Endovaginal US performed with an electronic biplane 180° rotational transducer provides an accurate evaluation of urethral morphology (rhabdosphincter and urethral smo-

The second section of the book “Pelvic floor disorders Imaging and Multidisciplinary Approach to Management” is entitled “Pelvic Floor Imaging” and consists of six chapters describing the different imaging techniques of normal female pelvic floor. In the first chapter “Endovaginal Ultrasono gra phy: Methodology and Normal Pelvic Floor Anatomy” Santoro et al. describe the role of high-resolution three-dimensional endovaginal ultrasonography (3D-EVUS) in the assessment of pelvic floor structures including muscles and the levator ani complex, the lower urinary tract, and the anorectal region. The methodology of this examination is reported in details including patient preparation, and position, technique of examination and manner of performing measurements. Many types of ultrasound transducers have been developed for pelvic floor assessment (mechanical radial probes with 360° field of view, electronic biplanar probes with linear and transverse curved arrays, and endfire probes). Endovaginal US performed with 360° rotational transducer gives an overall view of pelvic structures, allows their precise assessment and to perform reliable measurements. In the axial plane four standard levels for the evaluation are defined (Figure 1): Level 1: corresponding to the bladder base and the inferior one-third of the rectum; Level 2: corresponding to the bladder neck, the intramural part of the urethra, and the anorectal junction. At this level the levator ani muscle subdivisions (puboperinealis, puboanalis, pubovaginalis, puborectalis, iliococcygeus) can be identified; Level 3: corresponding to the inferior pubic rami and symphysis pubis, the midurethra, and the upper one-third of the anal canal; Level 4: corresponding to the superficial perineal muscles, the perineal body, the distal urethra, and the middle and inferior one-third of the anal canal. In the axial plane can be measured levator hiatus dimensions; paravaginal spaces area; pubovisceral muscle thickness; urogenital hiatus diameters and superficial perineal muscles lengths. Endovaginal US performed with an electronic biplane 180° rotational transducer provides an accurate evaluation of urethral morphology (rhabdosphincter and urethral smooth muscle) and vascularity and gives images of the posterior compartment (internal and external anal sphincters, anorectal junction, perineal body, rectovaginal septum) in the mid-sagittal plane. Using this transducer, it is also possible a dynamic assessment during contraction or Valsalva maneuvers. The second chapter “Translabial Ultrasonography: Metho dology and Normal Pelvic Floor Anatomy” by Peter Dietz describes technical requirements, equipment, and the methodology of transperineal ultrasound (2D/3D/4D TPUS) in the diagnostics of pelvic floor and lower urinary tract disorders. A convex transducer (frequency 3.58 MHz) is placed on the perineum providing midsagittal view of the pelvic organs (symphysis pubis, bladder, urethra, vagina, anorectum). 3D data is obtained with the use of volumetric probe that combines an electronic curved array of 38 MHz with mechanical sector technology, allowing fast motorized sweeps through a field of vision. 4D-US implies the real-time acquisition of volume US data, which can be represented in multiplanar reconstructions or rendered volumes. 4D-TPUS performed during Valsalva maneuver allows to visualize downwards displacement of the pelvic organs, to reveal pelvic organ prolapse, and to demonstrate distensibility of the levator hiatus. Measurements of diameters and areas of the levator hiatus in this plane appear highly repeatable and correlate well with those obtained on MRI. For the identification of levator trauma (detachment of the muscle from the inferior pubic rami) rendered volumes are used. However, the most reproducible method for identifying abnormalities of the puborectalis muscle at present seems to be tomographic or multislice imaging obtained during pelvic floor maximal contraction. The third chapter entitled “Endoanal and Endorectal Ultrasonography: Methodology and Normal Pelvic Floor Anatomy” written by G.A. Santoro and G. Di Falco reports in details the technique of 3D-EAUS and 3D-ERUS performed with 360° rotational transducer. In the axial plane, the anal canal is divided in three levels: Level 1 (upper level): corresponding to the puborectalis sling, the deep part of the external anal sphincter (EAS) and the complete ring of the internal anal sphincter (IAS); Level 2 (middle level): at this level the superficial transverse perinei muscles and the two complete rings of the EAS and the IAS are identified; Level 3 (lower level): corresponding to the subcutaneous part of the EAS. The muscles of the lower and the upper part of the anal canal are different. The deep part of the EAS cannot be differentiated from puborectalis muscle posteriorly due to similar echogenicity. Moreover, the differences between genders exist in the anterior part of the EAS: it is symmetrical at all levels in males; while in females, it is shorter anteriorly, and there is no evidence of an anterior ring high in the anal canal. EAUS provides excellent measurements of sphincter dimensions, however its most relevant utility is the detection of localized sphincter defects. Endorectal US is performed with a water-filled latex balloon covering the transducer in order to achieve good acoustic contact with the rectal wall and to have its adequate distension. Five layers are visualized: the first hyperechoic layer corresponds to the interface of the balloon with the rectal mucosal surface; the second hypoechoic layer corresponds to the mucosa and muscularis mucosae; the third hyperechoic layer corresponds to the submucosa; the fourth hypoechoic layer corresponds to the muscularis propria; the fifth hyperechoic layer corresponds to the serosa or to the Book review