Technical quality of CT colonography in relation with diverticular disease

Cortical surface analysis for focal cortical dysplasia diagnosis by using PET images

Focal cortical dysplasia (FCD) is a neurological disorder distinguished by faulty brain cell structure and development. Repetitive and uncontrollable seizures may be linked to FCD's aberrant cortical thickness, gyrification, and sulcal depth. Quantitative cortical surface analysis is a crucial alternative to ineffective visual inspection. This study recruited 42 subjects including 22 FCD patients who underwent surgery and 20 healthy controls (HC). For the FCD patients, T1-weighted and PET images were obtained by a PET-MRI scanner, and the confirmed epileptogenic zone (EZ) was collected from postsurgical follow-up. For the HCs, CT and PET images were obtained by a PET-CT scanner. Cortical thickness, gyrification index, and sulcal depth were calculated using a computational anatomical toolbox (CAT12). A cluster-based analysis is carried out to determine each FCD patient's aberrant cortical surface. After parcellating the cerebral cortex into 68 regions by the Desikan-Killiany atlas, a region of interest (ROI) analysis was conducted to know whether the feature in the FCD group is significantly different from that in the HC group. Finally, the features of all ROIs were utilised to train a support vector machine classifier (SVM). The classification performance is evaluated by the leave-one-out cross-validation. The cluster-based analysis can localize the EZ cluster with the highest accuracy of 54.5 % (12/22) for cortical thickness, 40.9 % (9/22) and 13.6 % (3/22) for sulcal depth and gyrification, respectively. Moderate concordance (Kappa, 0.6) is observed between the confirmed EZs and identified clusters by using the cortical thickness. Fair concordance (Kappa, 0.3) and no concordance (Kappa, 0.1) is found by using sulcal depth and gyrification. Significant differences are found in 46 of 68 regions (67.7 %) for the three measures. The trained SVM classifier achieved a prediction accuracy of 95.5 % for the cortical thickness, while the sulcal depth and the gyrification obtained 86.0 % and 81.5 %. Cortical thickness, as determined by quantitative cortical surface analysis of PET data, has a greater ability than sulcal depth and gyrification to locate aberrant EZ clusters in FCD. Surface measures might be different in many regions for FCD and HC. By integrating machine learning and cortical morphologies features, individual prediction of FCD seems to be feasible.

CT colonography: can we achieve an adequate bowel preparation without diet restriction?

OBJECTIVE

To evaluate if an adequate bowel preparation for CT colonography, can be achieved without diet restriction, using a reduced amount of cathartic agent and fecal tagging. To investigate the influence of patients' characteristics on bowel preparation and the impact on patients' compliance.

METHODS

In total, 1446 outpatients scheduled for elective CT colonography were prospectively enrolled. All patients had the same bowel preparation based on a reduced amount of cathartic agent (120 g of macrogol in 1.5 l of water) the day before the exam and a fecal tagging agent (60 ml of hyperosmolar oral iodinated agent) the day of the exam. No dietary restrictions were imposed before the exam. The bowel preparation was evaluated using a qualitative and quantitative score. Patients were grouped by age, gender, and presence of diverticula in both scores. Patients' compliance has been evaluated with a questionnaire after the end of the exam and with a phone-calling interview the day after the exam.

RESULTS

According to the qualitative score, adequate bowel preparation was achieved in 1349 patients (93.29%) and no statistical differences were observed among the subgroups of patients. Quantitative scores demonstrated that colon distension was significantly better in younger patients and without diverticula. A good patients' compliance was observed and most patients (96.5%) were willing to repeat it.

CONCLUSIONS

The lack of diet restriction does not affect the quality of CTC preparation and good patient's compliance could potentially increase the participation rate in CRC screening programs.

KEY POINTS

• An adequate quality bowel preparation for CT colonography can be achieved without diet restriction, using a reduced amount of cathartic agent (120 g of macrogol in 1.5 l of water) and fecal tagging (60 ml of hyperosmolar oral iodinated agent). • A bowel preparation based on the combination of a reduced amount of cathartic agent and fecal tagging, without diet restriction, allows obtaining good quality in more than 90% of patients. • The bowel preparation scheme proposed reduces the distress and discomfort experienced by the patients improving adherence to CTC.

Relationship between Barrett's esophagus and colonic diseases: a role for colonoscopy in Barrett's surveillance

BACKGROUND

Given that risk factors for Barrett's carcinogenesis are predictive, appropriate management and surveillance of Barrett's esophagus (BE) may be provided. The presence of colorectal neoplasms (CRNs) is a possible predictor of the development of BE and the progression to esophageal adenocarcinoma (EAC). We evaluated the relationship between BE or EAC and colonic diseases, including neoplasms and diverticulosis.

