Table 1. Advantages and limitations of auxiliary examination methods for penile vascular function.
| Methods | Author (year) | Parameters | Advantages | Limitations | Quantitative | Objective |
|---|---|---|---|---|---|---|
| Intra-cavernous injection | Virag (18) (1982) | Rigidity retention | Simple and rapid; first-line option; good repeatability; therapeutic effect; basic screening examination | Invasive; subjective evaluation; susceptible result; false positive results; risk of prolonged erection and priapism | No | No |
| Color duplex Doppler ultrasound | Lue et al. (19) (1985) | End-diastolic velocity; peak systolic velocity; resistive index | Non-invasive; second-line option; good repeatability; quantitative analysis; able to distinguish arterial ED | Time consuming; operator-dependent; complicated operation; less reliable in diagnosing venous ED | Yes | Yes |
| Selective penile angiography | Bähren et al. (20) (1988) | Imaging | Gold standard; affirmative examination | Time consuming; invasive and expensive; complicated operation; affected by methodology; requires postinterventional surveillance | No | Yes |
| Magnetic resonance arteriography | Dixon et al. (21) (1992) | Imaging | Almost noninvasive; good at evaluate pelvic structures; supplement to contraindications of angiography | Expensive; non-specific images; cannot detect the distal pudendal and penile arteries | No | Yes |
| Computed tomography angiography | Kawanishi et al. (22) (2001) | Imaging | Mild invasive; 3D-virtual images; independent of blood flow; direct detection of cavernosum; indicate other vascular diseases | Expensive; complicated operation; lack of standardization of the parameters | No | Yes |
| Dynamic infusion cavernosometry and cavernosography | Velcek et al. (23) (1982) | Imaging; induced flow; maintain flow; pressure decay; equilibrium pressure; cavernous artery occlusion pressure | Direct detection; third-line option; reflex venous reflux and leakage; good at diagnose venous ED | Invasive; time consuming; false positive results; complicated operation | Yes | Yes |
| Share wave elastography | Turkay et al. (24) (2017) | Share wave elastography value | Non-invasive; good repeatability; quantitative analysis | Lack of standardization of the parameters | Yes | Yes |
| Endo-PAT | Seager et al. (25) (2013) | Augmentation index; reactive hyperaemic index | Non-invasive; prediction of cardiovascular disease | Controversial; lack of standardization of the parameters | Yes | Yes |
ED, erectile dysfunction; PAT, peripheral arterial tonometry.