Canadian Association of Radiologists Practice Guidelines for Computed Tomography Colonography

Colon cancer is the third most common malignancy in Canada. Computed tomography colonography (CTC) provides a creditable and validated option for colon screening and assessment of known pathology in patients for whom conventional colonoscopy is contraindicated or where patients self-select to use imaging as their primary modality for initial colonic assessment. This updated guideline aims to provide a toolkit for both experienced imagers (and technologists) and for those considering launching this examination in their practice. There is guidance for reporting, optimal exam preparation, tips for problem solving to attain high quality examinations in challenging scenarios as well as suggestions for ongoing maintenance of competence. We also provide insight into the role of artificial intelligence and the utility of CTC in tumour staging of colorectal cancer. The appendices provide more detailed guidance into bowel preparation and reporting templates as well as useful information on polyp stratification and management strategies. Reading this guideline should equip the reader with the knowledge base to perform colonography but also provide an unbiased overview of its role in colon screening compared with other screening options.

Safety window for the transsphenoidal approach for pituitary tumours: a computed tomographic angiography study

BACKGROUND

The aims are to evaluate the morphometry of the sellar region and propose a safety window on the floor of the sella turcica for the transsphenoidal approach in a Hispanic population.

MATERIALS AND METHODS

We retrospectively analysed 150 computed tomographic angiography sellar region images from asymptomatic patients. The images were evaluated intraobservatory by an expert radiologist. We measured: intercarotid distance of cavernous segment; depth of sella turcica; skull base angle; anterior distance, the distance between anterior spinal nasal and floor of the sella turcica; posterior distance, the distance between anterior spinal nasal and posterior wall of the sella turcica; anterior surgical angle, formed between the floor of the nostril and superior limit of the anterior wall of the sella turcica; and posterior angle, formed between the floor of the nostril and the inferior limit of the posterior wall of the sella turcica.

RESULTS

Safety window was based on two measures: the intercarotid distance and depth. The mean of the safety window is 151.13 mm² and 147.60 mm² for men and women, respectively. The intercarotid distance was 17.83 mm. The depth of the sella turcica was 8.46 mm. The skull base angle was 112.13 grades. The anterior distance was 76.34 mm. The posterior distance was 87.59 mm. The anterior surgical angle was 32.76 grades. The posterior surgical angle was 87.59 grades.

CONCLUSIONS

The surgical approach space is smaller in females. It could significate a more complicated surgery in this population. Anatomical understanding could reduce complications in hospitals without a neuronavigation system.

The undiagnosed potential clinically significant incidental findings of neck CTA: A large retrospective single-center study

To assess the prevalence and missed reporting rate of potential clinically-significant incidental findings (IFs) in the neck CTA scans.All consecutive patients undergoing neck CTA imaging, from January 1, 2017 to December 31, 2018, were retrospectively evaluated by a radiologist for the presence of incidental findings in the upper chest, lower head and neck regions. These incidental findings were subsequently classified into 3 categories in terms of clinical significance: Type I, highly significant, Type II, moderately significant; and Type III, mildly or not significant. Type I and Type II IFs were determined as potential clinically significant ones and were retrospectively analyzed by another 2 radiologists in consensus. The undiagnosed findings were designated as those that were not reported by the initial radiologists. The differences in the rate of unreported potential clinically significant IFs were compared between the chest group and head or neck group.A total of 376 potential clinically significant IFs were detected in 1,698 (91.19%) patients, of which 175 IFs were classified as highly significant findings (Type I), and 201 (53.46%) as moderately significant findings (Type II). The most common potential clinically significant findings included thyroid nodules (n = 88, 23.40%), pulmonary nodules (n = 56, 14.89%), sinus disease (n = 39, 10.37%), intracranial or cervical artery aneurysms (n = 30, 7.98%), enlarged lymph nodes (n = 24, 6.38%), and pulmonary embolism (n = 19, 5.05%). In addition, 184 (48.94%) of them were not mentioned in the initial report. The highest incidence of missed potential clinical findings were pulmonary embolism and pathologic fractures and erosions (100% for both). The unreported rate of the chest group was significantly higher than that of the head or neck one, regardless of Type I, Type II or all potential clinically significant IFs (χ = 32.151, χ = 31.211, χ = 65.286, respectively; P < .001 for all).Important clinically significant incidental findings are commonly found in a proportion of patients undergoing neck CTA, in which nearly half of these patients have had potential clinically significant IFs not diagnosed in the initial report. Therefore, radiologists should beware of the importance of and the necessity to identify incidental findings in neck CTA scans.

