Utility of minimal preparation computed tomography colonography in detecting colorectal cancer in elderly and frail patients.

BACKGROUND: Colorectal cancers result in substantial morbidity and mortality to the Australian society each year. The usual investigation for bowel malignancy is optical colonoscopy (OC), with computed tomography colonography (CTC) used as an alternative investigation. The catharsis and colon insufflation associated with these investigations pose a higher risk in the elderly and frail. Risks include perforation, serum electrolyte disturbance and anaesthesia/sedation risks. Minimal preparation computed tomography colonography (MPCTC) eliminates these risks. AIMS: To audit the accuracy of a MPCTC programme for the investigation of colonic masses in symptomatic elderly and frail patients. METHODS: This paper audits a 6-year period of MPCTC in an Australian tertiary referral hospital. A total of 145 patients underwent MPCTC during the study period. RESULTS: There were seven true positives, two false positives and two false negatives. Analysis of this population indicates a sensitivity of 0.78 (95% CI 0.51-1.05), specificity of 0.99 (95% CI 0.97-1.01), positive predictive value (PPV) of 0.78 (95% CI 0.51-1.05) and negative predictive value (NPV) of 0.99 (95% CI 0.97-1.01). These findings are concordant with other published studies. CONCLUSIONS: This audit confirms that minimal preparation CT colonography is a reasonable alternative to OC and CTC in detecting colorectal cancer in symptomatic elderly and frail patients, without the procedural risks inherent in more invasive investigations. For most patients, MPCTC ruled out significant colorectal carcinoma with a high NPV.

A tale of two twists: mesentero-axial and organo-axial sigmoid volvulus.

INTRODUCTION: Sigmoid volvulus is a potentially devastating and life-threatening condition associated with sigmoid colon redundancy. Many of the classical radiological signs are considered to represent the two adjacent loops of bowel in a mesentero-axial volvulus. However, limited case reports and series have reported on an organo-axial subtype of sigmoid volvulus. This clinical entity is not widely understood. In this study, we assess the radiological and clinical features of mesentero-axial and organo-axial sigmoid volvulus. METHODS: After institutional board approval (CH62/6/2016-228), all computed tomography (CT) studies from 2011 to 2017 reported as sigmoid volvulus at a single institution were reviewed. The cases were reviewed by three radiologists retrospectively and the course of the bowel followed with a focus on assessing its rotational axis. In each case, the sigmoid volvulus was independently subclassified as mesentero-axial or organo-axial volvulus based on the axis of rotation of the volvulus. In addition, X-ray signs including disproportionate sigmoid dilatation, distended inverted 'U' in sigmoid, coffee bean sign, opposed wall sign, direction of apex of sigmoid loop, liver overlap sign, northern exposure sign and proximal colonic dilatation and CT features including whirl sign, 'X' marks the spot sign, split wall sign and number of transition points were reported for each case. The clinical management and outcomes including morbidity, mortality, endoscopic decompression and need for surgery were also evaluated. The subtype of volvulus was correlated with the above X-ray signs, CT features and clinical management and outcomes. Statistical analysis was conducted using Stata/MP, version 15 (StataCorp LP, College Station, TX, USA). RESULTS: A total of 38 scans were reviewed. There were 19 patients identified. Of these, six (32%) were reported as mesentero-axial and 13 (68%) as organo-axial volvulus. No X-ray signs were able to distinguish the two types of volvulus. The number of transition points on CT was predictive of volvulus subtype (OR 25, 95% CI: 1.30-1295.30, P = 0.01). Within the limitations of a small cohort, there was no statistically significant difference in unsuccessful endoscopic decompression, need for colectomy, repeated admissions or mortality between the groups. CONCLUSION: This study has demonstrated that organo-axial sigmoid volvulus may be as common as mesentero-axial volvulus. Distinguishing organo-axial from mesentero-axial volvulus can be achieved on CT, but not on abdominal X-ray. The number of transition points (two for mesentero-axial and one for organo-axial) may be used as a diagnostic feature for differentiating the two forms of volvulus.

Glossopharyngeal insufflation causes lung injury in trained breath-hold divers.

