Dr. John is Associate Professor of Radiology and Chief of the
Pediatric Radiology Section at the University of Texas Medical
School in Houston, TX. She is also a member of the editorial
advisory board of this journal.
U
ltrasound has developed into one of the most convenient and
versatile imaging tools available today, and in no area has it
gained greater popularity than in pediatrics. The non-intimidating
appearance of the equipment combined with the obvious advantages of
rapid scanning and lack of concern about ionizing radiation make it
a perfect tool for many pediatric applications. I confess that I
have developed a passion for ultrasound that compels me to try to
use it whenever possible. However, our increasingly cost-conscious
healthcare system requires us to critically analyze the expenses
incurred in obtaining radiologic diagnoses. Duplication of studies
to obtain a diagnosis is discouraged, requiring more careful
assessment of the circumstances under which various imaging
procedures are recommended.
One of the areas in pediatric imaging that has seen the most
controversy regarding the use of ultrasound is gastrointestinal
sonography. The gastrointestinal tract was once considered an area
of relative inaccessibility to the ultrasound beam, but improved
techniques and high-resolution technology have expanded the
opportunities to use ultrasound in this area in children. In my
practice, ultrasound has nearly completely replaced computed
tomography and contrast studies for the diagnosis of conditions
such as hypertrophic pyloric stenosis and appendicitis, and it is
used as a screening tool for intussusception and abdominal masses.
However, my enthusiasm for ultrasound is not shared by all
radiologists, and a considerable difference of opinion remains
concerning the optimal choice of imaging studies for such
conditions.
In view of these controversies, perhaps a versatile tool such as
ultrasound requires more flexible policies concerning both its use
and reimbursement for such use. For this purpose, ultrasound
studies can be grouped into three general categories: 1) screening
ultrasounds, which usually will be followed by other imaging
studies when positive findings are encountered (e.g., abdominal
masses, intussusception), 2) sonography to provide specific
additional information after a diagnosis has been made with another
type of study (e.g., to evaluate for urethral obstruction in a
child with Crohn's disease), and 3) ultrasound that can stand alone
as a substitute for other imaging studies (e.g., appendicitis).
Studies of the latter two types are easily justified, but many of
the disagreements about the use of ultrasound revolve around its
value as a screening tool.
An imaging study is most useful to screen for a condition if the
sensitivity is sufficiently high to preclude the need for
additional studies when the findings are negative. Intussusception
and hypertrophic pyloric stenosis are examples of conditions which
can be diagnosed with a high degree of accuracy by ultrasound.
1-3
An ultrasound which reveals no intussusception obviates the need
for contrast enema, to the great relief of the patient. However,
some radiologists argue that ultrasound becomes a superfluous study
when positive for intussusception because the nearly inevitable
enema reduction procedure that follows can also provide the
diagnosis. The opposite argument has been made for ultrasound of
hypertrophic pyloric stenosis, which is highly accurate when
positive, but which some researchers feel must be followed by
additional studies to look for other conditions when negative.
4
One possible solution to the dilemma is to establish protocols for
the use of ultrasound in these conditions, based on a clinical risk
assessment.
5
Children at low to moderate risk for intussusception or at high
risk for hypertrophic pyloric stenosis seem to benefit more from
screening ultrasonography because additional studies do not need to
be performed in such cases. As for the problem of added cost, it
may be worthwhile to employ limited ultrasound examinations for
minor costs in those instances when additional studies are
required. Alternatively, clinical problem-based charges could be
developed (e.g., "intussusception workup" or "gastric outlet
obstruction/reflux studies") that would allow the radiologist to
use ultrasound when needed without incurring additional charges.
The ultimate goal of such policies is to allow the radiologist more
flexibility in determining the types of examinations that will
provide the best information and outcome for each individual
patient.
Recent studies have addressed the impact of ultrasound on the
efficient and effective management of certain conditions, such as
abdominal pain.
6,7
More research is needed to assess the effects of sonography on the
short-term and long-term outcome in such conditions in children. On
a practical basis, until such information is available, we must
individually assess our practice patterns and the level of
confidence which we and our referring physicians afford to
sonographic diagnosis for these gastrointestinal conditions in
infants and children. In a physician's hands, ultrasound is a
powerful tool with benefits that are undoubtedly yet to be fully
discovered. We should continue to find creative ways to support the
use of ultrasound for pediatric diagnoses whenever possible.
References
1. Shanbhogue RLK, Hussain SM, Meradji M, et al:
Ultrasonography is accurate enough for the diagnosis of
intussusception. J Pediatr Surg 29(2):324-328, 1994.
2. John SD:
The value of ultrasound in children with suspected intussusception.
Emerg Radiol 5(5):297-305, 1998.
3. Hernanz-Schulman M, Sells L, Ambrosino MM, et
al:
Hypertrophic pyloric stenosis in the infant without a palpable
olive: Accuracy of sonographic diagnosis. Radiology 193:771-776,
1994.
4. Olson AD, Hernandez R, Hirschl RB:
The role of ultrasonography in the diagnosis of pyloric stenosis: A
decision analysis. J Pediatr Surg 33(5):676-681, 1998.
5. Bhisitkul DM, Shkolnik A, Donaldson JS, et al:
Clinical application of ultrasonography in the diagnosis of
intussusception. J Pediatr 121(8):182-186, 1992.
6. Carrico CW, Fenton LZ, Taylor GA, et al:
Impact of sonography on the diagnosis and treatment of acute lower
abdominal pain in children and young adults. AJR 172(2):513-516,
1999.
7. Chen EA, Luks FI, Gilchrist BF, et al:
Pyloric stenosis in the age of ultrasonography: Fading skills,
better patients? J Pediatr Surg 31(6):829-830, 1996.