Halligan et al. (2003) and Halligan (2004) have suggested that ‘a barium enema list is not the attractive proposition it once was’ and that ‘radiologists, both trainees and consultants, are less inclined to take an interest’ in barium enema; in addition, the lack of interest is compounded by the perception that the examination is ‘old fashioned and behind the cutting edge of imaging’. The belief that the sensitivity of the double contrast barium enema (DCBE) for colorectal cancer (CRC) is poor at only about 85% adds to the lukewarm view of the examination. Indeed, Shorvon (2003) implied that there is no room for improving the DCBE and that it is ‘on a developmental plateau’.

It has been suggested by Glick (1997) that there has been a bias against the DCBE associated with a number of studies in which 75–95% of missed cancers were perceptive errors rather than technical error. This finding would suggest that many of the possible shortcomings of the DCBE examination could be overcome by double reading.

However, it is possible to achieve a very high sensitivity if appropriate attention is given to technique. It may be the case that the image sequence of the DCBE has been optimized, but fluoroscopy equipment continues to improve and is now producing higher quality images at a fraction of the radiation dose required just a few years ago.

In the USA, the DCBE was considered to detect the majority of clinically important lesions and was therefore deemed to be an appropriate method for colorectal cancer screening (Winawer et al., 1997). These considerations were supported by the American College of Gastroenterology, The American Association of Colon and Rectal Surgeons and the American Society of Gastrointestinal Endoscopy. A survey of US radiologists, published in 2002, indicated that 75% believe the DCBE to be a ‘very effective’ colorectal cancer screening procedure and, at that time, Medicare approved DCBE as a CRC screening modality in the USA (Klabunde et al., 2002). Ciatto and Castiglione (2002), in reviewing the use of the DCBE within a screening program, also concluded that DCBE was a useful adjunct to screening colonoscopy.

Complications

Vora and Chapman (2004) reviewed 348 000 barium enemas performed by 59 radiographers; 89 complications were reported (1:3900) including five deaths (a mortality rate of 1:70 000). Culpan and Chapman (2002) reported on 54 complications in a review of 134 700 barium enema examinations performed over a 3-year period by 250 radiographers who had attended the Leeds barium enema training course. The complication rate was 1:2500; three deaths indicated a mortality rate of 1:44 900.

The complication and mortality rates for radiographers are not dissimilar to those reported by Blakeborough et al. (1997a) in reviewing the responses of 756 UK consultant radiologists who had performed 738 216 barium enemas in a 3-year period. A total of 82 complications were reported by 77 radiologists (1:9000) including three deaths (a mortality rate of 1:56 786).

Complications associated with the barium enema include perforations, cardiac events and cerebrovascular accidents. In reviewing rectal perforation after a barium enema, de Freiter et al. (2006) report that the most catastrophic course with a high mortality rate develops from sepsis and peritonitis resulting from intraperitoneal perforation. Also reported as prognostically unfavorable is the venous intravasation of barium.

Comment was also made in this paper regarding the introduction of excessive intracolonic pressures, excessive colonic distension and also concern regarding the use of rectal balloon catheters. These results compare favorably with colonoscopy (de Freiter et al., 2006). Updating the British Society of Gastroenterology guidelines, Teague (2003) refered to previous audits including one by Quine et al. (1995) (in which the 30 day mortality was found to be 1:2000) and he indicated there was no evidence to suggest that mortality rates had improved significantly since the 1990s.

Radiologic technologist and radiographer involvement

Price and Le Masurier (2007) reported results of a study that suggest radiographers are performing barium enema examinations in as many as 80% of district general hospitals (DGHs) in the UK. In the USA, Thompson et al. (2006) reported that, with training, radiologic technologists can perform and interpret fluoroscopic images as effectively as radiologists with a similar sensitivity, specificity, positive and negative predictive value. These results are also supported by Culpan et al. (2002) as well as Booth and Mannion (2005). A review on radiographer DCBE reporting by Law et al. (2008), demonstrating a 98% sensitivity to CRC, also strongly supports the view that examinations by radiographers can have a sensitivity and specificity similar to those carried out by radiologists.

Using smooth muscle relaxants

Hypotonia of the colon and rectum has a number of beneficial effects:

• Lack of peristalsis provides greater ease of barium flow

• Reduced prominence of haustral folds reduces the pooling of barium, resulting in greater ease of barium manipulation

• Due to luminal relaxation and distension there is a greater surface area visible

• Colonic spasm and discomfort are reduced.

The rectal infusion of agents such as 30 ml of peppermint oil solution has been demonstrated to have an antispasmodic effect (Asao et al., 2003). The most commonly used hypotonic agents are 20 mg in 1 ml hyoscine butylbromide (Buscopan) or 1 mg in 1 ml glucagon (Fink and Aylward, 1995; Goei et al., 1996). The IV injection of Buscopan is likely to have no effect on the diagnostic quality of the examination whether it is given before or after the infusion of barium (Elson et al., 2000).

It is not uncommon practice to avoid giving Buscopan in patients who have glaucoma, however, it has been reported by Fink and Aylward (1995) that the risk only relates to patients with undiagnosed (therefore untreated) angle closure glaucoma. The recommendation is to abandon the question about the presence of glaucoma and advise instead that patients should seek urgent medical advice should eye pain and visual loss develop. However, the authors did recommend caution in the presence of heart disease as this was considered of significant importance (Fink and Aylward, 1995).

The benefits and contraindications of Buscopan (from the Boehringer Ingelheim professional leaflet on 20 mg/1 ml solution ‘Buscopan’) and glucagon (from Novo Nordisk professional leaflet on glucagen 1 mg hypokit) are given in Table 13.1.

