Q. What is the SuperDimension Bronchus System?
A. The SuperDimension Bronchus System (SDS) describes an exciting new technology that allows bronchoscopists to access peripheral lung nodules and mediastinal lymph nodes with greater accuracy than ever before. The SDS system incorporates both image guidance and electromagnetic guidance to allow peripheral navigation through airways and accurate localization of mediastinal lymph nodes.

Q. How does SDS work?
A. SDS works by using electromagnetic guidance to map a patient�s own anatomy to a C.T. scan in real time, and subsequently using the C.T. images as a roadmap for navigation to reach a target lesion.

Q. How does the mapping work?
A. First, a high-resolution C.T. scan is done of the patient�s chest. Using the SDS software, the C.T. images are reconstructed three dimensionally in a multi-planar fashion. Several reference points that can be easily visualized during bronchoscopy are then embedded in the C.T. images. Generally, these points include the main carina, the right and left upper lobe carinas, and the right and left lower lobe carinas (fig. 1, 3). In addition, the target is also registered (fig 2). At the time of the bronchoscopy, the reference points that have been set on the C.T. are registered to their corresponding points within the patient�s airways using electromagnetic guidance. Once this C.T.-body registration is completed, the SDS software can map the patient�s anatomy to the C.T. scan in real time.

Q. What is electromagnetic guidance and how does it work?
A. During the procedure (the bronchoscopy), a Location Board is placed under the mattress that the patient is lying on. This Location Board emits an electromagnetic field around the patient. During the bronchoscopy, a Locatable Guide (LG) is inserted through the working channel of the scope. The LG has miniaturized sensors in its distal tip that send information on its location within the electromagnetic field back to the SDS software. Using the pre-defined registration points, the LG is advanced to those exact locations in real-time (see fig. 4), fusing the virtual registration point to its real-time location with the airways. This is done at each registration point, up to six points. Once the patient is mapped to the C.T. images, the LG�s location within the patient�s chest can now be placed within the C.T. images.

Q. How is navigation to a peripheral nodule achieved?
A. The LG is steerable�. That is, it can be flexed in eight directions. Using both multi-planar C.T. images and the software�s own guidance system, the LG can be steered as it is advance through the airways.

Q. How is the nodule biopsied once successful navigation has occurred?
A. The LG is encased within a reinforced channel called the Extended Working Channel (EWC). Once successful navigation has occurred, the LG is removed, leaving the EWC in place. Any biopsy tool (i.e. forceps, brush, needle) can now be placed through the EWC to obtain a tissue sample. At our St. Vincent�s Comprehensive Cancer Center, fluoroscopic verification of proper biopsy tool placement is done prior to tissue sampling (fig. 6). In addition, ROSE (Rapid On-Site Evaluation) is performed at the bedside to assess specimen adequacy and to assess for the presence of malignant cells after each biopsy is taken.

Q. Can the SDS system be used only for solitary nodules?
A. No. The SDS system can also be used to accurately biopsy any abnormal lymph nodes in the mediastinum, a process known as Guided Lymph Node Aspiration (GLNA). The system therefore can be used to biopsy enlarged mediastinal nodes to diagnose a primary lymph node process or to stage the mediastinum in lung cancer.

Q. Is the process of GLNA done the same way as the biopsy of solitary nodules?
A. Not exactly. The SDS GLNA software allows us to identify lymph nodes during the planning stage. During the procedure, after the registration phase has been completed, the GLNA software is engaged. This allows us to see in the virtual airway where the lymph node is by making the airway transparent in the virtual bronchoscopic view. These images are then correlated to the real-time anatomy using the real-time bronchoscopic image being displayed side-by-side with the virtual image. In addition, the LG can be used to identify puncture sites and puncture angles, making needle insertion precise and accurate. (See fig. 7).

Fig. 7 - GLNA mode. Shown, biopsy of right hilar (station 10R) node. Upper right quadrant shows virtual anatomy of RUL bronchus, with transparency; lymph node in green. Lower left quadrant shows coronal view of anatomy, targetand LG position. Lower right quadrant shows real-time position of LG, with relative target location in cross-hairs in inset box. Upper right quadrant shows freeze of ideal position, to guide needle entry point

Q. What mediastinal nodes can be accessed by the SDS system?
A. Any mediastinal node can be accessed using the SDS system. This includes paratracheal nodes, subcarinal nodes, AP-window nodes, and hilar nodes. These nodes, especially the subcarinal, AP window, and hilar nodes, are not easily accessible by mediastinoscopy, making the SDS system an attractive alternative to mediastinoscopy in the staging of lung cancer, or in the diagnosis of a mediastinal process.

Q. What patients would be appropriate for the SDS system?
A. Any patient who either has a solitary pulmonary nodule, or mediastinal lymphadenopathy, or both. The accuracy of the system is greatest for solitary nodules over 10mm in size.

Q. How long does the procedure take?
A. The procedure generally lasts about an hour. The time may vary depending on the location of the biopsy and how many biopsies need to be taken.

Q. Whom can I call for more information?
A. The SDS system is located at St. Vincent�s Comprehensive Cancer Center, and is under the direction of Joseph Cicenia, M.D., F.C.C.P. For more information, contact Dr. Cicenia at (212) 604-6071, or at jcicenia@svcmcny.org.