With ultrasound monitoring, analysis of the behavior of uterine leiomyomas (fibroids) and their impact on the course of pregnancy was undertaken in a group of 113 patients. Fibroid size changes were analyzed on the basis of trimesters. In the second trimester, smaller fibroids increased in size, whereas larger fibroids decreased in size. In the third trimester, a decrease in size was documented regardless of initial size. The most common patterns of echotexture were hypoechoic, heterogeneous, and echogenic rim. The development of a heterogeneous pattern or anechoic/cystic spaces on a follow-up study was accompanied in seven of ten patients by severe abdominal pain, compared with 12 cases of abdominal pain in 103 patients without such echotexture changes. Although the number of patients was small, the development of these patterns apparently indicates significant degeneration of the fibroid. Fibroids located in the lower uterine segment were accompanied by a higher frequency of cesarean section and retained placenta. Fibroids located in the uterine corpus were more frequently associated with early abortions. Multiple fibroids were accompanied by a higher frequency of malpresentation and premature contractions compared with cases with one or two fibroids.

This study seeks to exploit the high magnetic field environment of a clinical MRI scanner and demonstrate the technical feasibility of developing a catheter whose tip can be remotely oriented within the magnetic field by applying a DC current to a coil wound around the catheter tip to generate a magnetic moment and consequent deflection. To achieve arbitrary three-dimensional deflections, a three-axis coil was wound on a 1.5 Fr cylindrical catheter. By applying DC currents in the 100 mA range, this catheter was successfully guided through a 3D phantom maze, mimicking the vasculature, under MR imaging guidance. Feasibility was demonstrated that the strong ambient magnetic field of the MR scanner offers a special opportunity to develop simple devices that can be remotely steered to sites of clinical interest.

Current applied to wire coils wound at the tip of an endovascular catheter can be used to remotely steer a catheter under magnetic resonance imaging guidance. In this study, we derive and validate an equation that characterizes the relationship between deflection and a number of physical factors: theta/sin(gamma-theta) = nIABL/EI(A) where theta is the deflection angle, n is the number of solenoidal turns, I is the current, A is the cross-sectional area of the catheter tip, B is the magnetic resonance (MR) scanner main magnetic field, L is the unconstrained catheter length, E is Young's Modulus for the catheter material, and I(A) is the area moment of inertia, and y is the initial angle between the catheter tip and B. Solenoids of 50, 100, or 150 turns were wound on 1.8 F and 5 F catheters. Varying currents were applied remotely using a DC power supply in the MRI control room. The distal catheter tip was suspended within a phantom at varying lengths. Images were obtained with a 1.5 T or a 3 T MR scanner using "real-time" MR pulse sequences. Deflection angles were measured on acquired images. Catheter bending stiffess was determined using a tensile testing apparatus and a stereomicroscope. Predicted relationships between deflection and various physical factors were observed (R2 = 0.98-0.99). The derived equation provides a framework for modeling of the behavior of the specialized catheter tip. Each physical factor studied has implications for catheter design and device implementation.

Guidelines for the pretreatment work-up of clinical stage Ib cervical cancer need revision. MR imaging should be used as an adjunct to clinical evaluation.

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