Barton A Serrao C Thompson J Briffa K Transabdominal ultrasound to assess pelvic floor muscle performance during abdominal curl in exercising women. International Urogynecology Journal 26: 1789-1795 2015
A student from my Whole Woman Practitioner Training course recently sent me the above study for my observations and commentary. Of course there were the usual omissions and misconceptions of poorly designed studies that fill volumes in the urogynecology literature.
For example, childbearing (parity) was found to be the only risk factor for stress urinary incontinence (SUI), which 60% of subjects reported as being problematic. Yet, episiotomy was not considered to be a variable, even though midline episiotomy is a known risk factor in the development of SUI, and 75% of subjects with SUI were parous. Additional omissions included hysterectomy, c-section, incontinence procedures, and vaginal surgeries. Far more disturbing, however, is the fallacious “3D” imaging technology being used in these kinds of studies.
Welcome to the virtual reality of 3D medical ultrasound, which uses many of the volume rendering algorithms and technologies developed for the motion picture industry at Pixar Animation Studios in California, USA.
This astonishingly complex computer science is based on how a rendered volume of 2-dimensional images emits, reflects, absorbs, or occludes light. Light propagation algorithms are used to fill in the missing volume data to create a “3D” picture. Shadowy 2D ultrasound images are miraculously re-constructed to reveal fetal faces, heart valves, and bile ducts. Unfortunately, there is a dark side to 3D ultrasound imagining beyond the shadows, noise, and inconsistent data recognized by the industry.
Transabdominal ultrasound (TAUS) for imaging the pelvic floor in “real time” is accomplished by placing a curved transducer at the pubic hairline of a patient who is positioned on her back with knees bent. The transducer sends out an array of high-pitched sound beams through her pelvis from front to back. The raw beam data is captured in 3 polar coordinates, i.e., two angles describing the direction away from the transducer, and the depth of the tissue boundary that is reflecting the sound echo. This data must be converted by software to Cartesian coordinates (x-y axis) in order to be displayed. Multiple 2D images are instantly reconstructed again and again on a graphics card to give the illusion of movement in real time.
Figure 2 was taken from an industry video of a male contracting his pelvic floor. The ultrasound transducer has been placed horizontally at his pubic hairline. The abdominal wall is at the top of the frame, and the bladder is the large black circle in the middle. The white band at the bottom of the image is described as the pelvic floor. When the patient is asked to contract his pelvic floor muscles the floor appears to elevate, lifting the base of his bladder as well.
However, the image and interpretation are utterly deceptive. When the transducer is placed horizontally on the lower abdominal wall, it is industry standard that the images reflected on the monitor are in the transverse plane. If you were looking up or down through your torso, you would be viewing the transverse plane of your body.
When the transducer is turned 90 degrees to vertical the image is derived from the sagittal plane, or looking through the pelvis from one side to the other. TAUS does not routinely capture images from the frontal plane, which looks at the pelvis from front to back.
Figure 3 was captured from another “real time” video of a female asked by her physical therapist to contract her pelvic floor. When she contracts, her pelvic floor and bladder appear to lift up in the frontal plane. This movement is described by the clinician as, “The pelvic floor elevating the base of the bladder.” The patient is told she is doing a “good job” contracting her pelvic floor and lifting up her bladder.
TAUS gives the impression that the pelvic floor is moving up toward the head, and this is how the images are interpreted by physical therapists. In actuality, this structure is moving forward toward the lower abdominal wall. The reason the vagina and cervix cannot be visualized is because the image field has been sliced through a particular volume, and rendered to show only the bladder and pelvic floor. Removing regions that are not of interest in order to gain a clear view of features normally occluded is called “clipping”. Clipping tools are standard features in commercial 3D ultrasound systems.
Data registration is the process of transforming different imaging modalities, such as MRI and CT, into the same reference frame to achieve as much information about the underlying structure as possible. Shockingly, much of that data is based on the perspective of the “anterior pelvic plane”, an erroneous orientation of the standing human pelvis institutionalized by orthopedics. Slice and volume rendering for 3D ultrasound has been combined with standard Cartesian medical data from CT and MRI to create what is called “simultaneous, multi-volume ray casting.” The resulting image is based on a 500 year-old anatomical misconception of the actual position of the human pelvis. While this may not be an issue when imaging an ovarian cyst, it becomes nothing less than fraudulent when imaging the “pelvic floor.”
The structure that is “lifting” in Figures 2 & 3 is actually the pelvic wall moving the front rectal wall forward. However, the circular contraction of the vaginal sphincter also pulls the bladder backward toward the front vaginal wall. The net result is a posterior bladder wall that is displaced slightly upward with pelvic contractions instead of moved forward toward its natural position behind the lower abdominal wall.
Figure 4 clearly shows the error of viewing the transverse plane as the frontal plane. Image B even measures the “lift” of the pelvic floor. Yet, notice there is no corresponding movement of the bladder toward the abdominal wall.
Physical therapists are using transabdominal ultrasound to show a deceptive and deleterious view of pelvic anatomy. This is not the only fraudulent imaging technology being widely utilized by the medical system. So-called “3D” CT scans of the pelvis are artificially rendered to reinforce an antiquated and erroneous view of pelvic orientation upon which many orthopedic hip surgeries are based. Physical therapists who teach kegel exercises using TAUS as a feedback mechanism are being hoodwinked by an unconscionable industry, and in return are hoodwinking their patients.