Multiparametric radiomics nomogram may be used for predicting the severity of esophageal varices in cirrhotic patients

Background

To explore whether a multiparametric radiomics nomogram on computed tomography (CT) images based on radiomics and relevant parameters of esophageal varices (EV) can be used for predicting the EV severity in patients with cirrhotic livers.

Methods

From January 2016 to August 2018, 136 consecutive patients with clinicopathologically confirmed liver cirrhosis were included for the development of a predictive model. The patients were then divided into two groups, including non-conspicuous EV group (mild-to-moderate EV, n=30) and conspicuous EV group (severe EV, n=106) by using the endoscopic validation as the reference standard. The radiomic scores (Rad scores) were constructed using the binary logistic regression model from the radiomics features of regions of interest (ROIs) in the left liver (LL) and right liver (RL), respectively. The multiparametric nomogram combined the best performance Rad-score and EV-relevant factors, and the calibration, discrimination, and clinical usefulness of developed nomogram were evaluated using calibration curves, decision curve analysis (DCA) and net reclassification index (NRI) analysis respectively.

Results

The LL Rad-score calculated from radiomics features was selected with a relatively higher area under the curve (AUC) (AUC; 0.88, training cohort; 0.87, the validation cohort) compared with RL Rad-score (AUC; 0.86, training cohort; 0.83, the validation cohort). In addition, cross-sectional surface area (CSA) was identified as the important predictor (P<0.05), the multiparametric nomogram containing LL Rad-score and CSA was shown to have a better predictive performance and good calibration in the training model (C-index, 0.953, 95% CI, 0.892 to 0.973) and the validation cohort (C-index, 0.938, 95% CI, 0.841 to 0.961), resulting in an improved NRI (categorical NRI of 25.9%, P=0.0128; continuous NRI of 120%, P<0.001) and integrated discriminatory improvement (IDI) (IDI =13.9%, P<0.001). DCA demonstrated that the multiparametric radiomics nomogram was clinically useful.

Conclusions

A multiparametric radiomics nomogram, which incorporates the liver radiomics signature and EV-relevant indices, is a useful tool for noninvasively predicting EV severity and may complement the standard endoscopy for evaluating EV severity in patients with cirrhosis.

Laparoscopic management of enterohepatic migrated fish bone mimicking liver neoplasm: A case report and literature review

RATIONALE

Accidental ingestion of a foreign body is common in daily life. But the hepatic migration of perforated foreign body is rather rare.

PATIENT CONCERNS

A 37-year-old man presented with a history of vague epigastric discomfort for about 2 months.

DIAGNOSIS

A diagnosis of the foreign body induced hepatic inflammatory mass was made based on abdominal computed tomographic scan and upper gastrointestinal endoscopy.

INTERVENTIONS

The patient underwent laparoscopic laparotomy. During the operation, inflammatory signs were seen in the lesser omentum and segment 3 of liver. B- Ultrasound guided excision of the mass (in segment 3) was performed. Dissecting the specimen revealed a fish bone measuring 1.7 cm in length.

OUTCOMES

The patient recovered uneventfully and was discharged on day 5 after surgery.

LESSONS

This study shows the usefulness of endoscopy for final diagnosis and treatment in foreign body ingestion. Early diagnosis and decisive treatment in time are lifesaving for patients with this potentially lethal condition.

