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Pediatric Imaging |
1 From the Department of Radiology, Duke University Medical Center, Durham, NC. Received August 27, 1999; revision requested October 11; revision received October 27; accepted November 2. Address correspondence to L.F.D., Department of Radiology, Children's Hospital Medical Center, 3333 Burnet Ave, Cincinnati, OH 45229-3039 (e-mail: DONNELLY.LF@CHMCC.ORG).
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Abstract |
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 TOP Abstract IntroductionMATERIALS AND METHODSRESULTSDISCUSSIONReferences |
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MATERIALS AND METHODS: The number of children who required sedation to undergo body CT with a multisection helical scanner was recorded. The authors noted the type of examination and whether contrast material was used. The children were categorized according to age (
17 years, 6 years, 1 year).
RESULTS: In 219 CT examinations, only three children required sedation (1.4%). The sedation rate was 3% (three of 90) for children aged 6 years or younger and 8% (three of 37) for those aged 1 year or younger. Examinations were of the chest, abdomen, and pelvis in 68 patients, of the abdomen and pelvis in 112, and of the chest alone in 39. Contrast material was intravenously administered in 186 (85%) examinations. All scans were of diagnostic quality.
CONCLUSION: The rate of sedation was reduced threefold with multisection helical CT compared with standard helical CT, and the need for sedation was eliminated in some age groups.
Index terms: Anesthesia, **.992 • Computed tomography (CT), helical, **.12115, **.99 • Computed tomography (CT), in infants and children, **.12115, **.99
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Introduction |
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TOPAbstractIntroductionMATERIALS AND METHODSRESULTSDISCUSSIONReferences |
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Since CT became available about 25 years ago, it has quickly established and consistently played an important role in pediatric imaging. The long acquisition times of single-section nonhelical CT was the reason for sedation in 18% of all pediatric patients younger than 5 years who required sedation to allow for optimal imaging (1). With the advent of helical CT in the 1990s, the sedation rate was reduced to 10% because of faster scanning times (1). The recent availability of subsecond multisection CT scanners has again decreased the amount of time necessary to acquire image data. It has been suggested that with multisection helical CT, the need for sedation will be even further decreased (6). The rate of sedation in children of all ages (0–17 years) during single-section helical body CT at our institution has been 8% (7). We performed this study to evaluate the need for sedation during pediatric CT performed with multisection helical technology.
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MATERIALS AND METHODS |
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TOPAbstractIntroductionMATERIALS AND METHODSRESULTSDISCUSSIONReferences |
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In each case, the attending pediatric radiologist determined the need for sedation with input from the sedation nurses, CT technologists, patient and/or family, and primary health care provider. The need for sedation was assessed in the patient preparation area before the patient entered the CT scanning room to not delay the CT schedule. Depending on patient age and size, various methods and degrees of immobilization were used. For infants and small children, immobilization in the form of a papoose of blankets and adhesive tape was used when necessary. Coaching and encouragement by both staff and parents was often used.
The multisection helical CT technique varied with the patient size, body part being imaged, and indication for imaging. Section thickness ranged from 3.75 to 7.50 mm, table speed was typically 11.25 mm per gantry rotation, and gantry rotation was 0.8 second. The kilovolt peak was typically 120–140, and the milliamperage ranged from 80 to 180. Scanning duration was dependent on the length of the region being imaged. Patients who received intravenous contrast material received 2 mL of nonionic contrast material per kilogram of body weight by means of either manual injection (in cases where central venous catheters were used as the site of injection) or power injection at a rate of 2 mL/sec.
In our department, CT examinations are repeated if scans are not of diagnostic quality. Records were reviewed for any repeat examination. Records of any sedated patients were also reviewed for examinations originally performed without sedation but repeated later with sedation.
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RESULTS |
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TOPAbstractIntroductionMATERIALS AND METHODSRESULTSDISCUSSIONReferences |
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The mean patient age was 8 years (range, 2 months to 17 years). Thirty-seven patients were aged 1 year or younger (mean age, 8 months; age range, 2–12 months). Of these 37 patients, eight were aged 0 to 6 months and 29 were aged 7–12 months. Ninety patients ranged in age from 2 months to 6 years (mean age, 3 years).
Three patients required sedation, for a sedation rate of 1.4%. Two of the patients who required sedation were 11 months old, and one was 12 months old. Thus, the sedation rate was 3.3% for children aged 6 years or younger (n = 90) and 8.1% for those aged 1 year or younger (n = 37).
