The introduction of thrombolytic therapies capable of reversing the ischaemic injury has changed the neuroi-maging protocols, leading to the use of MR also in the emergency workup of these patients. Recent technological advances in hardware (magnet, gradients, coils) and software (ultrafast sequences, post-processing) allow morphological and functional studies to be performed with very short times of acquisition. In clinical practice, functional studies are increasingly being performed in combination with standard MR imaging: DWI and PWI enable identification of the ischaemic area and discrimination of irreversibly damaged tissue from tissue that can respond to treatment instituted in the very first hours from the event [3-5].
After CT has ruled out a haemorrhagic stroke, the current emergency neuroradiological protocol envisages a DWI and PWI study directed mainly at planning treatment. Selection of thrombolysis candidates requires morphological evaluation of the vascular district; this is why in the hyperacute phase the MR study may require angiographic (MRA) sequences for aetio-pathogenic investigations. In the chronic phase, when the patient's clinical condition has become stable, the neuroradiological protocol envisages a more detailed standard MR study and an MRA investigation to assess outcome and response to therapy.
The hyperacute-phase MR study consists at least of axial T1 sequences, axial FLAIR, DWI, 2D PC MRA (because it is faster than 3D TOF, which only depicts the large vessels of the circle of Willis) and, if a fibrinolytic treatment is envisaged, PWI sequences.
When the patient's condition has become stable, a spectroscopic study can be performed to establish lesion extension and prognosis, while possible recovery and final lesion extension can be investigated with higher-definition morphological and 3D TOF MRA sequences.
Was this article helpful?