Rabinstein AA. Treatment of Acute Ischemic Stroke. Continuum (Minneap Minn). 2017;23(1, Cerebrovascular Disease):62-81. doi:10.1212/CON.0000000000000420.
This is an excellent and comprehensive review of current acute stroke treatment. The three main principles of acute stroke care are: (1) achieve timely recanalization of the occluded artery and reperfusion of the ischemic tissue, (2) optimize collateral flow, and (3) avoid secondary brain injury. The author states there is incontrovertible evidence that IV thrombolysis with rtPA and endovascular thrombectomy with a retrievable stent improve neurologic outcomes in patients with acute ischemic stroke. Both treatments should be administered as quickly as possible after stroke onset, can be combined, and are safe in appropriately selected candidates. IV thrombolysis with rtPA is proven to be effective in improving functional outcomes after an ischemic stroke up to 4.5 hours after symptom onset. IV rtPA infused within 3 hours of symptom onset increases the chances of functional independence at 3 months by one-third. The benefit is time dependent and much stronger when the drug is administered within the first 90 minutes after symptom onset.
Regarding mechanical thrombectomy, the six positive trials shared the requirement of CT angiograms for patient screening (only patients with documented internal carotid artery or proximal middle cerebral artery occlusions could be entered into the studies), emphasized the importance of prompt intervention, and almost exclusively used retrievable stents to achieve reperfusion. All of the trials enrolled patients with severe neurologic deficits and good prestroke functional status who presented mostly within 6 hours of symptom onset. Major early ischemic changes on the baseline CT scan were a reason for exclusion. Patients treated with mechanical thrombectomy had high rates of reperfusion and much better functional outcomes at 90 days. Mechanical thrombectomy was also proven to be quite safe, with a pooled rate of …
Elshafeey N, Hassan I, Zinn PO, Colen RR. From K-space to Nucleotide. Top Magn Reson Imaging. 2017;26(1):1. doi:10.1097/RMR.0000000000000114.
Radiogenomics is a relatively new field within radiology that links different imaging features with diverse genomic events. Genomics advances provided by the Cancer Genome Atlas and the Human Genome Project have enabled researchers to harness and integrate this information with noninvasive imaging phenotypes to create a better 3-dimensional understanding of tumor behavior and biology. This review summarizes the radiogenomic literature regarding brain tumors, both glioblastoma and lower grades.
As you know, the typical gross appearance of glioblastoma on MR is characterized as an irregular, ring-enhancing tumor with a central necrotic core and surrounding area of FLAIR hyperintensity. Each of these 3 imaging components (aka. phenotypes) of the tumor reflect a distinct tumor biology such as neovascularization and active tumor [contrast-enhancing component], edema/invasion (peritumoral T2/FLAIR hyperintensity), or cell death (necrosis). As an example of the potential power of volumetric features of glioblastoma on prognosis, in a cohort of 78 patients glioblastoma tumor volumes were quantified and combined with patient age and Karnofsky performance score (KPS) to create an easy-to-use 3-step scoring system VAK (Volume-Age, KPS) that can predict patient outcome.
Additionally, specific genomic and epigenetic events have shown a predilection for specific locations within the brain. As background, MGMT, a gene that encodes for a DNA repair enzyme, is associated with a better survival in those patients with MGMT promoter methylation receiving alkylating agents such as temozolomide. In treatment-naive glioblastoma patients, it has been found that patients with unmethylated O-6- methylguanine-DNA methyltransferase (MGMT) promoter predominated in the right temporal lobe. Glioblastoma with MGMT promoter methylation, EGFR amplification, and EGFRvIII mutations tended to occur in in the left temporal lobe. Most IDH1-mutated and intact PTEN tumors were in the frontal lobe.
3 tables, …