Diagnostic Imaging of Intracranial Tumors in Adultseradiology.bidmc.harvard.edu/LearningLab/central/Hill.pdfDiagnostic Imaging of Intracranial Tumors in Adults ... cystic contents)

Brook J Hill, HMS/HST IVGillian Lieberman, MD

Diagnostic Imaging of Intracranial Tumors in Adults

Brook J Hill, Harvard Medical School, Year IVGillian Lieberman, MD, Beth Israel Deaconess

Hospital and Harvard Medical School

July 2003

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Patient P.W.

• P.W. is a 63 year-old female who complains of 1 month of progressive headache and confusion. She also reports constantly misplacing objects, increasing forgetfulness, feeling very tired, and “leaning to the left” while walking.

• Physical exam: Slight left facial droop; LEU finger-to-nose and rapid alternating movements abnormal; unsteady tandem gait with lean to left. Otherwise normal.

• Head CT at an OSH revealed a right frontal mass.

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Indications for Imaging

• Signs and/or symptoms suggestive of intracranial neoplasm:– PROGRESSIVE neurologic dysfunction– New onset seizures (or change in character)– Signs/symptoms of elevated intracranial

pressure (ICP)– Known systemic tumor with possible

intracranial metastasis

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Focal vs. General Signs/Sx

• Focal:– Focal seizures (25-50%)– Weakness– Sensory abnormalities– Gait changes– Speech disturbances– Visual defects

• General:– Papilledema (59%) – Generalized convulsions

(25-50%) – Headache (50%) – Mental changes– Nausea and vomiting– Signs/Sx of herniation

Focal signs/sx are caused by localized brain damage, while general signs/sx are caused by elevated ICP.

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Mental Changes Associated with Intracranial Tumors

• Psychomotor retardation– Impersistence in routine tasks– Inertia– Reduction in the range of mental

activity – Reduced initiative and spontaneity– Blunted affect

• Sleep disturbances– Insomnia– Early rising– Excessive daytime sleepiness

• Cognitive disturbances– Forgetfulness– Lack of concentration

– Language disorders– Concreteness– Faulty insight– Frank dementia

• Social disturbances– Disheveled appearance– Inappropriate behavior– Loss of inhibitions– Indifference to social practices

• "Psychological" symptoms– Depression– Hypomania– Euphoria– Emotional lability

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Menu of Tests Available

• MRI• CT• SPECT• PET• X-Ray

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MRI

• First-line diagnostic test for imaging of suspected intracranial tumors

• Multiplanar, high resolution, high contrast

• Standard protocols: T1, T2, proton density (PD)

• Advanced protocols: FLAIR, DSC, others

Sagittal

Axial

Coronal

Images from PACS,

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CT• Generally not recommended

to diagnose or follow intracranial tumors

• Single plane (axial)• Lower resolution than MRI• Less soft-tissue contrast• However, CT is the first-line

test for suspected intracranial hemorrhage

BIDMC, PACS

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MRI vs. CT

• Greater soft tissue contrast (e.g. white vs. grey matter)

• More sensitive to soft tissue abnormalities (i.e. can detect small differences in water content)

• Smaller amount of contrast needed• Better tumor characterization (e.g. subacute vs.

chronic hematomas, vascular lesions, cystic contents)

• Multiplanar imaging• Lack of beam hardening artifact near bony

structures • No ionizing radiation• Compatible with orthopedic implants, vascular

clips excluding aneurysm clips, dental fillings, and ventricular shunts

• Superior visualization of bony/calcific structures

• More rapid image acquisition• Easier monitoring of acutely ill

patients• Compatible with pacemakers,

ferromagnetic aneurysm clips, intraocular foreign bodies, and virtually all prostheses

• Better tolerated by claustrophobic patients

Benefits of MRI: Benefits of CT:

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SPECT• Single Photon Emission Computed Tomography• A multislice nuclear medicine study - “Brain scan”• 99mTc-hexamethyl-propylenamine-oxime (99mTc-HMPAO) • Provides functional information about regional cerebral blood

flow (rCBF), which helps: – determine tumor burden both before and after surgery– distinguish between viable tumor, necrosis, and edema after

surgical resection• Also used in dementia, cerebrovascular disease, epilepsy, encephalitis,

and trauma• Readily available, relatively inexpensive, and well-tolerated• Limitations:

