3D use allows lower dose for UAE
Utilization of 3D reconstructions from contrast-enhanced MRI as part of a uterine artery embolization (UAE) preprocedure enables clinicians to determine the best tube angle obliquity for fluoroscopic visualization of the origin of the uterine artery. This significantly reduces fluoroscopy time, radiation dose and contrast medium volume during that procedure, according to research published in this month’s issue of Radiology.
“Almost all patients who undergo UAE procedures are women of childbearing age, and because UAE requires fluoroscopic and angiographic imaging, the radiation exposure may affect the function of the ovaries,” wrote the authors of a prospective study conducted at the Institute for Diagnostic and Interventional Radiology at the Johann Wolfgang Goethe-University Frankfurt in Frankfurt am Main, Germany. “Because the patient is exposed to ionizing radiation during UAE, all procedures and radiation exposure should be governed by the principle of as low as reasonably achievable.”
The study was designed to evaluate the effect of preprocedural prediction of the best tube angle obliquity for visualization of the origin of the uterine artery by using 3D–reconstructed contrast material–enhanced MR angiography (MRA) on the radiation dose, fluoroscopy time, and contrast medium volume during the procedure.
A total of 40 patients (20 prospective/sample and 20 retrospective/control) participated in the research. Radiation dose, fluoroscopy time, and contrast medium volume for the 20 sample patients were compared with those for the 20 control patients.
In the 20 sample patients, contrast-enhanced MRA was performed before UAE and was used to predict the best tube angle obliquity for visualization of the uterine artery origin via 3D reconstruction of the MRA series. The 20 control patients were the last 20 consecutive patients who had undergone UAE performed by the same physician before the prospective portion of the study (for whom no angle was predicted).
Both the sample and control populations underwent contrast-enhanced MRA on a Siemens Healthcare 1.5T Magnetom Avanto system and a 3D-reconstructed volume-rendered view of the pelvic arterial tree was obtained.
“The uterine artery with its characteristic tortuous course was identified and traced backward to its origin, where the 3D-reconstructed figure of the pelvic arterial tree was slowly rotated in both directions in an attempt to visually identify the best obliquity that clearly delineated its origin,” the authors wrote. “In all 20 sample patients, the uterine artery was clearly identified on the 3D reconstructed model and could be successfully traced to its origin.”
The researchers used an application, Inspace, which provided a C-arm obliquity angle that corresponded to the rotated 3D figure. Two angles were suggested for each patient—one representing the best angle for visualization of the left uterine artery origin and the second representing the best angle for visualization of the right uterine artery origin. The physician performing the UAE was provided these angles and used them for fluoroscopy during the procedure.
The use of 3D modeling from MRA data provided significant reductions in radiation dose and contrast medium use during the UAE procedure, compared with the control group, the team reported. Radiation dose decreased by an average of 62 percent, fluoroscopy time shortened by 43 percent and contrast medium usage went down by 44 percent.
“We regard the current study as a step on a long road of utilization of 3D reconstruction in interventional radiology,” the authors wrote. “Further studies aiming to utilize such capabilities of 3D images in determining ovarian supply of uterine fibroids and to compare axial versus coronal 3D contrast-enhanced MR angiograms are required.”
“Almost all patients who undergo UAE procedures are women of childbearing age, and because UAE requires fluoroscopic and angiographic imaging, the radiation exposure may affect the function of the ovaries,” wrote the authors of a prospective study conducted at the Institute for Diagnostic and Interventional Radiology at the Johann Wolfgang Goethe-University Frankfurt in Frankfurt am Main, Germany. “Because the patient is exposed to ionizing radiation during UAE, all procedures and radiation exposure should be governed by the principle of as low as reasonably achievable.”
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| Three-dimensional–reconstructed contrast-enhanced MR angiographic image from the preembolization study. The model was rotated to a 40-degree left obliquity (contrary to the usual right oblique view used for the left uterine artery) for demonstration of |
The study was designed to evaluate the effect of preprocedural prediction of the best tube angle obliquity for visualization of the origin of the uterine artery by using 3D–reconstructed contrast material–enhanced MR angiography (MRA) on the radiation dose, fluoroscopy time, and contrast medium volume during the procedure.
A total of 40 patients (20 prospective/sample and 20 retrospective/control) participated in the research. Radiation dose, fluoroscopy time, and contrast medium volume for the 20 sample patients were compared with those for the 20 control patients.
In the 20 sample patients, contrast-enhanced MRA was performed before UAE and was used to predict the best tube angle obliquity for visualization of the uterine artery origin via 3D reconstruction of the MRA series. The 20 control patients were the last 20 consecutive patients who had undergone UAE performed by the same physician before the prospective portion of the study (for whom no angle was predicted).
Both the sample and control populations underwent contrast-enhanced MRA on a Siemens Healthcare 1.5T Magnetom Avanto system and a 3D-reconstructed volume-rendered view of the pelvic arterial tree was obtained.
“The uterine artery with its characteristic tortuous course was identified and traced backward to its origin, where the 3D-reconstructed figure of the pelvic arterial tree was slowly rotated in both directions in an attempt to visually identify the best obliquity that clearly delineated its origin,” the authors wrote. “In all 20 sample patients, the uterine artery was clearly identified on the 3D reconstructed model and could be successfully traced to its origin.”
The researchers used an application, Inspace, which provided a C-arm obliquity angle that corresponded to the rotated 3D figure. Two angles were suggested for each patient—one representing the best angle for visualization of the left uterine artery origin and the second representing the best angle for visualization of the right uterine artery origin. The physician performing the UAE was provided these angles and used them for fluoroscopy during the procedure.
The use of 3D modeling from MRA data provided significant reductions in radiation dose and contrast medium use during the UAE procedure, compared with the control group, the team reported. Radiation dose decreased by an average of 62 percent, fluoroscopy time shortened by 43 percent and contrast medium usage went down by 44 percent.
“We regard the current study as a step on a long road of utilization of 3D reconstruction in interventional radiology,” the authors wrote. “Further studies aiming to utilize such capabilities of 3D images in determining ovarian supply of uterine fibroids and to compare axial versus coronal 3D contrast-enhanced MR angiograms are required.”