Applied Radiology

As interventional procedures expand radiology beyond diagnostics, to treatment, equipment manufacturers are providing the technology to keep up with this trend.

Interventional CT suite

Picker International (Cleveland) recently announced its VenueTM suite for x-ray computed tomography (CT), designed to meet interventional radiology and radiation oncology needs. The suite includes PinPointTM (figure 1), an interventional planning tool; fluoro-assisted computed tomography (FACTSTM), a C-arm fluoro x-ray unit integrated into the CT system; continuous CT (CCTTM), a real-time reconstruction process; and C-ViewTM, which integrates a C-arm within the CT suite for fluoroscopic and digital-subtraction technology.

PinPoint is a frameless stereotactic device that includes an articulated stereotactic arm integrated into the CT scanner. The device enables radiologists to visualize and plan the simulated instrument path in relation to the target area, according to Picker. "All possible paths can be considered and critical structures can be safely avoided," said the company.

With FACTS, fluoroscopy can be used to visualize the delivery of treatment devices, with follow-up CT confirmation of the location-in one step, without moving the patient. Continuous CT can guide minimally invasive therapies involving motion prone areas, such as the thorax and diaphragm regions. And C-View provides "complete endovascular capability in the CT suite," according to Picker.

New oncology division

In May, Picker announced the formation of an oncology division. "The new division will incorporate magnetic resonance imaging (MRI), x-ray, ultrasound, and CT imaging modalities to provide the most advanced treatment planning system possible for oncology patients," said Tim Hansen, executive vice president at Picker. The company's ACQSIMTM, a CT planning system for external-beam radiation therapy, is a main product in the oncology division. According to Picker, the ACQSIM has an installed base of 200, holds 70% of the market share, and has led the conversion to 3-dimensional (3D) volume treatment planning.

The new Venue interventional radiology product line is being incorporated into the oncology systems division "to improve brachytherapy treatment for cancer patients," said Picker. "The combination of brachytherapy and external beam radiation gives us optimal tools for success," said James Hevezi, PhD, of The Cancer Therapy and Research Center (San Antonio, TX). With the PinPoint stereotactic arm and FACTS digital fluoro, "we can increase target precision" with "an innovative way of planning these procedures," said Dr. Hevezi.

Picker has established a medical advisory board to work on developing an oncology-specific CT device, according to Stephen Whisenhunt, general manager of oncology systems.

Uninterrupted interventional CT

According to GE Medical Systems (Milwaukee), the company's recently developed software called SmartViewTM allows radiologists "to conduct interventional CT procedures without interruption." Previously, high-quality images for CT-guided procedures were available, but did not match the speed of traditional fluoroscopy or ultrasound.

"SmartView was designed to overcome the trade-off between image quality and speed by reducing extraneous procedure time," said Ken Denison, manager of Americas CT Marketing at GE. "In a routine biopsy situation, for example, real-time imaging allows interventional radiologists to follow the needle all the way from the entry point to the target." Adjustments in trajectory can be made by monitoring the images displayed on an in-room image monitor, he explained, which is particularly helpful when multiple attempts are needed to place the needle correctly.

GE offers SmartView for its HiSpeedTM CT/i system. The mobile, flat-screen monitor can be positioned in the physician's line of sight during an interventional procedure. The real-time images allow for uninterrupted monitoring of the needle trajectory, eliminating the need to leave the scanning room to view images and return to make necessary adjustments. This technology, noted GE, makes the interventional procedure more efficient and also improves patient comfort.

Monitoring biopsies with CT fluoroscopy

Philips Medical Systems North America Company (Shelton, CT) is developing CT fluoroscopic capabilities for its line of Tomoscan Advanced Volume (AV) CT systems equipped with RapidViewTM. CT BiopsyView will enable physicians to monitor a range of interventional procedures in real-time. The fluoroscopic feature is intended for use in nonvascular applications in the lung, retroperitoneum, skeletal system, spine, and intracranium.

