Comparison of radiologists' confidence in excluding significant colorectal neoplasia with multidetector-row CT colonography compared with double contrast barium enema.

The aim of this study was to compare the confidence of experienced radiologists in excluding colonic neoplasia with CT colonography (CTC) compared with barium enema. 78 patients (median age 70 years, range 61-87 years, 44 women) underwent same day CTC and barium enema. Two radiologists experienced in reporting barium enema assessed whether the examination had excluded a polyp 6 mm or greater as "yes", "probably" or "no" for each of 6 colonic segments. Two different radiologists experienced in CTC independently performed the same assessment on the CT datasets. Responses were compared using a paired exact test. Formal barium enema and CT reports were compared with any endoscopic examination performed within 1 year. Studies reporting polyps 6 mm+ in patients not subsequently undergoing endoscopy were reviewed by two independent observers. Radiologists stated they had confidently excluded a significant lesion in 314 (71%) and 382 (86%) of 444 segments with barium enema and CTC, respectively (p<0.001). Confidence was significantly higher with CTC in the in the descending and ascending colon (p = 0.02 and p<0.001, respectively), and caecum (p<0.001). 22 patients underwent some form of endoscopy. Of five patients with proven colorectal neoplasia (including two with cancer), CTC and barium enema correctly identified five and three, respectively. In 56 patients not undergoing endoscopy, CTC reported 17 polyps 6 mm+, of which 16 were retrospectively classified as definite or probable. 11 could not be identified on the barium enema, even in retrospect. Confidence in excluding polyps 6 mm or larger is significantly greater with CT colonography particularly in the proximal colon.

Intra-individual comparison of patient acceptability of multidetector-row CT colonography and double-contrast barium enema.

AIMS: To compare the subjective acceptability of CT colonography in comparison with barium enema in older symptomatic patients, and to ascertain preferences for future colonic investigation. MATERIALS AND METHODS: The study population comprised 78 persons aged 60 years or over with symptoms suggestive of colorectal neoplasia, who underwent CT colonography followed the same day by barium enema. A 25-point questionnaire was administered after each procedure and an additional follow-up questionnaire a week later. Responses were compared using Wilcoxon matched pairs testing, Mann-Whitney test statistics and binomial exact testing. RESULTS: Participants suffered less physical discomfort during CT colonography (p = 0.03) and overall satisfaction was greater compared with barium enema (p = 0.03). On follow-up, respondents reported significantly better tolerance of CT colonography (p = 0.002), and were less prepared to undergo barium enema again (p < 0.001). Of 52 subjects expressing an opinion, all preferred CT to barium enema. CONCLUSION: Patient satisfaction was higher with CT colonography than barium enema. CT colonography caused significantly less physical discomfort and was overwhelmingly preferred by patients.

CT colonography practice in the UK: a national survey.

AIM: To determine the provision of computed tomography (CT) colonography in UK radiology departments. MATERIALS AND METHODS: A questionnaire relating to the availability of CT colonography, barriers to implementation, clinical indications, technique, and practitioners was posted to clinical directors of UK radiology departments. RESULTS: One hundred and thirty-eight departments responded. Fifty (36%) offered CT colonography in day-to-day clinical practice. Of those that did not, 68 of 87 (64%) cited limited scanner capacity as the main barrier. Of the 50 departments offering a service, 39 (78%) offered CT after incomplete colonoscopy, 36 (72%), after failed barium enema, and 37 (74%) as an alternative to barium enema. Of those offering a service, the number of studies performed varied between one per month (38%) to more than one per day (8%). Total experience varied between 20 or fewer studies (28%) to more than 300 (12%). Full bowel preparation was common (92%), as was dual positioning (90%). Colonography was interpreted by radiologists with a subspecialty interest in gastrointestinal imaging in 64% of centres offering a service. CONCLUSION: CT colonography is widely available in the UK, with approximately one-third of responders offering a service. Experience and throughput varies considerably. Limited CT scanner capacity is the major barrier to further dissemination.

CT colonography: methods, pathology and pitfalls.

Computed tomography colonography (CTC) is a relatively new technique that is currently challenging more established methods of large bowel imaging. Several workers have suggested CTC surpasses the barium enema and approaches conventional endoscopy for detection of colorectal neoplasia. Accurate diagnosis relies on technically good studies, the main aim of which is adequate bowel cleansing and distension. Furthermore, the learning curve is steep and normal colonic anatomy has to be re-learned in a CT context. This review aims to describe the technique, revise the imaging features of both normal and pathological colon, and to highlight potential diagnostic pitfalls and their avoidance.

Predictive value of impaired evacuation at proctography in diagnosing anismus.

