Non-invasive techniques in the diagnosis of bladder storage disorders

Aims: To review clinical studies thus have been conducted to develop non-invasive diagnostic tools in the storage phase of the micturition cycle.

Methods: Pub Med and Web of Science searches were carried out. The search covered the published data of non-invasive diagnostic techniques for detrusor overactivity (DO) and/or low compliance bladder in patients with urinary storage symptoms. The patho-physiological and clinical relevance of these methods were addressed. Diagnostic accuracy of these techniques was scrutinized.

Results: Eighteen studies were included in the review. Ultrasonography and biomarkers were the most investigated techniques in the diagnosis of storage disorders. Assessment of diagnostic accuracy was possible in four studies. The heterogeneity in data reporting was too high to conduct a meta-analysis. Ultrasonographic parameters and cut-off values have been developed to define DO; such as bladder wall thickness (BWT), detrusor wall thickness and bladder weight. The likelihood ratio of vaginal ultrasonography in measurement of BWT was good. Guidelines are currently developing to standardize the methodologies applied in these techniques. Laboratory biomarkers of DO are gaining more attention recently, but their specificity for DO should be carefully defined. Near infrared spectroscopy (NIRS) is potential non-invasive diagnostic method that is able to detect the DO episodes in real time. However, a solution needs to be found for motion artifacts in this technique.

Conclusion: Non-invasive diagnostic techniques for storage disorders show limited progress with some limitations. Yet these techniques still cannot replace the standard filling cystometry in standard clinical practice.