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
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.