Surgery – Diagnostic testing – Detecting nuclear – electromagnetic – or ultrasonic radiation
Reexamination Certificate
1999-09-29
2004-01-06
Lateef, Marvin M. (Department: 3737)
Surgery
Diagnostic testing
Detecting nuclear, electromagnetic, or ultrasonic radiation
C600S419000
Reexamination Certificate
active
06675037
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to Magnetic Resonance Imaging-Guided (MRI-Guided) medical procedures, particularly MRI-Guided interventional procedures and therapies that are performed on the breasts or mammaries of patients.
2. Background of the Art
The diagnosis and treatment of breast cancer is a major health care issue which affects the lives of more than 180,000 women annually, only considering the United States. While, early detection and treatment of breast cancer is a major factor for efficient patient management, there is significant technical space available for developing a highly efficient approach for diagnosing and characterizing breast cancer. Although numerous studies manifest an almost 100% sensitivity of MRI for the detection of breast cancer, the studies also demonstrate a widely varying specificity. These findings result in a patient management dilemma when lesions are detected with MRI and those lesions have not been seen with other gold standard modalities. MRI-Guided biopsy or MRI-Guided wire localization therefore will be important in integrating MRI into breast cancer management. Furthermore, it is reasonable to suggest that the combination of MRI diagnostic imaging, for example contrast agent perfusion, with MRI guided subcutaneous core biopsy may provide an improved method for the detection and characterization of breast cancer. In addition, breast conserving therapies (BCT), such as laser photo-ablation therapy, are under evaluation. These approaches require accurate positioning and monitoring of their effect (e.g. tissue temperature) during insertion and during the actual procedure. Visualization can be achieved in real-time with MRI systems. Thus an apparatus to position interventional devices and monitor their operation under MRI guidance would be likely to improve the success of diagnostic and therapeutic procedures.
Several MR-guided free-hand or stereotaxic apparatus have been implemented for interventions of the breast, such as preoperative localization, fine needle aspiration biopsy and core biopsy (U. Fischer, et al., “MR Imaging-Guided Biopsy Breast Intervention: Experience with Two Systems”
Radiology
192, 876-881, (1994); U. Fischer, et al., “MR-Guided Biopsy of Suspected Breast lesions with a Simple Stereotaxic Add-On Device for Surface Coils”
Radiology
200, 651-658 (1996)), (C. K. Cuhl, et al., “Interventional Breast MR Imaging: Clinical Use of a Stereotaxic Localization and Biopsy Device”
Radiology
204, 667-675 (1997); S. H. Heywang-Kobrunner, et al., “Prototype Breast Coil for MR-Guided needle Localization”
J. Comp. Assist. Tomogr.
18, 876-881 (1994)) and (S. Greenstein-Orel, et al., “MR Imaging-Guided Localization and Biopsy of Breast Lesions: initial Experience”
Radiology,
193, 97-102 (1994); E. K. Insko, et al., “Multicoil Array for High Resolution Imaging of the Breast”
Magn. Reson. Med.
37, 778-784 (1997)). The design and the operation of these devices are tailored for use inside the limited space of an MRI scanner, and a short contrast window (5 to 10 min). Such studies have demonstrated the feasibility of combining MRI, as a diagnostic modality, with MR-guided interventions of the breast. The common features of such devices are: (a) compression of the breast for better fixation, with one or two plates and (b) use of an arrangement of puncture channel (mesh) to correctly place the interventional probe. Despite their success, there are some limitations in these designs, particularly when they are compared with the non-MR stereotaxic devices. First, most of the devices provide compression along a specific orientation, usually medial-lateral, which may not be the optimal one, as for example for transversing the shortest path in the tissue or to reach areas such as the axilla. Second, in most of the devices the probe is directed by means of a mesh, and thus it can be only inserted perpendicular to the compression plates or with a slight “free-hand” angulation. This may not be the optimal approach, for example, when attempting to access tissue close to the chest wall, at the axilla or to avoid obstructions such as implants. The two single plate systems have the same limitations and in addition there is the potential for accidental rib puncture or highly invasive operations behind the nipples. The operation of the above devices requires the patient to be removed from the magnet, the probe inserted and then re-imaged, with the possibility that another insertion may be required to correct the initial one. This practice increases the length of the operation, and may not be always feasible due to the limited number of allowed injections of contrast material and the short duration of the contrast window.
Several types of interventional devices, including such devices as catheters, ultrasonic devices, transcanular devices, excavating tools, therapeutic tools (e.g., lasers, cryoablation, drug delivery, electrical stimulating devices, etc.) have been used in MRI-Guided procedures in the breast including within them MRI compatible features such as such as non-specific surface RF coils (U. Fischer, et al., “MR Imaging-Guided Biopsy Breast Intervention: Experience with Two Systems”
Radiology
192, 876-881, (1994); U. Fischer, et al., “MR-Guided Biopsy of Suspected Breast lesions with a Simple Stereotaxic Add-On Device for Surface Coils”
Radiology
200, 651-658 (1996)), modified RF coils (C. K. Cuhl, et al., “Interventional Breast MR Imaging: Clinical Use of a Stereotaxic Localization and Biopsy Device”
Radiology
204, 667-675 (1997); S. H. Heywang-Kobrunner, et al., “Prototype Breast Coil for MR-Guided needle Localization”
J. Comp. Assist. Tomogr.
18, 876-881 (1994)) and a multi-coil array (S. Greenstein-Orel, et al., “MR Imaging-Guided Localization and Biopsy of Breast Lesions: initial Experience”
Radiology,
193, 97-102 (1994); E. K. Insko, et al., “Multicoil Array for High Resolution Imaging of the Breast”
Magn. Reson. Med.
37, 778-784 (1997)). These RF coils, except for those shown in Greenstein-Orel, et al. and E. K. Insko, et al., are of standard dimensions and are not appropriate for use with the proposed apparatus since they will have a variable filling-factor for different degrees of breast compression. To address these issues, and others analyzed herein, different methodologies are needed in the field.
While endoscopic, arthroscopic, and endovascular therapies have already produced significant advances in health care, these techniques ultimately suffer from the same limitation. This limitation is that the accuracy of the procedure is “surface limited” by what the surgeon can either see through the device itself or otherwise visualize (as by optical fibers) during the course of the procedure. That is, the visually observable field of operation is quite small and limited to those surfaces (especially external surfaces of biological masses such as organs and other tissue) observable by visible radiation, due to the optical limitations of the viewing mechanism. MR imaging, by comparison, overcomes this limitation by enabling the physician or surgeon to non-invasively visualize tissue planes and structures (either in these planes or passing through them) beyond the surface of the tissue under direct evaluation. Moreover, MR imaging enables differentiation of normal from abnormal tissues, and it can display critical structures such as blood vessels in three dimensions. Prototype high-speed MR imagers which permit continuous real-time visualization of tissues during surgical and endovascular procedures have already been developed. MR-guided minimally invasive therapy is expected to substantially lower patient morbidity because of reduced post-procedure complications and pain. The use of this type of procedure will translate into shorter hospital stays, a reduced convalescence period before return to normal activities, and a generally higher quality of life for patients. The medical benefits and health care cost savings are likely to be very substantial.
New technologies
Lateef Marvin M.
Regents of the University of Minnesota
Schwegman Lundberg Woessner & Kluth P.A.
Shaw Shawna J.
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