Application of computed tomography and stereolithography to correct a complex angular and torsional limb deformity in a donkey

OBJECTIVE

To report the evaluation, surgical planning, and outcome for correction of a complex limb deformity in the tibia of a donkey using computed tomographic (CT) imaging and a 3D bone model.

STUDY DESIGN

Case report.

ANIMALS

A 1.5-year-old, 110 kg donkey colt with an angular and torsional deformity of the right pelvic limb.

METHODS

Findings on physical examimation included a severe, complex deformity of the right pelvic limb that substantially impeded ambulation. Both hind limbs were imaged via CT, and imaging software was used to characterize the bone deformity. A custom stereolithographic bone model was printed for preoperative planning and rehersal of the surgery. A closing wedge ostectomy with de-rotation of the tibia was stabilized with 2 precontoured 3.5-mm locking compression plates. Clinical follow-up was available for 3.5 years postoperatively.

RESULTS

CT allowed characterization of the angular and torsional bone deformity of the right tibia. A custom bone model facilitated surgical planning and rehearsal of the procedure. Tibial corrective ostectomy was performed without complication. Postoperative management included physical rehabilitation to help restore muscular function and pelvic limb mechanics. Short-term and long-term follow-up confirmed bone healing and excellent clinical function.

CONCLUSION

CT imaging and stereolithography facilitated the evaluation and surgical planning of a complex limb deformity. This combination of techniques may improve the accuracy of the surgeons' evaluation of complex bone deformities in large animals, shorten operating times, and improve outcomes.

Boerhaave's syndrome secondary to an incarcerated inguinal hernia: A case report

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Boerhaave’s syndrome is defined as the spontaneous perforation of the esophagus typically after forceful emesis.

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Although Boerhaave’s syndrome has been reported in association with different pathologies, there are no previous reports describing the concurrent surgical repair of an incarcerated inguinal hernia.

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A thoracotomy and two layered esophageal repair, followed by a groin exploration, small bowel resection and repair of an inguinal hernia were involved in the surgical management of this patient.

Introduction

Boerhaave’s syndrome is defined as the spontaneous perforation of the esophagus. Although it has been reported in association with different gastrointestinal pathologies, there are no previous reports in association with an incarcerated inguinal hernia containing ischemic small bowel.

Presentation of case

We present an unusual case of a gentleman who presented with severe chest pain after a 24-h period of emesis. He was found to have developed an esophageal perforation presumed secondary to an incarcerated inguinal hernia causing small bowel obstruction. The patient underwent a thoracotomy to repair the perforated esophagus followed by a groin exploration, small bowel resection and repair of the inguinal hernia.

Discussion

Boerhaave’s syndrome is well known to be a postemetic phenomenon in association with upper gastrointestinal obstruction. However, to our knowledge, this is the first reported case of esophageal perforation secondary to strangulated bowel in an inguinal hernia. In similar situations, we recommend the surgical correction of the esophageal perforation, followed by exploration and resection of any ischemic small bowel.

Conclusion

Here we present a patient who was diagnosed with a perforated esophagus after forceful emesis secondary to an incarcerated inguinal hernia containing ischemic bowel.

An analysis of the accuracy of computed tomography colonography when defining anatomy for novel full-thickness colonic excision techniques in early colonic neoplasia

AIM

Full-thickness laparo-endoscopic excision (FLEX) is a new technique developed for the full-thickness excision of colonic adenomas and, potentially, early cancer, avoiding the need for colectomy. FLEX requires accurate preoperative characterization of three key morphological features of the tumour, including its relation to the mesenteric border, its diameter and the circumferential extent of involvement of the bowel wall. This study evaluated the accuracy of CT colonography (CTC) for the assessment of these features in early colonic tumours.

METHOD

Consecutive patients undergoing CTC prior to colonic resection for complex benign polyps or UICC Stage 1 cancer were retrospectively analysed by two specialist gastrointestinal radiologists blinded to the subsequent histopathological findings. The location of the tumour in relation to the mesenteric border, its maximum diameter and the circumferential extent of involvement of the colonic wall were correlated with the histopathological examination of the surgical resection specimen. Pearson's correlation coefficient (r) and Kappa agreement (κ) were used to compare the maximum diameter and the circumferential extent of involvement of the colonic wall.

