Aims and objectives
Brainstem lesions pose a significant diagnostic challenge,
having a wide differential diagnosis on conventional MRI.
Multiparametric MRI can increase diagnostic confidence by accurately differentiating between neoplastic,
inflammatory or vascular lesions,
avoiding the need for invasive biopsy which carries a significant morbidity/mortality risk.
We demonstrate the utility of multiparametric MRI in diagnosing brainstem pathology.
Methods and materials
We performed a retrospective review of four patients with brainstem lesions who presented between 2015-2016 at the Queen Elizabeth Hospital Birmingham,
a tertiary neurosciences centre.
Definitive diagnosis (inflammatory vs.
neoplastic) was not established through conventional imaging.
All patients underwent multiparametric MRI on a 3T scanner consisting of T1/T2-weighted structural imaging,
dynamic susceptibility contrast perfusion imaging,
diffusion weighted imaging and single/multivoxel MR spectroscopy.
The choline:creatine (Cho:Cr) peak area ratio was calculated and correlations between rCBV ratio,
ADC,
Cho:Cr and radiological/clinical follow-up were recorded.
Results
Case 1
A previously well 20 year-old presented in August 2016 with acute ataxia,
slurred speech,
deafness and visual disturbance following recent travel.
On examination there was a complex ophthalmoplegia,
horizontal nystagmus,
sensorineural deafness,
cerebellar signs and spastic limbs.
Conventional MRI suggested a diagnosis of low grade brainstem glioma .
The oncologist recommended radiotherapy given the large infiltrative lesion.
Multiparametric MRI was performed; findings were not consistent with low grade glioma due to normal MI/Cr and the glutamine shoulder,
neither were they consistent with high...
Conclusion
Distinction between inflammatory and neoplastic aetiology is not always possible using conventional MRI.
Multiparametric MRI was more helpful than individual MRI features and reduced diagnostic uncertainty,
potentially avoiding the need for invasive biopsy.
The key features distinguishing inflammatory lesions from low-grade neoplasm were the raised glutamine and glutamate peaks,
normal MI/Cr and peripheral low diffusion.
Where tissue diagnosis is essential,
multiparametric MRI can help identify optimal biopsy targets.
Clinical/laboratory findings along with careful interpretation of multiparametric MRI can aid in establishing an accurate diagnosis.
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