– Inherently poorer resolution than PET, CT, and MRI – Absolute quantification of blood flow is not possible– Involves ionizing radiation

www.bae.ncsu.edu

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PET• Positron Emission Tomography• Also a multislice nuclear medicine study• Blood flow, oxygen uptake, and glucose consumption• Provides functional information about the metabolic profile of

tumors, enabling the radiologist to:– estimate aggressiveness of tumors (correlates with metabolic

activity) – distinguish viable recurrent tumor from radiation necrosis

after surgical resection• Better spatial resolution than SPECT• Limitations:

– Poor spatial resolution compared to CT and MRI – Expensive and therefore not universally available– Involves ionizing radiation

www.epub.org.br

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X-Ray

• “Historical” test for intracranial tumors, but common findings still important:– Erosion of dorsum sellae (elevated ICP)– “J-shaped” sella (chronic hydrocephalus)– Tumor calcification– Cranial vault erosion– Enlargement of middle meningeal groove (e.g.

meningioma)

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X-Ray: Erosion of Dorsum SellaeNormal Sella: Elevated ICP:

• Erosion into cancellous bone (white arrow) underlying sella

• Erosion of lamina dura (ld) of dorsum sellae (ds), often the earliest bony change with elevated ICP

Images adapted from Grainger & Allison's Diagnostic Radiology: A Textbook of Medical Imaging, 4th Ed., Copyright © 2001 Churchill Livingstone, Inc.

• Sella can reossify and remodel upon relief of elevated ICP

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X-Ray: “J-Shaped” SellaNormal Sella: Chronic Hydrocephalus:

Images adapted from Grainger & Allison's Diagnostic Radiology: A Textbook of Medical Imaging, 4th Ed., Copyright © 2001 Churchill Livingstone, Inc.

• Truncated dorsum sellae (ds)

• Large anterior clinoid process (acp)

• Deep sulcus chiasmaticus (sc)

• J-shape caused by direct pressure form dilated third ventricle

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X-Ray: Tumor Calcification

http://www.pathology.vcu.edu

• Tumors that often calcify:• Craniopharyngioma (40-80%)• Meningioma (15%)• Glioma (10-15%) • Lipoma

• Physiologic calcification:• Pineal (50%)• Choroid (50%)• Dura • Arachnoid granulations• Basal ganglia• Corotid arteries

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X-Ray: Tumor Calcification• Expansile radiolucent mass in sella tursica (open arrows)

• Dystrophic soft-tissue calcification

• Tissue diagnosis = Craniopharyngioma

• Erosion of dorsum sellae

http://www.pathology.vcu.edu

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X-Ray: Cranial Vault Erosion

• PATHOLOGIC TUMORS:– Epidermoid cyst, hamangioma, eosinic granuloma, multiple myeloma– Metastases (virtually always LYTIC in the skull, even if sclerotic

elsewhere in the body)• BENIGN CHANGES:

– Venous lakes, enlarged parietal foramina, parietal thinning • OTHERS:

– Pagets, osteomyelitis, leptomeningeal cyst

Meningioma, however, typically causes increased bone density due to trophic effects on the inner table.

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MRI (MP RAGE) with Gadolinium Contrast:

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Describing the Lesion

• Size and Shape• Location• Number• Density• Enhancement• Edema• Mass Effect

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Describing the Lesion: Location

• Intra-axial vs. Extra-axial:– Intra-axial = within the brain parenchyma– Extra-axial = outside the brain parenchyma– Step #1 in differentiating intracranial tumors– Not always possible to differentiate

• Supratentorial vs. Infratentorial:– Supratentorial = above the tentorium cerebelli– Infratentorial = below the tentorium cerebelli

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Describing the Lesion: Density

• CT: – Compare attenuation of lesion with

that of surrounding normal parenchyma (25-40 HU)

– Higher attenuation = cells (30-60 HU), hemorrhage (85 HU if acute), calcification

– Lower attenuation = fluid (0 HU if CSF), fat (-100 HU)

• MRI:– Compare signal intensity on

T1, T2 etc. with normal parenchyma

– T1:• High signal = adipose,

proteinacous fluid, contrast, low flow

• Low signal = bone, calcifications, fluid, air, high flow

– T2:• High signal = fluid,

hemorrhage, low flow• Low signal = bone,

calcifications, air, high flow

Because tumor often is the same attenuation as normal parenchyma, many tumors are missed on CT.

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Describing the Lesion: Enhancement

• Compare images taken before contrast administration with those taken after contrast administration

• “Nonenhancing, Homogenous, Ring, Heterogenous, Serpentine”• Normal blood-brain barrier (BBB) does NOT allow passage of iodine

or gadolinium contrast• BBB breakdown can be seen in infarction, infection, abscess,

neoplasia, and trauma• Neovascularity can be seen in tumor, infarction, infection

In general, malignant tumors enhance; benign tumors do not.

