1) CT Enterography technique (Oral contrast and low radiation dose issues). 2) CT signs of active inflammatory disease vs fibrostenosing or mixed. 3) Proposed Crohns disease report terminology. 4) Discuss what the gastroenterologist wants to know.

CT enterography can provide a comprehensive evaluation of the small bowel in patients with Crohns disease. This presentation will discuss technical tips for optimizing bowel distention and reducing radiation dose. Imaging findings of Crohn's disease, differentiating active inflammatory vs fibrostenosing disease and the proposed terminology for describing these findings will also be demonstrated and discussed. Important findings to detect and describe for gastroenterologists will be demonstrated.

To assess the role of computed tomography (CT), magnetic resonance imaging (MRI), ultrasonography (US) and scintigraphy in grading Crohn's disease (CD) activity.

MEDLINE, EMBASE and Cochrane databases were searched for studies evaluating CT, MRI, US and scintigraphy in grading CD activity as compared to (ileo)-colonoscopy, biopsies or intraoperative findings as the reference test. Two independent reviewers assessed the data. Three by three tables (none, mild, frank disease) were constructed for all studies and overall grading accuracy, overgrading and undergrading were calculated/summarized by fixed or random effects models.

Our search yielded 9356 articles, from which 19 articles were determined eligible for inclusion. A total of 549 patients were included. Per-patient data showed overall grading accuracy values for CT, MRI, US and scintigraphy of 86% (95%CI: 75-93%), 84% (95%CI: 67-93%), 44% (95%CI: 28-61%) and 40% (95%CI: 16-70%), respectively. CT and MRI data were pooled and showed similar overall grading accuracy estimates (P=0.8). CT and MRI showed similar overgrading (P=0.8) and undergrading (P=0.5). Per-segment data showed overall grading accuracy values for CT, MRI, US and scintigraphy of 87% (95%CI: 77-93%), 78% (95%CI: 72-82%), 66% (95%CI: 52-78%) and 86% (95%CI: 80-91%), respectively. CT showed similar grading accuracy to MRI (P=0.08) and scintigraphy (P=0.8). Both CT and scintigraphy showed higher grading accuracy than US (P=0.001 and P=0.003, respectively). Similar overgrading was seen between CT and MRI (P=0.7), CT and scintigraphy (P=0.2) and MRI and scintigraphy (P=0.09). MRI undergraded more than scintigraphy (P=0.004), while comparisons between CT and MRI and between CT and scintigraphy showed similar undergrading (P=0.1 and P=0.5, respectively).

CT and MRI showed similar high accuracy values and similar over- and undergrading both in the per-patient and per-segment analyses. Results for US and scintigraphy were inconsistent and limited data was available.

Both CT and MRI can be used for grading of Crohn's disease activity, with MRI being preferable as it lacks ionizing radiation exposure.

To prospectively determine whether MR enterography (MRE) performed with diffusion-weighted imaging (DWI) and without intravenous contrast is diagnostically noninferior to conventional contrast-enhanced (CE) MRE for evaluating Crohn's disease (CD).

Fifty adults suspicious of CD prospectively underwent clinical assessment, MRE, and ileocolonoscopy within 1 week and 44 patients finally diagnosed with CD (M:F, 34:10; 26.9±6.1 years) were analyzed. Conventional CE-MRE and DWI at b=900 s/mm² were performed. Unenhanced DWI-MRE (i.e. T2-weighted sequences + DWI) and CE-MRE (i.e. T2-weighted sequences + dynamic CE T1-weighted sequences) were reviewed in separate sessions with proper blinding, a washout period, and randomization. A total of 172 small bowel segments representing the entire spectrum from normalcy to severe inflammation in CD as seen on CE-MRE were chosen for the review. The primary endpoint was the proportional agreement between two MRE methods in diagnosing active bowel inflammation, with the noninferiority margin of 85% of agreement. Secondary analyses were performed about the agreement in interpreting penetrating diseases and regarding the MRE accuracy in the terminal ileum for diagnosing all severities of inflammation and for deep ulcers using the endoscopic findings as the reference standard.

The agreement between unenhanced DWI-MRE and CE-MRE in interpreting active bowel inflammation was 92.4% (159/172; one-sided 95% CI, >88.4%). Therefore, the noninferiority of DWI-MRE to CE-MRE was established. Of 8 segments with penetrating diseases shown on CE-MRE, DWI-MRE interpreted 6 segments concordantly, characterized 1 abscess discordantly as phlegmon, and neglected 1 sinus tract. In the 41 terminal ilea with endoscopic reference standard, unenhanced DWI-MRE and CE-MRE did not reveal significant differences in the sensitivity for diagnosing all severities of inflammation (94% [32/34] vs. 97% [33/34]; P=1) or for diagnosing deep ulcers (95% [20/21] for both; P=1).

