The University of Maryland Medical Center has begun using a sophisticated new imaging tool called the multislice CT scanner, which speeds diagnosis and treatment of patients, including trauma patients with severe injuries. The multislice CT scanner has created excitement among radiologists because it provides clearer pictures with more detail and in a lot less time than it takes for conventional spiral CT.
"The leap from spiral CT to the capabilities of the multislice CT is incredible," says Charles White, M.D., director of thoracic radiology at the University of Maryland Medical Center. "With multislice CT we get more detail and images in less time," adds Dr. White who is also professor of diagnostic radiology and nuclear medicine at the University of Maryland School of Medicine. "We are currently using multislice CT to evaluate lung cancer patients, detect blood clots in the pulmonary arteries and locate aneurysms in blood vessels."
"In one to two minutes, we can scan the entire body of a trauma patient and see all the internal injuries," says Stuart Mirvis, M.D., director of trauma radiology at the University of Maryland Shock Trauma Center and professor of diagnostic radiology and nuclear medicine at the University of Maryland School of Medicine. "With this scanner, we can even see minute details such as the tiny bones in the inner ear."
The multislice CT scanner is similar in appearance to the conventional spiral CT. The difference is in the number of images or slices the scanner generates per second. As the X-ray source and detectors move around the patient, the newer multislice CT captures up to four slices simultaneously in 0.5 seconds compared to spiral CT which captures one slice per second. Using the multislice CT, patients do not have to hold their breath for as long, and the technician uses less contrast material. In the next few months, the multislice CT scanner will be even faster with eight rows of detectors available, instead of four, says Dr. Mirvis. Even scanners with 16 and 32 rows are on the horizon. The greater number of rows allows the scanner to acquire more images per second.
"The multislice CT has many potential uses and we have really only begun to scratch the surface," says Barry Daly, M.D., vice chair of research development in the Department of Radiology at the University of Maryland Medical Center and professor of diagnostic radiology and nuclear medicine at the University of Maryland School of Medicine. "We are now doing more angiograms using CT and do not always need to use the traditional method of inserting a catheter. A CT angiogram requires no sedation, takes less time, and is less expensive; it is beginning to replace the conventional method."
An angiogram is performed to find blockages or abnormalities in the blood vessels and in some organs. It traditionally requires inserting a catheter through a small incision, usually made in the groin area, armpit, elbow or neck, and injecting a contrast dye into the catheter that helps make the vessel visible under X-ray. Using this method, an angiogram can take two hours or more. However, a multislice CT angiogram takes only about 10 minutes.
CT angiography is now used routinely to evaluate kidney transplant donors before the transplant to determine the health of the kidney and the number of blood vessels supplying it. CT angiography has been used to evaluate over 400 donors, and is part of a less invasive approach to kidney donation.
"This is a very exciting technology," says Dr. Mirvis. "The images are so clear we can reconstruct any hollow structure in the body, such as the esophagus, blood vessels or bowel, and can quickly see inside the structure to find potential problems. This is a dramatic improvement."
Multislice CT can also be used to screen for various cancers, more accurately determining whether the cancer has spread to other organs and can also be used to measure calcifications in the coronary arteries that could be early signs of cardiac blood vessel blockage.