Aim To investigate whether inclusion of quantitative data on blood flow distribu-tion compared with visual qualitative evaluation improve the reliability and diag-nostic performance of99 mTc-hydroxymethylene diphosphate three-phase bonescintigraphy (TPBS) in patients su spected for charcot neuropathic osteoarthrop athy(CNO) of the foot.Method A retrospective cohort study of TPBS performed on 148 patients with sus-pected acute CNO referred from a single specialized diabetes care centre. Thequantitative blood flow distribution was calculated based on the method describedby Deutsch et al. All scintigraphies were re-evaluated by independent, blindedobservers twice with and without quantitative data on blood flow distribution atankle and focus level, respectively. The diagnostic validity of TPBS was determinedby subseq uent review of clinical data and radiological examinations.Results A total of 90 patients (61%) had confirmed diagnosis of CNO. The sensitiv-ity, specificity an d accuracy of three-phase bone scintigraphy without/withquantitative data were 89%/88%, 58%/62% and 77%/78%, respective ly. Theintra-observer agreement improved signific antly by adding quantitative data in theevaluation (Kappa value 079/094) . The interobserver agreement was not signifi-cantly improved.Conclusion Adding quantitative data on blood flow distribution in the interpretationof TBPS improves intra-observer variation, whereas no difference in interobservervariation was observed. The sensitivity of TPBS in the diagnosis of CNO is high,but holds limited specificity. Diagnostic performance does not improve usingquantitative data in the evaluation. This may be due to the reference intervalsapplied in the study or the absence of a proper gold standa rd diagnostic proce-dure for comparison.