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Describing the Lesion: Edema and Mass Effect

• Edema Pattern:– “Vasogenic, ischemic, cytotoxic,

periventricular interstitial”• Mass Effect:

– Midline shift– Herniation (uncal, transtentorial, etc.)

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Patient P.W. – MRI Findings • 4 x 4.5 cm solitary mass

• Irregular border

• Right frontal lobe (intra-axial)

• Low signal core (necrosis)

• Heterogenous, ring

enhancement

• Vasogenic edema pattern

• Mild midline shiftPACS, BIDMC

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Patient P.W. – MRI Findings

PACS, BIDMC

• DDx (imaging alone):– Glioblastoma multiforme– Anaplastic astrocytoma– Metastatic tumor– Lymphoma– Tuberculoma– Abscess

• DDx (imaging + history):– Glioblastoma multiforme– Anaplastic astrocytoma– Metastatic tumor– Lymphoma

• Treatment = surgical excision

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All Images from PACS, BIDMC

Pre-Op:

POD #194

POD #83:Post-Op Day (POD) #1:

• T1, no gadolinium

• POD #1: tumor bed with high signal (acute hematoma + Surgicel)

• POD #83: tumor bed with low signal (resolving hematoma)

• POD #194: tumor bed enlarged with mixed signal (fluid + Gliadel wafers s/p second excision)

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Pre-Op:

POD #194POD #139

POD #83:POD #1:

• T1 + gadolinium

• POD #83: linear enhancement surrounding region of XRT (radiation necrosis); 2 x 2 cm heterogenously enhancing mass anteromedial to original tumor bed (recurrent tumor)

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Pre-Op:

POD #194POD #139

POD #83:POD #1:

• POD #139 (1 Day s/p resection of recurrent tumor): tumor bed with areas of no signal (air) and heterogenous signal (Gliadel wafers + Surgicel + blood)

• POD #194: Gliadel wafers; enhancing tumor bed margins with no signs of recurrence

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Pre-Op:

POD #194POD #139

POD #83:POD #1:

• T2

• POD #1: extensive vasogenic edema surrounding tumor bed

• POD #83: vasogenic edema of anterior right frontal lobe surrounding site of recurrent tumor

• POD #194: fluid-filled resection site with no surrounding edema

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FLAIR MRI• Fluid Attenuated Inversion Recovery

• Heavily T2 weighted

• CSF signal is nulled by sampling the MR image at an appropriate time after magnetization inversion, when longitudinal magnetization of CSF is zero

• Similar to STIR, except used for CSF instead of fat

• Allows better characterization of lesions adjacent to CSF-filled structures

• Clinically useful in several situations:– Intraxial brain tumors: differentiation between tumor and edema

– Tumor follow-up: identification of residual tumor at the resection margin

– Acute subarachnoid hemorrhage, Herpes encephalitis, Tuberous sclerosis, Mesial temporal sclerosis

• Limited by inability to fully suppress CSF signal when contaminated by blood/protein

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Pre-Op:

POD #194POD #139

POD #83:

• FLAIR MRI

• POD #83: Increased signal in tumor bed and region overlying resection site (fluid + blood/protein) as well as anterior frontal white matter (edema)

• POD #139: Heterogenous signal in tumor bed immediately post-op with persistent surrounding edema

• POD #194: High signal in tumor bed (fluid + blood/protein); white matter edema resolved

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DSC MRI• Dynamic Susceptibility Contrast-Enhanced MRI• A.K.A. “Susceptibility” MRI• Uses gradient echo or echo planar imaging techniques to enable measurement

of regional cerebral blood volume and regional cerebral blood flow• Provides functional information in addition to structural information• Multiple clinical uses in brain tumors:

– Provides additional information about the microvascular structure of gliomas (flow and permeability properties)

– Noninvasively grade gliomas

– Determine optimal biopsy sites

– Distinguish radiation necrosis from tumor regrowth

– Plan and follow irradiation, chemotherapy, and antiangiogenic therapy

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Pre-Op:

POD #194POD #139

POD #83:POD #1:

• DSC MRI

• POD #1: High signal in resection site (blood) with peripheral areas of very low signal (Surgicel)

• POD #83: Persistent high signal in resection site

• POD #139: Heterogenous, but mainly very low signal in resection site (mostly Surgicel + Gliadel with some blood)

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POD #194:POD #83:

T1:

2x2 cm low signal lesion in the left insular cortex.