Real-time monitoring will allow radiologists to correct for depth and direction of the needle puncture during the procedure, without having to wait for image reconstruction to check needle placement. In addition, the fine-needle control should reduce complications and increase accuracy. According to Philips, CT fluoroscopy should reduce the need for multiple scans to localize the lesion and needle tip. Additionally, a high frame-rate should nullify the impact of patient motion on image quality. The company predicts that CT fluoroscopy would reduce the biopsy procedure time by one-half to one-third.

Cook Inc. (Bloomington, IN) recently acquired Global Therapeutics (Broomfield, CO) to acquire new devices for interventional radiology, cardiology, and critical care. The Cook product line will now include a cold-laser, catheter-based system to treat neointimal hyperplasia (restenosis), a balloon for percutaneous transluminal coronary angioplasty (PTCA), and several coronary stents.

Usually, when radiologists discuss a three-dimensional (3D) volume created from tomographic data, they mean a 3D image on a workstation monitor or laser printout. Now, that image can become truly volumetric, transformed into a plastic anatomic model based on data generated from an x-ray computed tomography (CT) or magnetic resonance (MR) study (figure 2).

"Fused deposition modeling" technology

MedModeler, based on "fused deposition modeling" technology, was recently granted 510(k) pre-market clearance by the U.S. Food and Drug Administration (FDA). Indicated as an "image processing accessory," the device uses 3D surface-representation data or 2D contour data to create models made of medical-grade, nontoxic plastic. It can be used in a hospital or office environment. The build area is up to 10 ¥ 10 ¥ 10 inches, and the device is compatible with Windows NT and UNIX systems. According to Stratasys (Eden Prairie, MN), the manufacturer, MedModeler interfaces with "qualified CT/MR converter software packages."

The device can "support the needs of the surgeon and radiologist by providing a modeling system that can create patient-specific models," said Lisa Crump, vice president of business development at Stratasys. "A physician can gain additional information for making a diagnosis by examining a 3D model. The surgical team can utilize the model to formulate or rehearse operating techniques in advance of surgery, or as an aid in communication," she added.

Rapid prototyping technology replaces machine tooling

Stratasys, founded in 1989, manufactures rapid prototyping devices for medical, industrial, and consumer applications. Traditionally, engineers created 3D models and prototypes with conventional fabrication methods, such as machine tooling. With rapid prototyping, an engineer (or radiologist, technologist, etc.) can develop a model directly from computer data within minutes or hours.

Instead of carving a model from a larger piece of material, rapid prototyping is based on layering together thin, horizontal cross-sections of a computer-generated model. The layers may consist of plastic, wood, ceramic, or metal. With this layer-building approach, rapid prototyping machines can build almost any shape, including anatomic structures.

In the fused deposition modeling used by MedModeler, a temperature-controlled head extrudes thermoplastic material layer by layer, like a stack of CT or MR slices. As the material solidifies, it laminates to the preceding layer. S. Scott Crump, chairman and chief executive officer (CEO) of Stratasys, developed fused deposition modeling in 1988. Its U.S. patent was issued in 1992.

Did you ever wonder what consultants say to health maintenance organizations (HMOs) and managed care organizations (MCOs) when they're pitching to win the business of managing radiology services and to cut imaging costs? Here are excerpts from a brochure and cover letter sent to Applied Radiology from a "managed care imaging company."

"Establish clinically appropriate practice patterns and cost reductions will come."

"Simply cutting services will not reduce costs; changing practice patterns will."

"One of the most effective tools for reducing costs, our precertification program applies nationally recognized protocols to imaging requests-and fast."

Comparing utilization with "peer norms"

The company uses "comparative analysis and reporting software" to provide in-depth analyses of radiology practices that allow HMOs and MCOs to "compare practice patterns, utilization, and costs to similar provider groups or organizations." The company analyzes "cost and frequency of imaging services by diagnosis groups, clinical indicators (positivity, negativity, appropriateness), usage of multiple modalities or repeated imaging exams across a given diagnosis," as well as other data.

Reports can be generated that compare the statistical and clinical results of referring physicians. These comparative data help "in understanding how the imaging dollar is distributed relative to peer norms." The company "will then issue a letter to physicians who are ordering procedures unnecessarily, and will educate them on proper ordering for specific diagnoses."

The company predicts "it is able to save healthcare organizations up to 30% in imaging costs-without compromising quality of care."