METHODS

Patients (N = 5606) who underwent both colonoscopy and esophagogastroduodenoscopy between January 2016 and December 2017 at three institutions were enrolled. The relationships between the presence of colonic diseases and BE or EAC and other clinical or endoscopic predictors of the presence of BE were investigated retrospectively.

RESULTS

The prevalence of BE ≥ 1 cm and ≥ 3 cm in length was 13.0% and 0.52%, respectively. BE was closely related with the presence of colorectal adenoma (48.4% vs. 37.2% in non-BE; P < 0.001), adenocarcinoma (16.6% vs. 8.4%, P < 0.001) and colonic diverticulosis (CD) (34.1% vs. 29.3%, P < 0.001). In patients with long-segment BE, CRNs (79.3%, P < 0.001) and CD (48.2%, P = 0.038) were more common. EAC patients also had a statistically significantly higher incidence of CRNs than non-BE patients (87.5% vs. 45.6%, P = 0.027). Diverticulosis at the distal colon correlated significantly with EAC and BE (50.0%, P = 0.010 and 15.4%, P = 0.024, vs. 12.0% in non-BE). Multivariate analysis showed that CRNs (t = 8.55, P < 0.001), reflux esophagitis (t = 5.26, P < 0.001) and hiatal hernia (t = 11.68, P < 0.001) were predictors of BE.

CONCLUSIONS

The presence of CRNs was strongly associated with BE and EAC. Therefore, colonoscopy may be useful for establishing a strategy for the surveillance of BE.

Colonic distention and patient acceptance of CT colonography: supine/prone vs left/right lateral scanning

OBJECTIVE

To prospectively evaluate and complete the colonic distention and patient acceptance of CT colonography (CTC) in the supine/prone and left/right lateral positions.

METHODS

A total of 220 consecutive patients were alternately allocated to the supine/prone positioning or left/right lateral positioning group. Two readers scored the degree of colonic distention by segment using a 4-point Likert scale (4 = optimal, 3 = adequate, 2 = inadequate, 1 = collapsed). In addition, patients were asked to rate the discomfort due to positioning during each scan using a 3-point animated face scale (3 = difficult, 2 = somewhat unacceptable, 1 = easy).

RESULTS

The overall mean colonic distention scores for supine, prone, left lateral, and right lateral positions were 3.16, 3.29, 3.22, and 3.42, respectively. Of all, the right lateral position provided the best colonic distention (p < 0.01). Combined left lateral and right lateral positions provided more adequately distended segments compared with combined supine and prone positions (95.6% vs 90.7 %, respectively, p < 0.01). Patient acceptance was significantly lower in the prone position compared to other positions; however there was no difference in patient acceptance between the supine and left/right lateral positions.

CONCLUSION

Right lateral positioning provided the best colonic distention and good patient acceptance.

ADVANCES IN KNOWLEDGE

The left/right lateral position should be considered for routine CTC positioning protocols.

Assessment of 3 Bowel Preparation Protocols for Computed Tomography Pneumocolonography in Normal Dogs

OBJECTIVE

To investigate the effects of 3 different bowel preparation protocols on interpretation of computed tomography (CT) pneumocolonography images.

STUDY DESIGN

Experimental crossover design.

ANIMALS

Intact male, hound-cross, research colony dogs (n=4).

METHODS

All dogs received the 3 different bowel preparation protocols for CT pneumocolonography in the same order, with a minimum of 2 weeks between protocols. For each segment of large bowel, the subjective adequacy of bowel cleansing was assessed, residual fecal and bowel volumes were calculated, and the density of fecal material in the bowel lumen was measured. Linear mixed effect models that included a random dog effect were used to evaluate mean differences in outcome measures across protocols.

RESULTS

No dogs experienced any clinical problems associated with the protocols or CT pneumocolonography. Bowel cleansing was considered adequate for CT pneumocolonography interpretation for all 3 protocols. There was a significant effect of protocol on residual fecal volumes and the fecal:bowel volume ratio, with the 2 protocols that included an extended fast producing the lowest total residual fecal volumes. There was a significant effect of protocol on maximum measured density of residual fecal material with the 2 protocols including iodinated contrast having the highest density.

CONCLUSIONS

All protocols were sufficient for CT pneumocolonography interpretation and contrast-tagging of residual fecal material was successful with oral iopamidol administration. An at-home bowel cleansing protocol may provide adequate bowel cleansing for CT pneumocolonography image interpretation.

