Kidney Week

Abstract: TH-PO830

Total Kidney Volume (TKV) Measurements in Autosomal Dominant Polycystic Kidney Disease (ADPKD) by 3D Ultrasound (3D-US) vs. Ultrasound Ellipsoid (US-EL)

Session Information

• Cystic Kidney Diseases: Clinical
  November 07, 2019 | Location: Exhibit Hall, Walter E. Washington Convention Center
  Abstract Time: 10:00 AM - 12:00 PM

Category: Genetic Diseases of the Kidneys

• 1001 Genetic Diseases of the Kidneys: Cystic

Authors

• Akbari, Pedram, Toronto General Hospital UHN, Toronto, Ontario, Canada

Pedram Akbari,

• Nasri, Fatemeh, Toronto General Hospital UHN, Toronto, Ontario, Canada

Fatemeh Nasri,

• Quist, Crystal F., Toronto General Hospital UHN, Toronto, Ontario, Canada

Crystal F. Quist,

• Guiard, Elsa, Toronto General Hospital UHN, Toronto, Ontario, Canada

Elsa Guiard,

• Iliuta, Ioan-Andrei, University Health Network and University of Toronto, Toronto, Ontario, Canada

Ioan-Andrei Iliuta,

• Ahmed, Syed Essam, Toronto General Hospital UHN, Toronto, Ontario, Canada

Syed Essam Ahmed,

• Calvaruso, Luca, University Health Network, Toronto, Canada

Luca Calvaruso,

• Atri, Mostafa, University Health Network and University of Toronto, Toronto, Ontario, Canada

Mostafa Atri,

• Khalili, Korosh, University Health Network and University of Toronto, Toronto, Ontario, Canada

Korosh Khalili,

• Pei, York P., University Health Network and University of Toronto, Toronto, Ontario, Canada

York P. Pei,

Background

Total kidney volume (TKV) is a validated prognostic biomarker for risk assessment in ADPKD. TKV by magentic resonance imaging and manual segmentation (MRI-MS) is the “gold standard”, but is relatively expensive, time-consuming, and not readily accessible. 3D-US is a new technology which may provide greater precision and accuracy for measuring TKV than US-EL. Here, we report a comparative study of these two US techniques for TKV measurements against MRI-MS.

Methods

We conducted a prospective study of 123 patients recruited at a PKD specialty center who underwent a standardized 3D-US and MRI. Kidney volumes (i.e. single kidney and TKV) by 3D-US and US-EL measured by 5 different experienced ultrasound technicians were compared to those by MRI-MS derived from an experienced radiologist blinded to patient clinical results. Bland-Altman plots were used to assess the agreement of TKV measurements by US vs. MRI.

Results

Table 1 shows the study patient characteristics. We found the accuracy of TKV measurements by US was operator-dependent and varied between different technicians. Compared to MRI-MS, Bland-Altman plots of TKVs by 3D-US and US-EL revealed a similar bias (-9.0% vs. -10.2%), range of diagreement (-42.25 to 24.31% vs. -41.25 to 20.85%), and difference of greater than 20% (27.2% & 24.3%), respectively. Converting height and age-adjusted TKV's to the Mayo Class Imaging Class (MCIC) we found a misclassifcation rate of 22.8% and 23.5% by 3D-US and US-EL, respectively.

Conclusion

TKV measurements by 3D-US and US-EL are less accurate than MRI-MS. Both US tecniques displayed similar bias, accuracy, and are operator-dependent; however, TKV by US-EL is simpler to use and more readily available. These factors need to be considered when US-dervied TKV is used for risk assessment in ADPKD as misclassification of MCIC (esp. 1B to 1C) can have important clinical consequence.

Table 1. Patient characteristics

Funding

• Government Support - Non-U.S.