Accuracy of computed tomographic colonography in a nationwide multicentre trial, and its relation to radiologist expertise

OBJECTIVE

Reports on the accuracy of computed tomographic colonography (CTC) mainly involve series from expert institutions. The aims of this study were to assess CTC accuracy in a nationwide population and to relate it to radiologist performance in their initial training.

DESIGN

Nationwide multicentre trial.

SETTING

Twenty-eight radiologists, working in 26 mostly academic clinical units, were involved in the study after having attended a formal specialised 2-day training session on CTC. They worked through a training set of 52 cases with automatic feedback after an attempt at each case.

PATIENTS

The study enrolled 845 patients with average and high risk of colorectal cancer, 737 of whom had both complete CTC and videocolonoscopy data, which constituted the dataset.

INTERVENTIONS

Patients underwent same-day CTC followed by videocolonoscopy with segmental unblinding of CTC results.

MAIN OUTCOME MEASURES

Sensitivity, specificity and positive and negative predictive values for detection of polyps ≥ 6 mm in per-patient and per-lesion analyses of CTC without computer-aided detection.

RESULTS

Sensitivity, specificity and positive and negative predictive values for patients with polyps ≥ 6 mm were 69% (95% CI 61% to 77%), 91% (95% CI 89% to 94%), 67% (95% CI 59% to 74%) and 92% (95% CI 90% to 94%), respectively. Univariate analysis showed that the detection rate for polyps ≥ 6 mm was linked to neither radiologist case volume nor number of polyps, but was related to sensitivity achieved in the training set. Pooled sensitivity was 72% (95% CI 63% to 80%) versus 51% (95% CI 40% to 60%) for radiologists achieving above and below median sensitivity in the training set (61%), respectively. Multivariate analysis showed that sensitivity for polyps ≥ 6 mm in the training set was the only remaining significant predictive factor for subsequent performance.

CONCLUSIONS

Radiologist sensitivity CTC for detection of polyps ≥ 6 mm in training was the sole independent predictor for subsequent sensitivity in detection of such polyps.

[Diclofenac-induced colitis complicated by Klebsiella oxytoca infection]

A 25-year-old man presented with abdominal pain and bloody diarrhea. Colonoscopy showed hemorrhagic proctocolitis with superficial erosions. Histology was consistent with the diagnosis of ulcerative colitis and biopsy cultures were negative. Despite treatment with prednisolone (40 mg/day), his clinical condition deteriorated and he was referred to our institution. On repeated questioning, the patient reported self-medication with diclofenac (200 mg/day) for 6 weeks to treat tendinitis prior to the beginning of digestive symptoms. Rectosigmoidoscopy confirmed bleeding colitis and repeated biopsy cultures showed Klebsiella oxytoca. Corticosteroids were stopped and ofloxacin (400 mg/day) was prescribed for 14 days. Diarrhea quickly resolved. Colonoscopy 8 weeks later showed only patchy erythematous mucosa without bleeding or erosions. Two years later, the patient remains asymptomatic with normal total colonoscopy. The definitive diagnosis was de novo NSAID-induced colitis subsequently complicated by Klebsiella oxytoca infection.

Ischaemic colitis in a patient taking meloxicam

The safety of cyclo-oxygenase 2 (COX-2) preferential inhibitors such as meloxicam is debated. We describe a patient who presented with bloody diarrhoea after 15 mg meloxicam daily for 10 days for osteoarthritis. The endoscopic and histological features were consistent with the diagnosis of ischaemic colitis. Symptoms and endoscopic lesions quickly regressed within 1 week of meloxicam withdrawal. There was no evidence of another cause of colonic ischaemia. We suggest that meloxicam might have intestinal toxic effects when taken in high doses, because of reduced COX-2 selectivity.

[Protective effect of appendectomy on the development of ulcerative colitis. A case-control study]

AIMS

To examine by a case-control study the relationship between appendectomy and subsequent ulcerative colitis development in a French population.

METHODS

A total of 150 patients with ulcerative colitis were matched for age (+/- 5 years) and sex, with 150 controls recruited in a preventive medicine center. The following data were collected from medical records and by standardised questionnaire in consultation or by phone: appendectomy and tonsillectomy before the onset of ulcerative colitis, smoking habits and area of residence.

RESULTS

The rate of previous appendectomy in patients with ulcerative colitis was 8% (12/150) compared with 30.6% (46/150) in the control group (P=0.001). There was no significant association between ulcerative colitis and tonsillectomy (25.3 and 27.3% in the control and the ulcerative colitis groups, respectively). Smoking was more frequent in the control group (36%) than in the ulcerative colitis group (25.3%) but the difference was not significant (P=0.07). In multivariate analysis, the risk of developing ulcerative colitis was significantly lower after previous appendectomy (odds ratio=0.26; 95% confidence interval: 0.13-0.55; P=7 x 10(-4)).

CONCLUSION

Our study confirms the inverse association between appendectomy and subsequent ulcerative colitis, in a French population, after adjusting on smoking.

[Rectal leiomyosarcoma. 4 new cases]

We report four cases of leiomyosarcoma of the rectum suspected by endoscopic ultrasonography. Three patients were treated by local excision and one by abdominoperineal resection. An excision of the mass via a Kraske's approach was used. Leiomyosarcoma confined to the rectum wall can be treated by local excision. Endosonography can provide exact estimation of the lesion and is of great value in selecting the appropriate treatment. The treatment is surgical excision with wide margins. The histological stage and the presence or absence of metastases determine the therapeutic. Two patients in our series underwent radiation therapy. Chemotherapeutic agents including doxorubicin have had beneficial effect on recurrence or survival, only for higher grade sarcomas.

[Gastroprotective effect of an antacid coating agent in rats. Role of endogenous prostaglandins, capsaicin-sensitive afferents neurons and nitric oxide]

The aims of this study were: a) to demonstrate the gastroprotective effect of the antacid and mucosal coating agent Gastralgine (aluminium hydroxide and glycinate, magnesium trisilicate and simeticone) against ethanol- and indomethacin-induced gastric injury in the rat; b) to investigate whether gastroprotection elicited by this agent involves stimulation of capsaicin sensitive afferent neurons and activation of the nitric oxide system.

METHODS

Rats received intragastrically 2 mL of the antacid or distilled water followed 1 hr later by 2 mL of 100% ethanol ig or 30 mg of indomethacin sc. The surface of ethanol-induced lesions and the length of indomethacin-induced lesions were measured. The role of afferent neurons and endogenous nitric oxide in the prevention of ethanol-induced gastric damage was determined using respectively capsaicin and the inhibitor of nitric oxide biosynthesis, NG-nitro-L-arginine.

RESULTS

The antacid and mucosal coating agent significantly reduced the area of macroscopic lesions induced by ethanol and the length of lesions induced by indomethacin. Both functional ablation of afferent nerves and inhibition of nitric oxide synthesis significantly increased ethanol-induced gastric injury but failed to reverse the gastroprotective effect of the antacid against 100% ethanol.

CONCLUSIONS

The antacid and mucosal coating agent Gastralgine has a gastroprotective effect against ethanol- and indomethacin-induced injury in the rat. This property does not involve stimulation of capsaicin sensitive afferent neurons or synthesis of endogenous nitric oxide.