BACKGROUND AND OBJECTIVE: Glossopharyngeal insufflation (GI) is a technique practised by competitive breath-hold divers to enhance their performance. Using the oropharyngeal musculature, air is pumped into the lungs to increase the lung volume above physiological TLC. Experienced breath-hold divers can increase their lung volumes by up to 3 L. Although the potential for lung injury is evident, there is limited information available. The aim of this study was to examine whether there is any evidence of lung injury following GI, independent of diving. METHODS: Six male, competitive breath-hold divers were studied. CT of the thorax was performed during breath-holding at supramaximal lung volumes following GI (CT(GI)), and subsequently at baseline TLC (CT(TLC)). CT scans were performed a minimum of 3 days apart. Images were analysed for evidence of pneumomediastinum or pneumothorax by investigators who were blinded to the procedure. RESULTS: None of the subjects showed symptoms or signs of pneumomediastinum. However, in five of six subjects a pneumomediastinum was detected during the CT(GI). In three subjects a pneumomediastinum was detected on the CT(GI), but had resolved by the time of the CT(TLC). In two subjects a pneumomediastinum was seen on both the CT(GI) and the CT(TLC), and these were larger on the day that a maximal GI manoeuvre had been performed. The single subject, in whom a pneumomediastinum was not detected, was demonstrated separately to not be proficient at GI. CONCLUSIONS: Barotrauma was observed in breath-hold divers who increased their lung volumes by GI. The long-term effects of this barotrauma are uncertain and longitudinal studies are required to assess cumulative lung damage.

Fistulae involving the appendix: a systematic review of the literature.

BACKGROUND: The appendix has a unique place in surgical history. Although the first ever appendicectomy involved a fistula to the skin, fistulae involving the appendix remain uncommon and can lead to unique surgical considerations. METHODS: A systematic review of the literature was performed for case reports of appendiceal fistulae. We excluded cases in which the patient had a history of appendicectomy. Cases were categorized by site and aetiology, with information regarding relative frequency and demographics obtained. RESULTS: A total of 301 case reports of fistula involving the appendix were found. The most common sites of these fistulae were to the bladder (148 cases), skin (40 cases), vasculature (19 cases), umbilicus (16 cases) and to the gastrointestinal tract. The most common aetiology in sub-analysis was appendicitis alone (150 cases), with less common causes including appendiceal adenocarcinoma (32 cases) and congenital abnormalities (18 cases). There were significantly more appendiceal fistulae in males than in females, with a ratio of 1.7:1. In patients with appendiceal adenocarcinoma as a cause for fistula, there were significantly more females than males with a ratio of 2.3:1. CONCLUSION: In conducting a systematic review of case reports of fistulae involving the appendix, we identified 301 unique case reports, with a range of different sites and aetiologies.

Minimal preparation CT: A literature review of a minimally invasive imaging technique for colorectal cancer in a frail, aged population.

Colorectal cancer (CRC) is a common malignancy with increased incidence in the elderly. When CRC is suspected, patients are typically evaluated with optical colonoscopy (OC) or CT Colonography (CTC). Unfortunately, in the frail and elderly patient, these investigations can be difficult to perform and are often not tolerated. Minimal preparation computed tomography (MPCT) is a CT technique to evaluate the colon. Although protocols vary, typically, no preparation is required apart from administration of oral contrast for faecal tagging. The patient is scanned in the supine position only and without colonic insufflation. The study is reserved for 'old-old' frail patients with clinically suspected CRC who cannot tolerate or have failed OC or CTC. In the context of an ageing population, MPCT provides a simple, minimally invasive, readily available and well-tolerated test that is able to demonstrate clinically relevant disease. We review the literature on MPCT and discuss the benefits and limitations of this investigation.

Lumen loss in the first year in saphenous vein grafts is predominantly a result of negative remodeling of the whole vessel rather than a result of changes in wall thickness.

BACKGROUND: The use of saphenous vein grafts (SVG) in coronary artery bypass surgery is established but little is known of SVG remodeling during the first year in vivo. METHODS AND RESULTS: The feasibility of measuring total vessel diameter (lumen plus wall), lumen diameter, and wall thickness by a novel computed tomography (CT) method was established in phantom model tubes (r=0.98 for lumen diameter and r=0.98 for wall thickness) and in an initial clinical study of 14 patients correlating CT and intravascular ultrasound measurements of SVG (r=0.88 for total vessel diameter, r=0.85 for lumen diameter and r=0.89 for wall thickness). In a separate group of 42 patients (aged 66+/-10 years; 36 male, 6 female) undergoing coronary artery bypass grafting, SVG total vessel diameter, lumen diameter, and wall thickness were determined prospectively with multi-slice CT angiography at 1 and 12 months postoperatively. Mean total vessel diameter decreased from 5.95+/-0.83 mm to 5.39+/-0.87 mm, P<0.001 (range, -39% to +8% change). Twenty-six patients (62%) had a decrease of SVG vessel diameter (negative remodeling) >5%. Mean lumen diameter decreased from 3.69+/-0.66 mm to 3.36+/-0.68 mm, P<0.001, (range, -40 to +11% change). Surprisingly, mean wall thickness decreased from 1.14+/-0.27 mm to 1.01+/-0.21 mm (P<0.001; range, -48 to +33% change). CONCLUSIONS: Lumen loss in SVG between postoperative months 1 and 12 is predominantly caused by negative remodeling of the whole vessel rather than to changes in wall thickness. Therapies targeting negative remodeling may be required for optimal maintenance of SVG lumen in the first postoperative year.