Low-Dose MDCT ‘Better Option’ Than X-Rays For Imaging Children’s Sinuses

Low-dose MDCT of the sinuses in children is effective in diagnosing conditions such as sinusitis and middle ear fluid with a radiation dose comparable to standard x-rays. It also has more benefits, such as better accuracy, speed and a broader diagnosis potential, say researchers from Heilig Hart Hospital in Belgium.

For the study, the researchers compared the imaging results of 69 children who had undergone x-rays and 125 children who had undergone low-dose MDCT. They found that the mean effective radiation dose in x-rays was 0.0528 mSv and that the mean effective radiation dose for MDCT could be brought down to 0.0531 mSv without compromising diagnostic image quality.

According to the researchers, infections of the upper respiratory system are by far the most common cause of illness in infancy and childhood, accounting for approximately 50% of all illness in children younger than five years of age, and 30% in children between the ages of five and 12 years. “About 5 to 13% of these upper respiratory infections are complicated by sinusitis, so it is a common problem with children,” said Tom Mulkens, MD, lead author of the study.

According to the guidelines of the American College of Radiology, there is no need for imaging in children with uncomplicated acute sinusitis, but in children with a history of persistent, recurrent or chronic sinus disease imaging may be indicated. X-rays are frequently used for diagnosis of pediatric sinus problems because the physical examination can be difficult due to many other upper respiratory infections in children having the same physical symptoms, say the authors. However, using x-rays for this purpose is technically demanding. “Sinus x-rays in children are difficult both to perform and interpret. It’s hard to find the correct positioning, the children’s sinuses are small and there is an overall lack of accuracy, in addition to other complicating factors,” said Dr. Mulkens.

According to the researchers, MDCT offers a much better detailed image of the sinuses for diagnosis, but standard-dose CT imparts about ten times more radiation than x-rays. In the past, the child also had to lie completely still for a long time for good CT imaging, so the use of sedation was necessary. “With the advent of new technological developments, it is not only possible to substantially lower the radiation dose, but also to shorten the examination time to a factor of about eight to twenty, making sedation unnecessary,” said Dr. Mulkens.

Dr. Mulkens’ study also shows another advantage of the use of MDCT in these children. “MDCT displays the whole region of the ear, nose and throat in one examination, which is not possible with conventional x-ray radiographs. The presence of adenoid hypertrophy and fluid in the middle ears is frequently seen in children with recurrent upper respiratory infections and this can be diagnosed at the same time with the same low dose. Overall, in cases of persistent, recurrent and chronic sinus disease, we think low-dose MDCT is a better option than x-rays for the evaluation of sinus disease in children,” said Dr. Mulkens.

The study appears in the May 2005 issue of the American Journal of Roentgenology.