Case presentation. Sharon H. de Kock August 2012. 33yr female Referred with hx of numbness of 1 st 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. CLINICAL HISTORY.
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Sharon H. de Kock
Vasogenic oedema surrounding mass cause mass effect on lat ventricle and midline.
T1 relaxation is the process of longitudinal magnetization recovery after applying a RFP/ excitation to invert the vector.
Various natural occurring substances are responsible- (reduce T1 relaxation time)
*methemoglobin, *melanin, * lipid, *protein, *calcium, *iron, *copper and *manganese.HIGH SIGNAL INTENSITY ON T1WI
- MRI appearance of haemorrhages &
lesions containing blood depends on the
age of the blood.
- intracellular methemoglobin= early sub-
acute phase haemorrhage, 3-7d after
- extracellular methemoglobin= late sub-
acute phase, 8d-1mnth after onset.METHEMOGLOBIN-CONTAINING LESIONS
- therefore have intrinsically high signal
intensity on T1WI.
- attributed to paramagnetic interactions.METHEMOGLOBIN-CONTAINING LESIONS, Physical Properties cont.
- 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.
- rare, benign, congenital ectodermal
inclusion cysts, commonly in midline.LIPID-CONTAINING LESIONS, cont.
- uncommon benign intracranial lesions.
- contain gelatinous material.
- occur characteristically at the antero-
superior aspect of the 3rd ventricle.
- common benign remnants of the Rathke
cleft, may be located in sellar-/ supra-
sellar compartment.PROTEIN-CONTAINING LESIONS
- characteristically manifests as bilateral
regions of high signal in the lentiform
nucleus and substantianigra on T1WI.
- related to the accumulation of
- rare autosomal recessive condition.
- resultant abn copper metabolism & acc.
- basal ganglia & thalami commonly affected.MINERAL-CONTAINING LESIONS
Familiarity with substances and physical properties that contribute to T1 shortening is helpfull to formulate an appropriate Diff Dx.TAKE HOME POINT
Intracranial Lesions with High Signal Intensity on T1-weighted MR Images: Differential Diagnosis, RadioGraphics 2012; 32:499-516.