No visible lesions.

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POD #194:POD #83:

T1 + gadolinium:POD #139:

No visible lesions. 2x2 cm heterogenously enhancing lesion in left insular cortex (recurrent tumor).

No visible lesions.

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POD #194:POD #83:

T2:POD #139:

2x2 cm region of increased signal in left insular cortex.

8x8 mm region of increased signal in left insular cortex.


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POD #194:POD #83:

FLAIR:POD #139:




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POD #194:POD #83:

DSC:POD #139:


Subtle 10x10 mm region of increased signal in left insular cortex.

Barely visible 8x8 mm region of increased signal in left insular cortex.

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MRI vs. CTFLAIR MRI (POD #139): CT (POD #150):

Images from PACS, BIDMC


No visible lesions.

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Summary• Indications for intracranial imaging:

– Progressive neurologic dysfunction, Seizures, Elevated ICP, Known cancer with possibility of metastases

• Tests available: – MRI, CT, SPECT, PET, X-ray

• MRI is first-line test• SPECT and PET are functional studies and are good for follow-up• Describing the lesion:

– Size, Shape, Location, Number, Density, Enhancement, Edema, Mass Effect• FLAIR MRI: Nulls CSF signal, allowing better characterization of lesions

adjacent to or within CSF– Excellent for early detection of recurrent tumor

• DSC MRI: Provides functional information about regional blood volume and regional blood flow

– Allows noninvasive grading of gliomas

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Acknowledgements

• Dr. Gillian Lieberman• Dr. Steve Reddy• Pamela Lepkowski• Larry Barbaras• Atara, Becca, Brian, Dave, Heather, Raj, Sarah, Suzie,

Taylor, Tim, and Wynn

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Cha S, Johnson G, Wadghiri YZ, Jin O, Babb J, Zagzag D, Turnbull DH. Dynamic, contrast-enhanced perfusion MRI in mouse gliomas: Correlation with histopathology. Magn Reson Med 2003 May;49(5):848-55.

Essig M. Fast fluid-attenuated inversion recovery (FLAIR) MR imaging in the assessment of intraxial brain tumors. J Magn Reson Imag 1998;8:789-798.

Essig M. Contrast optimization of fluid-attenuated inversion-recovery (FLAIR) MR imaging in patients with high CSF blood or protein content. Magn Reson Med - 01-May-2000; 43(5): 764-7.

Essig M, Wenz F, Scholdei R, Bruning R, Berchtenbreiter C, Meurer M, Knopp MV. Dynamic susceptibility contrast-enhanced echo-planar imaging of cerebral gliomas: effect of contrast medium extravasation. Acta Radiol 2002;43:354-359.

Goetz CG, Pappert EJ. Textbook of Clinical Neurology. Philadelphia: Saunders, 1999.Hammoud DA, Belden CJ, Ho AC, Dal Pan GJ, Herskovits EH, Hilt DC, Brem H, Pomper MG. The surgical bed after BCNU polymer

wafer placement for recurrent glioma: serial assessment on CT and MR imaging. AJR Am J Roentgenol 2003 May;180(5):1469-75.Jackson A, Jayson GC, Li KL, Zhu XP, Checkley DR, Tessier JJ, Waterton JC. Reproducibility of quantitative dynamic contrast-

enhanced MRI in newly presenting glioma. Br J Radiol 2003 Mar;76(903):153-62.Jacobs AH, Winkler A, Dittmar C, Gossman A, Deckert M, Kracht L, Thiel A, Garlip G, Hilker R, Sobesky J, Vollmar S,

Kummer C, Graf R, Voges J, Wienhard K, Herholz K, Heiss WD. Molecular and functional imaging technology for the development of efficient treatment strategies for gliomas. Technol Cancer Res Treat 2002 Jun;1(3):187-204.

Latchaw RE, ed. MR and CT imaging of the Head, Neck, and Spine, 2nd ed. St Louis: Mosby, 1991. Li KL, Zhu XP, Checkley DR, Tessier JJ, Hillier VF, Waterton JC, Jackson A. Simultaneous mapping of blood volume and endothelial

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Rydberg JN, et al. Initial clinical experience in MR imaging of the brain with a fast fluid-attenuated inversion-recovery pulse sequence. Radiology 1994;193:173-180.

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Documents

Diagnostic Imaging of Intracranial Tumors in Adultseradiology.bidmc.harvard.edu/LearningLab/central/Hill.pdfDiagnostic Imaging of Intracranial Tumors in Adults ... cystic contents)