Maria Ciolina

Texture analysis as imaging biomarker of tumoral response to neoadjuvant chemoradiotherapy in rectal cancer patients studied with 3-T magnetic resonance.

ObjectiveThe aim of this study was to determine whether texture features of rectal cancer on T2-weighted (T2w) magnetic resonance images can predict tumoral response in patients treated with neoadjuvant chemoradiotherapy (CRT). Materials and MethodsWe prospectively enrolled 15 consecutive patients (6 women, 63.2 ± 13.4 years) with rectal cancer, who underwent pretreatment and midtreatment 3-T magnetic resonance imaging. Treatment protocol consisted of neoadjuvant CRT with oxaliplatin and 5-fluorouracile. Texture analysis using a filtration-histogram technique was performed using a commercial research software algorithm (TexRAD Ltd, Somerset, England, United Kingdom) on unenhanced axial T2w images by manually delineating a region of interest around the tumor outline for the largest cross-sectional area. The technique selectively filters and extracts textures at different anatomic scales followed by quantification of the histogram using kurtosis, entropy, skewness, and mean value of positive pixels. After CRT, all patients underwent complete surgical resection and the surgical specimen served as the gold standard. ResultsSix patients showed pathological complete response (pCR), and 4 patients, partial response (PR). Five patients were classified as nonresponders (NRs). Pretreatment medium texture-scale quantified as kurtosis was significantly lower in the pCR subgroup in comparison with the PR + NR subgroup (P = 0.01). Midtreatment kurtosis without filtration was significantly higher in pCR in comparison with PR + NR (P = 0.045). The change in kurtosis between midtreatment and pretreatment images was significantly lower in the PR + NR subgroup compared with the pCR subgroup (P = 0.038). Pretreatment area under the receiver operating characteristic curves, to discriminate between pCR and PR + NR, was significantly higher for kurtosis (0.907, P < 0.001) compared with all other parameters. The optimal cutoff value for pretreatment kurtosis was 0.19 or less. Using this value, the sensitivity and specificity for pCR prediction were 100% and 77.8%, respectively. ConclusionTexture parameters derived from T2w images of rectal cancer have the potential to act as imaging biomarkers of tumoral response to neoadjuvant CRT.

Colon capsule versus CT colonography in patients with incomplete colonoscopy: a prospective, comparative trial

Objective In case of incomplete colonoscopy, several radiologic methods have traditionally been used, but more recently, capsule endoscopy was also shown to be accurate. Aim of this study was to compare colon capsule endoscopy (CCE) and CT colonography (CTC) in a prospective cohort of patients with incomplete colonoscopy. Design Consecutive patients with a previous incomplete colonoscopy underwent CCE and CTC followed by colonoscopy in case of positive findings on either test (polyps/mass lesions ≥6 mm). Clinical follow-up was performed in the other cases to rule out missed cancer. CTC was performed after colon capsule excretion or 10–12 h postingestion. Since the gold standard colonoscopy was performed only in positive cases, diagnostic yield and positive predictive values of CCE and CTC were used as study end-points. Results 100 patients were enrolled. CCE and CTC were able to achieve complete colonic evaluation in 98% of cases. In a per-patient analysis for polyps ≥6 mm, CCE detected 24 patients (24.5%) and CTC 12 patients (12.2%). The relative sensitivity of CCE compared to CTC was 2.0 (95% CI 1.34 to 2.98), indicating a significant increase in sensitivity for lesions ≥6 mm. Of larger polyps (≥10 mm), these values were 5.1% for CCE and 3.1% for CTC (relative sensitivity: 1.67 (95% CI 0.69 to 4.00)). Positive predictive values for polyps ≥6 mm and ≥10 mm were 96% and 85.7%, and 83.3% and 100% for CCE and CTC, respectively. No missed cancer occurred at clinical follow-up of a mean of 20 months. Conclusions CCE and CTC were of comparable efficacy in completing colon evaluation after incomplete colonoscopy; the overall diagnostic yield of colon capsule was superior to CTC. Trial registration number NCT01525940.

Peritoneal carcinomatosis: imaging with 64-MDCT and 3T MRI with diffusion-weighted imaging

Peritoneal carcinomatosis is usually associated with a poor overall survival rate. Recently, introduction of more aggressive surgical treatment and intraperitoneal chemotherapy appears to significantly increase the overall survival rate for these patients. A detailed preoperative assessment of peritoneal carcinomatosis could be very challenging in the field of imaging, but a new aggressive surgical approach requires an accurate preoperative assessment of the disease. Cross-sectional imaging using CT and MRI with diffusion-weighted imaging (DWI) sequences is important for appropriate management of patients with peritoneal carcinomatosis. Appreciation of the spectrum of diagnostic patterns and pitfalls as well as different sites of involvement of peritoneal carcinomatosis using CT and DWI is crucial for appropriate surgical treatment.