RESULTS

Twenty-eight patients with early colonic neoplasia were included. All had had a surgical segmental resection. Four had a benign adenoma and 24 had a TNM Stage 1 cancer. Histopathological assessment of the resected surgical specimen showed that 21 of the 28 lesions were located on the mesenteric border. The median diameter was 35 (interquartile range 28-42) mm; 13 lesions involved less than one-third of the circumference, 11 between one and two-thirds and four more than two-thirds. CTC correctly identified the location of the lesion in relation to the mesenteric border in all 28 cases. Correlation between CTC and histopathology was good for the assessment of the maximum diameter of the lesion (r = 0.81) and the circumferential extent of involvement of the colonic wall (κ = 0.76).

CONCLUSION

CTC can accurately assess the key morphological features for the selection of patients with early colonic neoplasia for full-thickness laparo-endoscopic excision.

The safety of same-day CT colonography following incomplete colonoscopy with polypectomy

BACKGROUND

Concerns about the risk of bowel perforation for same-day computed tomography colonography (CTC) following an incomplete colonoscopy with polypectomy may lead to unnecessarily postponing the CTC.

OBJECTIVE

The objective of this article is to describe the complications including colon perforations associated with same-day CTC in a cohort who had polypectomies but an incomplete colonoscopy.

DESIGN

We conducted a retrospective study.

SETTING

Our study took place in a single, tertiary referral center.

PATIENTS

We studied consecutive patients who had CTC the same day as an incomplete colonoscopy with polypectomy.

INTERVENTIONS

Interventions included optical colonoscopy (OC), endoscopic polypectomies, and same-day CTC.

MAIN OUTCOME MEASUREMENTS

Our main outcome measurements included perforation rate with long-term follow-up.

RESULTS

A total of 3% of patients undergoing colonoscopy from January 2008 to December 2012 had same-day CTC following incomplete OC, and 72 polypectomies were performed in 34 (or 17%) of these patients. Incomplete colonoscopies were due to colon tortuosity and looping (25), severe angulations (five), colon mass (two), colon stenosis (one), bradycardia (one). Fifty-three percent of the OCs were screening for colon neoplasia, 29% diagnostic and 18% were surveillance of colon polyps. Most polyps were ≤ 5 mm, and found in the left colon. There were no reported complications or perforations associated with same-day CTCs during short- and long-term follow-up.

LIMITATIONS

Limitations of our analysis included retrospective single-center design, small number of patients for the occurrence, referral to same-day CTC was not standardized, inability to establish safety of CTC for specific scenarios such as after complex polypectomies, strictures, or advanced IBD.

CONCLUSIONS

Radiologists' apprehension to perform a CTC the same day as an incomplete colonoscopy following polypectomies because of perceived risk of perforation may be unfounded. More data are needed to determine the safety of same-day CTC in patients with high-risk findings during colonoscopy such as a stricture, severe IBD, and after complex polypectomies.

Abdominal computed tomography, colonography and radiation exposure: what the surgeon needs to know

AIM

Abdominal computed tomography (CT) improves the accuracy of clinical diagnosis and facilitates patient management. Radiation exposure must be considered by requesting clinicians and is especially relevant owing to the increasing use of CT colonography for diagnosis and screening of colorectal disorders. This review describes the radiation dose of abdominopelvic CT and colonography and attempts to quantify the risk for the clinician.

METHOD

Articles were searched in the PubMed and Medline databases using combinations of the MeSH terms 'radiation', 'abdominal computed tomography' and 'colonography'. Electronic English language abstracts were read by two reviewers and the full article was retrieved if relevant to the review.

RESULTS

Abdominopelvic CT and CT colonography convey significant radiation dose to the patient but also have considerable diagnostic potential. In the right clinical context, the radiation risk should not be overestimated. Techniques to reduce the dose should be used. Repeated imaging in certain patients is a concern and should be monitored.

