Imaging the Misshapen Head

Imaging the Misshapen Head

David Nielsen, MDPediatric Radiologist


• Objective:

– Better understand how to image the most common causes of a misshapen head


• Common causes:– Macrocephaly– Microcephaly– Craniosynostosis– Posterior plagiocephaly



Macrocephaly• Definition:

– Macrocephaly = Macrocrania

Macrocephaly• Definition:

– Macrocephaly = Macrocrania

– Head circumference > 2SD (> 95%) above the mean for age, sex, race, and gestation

What is the most common imaging finding in

macrocephaly?

A. B. C. D.

0% 0%0%0%

A. HydrocephalusB. Benign Enlarged

Subarachnoid Spaces (BESS)

C. Subdural HematomaD. Intracranial Mass

Macrocephaly• Ddx:

– #1: Benign Enlarged Subarachnoid Spaces (BESS)

– Also called:• Benign macrocrania• Benign extra-axial

collections• Benign external

hydrocephalus• Transient communicating

hydrocephalus

NL

BESS

Macrocephaly

• Benign enlarged subarachnoid spaces– Clinical:

Macrocephaly


• Macrocephaly presents between 3-6 months and peaks at about 7 months

Macrocephaly



• May have family history of macrocephaly

Macrocephaly



• May have family history of macrocephaly• Normal developmental/neurological exam

Macrocephaly



• May have family history of macrocephaly• Normal developmental/neurological exam• Stabilizes by 18 months along a curve paralleling the

95% curve

Macrocephaly



• May have family history of macrocephaly• Normal developmental/neurological exam• Stabilizes by 18 months along a curve paralleling the

95% curve• Spontaneously resolves by 24-36 months

Macrocephaly

• Benign enlarged subarachnoid spaces– Imaging:

Macrocephaly


• Symmetrical enlargement over the frontoparietal convexities and within the interhemispheric fissure, cortical sulci, and sylvian fissures

Macrocephaly



• No mass effect

Macrocephaly



• No mass effect• Same imaging characteristics as CSF

Macrocephaly



• No mass effect• Same imaging characteristics as CSF• Cortical veins course through the fluid

Macrocephaly



• No mass effect• Same imaging characteristics as CSF• Cortical veins course through the fluid• Ventricles are normal or mildly enlarged

Cortical veins

Benign enlarged subarachnoid spaces

Macrocephaly

Macrocephaly


Cortical veins

Macrocephaly• Ddx:

– #1: Benign Enlarged Subarachnoid Spaces (BESS)

– Other:• Hydrocephalus (HC)• Subdural hematoma• Intracranial mass (rare)• Congenital/

syndromic/metabolic (rare)

Macrocephaly

Clinical Presentation & Fontanel/Age ImagingDevelopmentally normal with open fontanel (<6 mo)

Ultrasound

Developmentally normal with closed fontanel (>6 mo)

CT (or MRI)

Developmentally abnormal with open or closed fontanel

MRI

• Imaging is based on development and fontanel/age:

Macrocephaly

Clinical Presentation & Fontanel/Age ImagingDevelopmentally normal with open fontanel (<6 mo)

Ultrasound


CT (or MRI)


MRI

MacrocephalyClinical Presentation & Fontanel/Age ImagingDevelopmentally normal with open fontanel (<6 mo)

Ultrasound

• Normal neurological exam with open fontanel


Ultrasound

• Normal neurological exam with open fontanel– Short-term clinical follow-up with serial head

circumference measurements with or without ultrasound


Ultrasound


circumference measurements with or without ultrasound• If head stabilizes (i.e. measurements again parallel the normal

curve), the likely diagnosis is BESS:


Ultrasound



curve), the likely diagnosis is BESS:– No imaging (or no additional imaging) is recommended


Ultrasound




• If head continues to enlarge disproportionate to the child’s growth (i.e. measurements do not again parallel the normal curve) and clinical exam is still otherwise normal:


Ultrasound




• If head continues to enlarge disproportionate to the child’s growth (i.e. measurements do not again parallel the normal curve) and clinical exam is still otherwise normal:

– Ultrasound to screen for severe hydrocephalus or large mass


Macrocephaly

Macrocephaly

Choroid plexus papilloma


Ultrasound


CT (or MRI)


MRI


Ultrasound


CT (or MRI)• Normal neurological exam with closed fontanel


Ultrasound



– Case-by-case risk/benefit assessment of short-term clinical follow-up with serial head circumference measurements versus imaging with CT (radiation risk) or MRI (sedation risk)


Ultrasound



– Case-by-case risk/benefit assessment of short-term clinical follow-up with serial head circumference measurements versus imaging with CT (radiation risk) or MRI (sedation risk)

– Each modality also has advantages for the clinical question to be answered (e.g. CT is preferred for bones)

Macrocephaly


6 mo 11 mo

Macrocephaly

Pilocytic Astrocytoma

MRI - Benign enlarged subarachnoid spaces

Macrocephaly


Ultrasound


CT (or MRI)