Diffusion-Weighted Magnetic Resonance Application in Response Prediction before, during, and after Neoadjuvant Radiochemotherapy in Primary Rectal Cancer Carcinoma

Introduction. Our interest was to monitor treatment response using ADC value to predict response of rectal tumour to preoperative radiochemotherapy. Materials and Methods. Twenty-two patients were treated with long course of radiochemotherapy, followed by surgery. Patients were examined by diffusion-weighted imaging MRI at three-time points (prior, during, and after radiochemotherapy) and were classified as responders and nonresponders. Results. A statistical significant correlation was found between preradiochemotherapy ADC values and during treatment ADC values, in responders (F = 21.50, P value <0.05). An increase in ADC value during treatment was predictive of at least a partial response. Discussion. Response of tumour to neoadjuvant therapy cannot be easily evaluated, and such capability might be of great importance in clinical practice, because the number of irradiated and operated patients may be superior to the number of who will really benefit from this multimodal treatment. A reliable prediction of the final clinical TN stage would allow radiotherapist to adapt multidisciplinary approach to a less invasive management, sparing surgical procedure in responder patients or even allowing an early surgery in nonresponders, which would significantly reduce radiochemotherapy related toxicity. Conclusion. Early evaluation of response during neoadjuvant radiochemotherapy treatment shows great promise to predict tumour response.

High positive predictive value of CT colonography in a referral centre.

AIM To assess the positive predictive value (PPV) of CTC in the clinical routine of a dedicated referral centre. MATERIAL AND METHODS All consecutive patients referred for CTC between May 2009 and May 2010 were considered for inclusion in this study. All the patients who, following the diagnosis of a>6 mm polyp or mass at CTC, underwent a post-CTC colonoscopy within eight weeks from diagnosis were included. Per patient PPV for lesions, adenomas and advanced neoplasia was calculated. Chi-square test was used for statistical comparison, and a p value<0.05 was considered to be statistically significant. RESULTS 516 patients were included in the study. Of them, 76 (14%) patients had at least one lesion≥6 mm on CTC. Overall, 59 (11%) patients were diagnosed at CTC with at least one polyp, 12 (2%) with a flat lesions, and 5 (1%) with a mass. Per-patient PPVs for any lesion>6 mm, neoplasia, and advanced neoplasia were 96% (95% CI: 92-100%), 68.4% (95% CI: 58-79%), and 30% (95% CI: 20-41%), respectively. PPV for neoplasia and advanced neoplasia was substantially higher for >10 mm lesions. CONCLUSION In dedicated centers, CTC appears to be a highly specific procedure, characterized by a very low rate of false-positive results for >6 mm lesions.

Adverse events of computed tomography colonography: An Italian National Survey ☆

AIM To retrospectively study the frequency and magnitude of complications associated with computed tomography (CT) colonography in clinical practice. METHODS A questionnaire on complications of CT colonography was sent to Italian public radiology departments identified as practicing CT colonography with a reasonable level of training. The frequency of complications and possible risk factors were retrospectively determined. Responses were collated and row frequencies determined. A multivariate analysis of the factors causing adverse events was also performed. RESULTS 40,121 examinations were performed in13 centers during the study period. No deaths were reported. Bowel perforations occurred in 0.02% (7 exams). All perforations were asymptomatic and occurred in patients undergoing manual insufflation. Five perforations (71%) occurred in procedures performed following a recent colonoscopy. There was no significant difference between perforations associated with rectal balloon (0.017%) and those that were not (0.02%). Complications related to vasovagal reaction (either with or without spasmolytic) occurred in 0.16% (63 exams). All vasovagal reactions resolved in less than 3h, without any sequelae. CONCLUSIONS Perforation rate at CT colonography in Italy is comparable with elsewhere in the world, occurring regardless of the experience of radiology centers. Although the risk is very small, it may not be negligible when compared with the risk of diagnostic colonoscopy.