CONCLUSION

Radiation risk can be quantified and presented simply in a manner that both patients and doctors can comprehend and evaluate. This approach will diminish misconceptions and allow a rational choice of diagnostic test.

Comparison of the accuracy of CT colonography and colonoscopy in the diagnosis of colorectal cancer

AIM

The available evidence was reviewed to compare the effectiveness of CT colonography with that of colonoscopy for colorectal cancer (CRC) screening.

METHOD

An electronic search was conducted using PubMed, EMBASE, the Cochrane Library and Centre for Reviews and Dissemination databases, from inception to July 2009. Studies were included if investigations used CT colonography for CRC screening in asymptomatic populations. Studies were excluded if investigations were conducted for the diagnosis of CRC or in elderly, high-risk or symptomatic populations.

RESULTS

Of the 213 references identified, nine studies were included. The specificity of CT colonography in screening for CRC was high, although it decreased with decreasing diameter of polyp to be detected. The sensitivity of CT colonography for the detection of polyps < 6 mm in diameter was low and heterogeneous, although it was higher for polyps > 10 mm. The main factors contributing to a greater sensitivity of CT colonography were the inclusion of only populations with an average CRC risk and colonic insufflation with CO2 . The incidence of adverse effects was very low for both tests.

CONCLUSION

CT colonography has high specificity but heterogeneous sensitivity, although in most cases it is not as sensitive or specific as conventional colonoscopy. CT colonography could therefore be useful as a screening test for populations with an average risk of CRC.

Computed tomographic evaluation of the proximal femur: A predictive classification in displaced femoral neck fracture management

BACKGROUND

Femoral neck fracture is truly an enigma due to the high incidence of avascular necrosis and nonunion. Different methods have been described to determine the size of the femoral head fragment, as a small head has been said to be associated with poor outcome and nonunion due to inadequate implant purchase in the proximal fragment. These methods were two dimensional and were affected by radiography techniques, therefore did not determine true head size. Computed tomography (CT) is an important option to measure true head size as images can be obtained in three dimensions. Henceforth, we subjected patients to CT scan of hip in cases with displaced fracture neck of femur. The study aims to define the term small head or inadequate size femoral head" objectively for its prognostic significance.

MATERIALS AND METHODS

70 cases of displaced femoral neck fractures underwent CT scan preoperatively for proximal femoral geometric measurements of both hips. Dual energy X-ray absorptiometry scan was done in all cases. Patients were treated with either intertrochanteric osteotomy or lag screw osteosynthesis based on the size of the head fragment on plain radiographs.

RESULTS

The average femoral head fragment volume was 57 cu cm (range 28.3-84.91 cu cm; standard deviation 14 cu cm). Proximal fragment volume of >43 cu cm was termed adequate size (type I) and of ≤43 cu cm as small femoral head (type II). Fractures which united (n = 54) had a relatively large average head size (59 cu cm) when compared to fractures that did not (n = 16), which had a small average head size (49 cu cm) and this difference was statistically significant. In type I fractures union rate was comparable in both osteotomy and lag screw groups (P > 0.05). Lag screw fixation failed invariably, while osteotomy showed good results in type II fractures (P < 0.05).

CONCLUSION

Computed tomography scan of the proximal femur is advisable for measuring true size of head fragment. An objective classification based on the femoral head size (type I and type II) is proposed. Osteosynthesis should be the preferred method of treatment in type I and osteotomy or prosthetic replacement is the method of choice for type II femoral neck fractures.