OBJECTIVE: We aimed to determine the positive predictive value of impaired evacuation during evacuation proctography for the subsequent diagnosis of anismus. SUBJECTS AND METHODS: Thirty-one adults with signs of impaired evacuation (defined as the inability to evacuate two thirds of a 120 mL contrast enema within 30 sec) during evacuation proctography underwent subsequent anorectal physiologic testing for anismus. A physiologic diagnosis of anismus was based on a typical clinical history of the condition combined with impaired rectal balloon expulsion or abnormal surface electromyogram. RESULTS: Twenty-eight (90%) of the 31 patients with impaired proctographic evacuation were found to have anismus at subsequent physiologic testing. Among the 28 were all 10 patients who evacuated no contrast medium and all 11 patients with inadequate pelvic floor descent, giving evacuation proctography a positive predictive value of 90% for the diagnosis of anismus. A prominent puborectal impression was seen in only three subjects during proctography, one of whom subsequently showed no physiologic sign of anismus. CONCLUSION: Impaired evacuation during evacuation proctography is highly predictive for diagnosis of anismus.

The effect of timing of intravenous muscle relaxant on the quality of double-contrast barium enema.

AIM: To determine whether the timing of buscopan administration during double-contrast barium enema examination (DCBE) affects diagnostic quality. MATERIALS AND METHODS: In a prospective setting, 100 consecutive adult out-patients referred for DCBE received 20 mg buscopan (hyoscine-N-butylbromide) intravenously, either before infusion of barium suspension (Group A) or after barium infusion and gas insufflation (Group B). A subjective assessment of ease of contrast medium infusion was made at the time of examination and the films subsequently analysed by two radiologists unaware of the mode of relaxant administration, who noted the quality of mucosal coating and made subjective and objective measurements of segmental distension. RESULTS: There was no significant difference in screening times, infusion difficulty or colonic contrast medium coating between the two groups. Subjective assessment of distension of the caecum, ascending colon, transverse colon and rectum were not significantly different. Patients receiving intravenous relaxant after barium and gas infusion had less subjective descending (P = 0. 05) and sigmoid (P = 0.04) colon distension, but there was no significant difference with respect to maximal bowel diameter in any of the segments measured. CONCLUSION: The timing of intravenous administration during DCBE is likely to have no significant effect on the diagnostic quality of the study.

Why is colonoscopy more difficult in women?

BACKGROUND: In our experience colonoscopy in women is more difficult than in men. A retrospective review of 2194 colonoscopies performed by a single experienced endoscopist (CBW) showed that 31% of examinations in women were considered technically difficult compared with 16% in men. METHODS: To investigate a possible anatomic basis for this finding, normal barium enema series from 183 female and 162 male patients were identified. From these barium enemas, measurements of colonic length and mobility were independently taken by two physicians who were unaware of each patient's gender. RESULTS: Total colonic length was greater in women (median, 155 cm) compared to men (median, 145 cm), p = 0.005, despite women's smaller stature (p < 0.0001). Although there were no significant differences in rectum plus sigmoid, descending, or ascending plus cecum segmental lengths, women had longer transverse colons (female median length, 48 cm; male median length, 40 cm), p < 0.0001. There were no differences in mobility of the descending colon and transverse colon between the sexes, but the transverse colon reached the true pelvis more often in women (62%) than in men (26%), p < 0.001. CONCLUSIONS: Colonoscopy appears to be a technically more difficult procedure in women. The reason for this may be due in part to an inherently longer colon.

Can barium enema indicate when colonoscopy will be difficult?

The barium enemas of 48 consecutive patients, who were technically difficult to intubate at colonoscopy, were compared to those of 46 patients who were not. Measurements were taken of colonic length and mobility, and an assessment made of diverticular disease. Rectosigmoid length (mean difficult group = 61 cm, mean control = 54 cm, P = 0.01) and total colonic length (mean difficult group = 157 cm, mean control = 140 cm, P < 0.0001) were greater in the difficult colonoscopy group as were transverse colon mobility (mean difficult group = 10 cm, mean control = 7 cm, P = 0.003) or redundancy (transverse colon reaching the true pelvis on the erect film); 65% difficult group vs 17% control group, P < 0.0001. The presence of moderate or severe diverticular disease was also greater in the difficult (23%) compared to the control (4%) group, P = 0.02. When available, assessment of a previous barium enema is a useful guide to probable technical difficulty of colonscopy. It may allow appropriate allocation of potentially difficult cases to specialist endoscopy lists.

Quantification of evacuation proctography.

PURPOSE: This study was designed to determine if evacuation proctography provides a clinically acceptable estimate of the time and completeness of rectal evacuation. METHODS: Rectodynamics, using a weight transducer and chart recorder to quantify the weight and rate of contrast expelled, was combined with evacuation proctography to assess agreement between the evacuation times recorded and the weight of contrast expelled compared with the lateral area change on proctography. RESULTS: Mean difference of evacuation times measured by the techniques was 0.1 seconds and the standard deviation of the differences was 1.9 seconds with 95 percent agreement limits of +/- 3.9 seconds. The mean difference between the percentage of contrast evacuated by weight and the change in rectal area on proctography was 4.3 percent. The standard deviation of the differences was 11.9 percent with 95 percent agreement limits of -19.5 percent and +28.1 percent. CONCLUSION: Evacuation proctography provides a valid estimation of the time and completeness of rectal evacuation.

Radiological investigation of chronic inflammatory bowel disease in childhood.

