiotherapy planning of head and neck tumors. Further promising results have been obtained in the detection of peritoneal carcinomatosis, especially in ovarian and gastric cancer. Data regarding the theranostics approach are still limited at present, and definitive conclusions about its efficacy cannot be drawn at present. Nevertheless, the use of FAPi-based radio-ligand to treat the TME has been evaluated in first-in-human studies and appears feasible. Although the pan-tumoral approach in molecular imaging showed promising results, its real impact in day-to-day clinical practice has yet to be confirmed, and multi-center prospective studies powered for efficacy are needed.

Performances of 18F-FDOPA PET/CT in the Preoperative Evaluation of the Peritoneal Cancer Index in Small Intestine Neuroendocrine Tumors.

Peritoneal carcinomatosis (PC) concerns up to 30% of patients with a neuroendocrine tumor (NET), especially of the small intestine. Aggressive management of carcinomatosis seems to be justified, especially with regard to possible mechanical complications. 18F-FDOPA PET/CT is known to be the most sensitive imaging modality for the detection of small bowel NET metastases, yet its performance in the detection of PC is not well studied. The main objective of our study is to evaluate the performances of preoperative 18F-FDOPA PET/CT in the prediction of surgical peritoneal cancer index. All patients referred to our center for an 18F-FDOPA PET/CT from October 2017 to January 2021 were retrospectively screened. Images were analyzed by a blinded nuclear medicine physician, and peritoneal abnormalities were reported to comply with the surgical peritoneal cancer index standard. Per patient analysis and per region analysis were then conducted. Thirty-three patients were included; 6 patients (35 regions) presented a peritoneal carcinosis. Peritoneal Carcinomatosis Index (PCI) estimated on 18F-FDOPA PET/CT was significantly and strongly correlated to surgical PCI (r = 0.96, P < 0.001). Patient-based sensitivity, specificity, negative predictive value, and positive predictive value for 18F-FDOPA PET/CT were 100%, 93%, 100%, and 75%, respectively. The agreement between 18F-FDOPA and surgery regarding PC was excellent (Cohen κ = 0.82 on per patient analysis, 0.74 on per region analysis). A preoperative estimation of PCI is achievable based on 18F-FDOPA PET/CT for small intestine NET and could allow to optimize surgical procedures and patient selection.

Positron Emission Tomography/Magnetic Resonance Imaging (PET/MRI) Versus the Standard of Care Imaging in the Diagnosis of Peritoneal Carcinomatosis.

To compare positron emission tomography (PET)/magnetic resonance imaging (MRI) to the standard of care imaging (SCI) for the diagnosis of peritoneal carcinomatosis (PC) in primary abdominopelvic malignancies. Identifying PC impacts prognosis and management of multiple cancer types. Adult subjects were prospectively and consecutively enrolled from April 2019 to January 2021. Inclusion criteria were: 1) acquisition of whole-body contrast-enhanced (CE) 18F-fluorodeoxyglucose PET/MRI, 2) pathologically confirmed primary abdominopelvic malignancies. Exclusion criteria were: 1) greater than 4 weeks interval between SCI and PET/MRI, 2) unavailable follow-up. SCI consisted of whole-body CE PET/computed tomography (CT) with diagnostic quality CT, and/or CE-CT of the abdomen and pelvis, and/or CE-MRI of the abdomen±pelvis. If available, pathology or surgical findings served as the reference standard, otherwise, imaging followup was used. When SCI and PET/MRI results disagreed, medical records were checked for management changes. Follow-up data were collected until August 2021. One hundred sixty-four subjects were included, 85 (52%) were female, and the median age was 60 years (interquartile range 50-69). At a subject level, PET/MRI had higher sensitivity (0.97, 95% CI 0.86-1.00) than SCI (0.54, 95% CI 0.37-0.71), P < 0.001, without a difference in specificity, of 0.95 (95% CI 0.90-0.98) for PET/MRI and 0.98 (95% CI 0.93-1.00) for SCI, P ¼ 0.250. PET/MRI and SCI results disagreed in 19 cases. In 5/19 (26%) of the discordant cases, PET/MRI findings consistent with PC missed on SCI led to management changes. PET/MRI improves detection of PC compared with SCI which frequently changes management.

