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CT Scan

Should a CT scan be obtained?

Author, date, country, and industry of funding Patient Group Strength of Evidence (GRADE) Research design Significant results Limitations

(Hsieh et al., 2010)

USA

317 infant subjects (range 1-24 months) urban population

Low- It is a cohort study based on a clinical guideline.

Prospective cohort

EEG (all subjects) abnormalities were found in half

CT (298/317 obtained) abnormalities were found in a third

MRI (182/ 317 obtained) abnormalities were found in 57%

Of the 193 normal CTs, 97 underwent MRI of which 32 (33%) had an abnormal MRI

The majority had more than one seizure upon presentation.

The incidence of seizures lasting longer than 20 minutes was 8.5%

30 subjects had a history of prematurity.

Increased likelihood of obtaining an MRI in younger infants.

 

Kodaphanhadeh 2006 Iran

125 subjects, children mean age 53 ±48 months (range-

1 month-15 years)

Low

Retrospective case series –no control group. Excluded those with seizures > 30 minutes or electrolyte abnormalities

Report on CT scan and MRI within the first hours of arrival

Neuro-imaging was obtained in 119 subjects (95%)

Emergent CT was performed in 108 (91%) and MRI in 11 (9%)

Neuro-imaging was normal in 107 (90%) of subjects.

Clinical significant results were found in 12 subjects (10%)

10 of the 12 subjects with abnormal findings had abnormal neurological examination.

 

Study design.

Sharma 2003 USA

500 subjects with new-onset afebrile seizure median age (16 mo range (0-21 years))

Low

Retrospective

Neuro-imaging was performed in 475/500. 25 subjects were not imaged.

Of the subjects who were scanned, CT was performed in 454/475, and MRI was performed in 21/475.

437/475 had neuro-imaging while in the ED. And 13 had neuro-imaging after the ED visit but within 72 hours of the visit.

Normal imaging results were reported in 395/475 subjects. [83%]

Clinically insignificant results were reported in 42/475 [9%]

Clinically significant events were reported in 38/475 subjects [8%]

Using Partition analysis, 3 variables partitioned the subjects into 4 groups

Variables

Presence of pre disposing condition, focality of the seizure and age

Groups

Predisposing condition- High risk

No predisposing condition

Non-focal seizure- low risk

Focal seizure- age dependent

Age > 33 months low risk

Age < 33 months high risk

5/6 subjects who fell in the low risk group by partition analysis had abnormal findings on physical/neurological exam.

One subject subsequently diagnosed with grey matter heterotopias had a normal physical and neurological exam.

Retrospective design

 

These guidelines do not establish a standard of care to be followed in every case. It is recognized that each case is different and those individuals involved in providing health care are expected to use their judgment in determining what is in the best interests of the patient based on the circumstances existing at the time. It is impossible to anticipate all possible situations that may exist and to prepare guidelines for each. Accordingly these guidelines should guide care with the understanding that departures from them may be required at times.