Transcript Case presentation

Case presentation
Sharon H. de Kock
August 2012
33yr female
 Referred with hx of numbness of 1st 2
digits of Rt hand, also focal convulsions
affecting the Rt corner of her mouth.
 According to pt she was healthy before
Feb ‘12.
 No other relevant hx/ illnesses.
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CLINICAL HISTORY
GCS 15/15
 Orientated to place, person, time.
 Higher functions in tact.
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CLINICAL EXAMINATION
CXR
 MRI of Brain & Spine
 Scintigram
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SPECIAL INVESTIGATIONS
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Multiple high signal nodules and mass on T1.
Involving the cerebrum and cerebellum.
Intra-axial.
Largest in Lt parietal region approx 3.5 x 4
cm axially & 4.5 cm cranio-caudally.
Largest in post fossa on Lt approx 1.3 cm CC
& 2 x 2.2 cm axially.
Spectroscopy of Lt large parietal mass:
lactate peak suggestive of necrosis/ infection,
no increased Ch/NAA ratios.
MRI FINDINGS
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Vasogenic oedema surrounding mass
cause mass effect on lat ventricle and
midline.
Basal cisterns patent.
Prominent post C enhancement.
Central necrosis.
GE: blooming artefact suggestive of
hemosiderin & chronic blood.
MRI FINDINGS cont.
No abnormal signal changes in the spinal
cord.
 Few high signal intensity lesions in the
vertebral bodies- T4, T11 & L4- ?fat.
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MRI FINDINGS cont. (spine)
Haemorrhagic mets.
 Meningeal melanotosis
 Neuro-cutaneous melanosis.
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DIFF DX
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No convincing evidence of skeletal mets.
SKELETAL SCINTIGRAM
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METASTATIC MALIGNANT MELANOMA
ANATOMICAL PATHOLOGY
T1 relaxation is the process of longitudinal
magnetization recovery after applying a
RFP/ excitation to invert the vector.
 Occurs as energy from the spinning nuclei
is dissipated into surrounding areas.
 Substances with intrinsic shorter T1
relaxation times demonstrate higher
signal intensity on T1WI.
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T1 PHYSICS
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Various natural occurring substances are
responsible- (reduce T1 relaxation time)
*methemoglobin, *melanin, * lipid,
*protein, *calcium, *iron, *copper and
*manganese.
HIGH SIGNAL INTENSITY ON
T1WI
CLASSIFICATION
CLASSIFICATION
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Physical Properties:
- MRI appearance of haemorrhages &
lesions containing blood depends on the
age of the blood.
- intracellular methemoglobin= early subacute phase haemorrhage, 3-7d after
onset.
- extracellular methemoglobin= late subacute phase, 8d-1mnth after onset.
METHEMOGLOBIN-CONTAINING
LESIONS
- produce T1 shortening effects.
- therefore have intrinsically high signal
intensity on T1WI.
- attributed to paramagnetic interactions.
METHEMOGLOBIN-CONTAINING
LESIONS, Physical Properties cont.
Cavernous Malformations:
- congenital/ acquired vascular anomalies.
- occur in approx. 0.5% of general
population.
 Cerebral Venous Thrombosis:
- unusual condition.
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METHEMOGLOBIN-CONTAINING
LESIONS
CAVERNOUS MALFORMATION
CEREBRAL VENOUS THROMBOSIS
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Physical Properties:
- demonstrate high signal intensity on
T1WI because of the paramagnetic
effects of stable free radicals and metal
scavenging effects.
MELANIN-CONTAINING LESIONS
Metastatic Melanoma:
- intracranial mets occur in nearly 40% of
pts with malignant melanoma.
- high signal intensity also can result from
haemorrhage within these lesions.
 Prim Diffuse Meningeal Melanomatosis:
- aggressive form of prim intracranial
melanoma, extremely rare.
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MELANIN-CONTAINING LESIONS
PRIMARY DIFFUSE MENINGEAL
MELANOMATOSIS
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Neurocutaneous Melanosis:
- uncommon congenital condition
characterized by multiple giant or hairy
nevi and melanin containing leptomeningeal lesions without evidence of
extracranial melanoma.
MELANIN-CONTAINING LESIONS,
cont.
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Physical Properties:
- short T1 relaxation time of hydrogen
nuclei within lipid molecules.
- produces high signal intensity on T1WI.
LIPID-CONTAINING LESIONS
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Intracranial Lipomas:
- rare congenital malformation.
- arise from abnormal differentiation of
the persistent primitive meninx.
- commonly occur in pericallosal region,
often associated with disgenesis or
agenesis of the corpus callosum.
LIPID-CONTAINING LESIONS
INTRACRANIAL LIPOMA
Teratomas:
- true neoplasms, usually contain tissue
derived from all three germ cell layers.
- mostly benign, malignant variants exist.
- most frequently found in the cerebral
hemispheres and pineal gland.
 Dermoid Cysts:
- rare, benign, congenital ectodermal
inclusion cysts, commonly in midline.
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LIPID-CONTAINING LESIONS,
cont.
PINEAL TERATOMA
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Physical Properties:
- high signal intensity of certain lesions on
T1WI can be attributed to their protein
content and the hydration layer effect.
PROTEIN-CONTAINING LESIONS
Colloid Cyst:
- uncommon benign intracranial lesions.
- contain gelatinous material.
- occur characteristically at the anterosuperior aspect of the 3rd ventricle.
 Rathke Cleft Cyst:
- common benign remnants of the Rathke
cleft, may be located in sellar-/ suprasellar compartment.
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PROTEIN-CONTAINING LESIONS
COLLOID CYST
RATHKE CLEFT CYST
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Physical Properties:
- Calcium is a diamagnatic substance that
may appear bright on T1WI.
- Other minerals that have T1 shortening
effects include manganese, copper and
iron.
MINERAL-CONTAINING LESIONS
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Hepatic Encephalopathy:
- characteristically manifests as bilateral
regions of high signal in the lentiform
nucleus and substantia nigra on T1WI.
- related to the accumulation of
manganese.
Wilson Disease:
- rare autosomal recessive condition.
- resultant abn copper metabolism & acc.
- basal ganglia & thalami commonly affected.
MINERAL-CONTAINING LESIONS
HEPATIC ENCEPHALOPATHY
WILSONS DISEASE
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Familiarity with substances and physical
properties that contribute to T1
shortening is helpfull to formulate an
appropriate Diff Dx.
TAKE HOME POINT
Could still not find the primary lesion.
 Referred to Oncology.
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OUR PT?
Intracranial Lesions with High Signal
Intensity on T1-weighted MR Images:
Differential Diagnosis, RadioGraphics
2012; 32:499-516.
 Grainger & Allison’s Diagnostic Radiology,
5th Edition, Volume 2.
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REFERENCES