Gallbladder and muscular endometriosis: a case report

A 55-year-old woman referred to Radiology Department, with abdominal mass and chronic indefinite and vague abdominal pain, most severe in right hypochondrium and accentuated during menstruation. A history of two cesarean sections was revealed. The patient underwent an ultrasound and Computed Tomography with intravenous contrast media revealing the presence of gallbladder and abdominal wall hyperenhancing masses. Finally, Magnetic Resonance study with intravenous administration of paramagnetic contrast media confirmed the involvement of gallbladder by a solid tissue and the presence of a solid nodule on the abdominal wall. Considering imaging features and the contrast enhancement of the nodules, the patient was sent to surgery. Surgical removal of both gallbladder and abdominal solid implant was performed and histology confirmed the diagnosis of gallbladder and abdominal wall endometriosis.

Peritoneal and pleural fluids may appear hyperintense on hepatobiliary phase using hepatobiliary MR contrast agents

AimTo describe the effect of hepatobiliary-specific MR imaging contrast agent (HBCA) administration on the signal intensity of peritoneal and pleural fluid effusions on T1-weighted MR images.Materials and methodsFrom October 2015 to May 2016 139 patients (mean 60±10 years old, 69 % males) with peritoneal or pleural effusions without biliary leakage who underwent HBCA-MRI (Gd-BOPTA or Gd-EOB-DTPA) at 1.5T and 3T were included from two centres. The fluid signal intensity was classified as hypo/iso/hyperintense before/after HBCA administration. The relative signal enhancement (RE) was calculated.ResultsOn hepatobiliary phase (HBP), peritoneal fluids appeared hyper/isointense in 88–100 % and pleural effusions in 100 % of the patients following Gd-BOPTA administration. All fluids remained hypointense following Gd-EOB-DTPA. The signal intensity of fluids increased with both HBCA but RE was significantly higher following Gd-BOPTA (p=0.002 to <0.001). RE was correlated with HBP acquisition time-point (r=0.42, p<0.001 and r=0.50, p=0.033 for peritoneal and pleural fluids).ConclusionThe signal intensity of pleural and peritoneal fluids progressively increases following HBCA administration in the absence of biliary leakage. Due to its later hepatobiliary phase, this is more pronounced after Gd-BOPTA injection, leading to fluid hyperintensity that is not observed after Gd-EOB-DTPA injection.Key Points• Fluids appear hyper/isointense on HBP in most patients after Gd-BOPTA injection.• Fluids remain hypointense on HBP after Gd-EOB-DTPA injection.• RE of fluids increases with time after liver-specific Gd injection.• RE of fluids is higher in patients with chronic liver disease.

Haralick's texture analysis applied to colorectal T2-weighted MRI: A preliminary study of significance for cancer evolution

Haralicks features have been extensively used in texture analysis of medical images. In this contribution, we have applied Haralicks to T2-weighted colorectal MRI for a possible cancer evaluation. In particular, the T2-MRI images of 8 patients with colorectal pathology were identified as early stage malignant and later stage malignant using the whole amount of follow-up exams by radiologists. 192 Haralicks textural features were computed from normalized gray level co-occurrence matrix with respect to four different directions. Mean and standard deviation were also calculated for the extracted features to assess the statistical significance of results. Among all the extracted features, only 5 from 14 Haralicks textural features (viz. energy, contrast, correlation, entropy and inverse difference moment (IDM)) were found as significant for colorectal cancer evaluation. In future research, these five Haralicks textural features may be useful to detect and evaluate colorectal cancer as well as constitute a basis for predicting the prognostic trend of the disease.

Magnetic resonance tumor regression grade (MR-TRG) to assess pathological complete response following neoadjuvant radiochemotherapy in locally advanced rectal cancer

This study aims to evaluate the feasibility of a magnetic resonance (MR) automatic method for quantitative assessment of the percentage of fibrosis developed within locally advanced rectal cancers (LARC) after neoadjuvant radiochemotherapy (RCT). A total of 65 patients were enrolled in the study and MR studies were performed on 3.0 Tesla scanner; patients were followed-up for 30 months. The percentage of fibrosis was quantified on T2-weighted images, using automatic K-Means clustering algorithm. According to the percentage of fibrosis, an optimal cut-off point for separating patients into favorable and unfavorable pathologic response groups was identified by ROC analysis and tumor regression grade (MR-TRG) classes were determined and compared to histopathologic TRG. An optimal cut-off point of 81% of fibrosis was identified to differentiate between favorable and unfavorable pathologic response groups resulting in a sensitivity of 78.26% and a specificity of 97.62% for the identification of complete responders (CRs). Interobserver agreement was good (0.85). The agreement between P-TRG and MR-TRG was excellent (0.923). Significant differences in terms of overall survival (OS) and disease free survival (DFS) were found between favorable and unfavorable pathologic response groups. The automatic quantification of fibrosis determined by MR is feasible and reproducible.