Magnetic Resonance Imaging-Guided High-Intensity Focused Ultrasound Ablation of Uterine Fibroids: Effect of Bowel Interposition on Procedure Feasibility and a Unique Bowel Displacement Technique

<div><p>Purpose</p><p>To evaluate the effect of bowel interposition on assessing procedure feasibility, and the usefulness and limiting conditions of bowel displacement techniques in magnetic resonance imaging-guided high-intensity focused ultrasound (MR-HIFU) ablation of uterine fibroids.</p><p>Materials and Methods</p><p>Institutional review board approved this study. A total of 375 screening MR exams and 206 MR-HIFU ablations for symptomatic uterine fibroids performed between August 2010 and March 2015 were retrospectively analyzed. The effect of bowel interposition on procedure feasibility was assessed by comparing pass rates in periods before and after adopting a unique bowel displacement technique (bladder filling, rectal filling and subsequent bladder emptying; BRB maneuver). Risk factors for BRB failure were evaluated using logistic regression analysis.</p><p>Results</p><p>Overall pass rates of pre- and post-BRB periods were 59.0% (98/166) and 71.7% (150/209), and in bowel-interposed cases they were 14.6% (7/48) and 76.4% (55/72), respectively. BRB maneuver was technically successful in 81.7% (49/60). Through-the-bladder sonication was effective in eight of eleven BRB failure cases, thus MR-HIFU could be initiated in 95.0% (57/60). A small uterus on treatment day was the only significant risk factor for BRB failure (B = 0.111, <i>P</i> = 0.017).</p><p>Conclusion</p><p>The BRB maneuver greatly reduces the fraction of patients deemed ineligible for MR-HIFU ablation of uterine fibroids due to interposed bowels, although care is needed when the uterus is small.</p></div

MR Imaging Parameters.

<p>MR Imaging Parameters.</p

Multivariate Analysis of Risk Factors for Failure of the BRB Maneuver.

Multivariate Analysis of Risk Factors for Failure of the BRB Maneuver.</p

A typical example of the BRB maneuver attempted in the case of a 34 year-old woman with a fibroid in a forward-bent uterus.

<p>A. A sagittal survey scan showed that the bowel loops (arrow) were interposed between the uterus and the anterior abdominal wall. F and U indicate the target fibroid and the urinary bladder respectively. Dotted lines delineate the margins of each structure, and transparent orange triangles represent the planned HIFU beam path. B. After filling with 500 mL of saline, the urinary bladder (U) was distended and displaced the uterus cranially. However, the interposed bowel loops (arrow) were still in the anticipated sonication path. F indicates the target fibroid. Dotted lines delineate the margins of each structure. C. The rectum (R) was filled with 150 mL of gel. The distended rectum pushed the uterine cervix and the uterus antero-cranially, which displaced the bowel loops (arrow) out of the anticipated sonication path. F indicates the target fibroid and U indicates the urinary bladder. Dotted lines delineate the margins of each structure. D. The uterus descended after drainage of the urinary bladder (U), although the previously-interposed bowel loops (arrow) remained out of the anticipated sonication path. After a successful BRB maneuver, MR-HIFU ablation was performed. F indicates the target fibroid and R indicates the rectum. Dotted lines delineate the margins of each structure.</p

Baseline Features of the Study Population.

<p>Baseline Features of the Study Population.</p

A successful BRB maneuver for a backward-bent uterus in a 43 year-old woman with a uterine fibroid.

<p>A. A sagittal survey scan revealed the backward-bent uterus located in the deep pelvic cavity and the interposed bowel loops. The size of the uterus was 90 mm in its largest dimension. F and U indicate the target fibroid and the urinary bladder, respectively. Dotted lines delineate the margins of each structure, and transparent orange triangles represent the planned HIFU beam path. B. The urinary bladder (U) was filled with 500 mL of saline and then the rectum (R) was filled with 100 mL of gel. The uterus was shifted antero-crainally. However, the bowel loops (arrow) continued to block the target fibroid (F). Dotted lines delineate the margins of each structure. C. The urinary bladder (U) was partially emptied by draining 100 mL of urine and the rectum (R) was filled further with 100 mL of gel. The target fibroid (F) was shifted anteriorly, but the bowel loops (arrow) were still in the anticipated sonication path. Dotted lines delineate the margins of each structure. D. After fully emptying the urinary bladder (U), the uterus was moved antero-caudally close to the abdominal wall, and the bowel loops (arrow) were displaced completely out of the sonication path. After a successful BRB maneuver, MR-HIFU ablation was performed. F indicates the target fibroid and R indicates the rectum. Dotted lines delineate the margins of each structure.</p

A case of technical failure of the BRB maneuver in a 42 year-old woman with a fibroid in a forward-bent uterus. The patient did not undergo GnRH agonist pretreatment.

<p>A. Sagittal image of screening MRI showed a uterine fibroid of the submucosal type (F). The uterus was bent forward and measured 108 mm in its largest dimension. The bowel loops were interposed. F indicates the target fibroid and U indicates the urine-filled urinary bladder. Dotted lines delineate the margins of each structure. B. On treatment day, a sagittal image from the survey scan revealed that more bowel loops (arrow) were interposed and the uterus shrank to 68 mm for an unknown reason. F and U indicate the target fibroid and the urinary bladder, respectively. Dotted lines delineate the margins of each structure, and transparent orange triangles represent the planned HIFU beam path. C. The urinary bladder (U) was filled, followed by the rectum (R). However, the bowels (arrow) were located within the anticipated sonication path, even after transducer angulation. Moreover, the target fibroid (F) was too deeply located to allow a safe and effective ablation. Dotted lines delineate the margins of each structure. D. After emptying the urinary bladder (U), the bowel loops (arrow) descended again completely blocking the target fibroid (F). R indicates the rectum. Dotted lines delineate the margins of each structure. E. The urinary bladder (U) was filled with saline (300 mL) again. However, there was still a bowel loop anterior to the uterus. Urinary bladder filling and emptying was repeated 5 times in this particular case. F and R indicate the target fibroid and the rectum, respectively. Dotted lines delineate the margins of each structure. F. Further filling of the urinary bladder (U) with saline (500 mL in total) and the rectum (R) with gel (350 mL in total) did not satisfactorily displace the interposed bowel loop (arrow). Therefore, the procedure was terminated without initiation of MR-HIFU sonication. Dotted lines delineate the margins of each structure.</p

Multidisciplinary approach is associated with improved survival of hepatocellular carcinoma patients - Fig 1

Kaplan-Meier survival curves of patients with hepatocellular carcinoma according to the management through multidisciplinary tumor board in the entire cohort (A) and in the exactly matched cohort (B). Abbreviations: MDT, multidisciplinary tumor board.</p

Baseline characteristics.

Baseline characteristics.</p

Factors associated with overall survival.

Factors associated with overall survival.</p