ROLE OF STAGING LAPAROSCOPY IN THE PRE-OPERATIVE STUDY OF GASTRIC CANCER: EXPERIENCE AT OUR CENTRE

Background: One of the main prognostic factors in the treatment of gastric cancer is the presence of peritoneal carcinomatosis (PC), and its preoperative diagnosis is essential to avoid unnecessary laparotomies. Despite the development of different radiological diagnostic tests, sensitivity in the detection of PC does not reach 50%. Staging laparoscopy is a diagnostic method with a low complication rate and rapid recovery, which allows patients with peritoneal disease to avoid delays in cancer treatment

Metabolic active peritoneal sites affect tumor debulking in ovarian and peritoneal cancers

Rationale and objectivesTo evaluate the impact of metabolic parameters in the peritoneal cavity on the likelihood of achieving complete tumor debulking in patients with ovarian and peritoneal cancers.Materials and methodsForty-nine patients with ovarian and peritoneal cancers were included, who underwent pre-operative 18F-fluorodeoxyglucose Positron Emission Tomography/Computed Tomography (18F-FDG PET/CT). The immediate surgical outcome was dichotomized into complete and incomplete tumor debulking. 18F-FDG PET/CT was qualitatively and quantitatively assessed by scrutinizing 15 anatomical sites for the presence of peritoneal carcinomatosis (PC). Patient-based and site-based diagnostic characteristics were described. Metabolic parameters (SUVmax, metabolic tumor volume and total lesion glycolysis) and the number of 18F-FDG avid peritoneal sites were evaluated between the two groups. Receiver operating curve (ROC) analysis was performed to determine the optimal cut-off value in predicting incomplete tumor debulking.ResultsTwenty-seven out of the 49 patients had PC and 11 had incomplete debulking. Patient-based and site-based accuracies for detection of PC were 87.8 and 97.6%, respectively. The number of 18F-FDG avid peritoneal sites was significantly different between complete and incomplete debulking groups (0.6 ± 0.8 versus 2.3 ± 1.7 sites respectively, p = 0.001), and the only independent significant risk factor among other metabolic parameters tested (odd ratio = 2.983, 95% CI 1.104–8.062) for incomplete tumor debulking with an optimal cut-off value of ≥4 (AUC = 0.816).ConclusionThe number of 18F-FDG avid peritoneal sites increased the risk of incomplete tumor debulking after surgery and potentially useful in assisting treatment stratification in patients with ovarian and peritoneal cancers.

A computed tomography-based nomogram for preoperative prediction of synchronous peritoneal carcinomatosis in colorectal cancer.

14 Background: Peritoneal carcinomatosis (PC) of colorectal cancer remain poor and is considered to be the terminal stage. Early detection of PC can bring survival benefit for chances of complete cytoreductive surgery. In this study, we have developed and validated a CT-based nomogram for preoperative prediction of synchronous PC in CRC. Methods: The CT-based nomogram optimized for image classification of PC was developed and validated in a large cohort. The specific features of synchronous PC were extracted from preoperative CT arterial stage scans by radiologists. A CT-based model was constructed by Boruta algorithm and multivariate logistic regression in the training set and validated in the test set. A CT-based nomogram was then built to predict the risk value of PC. The performance and efficacy of this nomogram to discriminate PC were assessed. Results: A total of 170 eligible CRC patients with synchronous PC were randomly divided into a training set (n = 92) and a validation set (n = 78). After processing and partition, five items of PC-related features including tumor location, cT stage, distant metastasis, thickened greater omentum and pelvic nodules were enrolled into this CT-based model. In the training set, the ROC shows AUC of CT-based model was 0.929(95% CI: 0.764-0.946). The sensitivity was 73.2% and the specificity was 98.3%. The positive predictive value (PPV) was 82.26%, while the negative predictive value (NPV) was 100%. In the test set, AUC by the ROC was 0.855(95% CI: 0.764-0.946). The sensitivity of CT-based model was 72.7% and the specificity was 93.3%. The PPV was 82.35%, while the NPV was 88.89%. These results show high predicted accuracy of CT-based model in diagnosis of synchronous PC both in the training set and test set. A nomogram based on these five preoperative predictors of PC was created. This CT-based nomogram showed good diagnostic performance by calibration curve. The decision curves analysis revealed high benefit of this CT-based nomogram in clinical decision. Conclusions: The CT-based nomogram has shown great potential in the detection and diagnosis of synchronous peritoneal metastasis in colorectal cancer.

