Technetium 99m-labelled-sucralphate isotope scanning in the detection of peptic ulceration

Faecal calprotectin: a marker of inflammation throughout the intestinal tract

OBJECTIVE

To assess the potential of measuring the calcium-binding protein calprotectin in faeces as a method of screening for alimentary inflammation and neoplasia.

SETTING

Hospital day services unit for endoscopy and faecal analysis in the clinical biochemistry department.

PARTICIPANTS

Consented patients attending for routine endoscopy were requested to provide faeces. Seventeen of the initial 30 patients provided faeces before and 1 week after endoscopy. After this, 116 patients for planned endoscopy provided faeces before endoscopy. The group comprised 43 patients with upper-gastrointestinal lesions, seven patients with inflammatory bowel disease, seven patients with irritable bowel syndrome, 31 patients with colonic disorders, and 28 normal people. A final 18 patients with known inflammatory bowel disease (seven patients), gastric carcinoma (one patient), colorectal cancer (eight patients) and colorectal adenoma (two patients) had faeces analysed.

METHOD

Faeces were analysed by the Nycotest PhiCal enzyme-linked immunosorbent assay (ELISA) (Nycomed, Oslo, Norway), and the final 18 patients were analysed by the newer version marketed as Calprest.

RESULTS

No definite differences between pre- and post-endoscopy calprotectin were found, but it was considered preferable in the subsequent patients to analyse pre-endoscopy faeces. Upper-gastrointestinal disorders showed little difference in calprotectin levels, Barrett's oesophagus (median 6.8 mg/l), gastric ulcer (median 6.5 mg/l) or gastritis/duodenitis (median 5.2 mg/l), but these levels were all higher than the median calprotectin level of normal subjects (4.5 mg/l). The oesophageal and gastric carcinoma median was elevated significantly at 30 mg/l. Inflammatory bowel disease was also associated with marked elevation (Crohn's disease, 31.2 mg/l; ulcerative colitis, 116.2 mg/l). Colorectal polyps (median 3.7 mg/l) and adenoma (median 3.8 mg/l) showed no elevated levels in contrast to colorectal carcinoma (median 53.4 mg/l). The elevated calprotectin in inflammatory bowel disease and colorectal carcinoma combined gave a sensitivity of 81.8% and a specificity of 73.2%.

CONCLUSIONS

Calprotectin levels are elevated in inflammation and cancer but are not helpful in differentiating between these disorders. In our series, calprotectin was not elevated in colonic polyps or adenomata. Calprotectin could be helpful as a screening method in a general gastroenterology population for inflammatory bowel disease and those with carcinoma, as well as assessing and monitoring disease activity in inflammatory bowel disease.

Detection of caustic oesophageal injury with technetium 99m-labelled sucralfate

BACKGROUND/PURPOSE

Radiolabelled sucralfate has been used to show the extent and severity of reflux oesophagitis, peptic ulceration, and inflammatory bowel disease. Endoscopy under general anaesthetic has been the preferred method to assess the injury after caustic ingestion. The aim of this study was to assess whether sucralfate has an affinity for the chemically injured oesophageal mucosa and, if so, to assess the accuracy of radiolabeled sucralfate as an indicator of presence and extent of oesophageal injury.

METHODS

A prospective study was conducted of 22 patients with mean age of 30 months (range, 13 to 90) admitted consecutively with a history of caustic ingestion between January 1998 and January 2000. A sucralfate-labelled scan followed by endoscopic assessment of upper gastrointestinal tract with documentation of extent and grade of injury was performed in all patients within 24 hours of admission except the first 6 who underwent scan after the endoscopy. The sucralfate was labelled by the direct stannous reduction method. Oesophageal transit was studied by recording 120 images (64 x 64 matrix size) at 1 image per second while the child swallowed 5 mL of labelled sucralfate containing 2 to 3 MBq Technetium 99m. Retention of radiolabelled oesophageal activity was considered abnormal.

RESULTS

The caustic substances ingested were household cleaners in 18, potassium permanganate in 3, and pool chlorine in 1. There were 11 scans that showed residual activity in the oesophagus, which correlated exactly with endoscopic findings. The other 11 patients had normal oesophageal mucosa, but 2 were found to be falsely positive on scanning. In 2 cases repeat sucralfate scan results correlated well with the healing process assessed endoscopically.

CONCLUSIONS

The results indicate that technetium 99m sucralfate swallow is an accurate technique for assessing oesophageal injury after ingestion of caustic substances. In addition, it may be used to document healing.

99mTc-sucralfate scintigraphy in inflammatory bowel disease

Technetium-99m-labeled albumin-sucralfate was orally administered to 11 patients (Crohn's disease, 8; ulcerative colitis, 3) and 3 healthy volunteers. Serial scintigraphy was performed, and scintigraphic interpretations were compared with radiographic and endoscopic findings in an open study. We were not able in any patient to relate the scintigraphic findings to the localizations of inflammatory bowel disease, nor could we distinguish the scans in the patients from the scans of the healthy volunteers. We conclude that 99mTc-albumin-sucralfate scintigraphy is of no value in the detection of inflammatory bowel disease.

Dynamic radionuclide imaging with 99mTc-sucralfate in the detection of oesophageal ulceration

Standard oesophageal scintigraphic techniques using 99mTc-colloids rarely identify oesophageal mucosal damage. Sucralfate can be labelled with 99mTc for the detection of oesophageal mucosal ulceration. This method uses two separate supine swallows of 10 MBq 99mTc-colloid in 10 ml, followed by a single supine swallow of 30 MBq 99mTc-sucralfate. The data are processed to give time-activity curves, mean transit times and condensed dynamic images. When oesophageal ulceration is detected, the time-activity curves using sucralfate show residual activity in the oesophagus after the transit time indicated by the colloid swallow. The condensed dynamic image shows a persistence of activity at the level of the ulceration. Erect sucralfate images taken immediately after the dynamic sequence show no oesophageal localisation. The results from a study of 62 patients have shown excellent correlation between the dynamic 99mTc-sucralfate images and endoscopy findings. Sequential sucralfate studies for healing also correlate well. The use of labelled sucralfate to detect oesophageal ulceration could modify the indications for endoscopy in gastrooesophageal reflux disease.

Detection of inflammatory bowel disease in adults and children: evaluation of a new isotopic technique

The distribution of radioactivity after the oral administration of sucralfate labelled with technetium-99m was studied in 33 patients with Crohn's disease (13 adults, 20 children), 10 with ulcerative colitis (four adults), and 29 controls (23 with upper intestinal disease, four irritable bowel, one hypolactasia, and one malrotation of the gut). Positive scans were obtained in all patients with ulcerative colitis and 29 of 31 with active Crohn's disease. The scans of two patients with inactive Crohn's disease were negative. There were two false negative scans in patients with Crohn's colitis and one false positive scan. Overall, sensitivity was 95% and specificity 97%. Comparison with radiology in 39 patients showed similar distribution of disease in 24 and more extensive disease in 12. The scan was inexpensive, simple to perform, well tolerated, allowed small and large bowel to be visualised simultaneously, and used a lower dose of radiation than barium studies. It may prove useful as a screening test for inflammatory bowel disease and in the serial assessment of disease activity.