Clinical indications for performing CT in the sedated patients included neuroblastoma, abscess, or tyrosinemia. All three of these patients were extremely agitated before being placed on the CT scanner and were believed to be unlikely candidates for successful imaging without sedation. Of the three sedated patients, two underwent studies of the abdomen and pelvis and one underwent a study of the chest, abdomen, and pelvis. All three of the sedated patients received intravenous contrast material. The two 11-month-old patients received oral chloral hydrate, and the 12-month-old patient received intravenous pentobarbital sodium.
All CT scans were considered to be of diagnostic quality by the pediatric radiologist interpreting the images. None of the CT scans obtained without sedation were believed to be suboptimal; therefore, none of those examinations were repeated with sedation.
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DISCUSSION |
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TOPAbstractIntroductionMATERIALS AND METHODSRESULTSDISCUSSIONReferences |
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In contrast, CT scanners are now available with multidetector array technology, which allows for multivolume data collection from each complete gantry rotation (10–12). This technology refers to a special CT system equipped with a multiple-row detector array (in our institution, a four-section–per–rotation scanner), as opposed to a single-row detector array. It allows for simultaneous scanning of multiple volumes at different locations along the z axis, which results in rapid table speeds and the opportunity to greatly increase the speed of data acquisition. Using this technology, one can achieve z-axis resolution that is similar or superior to that of the single-row detector array helical scanner with a greater range of anatomic coverage and a shorter total acquisition time (10–12). The duration of scanning has been reportedly reduced three- to fivefold (12).
In our experience, this faster data acquisition with the multisection technique has resulted in a decrease in the frequency of examinations requiring sedation. For the patients in the 0–6-year age group, the rate changed from 10% with helical single-section CT scanners (1) to 3.3% with the multidetector array CT scanner. Other investigators (2) have demonstrated a reduction in the sedation rate from 86% with conventional CT to 57% with helical CT in infants aged 1 year or younger. Our results from the same age group demonstrate a reduction to 8.1% (n = 37) with use of multisection technology. For pediatric patients of all ages (0–17 years), our previous rate of sedation for body imaging was 8% (7). This has decreased to 1.4% with multisection helical CT.
The frequencies of sedation for CT from different studies are compared in the Table. The differences between sedation rates for young patients within studies performed at different institutions may reflect the patient populations. The study by Kaste et al (2), in which young patients had a 32% sedation rate for single-section helical CT, was performed at a cancer center. In contrast, White's study (1), in which young patients had a sedation rate of 18%, was performed at a general pediatric hospital. Regardless, all study findings we know of show a decrease in rates of sedation when faster CT scanners are used.
In the present study, we did not need to sedate any patients aged 2–6 years, an age group that has frequently required sedation when single-section helical CT is performed (2). The benefits of reducing the need for or obviating sedation in any age group are multiple and include less risk to the child, decreased parental anxiety, increased patient throughput, and decreased cost—including decreased need for sedatives and personnel. Drug administration and patient monitoring during sedation and recovery require personnel time. In addition to savings related to a decrease in the amount of sedatives, savings can be related to more efficient use of staff. A CT nurse responsible for caring for a sedated pediatric patient and monitoring his or her condition for 1–4 hours is unable to perform other department tasks.
This study had several limitations. One limitation was that the total number of examinations performed with our multisection scanner was relatively low compared with the number of examinations performed by others with a single-section helical technique (1,2). The relatively small number of patients was due to the facts that this scanner has been in place for only 11 months at our institution and that pediatric patients are randomly scanned with one of our five scanners. Because sedation rates have decreased with this new scanner, efforts are being made to use this scanner for all body CT examinations in patients aged 0–6 years. Finally, in this study we did not specifically document differences in image quality and artifacts. Qualitatively, however, the interpreting pediatric radiologists did not notice a difference from the conventional helical technique, and all scans were of diagnostic quality. There was no increase in motion-related artifacts, and no repeat examinations were needed.
In summary, the introduction of multisection helical technology provided a threefold decrease in the sedation rate in young children compared with the rate for single-section helical CT. In addition, the need for sedation in patients older than 1 year was totally eliminated. As scanning times continue to decrease with improvements in CT technology, we can expect a further reduction in the need for sedation in pediatric patients.
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Footnotes |
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Author contributions: Guarantors of integrity of entire study, J.N.P., L.F.D.; study concepts and design, J.N.P., L.F.D., D.P.F.; definition of intellectual content, J.N.P., L.F.D., D.P.F.; literature research, J.N.P., L.F.D., D.P.F.; clinical studies, J.N.P., L.F.D., D.P.F.; data acquisition, J.N.P.; data analysis, J.N.P., L.F.D., D.P.F.; manuscript preparation, J.N.P.; manuscript editing and review, J.N.P., L.F.D., D.P.F.
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References |
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