MRI


Ultrasound


CT or MRI


MRI• Abnormal developmental/neurological exam with open or closed fontanel


Ultrasound


CT or MRI


MRI• Abnormal developmental/neurological exam with open or closed fontanel– MRI to evaluate brain parenchyma, extra-axial spaces

Macrocephaly

Non-communicating hydrocephalus

Macrocephaly

Anaplastic medulloblastoma


Ultrasound


CT (or MRI)


MRI• This approach to imaging macrocephaly reduces both unnecessary imaging and radiation exposure

References:Smith, MR, JC Leonidas, J Maytal. The Value of Head Ultrasound in Infants with Macrocephaly. Pediatric Radiology 1998; 28:143-146.Wilms G, Vanderschueren G, et al. CT and MR in infants with pericerebral collections and macrocephaly: benign enlargement of the subarachnoid spaces versus subdural collections. American Journal of Neuroradiology 1993; 14:855-860.Hudgins, R, Boydston WR. All Heads Great and Small, Macrocephaly. Children’s Healthcare of Atlanta. http://www.choa.org/default.aspx?id=921. Accessed June 15, 2008.

12-month-old male with macrocephaly and

developmental delay. What study is indicated?

A. B. C. D.

0% 0%0%0%

A. UltrasoundB. CTC. MRID. Brain PET scan





Microcephaly• Definition:

– Head circumference < 2SD (< 5%) below the mean for age, sex, race, and gestation

Microcephaly• Ddx:

– Congenital malformation

– Infection (TORCH)– Hypoxia-Ischemia – Old trauma– Toxic/Metabolic

Microcephaly• Clinical:

– Abnormal developmental or neurological exam

• Imaging:– MRI

Polymicrogyria





Craniosynostosis

• Definition:– Premature fusion of

cranial sutures• Synonyms:

– Craniostenosis, sutural synostosis, cranial dysostosis

• M:F = 3:1

Craniosynostosis

• Incidence: 3-5 cases per 10,000 live births– Sagittal – 56% (1/3600)

• Scaphocephaly

Craniosynostosis


• Scaphocephaly

Craniosynostosis


• Scaphocephaly– Coronal – 26% (1/7700)

• Brachycephaly

Craniosynostosis



• Brachycephaly

Craniosynostosis



• Brachycephaly– Metopic – 8% (1/25,000)

• Trigonocephaly

Craniosynostosis




• Trigonocephaly

Craniosynostosis




• Trigonocephaly– Lambdoid – 5% (1/40,000)

• Brachycephaly (bilateral) or Trapezoid skull (unilateral)

1

Craniosynostosis






– Other /syndromic – 5%

1






– Other /syndromic – 5%

1

Craniosynostosis

Posterior Plagiocephaly

• Posterior plagiocephaly:


• Posterior plagiocephaly:– Synonyms:

• positional plagiocephaly, deformational plagiocephaly, positional molding, postural flattening




– Commonly seen since “Back to Sleep” began in the 1990’s




– Commonly seen since “Back to Sleep” began in the 1990’s– Asymmetrical flattening of the posterior skull due to

recumbent/sleep position





recumbent/sleep position – Does not usually require imaging





recumbent/sleep position – Does not usually require imaging– Must distinguish from lambdoid synostosis

Otherwise normal child with posterolateral flattening

Normal sutures/positional plagiocephalySagittal Lambdoid Coronal




NL

Normal sutures/ positional

plagiocephaly

CraniosynostosisLambdoid synostosis

Craniosynostosis

Risk Category ImagingLow risk – developmentally normal and posterior or posterolateral flattening only

No imaging, or 4-view skull x-ray study

Intermediate risk – children who don’t clearly fit into the low or high risk group

Low-dose head CT

High risk – developmentally abnormal and/or obvious head deformity almost certainly needing surgery

Standard head CT with 3D reformations

• When imaging is required, it depends on the risk category as determined by history/physical:

Craniosynostosis




Low-dose head CT



• When imaging is required, it depends on the risk category as determined by history/physical:

CraniosynostosisRisk Category ImagingLow risk – developmentally normal and posterior or posterolateral flattening only


• Plain films:



• Plain films: • Lowest radiation dose



• Plain films: • Lowest radiation dose• Adequate screening for all craniosynostosis


Normal sutures/positional plagiocephalySagittal Lambdoid Coronal


Craniosynostosis




Low-dose head CT



Craniosynostosis




Low-dose head CT



CraniosynostosisRisk Category ImagingIntermediate risk – children who don’t clearly fit into the low or high risk group

Low-dose head CT

• Low-dose head CT:


Low-dose head CT

• Low-dose head CT: • ~80% less radiation than standard head CT


Low-dose head CT

• Low-dose head CT: • ~80% less radiation than standard head CT• Optimized for evaluation of the bones/sutures

Craniosynostosis – Intermediate Risk

Standard CT Low Dose CT

Standard CT Low Dose CT


Child with mild developmental delay and right

parieto-occiptal flattening

NLNormal sutures/ positional

plagiocephaly


Child with developmental delay and left posterior

flattening

Normal sutures/ posterior

plagiocephaly


NL


Low-dose head CT

• Low-dose head CT: • ~80% less radiation than standard head CT• Optimized for evaluation of the bones/sutures• Only at CMH

Why you send patients here!

