Sonographic evaluation of prostatic artery embolization: Far beyond size measurements

Table 1 Summary of the ultrasonography modalities which are applied for evaluation of prostatic artery embolization

Modality	Parameter/feature evaluated	Approach	Technique/methodology	Expected finding after successful PAE
Gray-scale US	PV	t.a., t.r.	Measurement at 3 planes, ellipsoid formula	PV reduction
	IPP	t.a., t.r.	Unidimensional measurement	IPP reduction
	PVR	t.a.	Measurement at 3 planes, ellipsoid formula	PVR reduction
CEUS	Prostatic enhancement and infarction	t.a., t.r.	Bolus i.v. injection of 2nd generation US contrast agent. Measurement at 3 planes, ellipsoid formula	Prostatic infarcts preferably exceeding 10% of PV
US-elastography	Tissue stiffness (YM, EM, SWV)	t.r.	Shear-wave elastography	YM, EM, SWV reduction
	Tissue stiffness Elasticity (E) index	t.r.	Strain elastography	E-index reduction
Intraprocedural gray-scale US	Prostate echogenicity	t.a.	Visual assessment	Multiple strong echoes at the embolized area
Intraprocedural CEUS-i.a.	Distribution of contrast enhancement within and/or around prostate	t.a.	i.a. administration of diluted US contrast agent. Scanning as for CEUS post-PAE	Rapid, intense enhancement of the targeted prostatic lobe. Absence of extraprostatic enhancement
Intraprocedural CEUS-i.v.	As for CEUS post-PAE	t.a.	As for CEUS post-PAE	As for CEUS post-PAE

US: Ultrasound; CEUS: Contrast-enhanced ultrasound; PV: Prostate volume; PVR: Post-void residual volume; IPP: Intravesical prostatic protrusion; t.a.: Transabdominal; t.r.: Transrectal; i.v.: Intravenous; i.a.: Intraarterial YM-Young modulus; EM: Elastic modulus; SWV: Shear-wave velocity; PAE: Prostatic artery embolization.