DWI-MRE was noninferior to CE-MRE in diagnosing bowel inflammation but showed more considerable discordance with CE-MRE in diagnosing penetrating diseases.

DWI-MRE may substitute CE-MRE for evaluating bowel inflammation in CD patients who are contraindicated for the use of intravenous contrast and are not suspicious of having penetrating diseases.

1) Understand the role of CT for occult GI bleeding. 2) Understand and implement specific CT protocol optimized to detect source of occult GI bleed. 3) Detect and diagnose the various causes of occult GI bleed.

To prospectively determine the sensitivity of 64-slice MDCT angiography in detecting and diagnosing the cause of obscure gastrointestinal bleed (OGIB).

The study included 132 patients (male 93, female 39) in the age range of 3 -87 years (average age 55.13 years) who were referred to radiology department as part of workup for clinically evident gastrointestinal bleed or as part of workup for anemia (with and without positive fecal occult blood test) between 2007-2013. MDCT angiography was performed only after conventional upper endoscopy and colonoscopy were negative. Following a non-contrast scan, all patients underwent triple-phase contrast CT scan using a 64-slice CT scan system. The diagnostic performance of MDCT angiography was compared to the results of capsule endoscopy, 99m-technetium-labeled red blood cell scintigraphy (99mTc-RBC scintigraphy), digital subtraction angiography, and surgery whenever available.

CT scan showed positive findings in 80 of 132 patients. The sensitivity, specificity, positive predictive value, and negative predictive values of MDCT angiography for detection of bleed were 74.7%, 66.7%, 81.2%, and 57.7%, respectively. Capsule endoscopy was performed in 36 patients and was positive in 21 patients (sensitivity 78.2%). 99mTc-RBC scintigraphy was performed in 16 patients and was positive in 10 patients (sensitivity 71.4%). Digital subtraction angiography was performed in 34 patients and was positive in 28 patients (sensitivity 90.3%).

MDCT angiography is a sensitive and noninvasive tool that allows rapid detection and localization of OGIB. It can be used as the first-line investigation in patients with negative endoscopy and colonoscopy studies. MDCT and capsule endoscopy have complementary roles in the evaluation of OGIB.

MDCT angiography is a sensitive and noninvasive tool that allows rapid detection and localization of obscure gastrointestinal bleed and can be used as the first-line investigation in patients with negative endoscopic studies.

1) To review the MRI techniques for evaluating fistula-en-ano. 2) To review the MR findings of fistula-en-ano.

The presentation will provide a comprehensive overview of the role of MR in staging rectal cancer

To minimize the false-negative rate (FNR) of preoperative MRI in the diagnosis of lymph node (LN) metastasis in patients with clinical T1 or T2 rectal cancer. Local excision can reduce the morbidities from radical surgery, but has shown high local recurrence rates due mainly to undetected LN metastasis. Ideally, minimized FNR for detecting LN metastasis would maximize the identification of patients suitable for local excision.

A total of 246 patients with clinical T1/T2 rectal cancer who underwent MRI within one month before surgery were included in this study. The tumor location, morphology, tumor diameter/volume, and depth of tumor invasion were evaluated using MRI. Patients were categorized into three groups according to the LN size and morphology: Group 1, no discernible regional LN or all visible LNs <3 mm; Group 2, not belonging to either Group 1 or 3; and Group 3, at least one LN >5 mm or showing irregular margins or internal heterogeneity.

Lower LN group and partial tumor invasion of the muscular layer were significantly associated with lower risks of LN metastasis. When it was considered negative for LN metastasis if the patient belonged to LN Group 1 or 2 regardless of the depth of tumor invasion, the FNR were 13.6%. When only LN Group 1 was considered negative for LN metastasis, the FNR was still 9.7%. Addition of invasion depth to the diagnostic criteria decreased the FNR from 13.6% to 5.8% (LN Group 1/2 with partial tumor invasion) and from 9.7% to 3.2% (LN Group 1 with partial tumor invasion).

Inclusion of tumor invasion depth in LN evaluation using preoperative MRI can reduce the FNR for LN metastasis in patients with clinical T1 or T2 rectal cancer.

We can better identify a low risk group for regional LN metastasis among patients with early-stage rectal cancer by assessing the depth of tumor invasion and regional LNs using preoperative MRI. Application of these criteria may help minimize the likelihood of offering local excision to a patient who might have LN metastasis.

To assess the clinical diagnostic value of functional imaging, combining quantitative parameters of ADC and SUV max, before and after chemo-radiation therapy, in prediction of tumor response of patients with rectal cancer, related to tumor regression grade at histology.

