Frontal Sagittal Diameter Measurement by Computed Tomography (Scout Image)
This test measures the distance across the front part of your head from front to back (the frontal sagittal diameter) using a CT scan scout image. It is a measurement taken before or during a CT scan to assess head size and shape.
["The frontal sagittal diameter is a head measurement obtained from a CT scan that helps your care team evaluate skull and brain structure."]
Key facts at a glance
- LOINC
- 96917-0
- Short code
- CT Avg diam frontal scout
- Synonyms
- CT Avg diam frontal scout
- Category
- chemistry
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- ct
- Specimen volume
- 5 mL
- Stability
- Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
- Hemolysis max
- 500
- Lipemia max
- 1000
- Icterus max
- 500
- TAT
- 4–24 hours
- Order
- routine
What Is Being Measured
The frontal sagittal diameter is the distance from the front (anterior) to the back (posterior) of the upper part of your skull. It is one of several head measurements used to describe the size and shape of the head. This value is captured from a scout image, which is a quick overview picture taken at the start of a CT scan.
How the Measurement Is Obtained
You do not need to do anything special for this measurement. During a CT scan, a scout image is taken first to help plan the scan; this image is also used to record head dimensions. The measurement itself is done by the technologist or by software from that image, so it adds no extra steps for you.
Why Your Care Team May Order It
Head diameter measurements can help evaluate head shape, growth, or the size of the skull and brain spaces. They may be used when a child's head size or shape is a concern, or to compare your measurements over time. The specific reason will depend on your health history and your provider's assessment.
What the Results Mean
Your provider will interpret the measurement alongside your symptoms, other imaging, and any earlier measurements. A single value is rarely meaningful on its own. Because normal values vary with age and body size, ask your care team to explain what your result means for you.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Head diameter measurements can support the evaluation of conditions that affect skull shape or size, such as craniosynostosis or abnormal head growth, and can help monitor changes over time. The frontal sagittal diameter is one of several dimensions your provider may combine with other findings, so it should be interpreted in context rather than as a standalone diagnosis.
Frequently asked questions
Is this measurement painful?
Do I need to prepare in any way?
Will I get a number to compare with normal values?
Sources
- 1
- 2Lab Tests OnlineSource
- 3
Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.
This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.
This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.
If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.
Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy