OB/GYN SPECIALISTS SUGGEST AN “ULTRASOUND FIRST” APPROACH TO IMAGING FEMALE PELVIS
Owing to advances in ultrasound technology, obstetricians and gynecologists are sticking to ultrasound as a more cost-effective and safer method compared to other modalities. They recommend using ultrasound as the first choice for patients with pelvic symptoms. The initiative set forth in 2012 by the American Institute of Ultrasound in Medicine (AIUM) was detailed in the American Journal of Obstetrics and Gynecology. Supported by clinical evidence, AIUM launched, “Ultrasound First” in 2012 to show that using ultrasound before other modalities is equally, and in some cases, more effective when imaging the female pelvis.
“This recommendation applies particularly to obstetric and gynecologic patients. A skillfully performed and well-interpreted ultrasound usually eliminates the need to perform additional more costly and complex crosssectional imaging techniques,” explained lead author and AIUM president Beryl R. Benacerraf, MD, Clinical Professor in Obstetrics, Gynecology, and Reproductive Biology and Radiology at Harvard Medical School, and Brigham and Women’s Hospital.
There are numerous reasons for choosing ultrasound over other imaging modalities. One of the main reasons is that many women presenting with pelvic symptoms are sent for CT or MRI scans, which often result in confusing and unclear results, apart from the obvious radiation exposure from CT scans. As the former President of AIUM and coauthor Steven R. Goldstein, MD, Professor of Obstetrics and Gynecology at the NYU School of Medicine has stated, “The use of CT scans has tripled since 1993. An estimated 29,000 future cancers could be related to CT done in the U.S. in 2007. The largest contribution to this projected risk of cancer (14,000 cancers) was attributed to CT of the pelvis and abdomen.”
He continued, saying that, “For example, patients with suspected kidney stones frequently have a CT scan first, despite the associated radiation burden. In a recent study, most of the patients evaluated first by ultrasound did not ultimately need a CT scan, sparing radiation exposure.”
The recommendations for ultrasound being the first choice are also grounded in advanced technologies that have recently become widely available. Now, doctors can use 3D volume imaging for realtime investigation of pelvic organs as well as Doppler ultrasound which allows realtime evaluation of blood flow without the use of contrast agents (unlike CT, MRI).
Ultrasound scans used to be a series of black and white fuzzy images that depended heavily on the operator and were limited to specific angles/views. But now, with 3D Volume imaging, doctors can get full volume data with automated tools that take hundreds of images and reconstruct them into 3D images which can be manipulated in any orientation. Dr. Benacerraf emphasized that, “We must educate the medical community to consider adopting 3D ultrasound as the first assessment tool for specific gynecologic indications, such as evaluating the uterus for Müllerian anomalies or localization of IUDs or other intracavitary lesions”.
2D and 3D inverse view of a hydrosalpinx
- Twodimensional oblique view of a multiseptate adnexal fluid collection, suspected of being a hydrosalpinx. Numbers 1 and 2 are normal caliper measurement numbers inserted by machine.
- Threedimensional inverse mode view of the same adnexal fluid collection definitively demonstrates a hydrosalpinx.
With the use of the inverse mode, the cystic areas all become solid, and the solid areas disappear from the image; hence, a cast of the hydrosalpinx can be viewed even as it traverses multiple planes.
Another very important advancement in ultrasound transducer technology is the transvaginal transducer which allows operators to place a probe as close as possible to the target organs.
Two-dimensional color blood flow Doppler view of a large ovarian cancer.
Note the extensive solid areas and abundant blood flow. Note that the vessels are irregular, beaded, and often confluent in the image, which is typical of neovascularity.
Doppler ultrasound imaging, an important innovation which no modern ultrasound machine can go without, maps blood flow around lesions in the pelvis without using contrast agents. Characteristic blood flow patterns can then be used to differentiate benign cysts and other lesions from cancers which have ample and disorganized blood flow patterns. Color Doppler can also be used to differentiate an endometrioma from an ovarian tumor or fibroma.
As more Ob/Gyn experts adopt an ultrasound first approach to patients with pelvic symptoms, the more time and money they will save compared to other imaging modalities, while at the same time providing comparable results.
Benacerraf. Consider ultrasound first for imaging the female pelvis. Am J Obstet Gynecol 2015.
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