Recent progress in the diagnosis and management of chronic thromboembolic pulmonary hypertension

Chronic thromboembolic pulmonary hypertension (CTEPH) is a form of pulmonary hypertension caused by non-resolving thromboembolisms of the pulmonary arteries. In Japan, in contrast to Western countries, CTEPH is more prevalent in women. A Japanese multicenter study reported that a form of CTEPH unrelated to deep vein thrombosis is associated with HLA-B⁎5201, suggesting that this form of CTEPH may be associated with vasculopathy. CTEPH can be cured by pulmonary endarterectomy, provided that the thrombi are surgically accessible; thus, early diagnosis is important, and all patients with exertional dyspnea should be evaluated for pulmonary hypertension. Ventilation/perfusion scans provide an excellent non-invasive means to distinguish CTEPH from pulmonary arterial hypertension. Similarly, computed tomographic pulmonary angiograms allow for the detection of thrombi and evaluation of pulmonary hemodynamics in a minimally invasive manner. Importantly, the absence of subpleural perfusion on pulmonary angiograms can suggest the presence of small vessel disease. Small vessel disease might be involved in the pathogenesis of CTEPH, and its detection is essential in preventing operative death. Although no modern therapies for pulmonary arterial hypertension have been approved for treatment of CTEPH, a recent randomized control trial of riociguat in patients with CTEPH demonstrated that riociguat significantly improved 6-min walking distance. Further investigations into treatments that target endothelial dysfunction and hyperproliferative CTEPH cells are needed. Recently, balloon pulmonary angioplasty has emerged as a promising treatment modality in Japan. A specialized medical team, including at least one expert surgeon, should make decisions regarding patients' candidacy for pulmonary endarterectomy and/or balloon pulmonary angioplasty.

Management of dilated ascending aorta during aortic valve replacement: valve replacement alone versus aorta wrapping versus aorta replacement

OBJECTIVES

The optimal management of dilated ascending aorta during aortic valve replacement (AVR) remains controversial. This study compared the outcomes among 3 different managements (AVR alone, aorta wrapping, and aorta replacement) for the dilated ascending aorta.

METHODS

The study enrolled 499 consecutive non-Marfan patients undergoing AVR in the presence of the ascending aorta dilatation (40 to 55 mm). We evaluated rates of death and aortic events; in addition, we evaluated the aortic expansion rate by serial echocardiography.

RESULTS

The surgery involved AVR alone (n = 362), aorta wrapping (n = 67), or aorta replacement (n = 70). Early mortality occurred in 1.2% (n = 6, P = .61). Throughout 1590.0 patient-years of follow-up, 47 deaths occurred. The 5-year survival rates were 90.1% ± 2.0%, 91.8% ± 3.5%, and 82.2% ± 7.5% in the AVR alone, aorta wrapping, and aorta replacement groups, respectively (P = .64). One aortic event (acute type A dissection) occurred in the AVR alone group. For the AVR alone group, the median aortic expansion rate was -0.6 mm/y (interquartile range, -3.2 to 0.6 mm/y). The aortic expansion rates were affected neither by the morphology of aortic valves (bicuspid vs tricuspid; P = .10) nor by the initial aorta diameter (γ = -0.31, P = .61). Clinically relevant aortic expansion (≥5 mm/y) was observed only in 5 patients; of these patients, 2 showed the aortic diameter of 60 mm or greater at the end of follow-up.

CONCLUSIONS

Compared with concomitant aortic wrapping or replacement, AVR alone achieved similar clinical outcomes, showing considerably low risks of adverse aortic events or relevant aortic expansion in dilated ascending aorta. These findings argue against routine aortic replacement at the time of AVR.

Cost-effectiveness of colorectal cancer screening - an overview

There are several modalities available for a colorectal cancer (CRC) screening program. When determining which CRC screening program to implement, the costs of such programs should be considered in comparison to the health benefits they are expected to provide. Cost-effectiveness analysis provides a tool to do this. In this paper we review the evidence on the cost-effectiveness of CRC screening. Published studies universally indicate that when compared with no CRC screening, all screening modalities provide additional years of life at a cost that is deemed acceptable by most industrialized nations. Many recent studies even find CRC screening to be cost-saving. However, when the alternative CRC screening strategies are compared against each other in an incremental cost-effectiveness analysis, no single optimal strategy emerges across the studies. There is consensus that the new technologies of stool DNA testing, computed tomographic colonography and capsule endoscopy are not yet cost-effective compared with the established CRC screening tests.