The Value of Contrast-Enhanced CT in the Detection of Residual Disease After Neo-Adjuvant Chemotherapy in Ovarian Cancer

To evaluate the diagnostic performance of contrast-enhanced computed tomography (CT) in predicting residual disease following neo-adjuvant chemotherapy (NACT) in stage III/IV ovarian cancer. This was a retrospective observational cohort study including consecutive patients with primary stage III/IV ovarian cancer who received NACT before interval debulking surgery. CT findings before interval debulking surgerywere correlated with histological/surgical findings. Diagnostic characteristics were calculated on patient-based and lesion-based analyses. False negative results on peritoneal carcinomatosis detection were correlated with lesion size and site. On patient-based analysis, CT (n = 58) had a sensitivity, specificity, positive predictive value, negative predictive value and accuracy of 92.16%, 57.14%, 94.00%, 50.00%, and 87.93%. On lesion-based analysis, the sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were 63.01%, 73.47%, 82.51%, 50.00%, and 66.51%. False negative results were associated with lesion size (p < 0.001). The diagnostic performance of CT on the detection of peritoneal carcinomatosis was low at the subdiaphragmatic spaces, bowel serosa and mesentery (p < 0.001). CT had low negative predictive value in determining residual disease following NACT on both patient-based and lesion-based analyses, especially for non-measurable lesions and at the subdiaphragmatic spaces, bowel serosa and mesentery.

Magnetic Resonance Assessment of Peritoneal Carcinomatosis: Is There a True Benefit From Diffusion-Weighted Imaging?

PurposeTo assess the added value of diffusion weighted imaging (DWI) with intermediate (500 s/mm2) and high (1000 s/mm2) b values when combined to conventional contrast-enhanced magnetic resonance imaging (MRI) in identifying peritoneal neoplastic involvement. MethodsTwenty-four patients with peritoneal carcinomatosis from gastrointestinal or gynecological tumors were retrospectively evaluated. All patients underwent peritonectomy with hyperthermic intraoperative chemotherapy and 1.5 T MRI including DWI with 500 s/mm2 and 1000 s/mm2 b values within 1 month from surgery. Images were independently reviewed by 2 radiologists with different experience in abdominal MRI in 3 separate reading sessions, the first including conventional MR images alone (T2-weighted, T1-weighted pre- and post gadolinium injection), the second conventional MRI and DWI with a b value of 500 s/mm2 (b 500-DWI), and the third conventional MRI and DWI with a b value of 1000 s/mm2 (b 1000-DWI). Apparent diffusion coefficient maps were included in the DWI analyses. Peritoneal dissemination was assessed in 9 anatomical sites, including right and left subphrenic space, paracolic gutters, small bowel mesentery, greater omentum, gastric-bowel serosa, free peritoneal surfaces, rectosigmoid-colon mesentery, and pelvis. The presence or absence of peritoneal dissemination for each patient and for each site was scored using a 5-point confidence scale. Sensitivity, specificity, and area under the curve (AUC) for identifying per-site peritoneal implants were calculated for each reader at each reading session. Interobserver agreement was evaluated using kappa statistics. ResultsFor both readers, the sensitivity and AUC values resulting from combined interpretation of conventional MRI and DWI (both b500-DWI and b1000-DWI) were significantly higher than those of conventional MRI alone (P < 0.001). The added value of DWI was greater for the less experienced reader (sensitivity 0.55, specificity 0.73, AUC 0.64 on conventional MRI; sensitivity 0.75, specificity 0.72, AUC 0.74 on b500-DWI; sensitivity 0.87, specificity 0.72, AUC 0.80 on b1000-DWI) than for the more experienced reader (sensitivity 0.63, specificity 0.75, AUC 0.70 on conventional MRI; sensitivity 0.76, specificity 0.77, AUC 0.77 on b500-DWI; sensitivity 0.85, specificity 0.72, AUC 0.79 on b1000-DWI), although the differences between the 2 observers were not statistically significant. Interobserver agreement resulted to be fair (κ = 0.30) when dealing with conventional MRI alone. The addition of b500-DWI and b1000-DWI to conventional MRI allowed to reach a substantial agreement (κ = 0.75). ConclusionsThe combined interpretation of high b value DWI and conventional MRI provides increased sensitivity and diagnostic performance in detection of peritoneal carcinomatosis in oncologic patients.