Table 13.1 Hyascine butylbromide (Buscopan) versus glucagon (Glucagen)

Hypotonic agent	Buscopan	Glucagen
Benefits	Good hypotonia achieved	Can be used in the presence of narrow angled glaucoma
	Good colonic distension
	Good active duration lasting for most of the examination
	Significantly cheaper
Side effects	Temporary tachycardia	Can cause nausea
	Blurred vision	Shorter acting
	Dizziness	Poorer colonic distension
	Drying of the mouth
Contraindications	Myasthenia gravis	Insulin dependent diabetes (glucagon has the opposite effect to insulin)
	Megacolon
	Narrow angle glaucoma
	Tachycardia
	Prostatic enlargement with urinary retention
	GI stenosis or paralytic ileus
	Poorly controlled angina
Relative contraindications		Elderly patient with a heart condition
		Pheochromocytoma
		Insulinoma
		Glucagonoma

The double contrast barium enema

Good bowel preparation is an important precursor to a successful DCBE (see Chapter 3). Poor coating or residue can mask or mimic pathology and should be reported as such and an alternative strategy should be suggested (e.g. a limited repeat examination following further bowel preparation, to review those areas not well demonstrated).

Prior to commencement of the examination, talking to the patient can determine the success of the bowel preparation as well as contraindications to the use of hypotonic agents. The practitioner can also identify any limitations of mobility and the nature and degree of any comorbidities, as this might have a bearing on the approach to the examination.

The predominant difference in rectal tube types is related to whether or not they have a balloon cuff. There is limited advantage to having a cuff, as it can assist with contrast retention in a patient with poor sphincter control. However, significant complications can occur, such as perforation, following inadvertent cuff insufflation and barium infusion within the vagina due to incorrect tube placement. Colonic perforation following cuff insufflation in the rectum is associated with high, artificially induced, intraluminal pressure. It has been advised that balloon cuffs should be avoided (Blakeborough et al., 1997b; Chapman and Blakeborough, 1998; Culpan and Chapman, 2002).

The objective standard of all DCBE techniques should be the same:

To provide a collective series of images that demonstrate the whole of the distended colon and rectum in double contrast (with a record of the appendix, terminal ileum or ileocecal valve to confirm arrival at the cecal pole).

If the standard has not been met, the examination, although it may be considered diagnostic is, by definition, technically suboptimal.

The technique described below using ‘C’ arm fluoroscopy is only one of a number of approaches to the DCBE. As long as the objective standards are met and there is consistency of approach, local variances need not be of any consequence.

Air or CO₂ double contrast

Air or carbon dioxide (CO₂) can be given to insufflate the bowel. Although practitioners need to be aware of the risks associated with over distension of the colon, if the bowel is collapsed in any view, consideration should be given to increasing gas input.

There are numerous papers discussing the benefits of air and CO₂. CO₂ dissolves faster and, although the mucosal coating is the same, the discomfort of CO₂ is reported as less. However, air is considered to provide better distension and this might outweigh the advantages in patient acceptability that CO₂ provides. Should colic result from air distension or should the effect of the chosen hypotonic agent wear off, maintaining rectal intubation will allow colonic decompression at any time but, particularly, as a routine at the end of the examination (Scullion et al., 1995, Holemans et al., 1998). One example of a DCBE protocol follows:

• With the patient supine for the injection of an IV smooth muscle relaxant, they are then turned into the left lateral position whereupon a rectal catheter is inserted. Care must be given to guard against vaginal intubation. If intubation is problematic (from, for example, prostatic enlargement), digital examination of the rectum can give guidance in directing the tube. The tube is left in situ for the duration of the examination to allow barium to be drained and replaced with air/CO₂ at any time as well as draining and decompressing the bowel upon completion of the examination.

• The intubated patient is turned prone and the tube taped low to the legs to help with any subsequent barium drainage. A solution such as 567 g EZ EM barium diluted with 550 ml H₂O (103% w/v) is infused with the table tilted a few degrees head down. Intermittent fluoroscopy is of value to confirm flow of barium and that no obstruction is present, in addition a pedunculated polyp, if present, may be seen oscillating within the barium flow. Occasional direct inspection of the tube will help identify if there is any barium seepage.

• Contrast should not be allowed to pass beyond the mid transverse colon. If barium is allowed to reach the right colon, it may well superimpose and denigrate subsequent imaging of the sigmoid colon. The patient is turned from the prone position via their left side to the supine, then to a position turned 45 degrees to the right to coat the rectum and sigmoid. Reversing the patient’s direction the patient is turned prone once more.

• Focusing now only on the colon and rectum, a couple of puffs of air are passed into the rectum to break up the barium column and raise the rectal pressure, and the rectum is then drained of barium.

• Gently puffing air into the rectum, the patient is turned via their left side to the right anterior oblique (RAO) position (Figure 13.1). Depending on the field size capability of the fluoroscopy unit, an RAO of the rectum and sigmoid can be followed by an RAO image of the proximal sigmoid/distal descending colon.

• The patient is now turned via their left side into the prone position and any pooled barium is drained from the rectum and then re-inflated with air. A prone image is taken of the rectum and sigmoid (Figure 13.2) and, if using the ‘C’ arm, a view is also taken of this region with optimum caudal angulation (Figure 13.3) suggestive of Hampton’s view.

• Continuing turning the patient towards the left, the left posterior oblique (LPO) (Figure 13.4) is a mirror image of the RAO and, as such, barium pooling in any loop in one view will be replaced by air in the mirrored image.

• Rotating the patient in the same direction a right lateral image (Figure 13.5) is acquired, making sure the hips are super imposed. This view not only gives a good view of the rectum but is the best view to demonstrate the pre-sacral space. This completes the standard views of the rectosigmoid.