The radiological investigations relevant to chronic IBD are described briefly with emphasis placed on compression techniques in small bowel studies. A classification for reporting small bowel Crohn's disease is proposed, where the disease is staged as early, advanced or complicated, and the extent of involvement measured directly from the film. The terminal ileum may be normal in 20% of children with proximal Crohn's disease, so that ileoscopy should not be used to exclude small bowel disease. Radiological assessment of the small bowel is important in management. Surgical referral was based on the radiological changes in 6% of patients, and in 24% the presence of extensive uncomplicated small bowel Crohn's disease led to treatment with elemental diet. The use of some specialized examinations, such as the instant and ileostomy enema, are discussed.

Benefit of intravenous muscle relaxants during barium follow through.

The value of an intravenous (i.v.) smooth muscle relaxant during barium follow through (BaFT) examination has been evaluated in a prospective study of 51 patients. Spot compression films pre- and post-relaxant were compared. Relaxant-induced hypotonia improved image quality in 33 (64.8%) patients by facilitating bowel loop separation and/or graded compression. Additional diagnostic information was obtained in 14 (27.5%), and reporting confidence was improved in 19 (37.3%) patients. A marked analgesic effect occurred in seven patients with Crohn's disease, ameliorating pain that otherwise prevented full compression. Intravenous relaxants are recommended when high tone makes compression difficult, to help separate overlying loops and where pain in Crohn's disease prevents adequate compression.

Barium radiology.

The role of barium radiology in the diagnosis and assessment of inflammatory bowel disease is discussed. A primary diagnostic role is maintained in the small bowel, though in the colon endoscopy with biopsy is being used more frequently. The instant enema is safer in acute colitis. Advanced and complicated disease are more accurately assessed radiologically, as barium studies map out disease more clearly and show mural and extramural components.

Colonic preservation reduces need for parenteral therapy, increases incidence of renal stones, but does not change high prevalence of gall stones in patients with a short bowel.

Forty six patients with less than 200 cm of normal jejunum and no functioning colon were compared with 38 patients with similar jejunal lengths in continuity with a functioning colon. Women predominated (67%), and the most common diagnosis in each group was Crohn's disease (33 of 46 no colon, 16 of 38 with colon). All patients without a colon and less than 85 cm of jejunum and all those with a colon and less than 45 cm jejunum needed long term parenteral nutrition. Six months after the last resection 12 of 17 patients with less than 100 cm jejunum and no colon needed intravenous supplements compared with 7 of 21 with a colon. Between 6 months and 2 years, little change occurred in the nutritional/fluid requirements in either group, though there was weight gain. Of 71 patients assessed clinically at a median of 5 years, none with more than 50 cm of jejunum and a colon needed parenteral supplements. Most (25 of 27) of those without a colon who did not need parenteral supplements required oral electrolyte replacement compared with few (4 of 27) with a colon. None of the patients without a colon developed symptomatic renal stones compared with 9 of 38 (24%) with a colon (p < 0.001). Stone analysis in three patients showed calcium oxalate. Gall stone prevalence was high but equal in the two groups--43% of those without and 44% of those with a colon.

Determining the minimal interval between cleansing water enema and double-contrast barium enema examination.

In a prospective study 59 consecutive outpatients having double-contrast barium enemas (DCBE) were randomised into four groups. Each group had their enema performed at either a 15, 30, 45 or 60 minute interval following the end of a 1.5 litre cleansing water enema. Review of the films by two radiologists demonstrated that adequate mucosal coating was obtained after 45 minutes. The DCBE should therefore be performed at a minimum time interval of 45 minutes following colonic lavage, and not beforehand.

The effect of oral magnesium-containing bowel preparation agents on mucosal coating by barium sulphate suspensions.

Alteration in the quality of mucosal coating by barium sulphate suspension observed during double-contrast barium enema (DCBE) examinations when an oral magnesium-containing purgative (Picolax) was used as sole bowel preparation has been investigated in vivo. Small amounts of Picolax were found to produce a linear increase in apparent viscosity and thixotropy, due to flocculation. The effect of equivalent concentrations of acid was significantly less (p less than 0.01), and of magnesium chloride was significantly greater (p less than 0.05), whereas magnesium citrate was comparable to Picolax, demonstrating the deflocculating effect of citrate on the flocculating action of magnesium ions. It is suggested that colonic residue from orally ingested magnesium-containing purgatives may contain sufficient magnesium ions to increase viscosity of the barium suspension and visibly affect its coating during DCBE.

Technique and evaluation of the double contrast ileostomy enema.

A simple method for double contrast examination of the distal ileum in patients with a terminal ileostomy is described, using stomal intubation with a Foley catheter, syringe injection of barium, and air insufflation with smooth muscle relaxation. In 40 examinations the median length of ileum filled was 55 cm (range 20 to 140) with 38% of this length visualised in double contrast in a single view. The prestomal ileum was demonstrated clearly in 85%. Nine out of 18 patients with an abnormal ileostomy enema also had a barium follow through examination. The ileostomy enema made a significant contribution to the diagnosis in five of the nine patients.