Feasibility of approximate measurement of bladder volume in male patients using the Lilium α-200 portable ultrasound bladder scanner.

ABSTRACT

OBJECTIVE: This study examined the accuracy of a new portable ultrasound bladder scanner, the Lilium α-200 (Lilium Otsuka, Kanagawa, Japan), by evaluating the correlation between bladder volumes periodically measured by the Lilium α-200 and instilled volume during video-urodynamic studies (V-UDS). METHODS: Using the Lilium α-200, fluid volume was measured prospectively in the bladders of patients with lower urinary tract dysfunction during V-UDS. This was done both immediately after micturition (for assessment of post-void residual [PVR] volume) and at 1-minute intervals during filling cystometry with patients in the supine position. These measurements were then compared with the PVR volume obtained directly by catheter drainage and instilled volume during cystometry using paired t tests and Spearman's rank correlation. RESULTS: Fifteen male patients (median age 70.5 years; range 18-84 years) were included in the study. The PVR volume measured by the Lilium α-200 was strongly correlated with that obtained by catheter drainage (r = 0.94; P < 0.0001). There was a strong correlation between instilled and bladder volumes measured by the Lilium α-200 at every minute during and at the end of instillation (281 measurements in 15 patients; r = 0.86; P < 0.0001). However, the relative error of bladder volumes measured by the Lilium α-200 during cystometry showed considerable variation (mean [± SD] 5.6 ± 62.9%). CONCLUSIONS: Bladder volumes measured periodically by the Lilium α-200 during cystometry were strongly correlated with actual PVR or instilled volumes. However, they showed considerable variation and may not predict actual volume accurately. The Lilium α-200 is feasible for obtaining an approximate measure of bladder volume.