Low Radiation CT at CMH

• Dedicated low-dose pediatric protocols for:– Paranasal sinuses– Scoliosis spines– Cranial dermoid cysts– Facial bones– Cleft palate– Etc.

Craniosynostosis




Low-dose head CT



Craniosynostosis




Low-dose head CT



CraniosynostosisRisk Category ImagingHigh risk – developmentally abnormal and/or obvious head deformity almost certainly needing surgery


• Standard head CT:



• Standard head CT: • Higher radiation dose




• Infants are significantly more affected by radiation (cancer risk)• Infants have a longer lifespan to manifest the effects (cancer risk)





• Use to evaluate skull and brain





• Use to evaluate skull and brain• Used by the surgeon for pre-surgical planning

• This is NOT a prerequisite for a plastic surgery consultation





• Use to evaluate skull and brain• Used by the surgeon for pre-surgical planning

• This is NOT a prerequisite for a plastic surgery consultation• Do not use as a screening exam for craniosynostosis

Craniosynostosis – High Risk

History: clinical exam suggesting coronal synostosis

NL


History: pre-operative coronal synostosis repair


History: pre-operative sagittal synostosis repair


History: pre-operative sagittal synostosis repair

3D Surface Rendering Max Intensity Projection Intracranial Superior View


History: pre-operative sagittal synostosis repair111111111111111111111111111111111111111111111111111111111111111111


History: pre-operative lambdoid synostosis repair

111111111111111111111111111111111111111111

NL

NL


No imaging, or 4-view skull (plain films)


Low-dose head CT



• This approach to imaging craniosynostosis and posterior plagiocephaly reduces both unnecessary imaging and radiation exposure

6-month-old infant with flat posterior skull & normal development. Which study is indicated?

A. B. C. D.

0% 0%0%0%

A. 3D CTB. MRIC. UltrasoundD. No imaging



Clinical Presentation & Fontanel/Age ImagingDevelopmentally normal with open fontanel (<6 mo) UltrasoundDevelopmentally normal with closed fontanel (>6 mo) CT (or MRI)Developmentally abnormal with open or closed fontanel

MRI

How to Image Macrocephaly:

How to Image Craniosynostosis/Posterior Plagiocephaly:





Low-dose head CT




MRI







Low-dose head CT




MRI







Low-dose head CT




MRI


• (






Low-dose head CT




MRI







Low-dose head CT


Standard head CT with 3D reformationsHow to Image Children in KC!

References1. Arch, Michael and Donald P. Frush. “Pediatric Body MDCT: A 5-year follow up survey of scanning

parameters used by Pediatric Radiologists.” AJR 2008; 191: 611-617.2. Brenner DJ, Hall EJ. Computed tomography: an increasing source of radiation exposure. N Engl J Med

2007; 357:2277-2284.3. Brenner, DJ Estimating cancer risks from pediatric CT: going from the qualitative to the quantitative.

Pediatric Radiology 2002: 32: 228-2314. Brenner DJ, Elliston CD, Hall EJ, and WE Berdon. Estimated risks of radiation-induced fatal cancer

from pediatric CT. AJR 2001;176: 289-296 5. Cohen, MM Jr. Epidemiology of Craniosynostosis. In: Cohen, MM Jr, ed Craniosynostosis:

diagnosis, evaluation, and management, 2nd ed. New York: Oxford University Press, 2000: 112-118.6. Goske MJ, et. al. The ‘Image Gently’ campaign: increasing CT radiation dose awareness through a

national education and awareness program. Pediatr Radiol 2008 38:265-269.7. The Image Gently Campaign: Working Together to Change Practice. AJR February 2007; 100:273-274.8. Lajeunie, E, Le Merrer, et al. Genetic study of nonsyndromic coronal craniosynostosis. Am J Med

Genet 1995; 55: 500-5049. Lee, CI, Haim, AH, Monico, EP et al. Diagnostic CT scans: assessment of patient, physician, and

radiologist awareness of radiation dose and possible risks. Radiology 2004; 231: 393-398.10. Medina, LS, R Richardson, and K Crone. Children with Suspected Craniosynostosis: A Cost

Effectiveness Analysis of Diagnostic Strategies. AJR 2002; 179: 215-221.11. “One size does not fit all: Reducing Risks from Pediatric CT” ACR Bulletin February 2001 57(2): 20-

23. 12. Slovis, Thomas L. Introduction to Seminar in Radiation Dose Reduction. Pediatric Radiology (2002)

32: 707-70813. Silvio Podda Craniosynostosis Management. E-medicine. Accessed 3/18/11

Thanks/Contributed:

Julianne Dean, MDTiffany Lewis, DO

Lisa Lowe, MDTrent Phan, DO

Cindy Taylor, MD

Documents

Imaging the Misshapen Head