A total of 51 patients with biopsy proven diagnosis of rectal carcinoma were enrolled in our study. All patients underwent a whole body 18 FDG PET/CT scan and a pelvic MR examination including DW imaging for staging (PET 1, RM1) and after completion (6.6.weeks) of neoadjuvant chemoradiation treatment (PET 2, RM 2). Subsequently all patients underwent total mesorectal excision and the histological results were compared with imaging findings. The MR scanning, performed on 1,5 T magnet (Philips,Achieva), included T2-weighted multiplanar imaging and in addition DW images with b-value of 0 and 1000 mm²/sec. On PET/CT the SUV max of the rectal lesion were calculated in PET1 and PET2. The percentage decrease of SUVmax(ΔSUV) and ADC (ΔADC) values from baseline to presurgical scan were assessed and correlated with pathologic response classified as tumor regression grade (Mandard's criteria;TRG 1= complete regression,TRG 5= no regression).

At histology,according to Mandard's criteria,33 tumors(68%) showed complete or subtotal regression(TRG1-2) and were classified as responders;18 tumors(32%) were classified as non-responders(TRG3-5).Considering all patients,the mean values of SUVmax in PET 1 was higher than mean value of SUVmax in PET2 (p<0.001),whereas mean ADC values was lower in MR 1 than MR2 (p<0.001).The best predictors for TRG response were SUV2(threshold of 4.4) and ADC2(1.28x10-3mm2/s); combining in a single analysis median quantitative value, the PPV in predicting different group category response,related to TRG system,presented an overall AUC of 96%, higher than DWI(88.2%) or SUVmax(93.3%).

In era of PET/MRI the combination of functional data derived from DWI and PET/CT represents the most accurate method to evaluate the response to treatment in LARC patients, with repeatable accuracy values higher than those reported for other conventional imaging techniques.

The functional imaging combining ADC and SUVmax permits to detect changes in cellular tissue structures useful for the assessment of tumour response after the neoadjuvant therapy in rectal cancer patients.

1) Understand the recent developments in CTC screening, including guideline updates and coverage determinations. 2) Appreciate the potential added value of extracolonic data for wellness and screening. 3) Become aware of emerging data with regard to other competing CRC screening tools.

The presentation will provide an update on the current status of guidelines and coverage issues for CTC screening. Recent clinical data for CTC will be reviewed, including the potential value-added assessment from extracolonic findings.

The diagnostic performance of optical colonoscopy (OC) for colorectal polyp detection has been estimated in previous CT colonography (CTC) trials using segmental unblinding of CTC findings. However, these estimates do not account for lesions missed by OC after unblinding, which have been unavoidably labeled as CTC false positives. Our purpose was to determine how many discordant lesions in our clinical practice actually prove to be OC false negatives on subsequent examination.

During a 113 month period, 9,336 patients (mean age 57.1±8.0 years, M:F 4,210:5,126) underwent CTC at a single center, yielding 2,606 non-diminutive polyps. Of 1,731/2,606 polyps that underwent follow-up OC, 1,550 (90%) were concordant and 181 (10%) were discordant. CTC results (size, location, morphology) were revealed to colonoscopists prior to OC. After independent consensus review by at least two radiologists, 115 discordant findings were felt to be possible OC false negatives, and were further evaluated at repeat CTC and/or OC.

Of the 115 possible OC false negatives, 37 were either lost to follow-up or still awaiting follow-up at the time of study. Of the remaining 78 polyps 31 (40%) were confirmed to be OC false negatives at follow-up evaluation (26 by OC, 5 by CTC), and 47 (60%) were again not found, and remain CTC false positives. Compared with CTC false positives, OC false negatives were more likely to be larger (10.6 ± 5.3 mm vs 8.5 ± 3.3 mm, p=0.034) and to have higher diagnostic reader confidence at initial CTC (mean 2.8/3 vs 2.3/3, p=0.001). OC false negatives were more likely than OC/CTC concordant polyps to be located in the right colon (71% vs 47%, p=0.010). Of OC false negatives confirmed at subsequent OC, 17/26 (65%) had adenomatous histology (1 tubulovillous adenoma, 11 tubular adenoma, 5 serrated adenoma), of which 6 were advanced lesions.

Among discordant polyps at OC following positive CTC, OC false negatives are a common occurrence even when CTC findings are known prior to colonoscopy. Proven OC false negatives were ≥10 mm on average, more likely to be located in the right colon, and called with higher diagnostic confidence on CTC. Most ultimately resected OC false negatives proved to be adenomatous histology, including a substantial fraction of advanced lesions.

An understanding of missed polyps at colon cancer screening is vital to improving detection and patient care.