Correspondence

Three-Dimensional CT Diagnosis of Maxillofacial Trauma

N Engl J Med 1994; 330:69January 6, 1994

Article

To the Editor:

The “Three-Dimensional CT Diagnosis of Maxillofacial Trauma” (Images in Clinical Medicine, July 8 issue)1 contains remarkable pictures. At first I thought they were a Steven Spielberg creation. They surely represent the technological wizardry of American medicine. Unfortunately, this image does not tell the entire story.

It is clear that technological advances have fueled increases in health care costs. Although it is unlikely that we will ever shy away from new forms of technology, their inappropriate use arouses greater concern than do their costs.

These reconstructed computed tomographic (CT) images are appealing. I could not help but be drawn to them. If I were a medical student, they would certainly make me think about pursuing a career in diagnostic radiology. However, there is no mention either of their cost or of whether they are any more helpful in diagnosis than a plain radiograph, a simple CT scan, or even physical diagnosis. Even in medicine, what we learn can be influenced by the presentation of incomplete information.

Howard Bauchner, M.D.
Boston University School of Medicine, Boston, MA 02118

1 References

1. 1

   Fox LA. Three-dimensional CT diagnosis of maxillofacial trauma. N Engl J Med 1993;329:102-102
   Full Text | Web of Science | Medline

To the Editor:

The CT scans entitled “Three-Dimensional CT Diagnosis of Maxillofacial Trauma” actually reveal a more extensive injury than is described. The patient has not only a fractured zygoma, but also a minimally displaced heminasoethmoidal orbital fracture, with fracture lines extending across the piriform buttress and the lower maxilla on the right and through the medial portion of the orbit. These fractures are barely visible on the axial images shown in Panel A and Panel B and actually are seen most clearly in Panel C and Panel E.

Paul N. Manson, M.D.
Maryland Institute for Emergency Medical Services Systems, Baltimore, MD 21201

Author/Editor Response

The authors reply:

To the Editor: CT scans are the standard of care for skull fractures, since physical examination and plain radiography have been shown to be inadequate for the study of many correctable abnormalities1. The relative diagnostic performance of three-dimensional CT-scan reconstructions in the evaluation of complex facial fractures is less well established. The scans reproduced in the Journal were created on a Sun Workstation with Analyze software2. Similar software was available with the CT scanner located in the emergency room where the patient was examined. The cost of the software used in the three-dimensional reconstruction was approximately $20,000 (list price). This scanner has performed about 20,000 scans in the past five years. Perhaps 3 to 5 percent of examinations involve subsequent processing, and one sheet of film (costing about $5) is used for each three-dimensional study. Processing of data on the CT console has become a routine procedure. The marginal cost (an extra 5 to 10 percent, we estimate) of adding a three-dimensional reconstruction is small in terms of the total cost of the examination.

The benefit to patients and the cost effectiveness of a three-dimensional display are difficult to isolate and measure. CT scanners are expensive capital items with high costs, both fixed and variable3. Improvements that make their results more useful or convenient may provide benefits that can justify their use in selected institutions. Three-dimensional CT reconstructions are a prime example. The resulting images have been shown to provide improved diagnostic performance as compared with conventional imaging methods in certain applications4. Anatomical information is displayed in a form that is familiar and consistent with the clinician's everyday experience.

Dr. Manson is correct. The caption to the image concentrated on the most obvious component of the fractures and used the case to illustrate the classic “tripod” fracture.

Lee A. Fox, B.S.
Michael W. Vannier, M.D.
Ronald G. Evens, M.D.
Washington University School of Medicine, St. Louis, MO 63110

4 References

1. 1

   Kuhns LR, Thornbury JR, Fryback DG. Decision making in imaging. Chicago: Year Book, 1989:673-7.
   

2. 2

   Robb RA, Barillot C. Interactive display and analysis of 3-D medical images. IEEE Trans Med Imag 1989;8:217-226
   CrossRef | Web of Science | Medline

3. 3

   Evens RG. The economics of computed tomography: comparison with other health care costs. Radiology 1980;136:509-510
   Web of Science | Medline

4. 4

   Gillespie JE, Gholkar A, Isherwood I. Three-dimensional computed tomographic reformations: assessment of clinical efficacy. In: Udupa JK, Herman GT, eds. 3D imaging in medicine. Boca Raton, Fla.: CRC Press, 1991:104-43.
   

Citing Articles (2)

Citing Articles

1. 1

   J. Hoffmann, F. Dammann, S. Reinert. (2002) INITIAL EXPERIENCE WITH INTRAOPERATIVE COMPUTED TOMOGRAPHY IN MAXILLOFACIAL SURGERY. Biomedizinische Technik/Biomedical Engineering 47:s1a, 470-473
   CrossRef

2. 2

   James T. Rhea, Patrick M. Rao, Robert A. Novelline. (1999) HELICAL CT AND THREE-DIMENSIONAL CT OF FACIAL AND ORBITAL INJURY. Radiologic Clinics of North America 37:3, 489-513
   CrossRef