Evaluation of early treatment response and predicting the need for colectomy in active ulcerative colitis with 99mTc-HMPAO white blood cell scintigraphy.

UNLABELLED The rate of treatment failure in acute exacerbation of ulcerative colitis (UC) still reaches 20%-30%. Early identification of nonresponders to therapy is important, since intensified or other medical treatment or, ultimately, colectomy should be considered to reduce morbidity. Because 99mTc-hexamethylpropyleneamine oxime (99mTc-HMPAO) white blood cell (WBC) scintigraphy is accurate in determination of the severity and extent of UC lesions, the aim of this study was to assess whether WBC scintigraphy can predict early treatment failure in patients with an acute attack of UC. METHODS We included 20 consecutive patients (7 women, 13 men; mean age +/- SEM, 36.8 +/- 10.9 y) with a history of UC who were hospitalized with severe exacerbations. All patients underwent endoscopy and scintigraphy within 24 h of admission and 1 wk after beginning treatment. WBCs were labeled with 200 MBq 99mTc-HMPAO. SPECT of the abdomen was performed 60 min after WBC reinjection. Maximum tracer uptake in the different colon segments was defined and expressed as a ratio of lumbar bone marrow uptake. The scintigraphic activity score (SAS) was expressed as the sum of segmental colon uptake ratios. Scintigraphic evolution was considered favorable when the SAS decreased by > or =50% and SPECT uptake ratios after therapy were < or =1.5 per segment. Rectosigmoidoscopy with biopsy was performed within 24 h after scintigraphy. RESULTS Outcome analysis after 3 mo showed 6 of 20 patients in clinical and endoscopic or histologic (rectosigmoid) remission, without alteration of treatment (responders). Of the other patients (nonresponders), 5 of 14 received a colectomy, 5 of 14 received prolonged or intensified treatment, and 4 of 14 received other treatment. In the responders group, the SAS (determined 1 wk after beginning therapy) significantly decreased in all patients. In the group of nonresponders, 10 patients had an increase of >10% in the SAS, 2 patients had an unchanged SAS, and 2 patients had a decreased SAS of >10% but had a residual mean segmental WBC uptake ratio of >1.5. There was a statistically significant difference between the responders and nonresponders (P < 0.01). CONCLUSION Repeated 99mTc-HMPAO scintigraphy seems to be able to predict therapy resistance in UC within 1 wk after beginning treatment.