Whole-body diffusion-weighted MRI for operability assessment in patients with colorectal cancer and peritoneal metastases

BackgroundCorrect staging of patients with colorectal cancer is of utmost importance for the prediction of operability. Although computed tomography (CT) has a good overall performance, estimation of peritoneal cancer spread is a known weakness, a problem that cannot always be overcome by Fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG-PET/CT); especially in infiltrative and miliary disease spread. Due to its high spatial and contrast resolution magnetic resonance imaging (MRI) with diffusion-weighted imaging (DWI) might have a better performance. Our aim was to evaluate the added value of whole-body diffusion-weighted MRI (WB-DWI/MRI) to CT for prediction of peritoneal cancer spread and operability assessment in colorectal cancer patients with clinically suspected peritoneal carcinomatosis (PC).MethodsThis institutional review board approved retrospective study included sixty colorectal cancer patients who underwent WB-DWI/MRI in addition to CT for clinically suspected peritoneal metastases. WB-DWI/MRI and CT were assessed for detecting PC following the peritoneal cancer index (PCI), determination of PCI-score categorized as PC < 12, PCI = 12–15 and PCI > 15, detection of nodal and distant metastases and estimation of overall operability. Histopathology after surgery and biopsy and/or 6 months follow-up were used as reference standard.ResultsFor detection of PC, CT had 43.2% sensitivity, 95.6% specificity, 84.5% positive predictive value (PPV) and 75.2% negative predictive value (NPV). WB-DWI/MRI had 97.8% sensitivity, 93.2% specificity, 88.9% PPV and 98.7% NPV. WB-DWI/MRI enabled better detection of inoperable distant metastases (all 12 patients) than CT (2/12 patients) and significantly improved prediction of PCI category [WB-DWI/MRI PCI < 12: 37/39 patients (94.9%); PCI = 12–15: 4/4 patients (100%); PCI > 15: 16/17 patients (94.1%) versus CT PCI < 12: 38/39 patients (97.4%); PCI = 12–15: 0/4 patients (0%); PCI > 15: 2/17 patients (11.8%); p < 0.0001)]. WB-DWI/MRI improved prediction of inoperability over CT with 90.6% sensitivity compared to 25% (p < 0.0001).ConclusionsWB-DWI/MRI significantly outperformed CT for estimation of spread of PC, overall staging and prediction of operability. Pending validation in larger prospective trials, WB-DWI/MRI could be used to guide surgical planning and minimize unnecessary exploratory laparotomies.

Diagnostic accuracy of 18F-FDG PET/CT for detection of peritoneal carcinomatosis; a systematic review and meta-analysis.

The current review aimed to investigate the performance of the diagnostic accuracy of 18F- fludeoxyglucose positron emission tomography/CT (PET/CT) in detecting peritoneal carcinomatosis (PC) through a systematic review and meta-analysis. The MEDLINE via PubMed and EMBASE from the earliest available date of indexing to 31 March 2017, were searched for studies evaluating the diagnostic performance of 18F-FDG PET/CT in detecting PC. We evaluated the pooled sensitivities and specificities across included studies, calculated positive and negative likelihood ratios (LR+ and LR-), and plotted summary receiver operating characteristic curves. Deek's funnel plot asymmetry tests were used to assess the possible underlying publication bias. The current meta-analysis demonstrated no significant publication bias (p = 0.21). Across 14 studies (671 patients), the overall sensitivity of 18F-FDG PET/CT was 0.87 [95% CI (0.77-0.93)] with heterogeneity (χ2 = 94.2, p = 0.00) and a pooled specificity of 0.92 [95% CI; (0.89-0.94)] with heterogeneity (χ2 = 20.6, p = 0.08). LR syntheses gave an overall LR+ of 10.4 [95% CI (7.5-14.5)] and LR- of 0.14 [95% CI (0.08-0.26)]. The pooled diagnostic odds ratio was 73 [95% CI (34-159)]. In univariate meta-regression analysis, publication year and cohort homogeneity were the potent sources of heterogeneity. However, in multivariate meta-regression, no definite variable was the source of the study heterogeneity. 18F-FDG PET/CT demonstrated good sensitivity and specificity for the detection of PC. Further large multicentre studies would be necessary to substantiate the diagnostic accuracy of 18F-FDG PET/CT for the diagnosis of PC in various cancers. Advances in knowledge: 18F-FDG PET/CT showed good diagnostic performance in the evaluation of PC and could provide additional information for that purpose in various cancers.

