Evaluation of Blunt Abdominal Trauma Using PACS-Based 2D and 3D MDCT Reformations of the Lumbar Spine and Pelvis

Brian C. Lucey; Joshua W. Stuhlfaut; Aaron R. Hochberg; Jose C. Varghese; Jorge A. Soto

Disclosures

Am J Roentgenol. 2005;185(6):1435-1440. 

In This Article

Discussion

MDCT with multiplanar reconstructions and 3D reconstructions exquisitely delineates the extent of injury and yields a certainty in diagnosis when evaluating the lumbar spine and pelvis after blunt abdominal trauma.[12,13,14] The widespread availability of MDCT has removed many of the difficulties associated with lumbar spine and pelvis evaluation using incremental CT scanners. There has been little debate in deciding that CT is superior to radiography in the evaluation of the spine in the trauma patient.[5,6,7,8,9,10,11,12,13,14]

The difficulties faced by abdominopelvic CT in replacing radiography for evaluating the lumbar spine stem primarily from the days of incremental CT scanners. These scanners would usually obtain slices through the abdomen up to 8 mm in thickness. Although this was often sufficient to identify lumbar spine fractures, precise evaluation of the fractures was difficult, particularly in deciding whether bone fragments impinged on the spinal canal or if bone fragments were present in the hip joint. In addition, multiplanar reconstructions were unsatisfactory with such thick slices. As a result, trauma and orthopedic surgeons have traditionally requested repeat CT scans through areas of known or suspected fractures seen on the abdominal CT scans obtained using thin slices, often on the order of 2 mm in thickness.[16]

With the widespread use of MDCT in the evaluation of trauma patients, thin slice images are routinely obtained resulting in a large data set that is ideally suited to multiplanar reconstruction and 3D reconstruction. The reconstruction interval used is frequently smaller than the 2-mm slices previously requested by the trauma and orthopedic surgeons. This obviates repeat dedicated thin-slice CT through the region of interest. As can be seen from our results, 10 patients had a repeat CT examination of an area of the lumbar spine for further evaluation of a lumbar spine fracture found on the abdominal CT scan. None of these images depicted new diagnostic information. In addition, 12 patients had repeat dedicated pelvic CT examinations, none of which yielded new diagnostic information. As a result, we no longer perform repeat thin-slice CT through the lumbar spine or pelvis for this purpose alone.

One often touted disadvantage to performing multiplanar and 3D reconstructions routinely is the time element that is traditionally associated with it.[17,18,19] In most institutions, MDCT data must be sent to a dedicated 3D workstation so that these reconstructions can be performed. Given the large size of the data sets, this may take considerable time. In addition to the time taken for data transfer, the dedicated 3D workstation is not always located close to the CT interpretation workstation in the emergency department. This places an added inconvenience to using multiplanar reconstructions and 3D reconstructions.

At our institution, the ability to perform reconstructions is built in to our software at the CT interpretation workstations. This means that there is no increased delay while sending images to a separate workstation. The availability of multiplanar reconstruction and 3D reconstructions is also one mouse click away. The MDCT data from abdominal CT can be converted into coronal and sagittal views of the lumbar spine in approximately 15-20 sec. This results in the ability to evaluate the lumbar spine and pelvis rapidly purely on basis of the CT data derived from abdominal CT, which in turn enables faster decision making by the trauma team regarding patient management.

Evaluating the lumbar spine on the basis of abdominal CT data when managing a patient in the setting of major trauma saves time in many ways. First, removing the necessity for obtaining conventional radiographs eliminates the time taken to obtain adequate images of the lumbar spine. Repeated attempts to obtain satisfactory imaging are eliminated because there is an increased certainty of diagnosis with CT. Time is also saved later by eliminating the requirement for dedicated lumbar spine CT. The patient may also be removed from spinal precautions once the spine has been cleared. If this can be done immediately, the patient benefits from increased comfort and staff do not have as much to fear from patient manipulation. There is the added benefit of decreasing the overall radiation dose to the patient by eliminating the requirement for radiography and dedicated CT. This is helpful because many major trauma patients are in the younger age group.

Another consideration to removing the requirement for radiography and repeat CT comes in the form of health care cost reduction. In the current environment of fiscal rectitude, any alteration to the health care algorithms that may lead to a reduction in overall health care cost is welcome. Although we did not perform an analysis of cost for this study, the overall savings would result from performing 22 fewer dedicated CT examinations, 83 lumbar spine series (74 initial and nine repeat), 28 repeat pelvic conventional radiography examinations, and 67 three-view pelvic series.

In conclusion, multiplanar reconstruction and 3D reconstruction of MDCT data of the abdomen and pelvis in patients with blunt abdominal trauma is sufficient to obviate performing radiography of the lumbar spine. Dedicated thin-collimation CT of the lumbar spine or pelvis is no longer necessary. This saves radiation exposure, cost, technician and radiologist time, and, most importantly, time for the trauma team in the management of critically ill patients.

Comments

3090D553-9492-4563-8681-AD288FA52ACE

processing....