Pial Enhancement



Pial Enhancement


Yoshimi Anzai, MD, MPH

Judy Tan, MD



DIFFERENTIAL DIAGNOSIS


Common



  • Meningitis


  • Metastases, Meningeal


  • Cerebral Infarction, Subacute


  • Neurosarcoid


Less Common



  • Vasculitis


  • Glioblastoma Multiforme


  • Sturge-Weber Syndrome


  • Moyamoya


Rare but Important



  • Wegener Granulomatosis, Brain


  • Lyme Disease


  • Dural A-V Fistula


  • Meningioangiomatosis


  • Neurocutaneous Melanosis


ESSENTIAL INFORMATION


Key Differential Diagnosis Issues



  • Pia is innermost layer of leptomeninges which covers brain & invaginates into sulci


  • Enhancement is typically related to infectious/inflammatory, vascular or neoplastic processes


  • Differentiate infectious & noninfectious processes to narrow differential


Helpful Clues for Common Diagnoses



  • Meningitis



    • Typical signs & symptoms of infection: Fever, neck stiffness, increased WBC


    • Can be divided into pyogenic, lymphocytic & chronic meningitis


    • TB, fungal meningitis often basilar & confluent


    • FLAIR MR: Sulcal hyperintensity


    • Normal enhanced brain MR does not exclude meningitis (clinical diagnosis)


  • Metastases, Meningeal



    • Nodular or mass-like leptomeningeal enhancement typical


    • Common primary tumors include breast, lung, melanoma & lymphoma


    • Primary tumor often known


  • Cerebral Infarction, Subacute



    • May see enhancement in late acute or early subacute infarct


    • Gyriform enhancement in a vascular territory typical



      • Associated with wedged-shaped area of T2/FLAIR hyperintensity


  • Neurosarcoid



    • Pial enhancement often associated with dural mass(es)



      • Predilection for basal cisterns


    • Parenchymal disease & leptomeningeal disease (approximately 1/3 each)


    • Facial nerve palsy & other cranial neuropathies common


    • Review CXR to look for bilateral symmetrical hilar lymphadenopathy


Helpful Clues for Less Common Diagnoses



  • Vasculitis



    • Heterogeneous group of CNS disorders characterized by nonatheromatous inflammation & necrosis of vessel walls


    • In addition to pial enhancement, may see T2 hyperintensities, hemorrhage &/or restricted diffusion


    • DSA/CTA: Alternating stenosis & dilatation primarily 2nd & 3rd order branches


  • Glioblastoma Multiforme



    • May cause focal or diffuse pial enhancement in addition to primary enhancing mass



      • Related to primary extension of tumor or metastases


  • Sturge-Weber Syndrome



    • Enhancement related to pial angiomatosis: Unilateral 80%, bilateral 20%


    • Cortical Ca++, atrophy, & enlarged ipsilateral choroid plexus


    • Occipital, parietal & frontal/temporal lobes


  • Moyamoya



    • Idiopathic progressive arteriopathy of childhood


    • Progressive narrowing of distal ICA & proximal circle of Willis vessels with secondary collateralization


    • Cloud-like lenticulostriate & thalamostriate collaterals on angiography


    • Lenticulostriate collaterals: Enhancing “dots” in basal ganglia & “net-like” thin vessels in basal cisterns


    • FLAIR: “Ivy sign”: Slow-flowing engorged pial vessels, thickened arachnoid


    • Leptomeningeal enhancement (contrast-enhanced “ivy sign”)



Helpful Clues for Rare Diagnoses

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Aug 7, 2016 | Posted by in NEUROLOGY | Comments Off on Pial Enhancement

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