Evaluation of recurrence in gastric carcinoma: Comparison of contrast-enhanced computed tomography and positron emission tomography/computed tomography

AIMTo compare the value of contrast-enhanced abdominal computed tomography (CT) and fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) for detecting gastric carcinoma recurrence.METHODSWe retrospectively examined data from 2475 patients who underwent both contrast-enhanced abdominal CT and FDG PET/CT for the surveillance of gastric carcinoma curative resection. Patients had an interval of less than 1 mo between their CT and PET/CT scans. Sixty patients who had recurrence were enrolled. Among 1896 patients who did not have recurrence, 60 were selected by simple random sampling. All CT and PET/CT images were reviewed retrospectively by two reviewers blinded to all clinical and pathologic information except curative resection due to gastric carcinoma.RESULTSThe pathological stage of the recurrence group was statistically significantly higher than that of the control group (P < 0.001). In the 60 patients who had recurrence, there were 79 recurrent lesions. Forty-four patients had only one location of recurrence, 13 patients had two locations, and 3 patients had three. In the detection of patient-based overall recurrence, no statistically significant differences existed between the two modalities (P = 0.096). However, for peritoneal carcinomatosis, CT had a statistically significantly higher sensitivity compared to PET/CT (96% vs 50%, P = 0.001). Adenocarcinoma was the most common type of gastric carcinoma. On the pathology-based analysis, CT also had a statistically significantly higher sensitivity compared to PET/CT (98% vs 80%, P = 0.035).CONCLUSIONContrast-enhanced CT was superior to PET/CT in the detection of peritoneal carcinomatosis and pathologic type of adenocarcinoma.

Endoscopic ultrasonography can avoid unnecessary laparotomies in patients with pancreatic adenocarcinoma and undetected peritoneal carcinomatosis

Background/ObjectiveTo assess the relationship between the presence of ascites detected by endoscopic ultrasonography (EUS) and peritoneal carcinomatosis (PC) in patients with pancreatic adenocarcinoma. MethodsConsecutive patients who underwent a EUS for preoperative staging of a pancreatic adenocarcinoma between 1998 and 2014 were retrospectively reviewed. The diagnosis of PC was confirmed by histopathology or peritoneal fluid cytology. The main outcome of the study was the relationship of ascites at EUS and PC in patients with pancreatic cancer. Secondarily, to evaluate the relationship between this finding and survival as well as the development of PC during follow-up. ResultsA total of 136 patients were included: 30 patients with local unresectable tumor or metastatic disease and 106 potentially-resectable candidates based on CT staging. EUS showed ascites in 27 (20%) patients, of whom 8 (29.6%) had PC. The sensitivity, specificity, PPV, NPV and accuracy of ascites by EUS in the detection of PC in this group of patients were 67%, 85%, 30%, 96% and 83%, respectively. Ascites detected by EUS was the only independent predictive factor of PC with an OR of 11 (CI 95%: 3–40). The detection of ascites by EUS was associated with a shorter survival (median survival time 7,3 months; range 0–60 vs 14.2 months; range 0–140) (p = 0.018) and earlier development of PC during follow-up (median 3.2 months, range 1.4–18.1 vs 12.7 months, range 5.4–54.8; p = 0.003). ConclusionThe finding of ascites at EUS in patients with pancreatic adenocarcinoma is highly associated with PC and a poor outcome.

Specific computed virtual chromoendoscopy for detection of peritoneal carcinomatosis: an animal study.

Detection of an incipient Peritoneal Carcinomatosis (PC) is still challenging, and there is a crucial need for technological improvements in order to diagnose and to treat early this condition. The aim of this study was to create a murine model of incipient PC and to explore the PC with Fujinon Intelligent Chromo Endoscopy (FICE) in order to determine the wavelengths of the white light (WL) spectre that offer the highest contrast between PC nodules and surrounding peritoneum. Eighteen BALB/c mice had intraperitoneal injection of murine colonic cancer CT26 cells. Peritoneal exploration with FICE was performed at different times. For each PC nodule, 1 WL and 10 FICE images were recorded. Each image was then divided into its elementary red, green and blue band images. Depending on the FICE channel, each elementary image corresponds to a specific wavelength of the WL spectre. Through numerical analysis of these images, the value of the nodule and the background peritoneum were obtained, and the contrast value was calculated. Contrast values obtained with the different wavelengths were then compared. PC grew in all the mice. The number as well as the size of PC nodules was increasingly high depending on the day of exploration. Mean PCI was 1.6 ± 1.2 at day 5, 7.7 ± 2.6 at day 8 and 15.0 ± 7.3 at day 10. A total number of 1805 elementary images of PC nodules were analysed. The wavelength that offered the best contrast between PC nodules and background peritoneum was 460nm with a mean contrast value of 0.240 ± 0.151 (p < 0.0001). This murine model of incipient PC is effective, reliable and reproducible. A monochromatic light with a wavelength at 460nm offers the highest contrast between PC nodules and background peritoneum, allowing a better detection of PC.