CJK 08. A real-time motion analysis of penile erection with Turbo-FLASH MR imaging system

Objectives: There have been no reports of real-time image analysis in the corpus cavernosum from the initiation to the end of erection without artificial induction. Using Turbo-FLASH MRI, we were able to obtain a series of high resolution images through tumescence, maintenance and detumescence phases of erection. The aim of this study was to analyze the dynamic morphological changes in the penis during a normal erection.

Materials and Methods: The participants in this study included 5 healthy volunteers without experience of erectile dysfunction. Ages ranged from 22 to 47 (median 33) years. IIEF-5 score ranged from 22 to 25 (median 23) points. Audio-visual sexual stimulation was used to induce erection.

MRI was conducted using Siemens MAGNETOM Sonata 1.5T with body array and spine coils. True-FISP sequence was used with conditions of TR: 4.38 ms, TE: 2.19 ms, and scan time: 0.85 sec/slice. Using dynamic images, the volume of the corpus cavernosum within the tunica albuginea were consecutively calculated by measuring length, width, and thickness in sagittal and coronal section during all phases of a normal erection.

Morphological changes were evaluated with indices including the maximum changes in the volume between latent and full erection phases of the corpus cavernosum as well as the consecutive volume increase rate per second.

Results: From initiation to completion of erection, range of time required from 110 to 120 (median 115) seconds, changes in volume of corpus cavernosum ranged from 28 to 35 (median 32) mL. Maximum volume increase rate ranged from0.5 to 0.8 (median 0.66) ml/sec (Figure 2).

Conclusions: By using Turbo-FLASH MRI, dynamic phases of a normal erection can be analyzed calculating the maximum changes in volume of corpus cavernosum as well as volume increase rate per second. Further study is warranted to prove these novel parameters as a measurement of vascular function.