The Current Role of Radiologic and Endoscopic Imaging in the Diagnosis and Follow-Up of Colonic Diverticular Disease

OBJECTIVE

Colonic diverticular disease is among the most prevalent conditions in Western society and is a common cause for outpatient visits and hospitalizations. The role of imaging is in evolution, but it has proven useful in confirming clinically suspected disease, assessing severity and complications, and directing patient management.

CONCLUSION

This review focuses on the current role of radiologic and endoscopic imaging in distinct clinical scenarios of diverticular disease, with emphasis on diverticulitis and its follow-up.

Prognostic Value of the Diverticular Disease Severity Score Based on CT Colonography: Follow-up in Patients Recovering from Acute Diverticulitis

RATIONALE AND OBJECTIVES

To assess the prognostic value of a diverticular disease severity score (DDSS) based on computed tomography colonography (CTC) after acute diverticulitis (AD).

MATERIALS AND METHODS

Of 252 patients who had an AD episode, we finally selected 46 patients who underwent both conventional CT at the acute event and CTC after 9 ± 7 weeks. Of these 46 patients, 17 underwent elective surgery after CTC. Disease severity was assessed with a 0-4 modified Hinchey CT-based score and a 1-4 CTC-based DDSS. A phone survey was performed 27 months later (range 4-52) for the 29 patients not surgically treated.

RESULTS

Significant correlation was found between CTC-based DDSS and clinical follow-up (P = 0.022) or elective surgery (P = 0.007), but not between clinical follow-up and CT-based score, extraluminal gas, C-reactive protein serum level, age, gender, or first versus recurrent AD episode. CTC demonstrated relevant additional findings in five of 46 (11%) patients: two AD complications (enterocolic and enterotubal fistulae), two colon cancers, and one extracolonic (lung) cancer.

CONCLUSIONS

The CTC-based DDSS showed a prognostic value and correlated with the risk of undergoing surgery, and clinically relevant additional findings were found in more than 10% of patients. CTC could be the preferred test in patients recovering after AD.

Missed lesions at CT colonography: lessons learned

Misinterpretation at CT colonography (CTC) can result in either a colorectal lesion being missed (false-negative) or a false-positive diagnosis. This review will largely focus on potential missed lesions-and ways to avoid such misses. The general causes of false-negative interpretation at CTC can be broadly characterized and grouped into discrete categories related to suboptimal study technique, specific lesion characteristics, anatomic location, and imaging artifacts. Overlapping causes further increase the likelihood of missing a clinically relevant lesion. In the end, if the technical factors of bowel preparation, colonic distention, and robust CTC software are adequately addressed on a consistent basis, and the reader is aware of all the potential pitfalls at CTC, important lesions will seldom be missed.

Diverticular disease severity score based on CT colonography

OBJECTIVE

We propose a diverticular disease severity score (DDSS) based on CT colonography (CTC) findings.

METHODS

Seventy-nine patients (62 ± 14.5 years) underwent CTC after recovering from an episode of acute diverticulitis. Two independent readers classified each case using a four-point scale (DDSS), based on maximum sigmoid colon wall thickness (MSCWT) and minimum lumen diameter at CTC: 1 = MSCWT <3 mm, lumen diameter ≥15 mm; 2 = MSCWT 3-8 mm, lumen diameter ≥5 mm; 3 = MSCWT ≥8 mm, lumen diameter ≥5 mm; 4 = MSCWT ≥8 mm, lumen diameter <5 mm. Intra- and interobserver reproducibility was evaluated. Of 79 patients, 32 (40 %) underwent surgery after CTC; MSCWT was directly measured on the pathological specimen.

RESULTS

Intra- and interobserver reproducibility of DDSS were almost perfect (k = 0.90-0.84). DDSS significantly correlated with the probability of surgery (P = 0.001). After surgery, histopathology revealed acute/chronic diverticular inflammation only in 29 cases, and superimposed sigmoid cancer (n = 2) or Crohn's disease (n = 1) in 3 patients with a DDSS of 4. MSCWT at histopathology correlated with DDSS (P = 0.008).

CONCLUSION

DDSS is highly reproducible and correlates with pathological MSCWT. Nearly 1 in 3 patients with a DDSS of 4 had significant superimposed histopathology. CTC with DDSS can provide colorectal surgeons with valuable information.

KEY POINTS

• A diverticular disease severity score (DDSS) based on CT colonography is proposed. • This DDSS is based on sigmoid colon wall thickness and lumen diameter. • High scores may be associated with relevant coexisting lesions. • A CTC-based DDSS may influence therapeutic decision-making.