Assessment of post-thrombectomy brain hemorrhage in acute ischemic stroke with dual-energy CT: how reliable is it in clinical practice?

PURPOSE: Acute ischemic stroke is currently among the main causes of mortality in Western countries. The current guidelines suggest different flowcharts of diagnostic work-up and treatment modalities, including endovascular thrombectomy. Immediately after intra-arterial recanalization, a brain CT scan is usually performed to assess for the presence of peri-procedural complications; in this setting, it is very hard, if possible, to differentiate blood from iodinated contrast material, which is normally present in ischemic tissue because of BBB disruption. Dual-energy CT may be used for this purpose, exploiting its ability to discriminate different materials. MATERIALS AND METHODS: We retrospectively studied 44 patients with acute ischemic stroke who were treated with endovascular recanalization at San Giovanni Bosco Hospital in Turin and were then scanned with DECT technology. Subsequent scan was used as standard, since iodine from contrast staining is usually reabsorbed in 24 h and blood persists longer. A χ2 test of independence was performed to examine the relationship between blood detected by DECT scan after the endovascular procedure and the presence of blood in the same areas on the following scans, with a significant result: χ2 (1, N = 37) = 10.7086, p = 0.0010. RESULTS: Patients with blood detected on DECT scans had a double chance of having hemorrhagic infarction in follow-up scans, (RR 2.02). The sensitivity and specificity of DECT were respectively 70% and 90%, with an overall diagnostic accuracy of 76% and a positive and negative predictive value, respectively, of 95% and 53%. CONCLUSION: Dual-energy CT scan after endovascular recanalization in ischemic stroke identifies early hemorrhagic infarction with excellent specificity and good overall diagnostic accuracy, representing a reliable diagnostic tool in everyday clinical practice.

Cerebral white matter Hyperintensities in HIV-positive patients.

White matter hyperintensities (WMHs) have been associated with neurological complications including cognitive impairment. WMHs have been often described in HIV positive subjects and they have been linked to neurocognitive impairment, cerebrospinal fluid (CSF) residual viral replication and biomarkers of monocyte activation. Aim of this study was to grade WMHs in HIV-positive individuals using a simple visual scale and to explore their severity with clinical, neurocognitive and biomarker characteristics. Brain MRIs were retrospectively evaluated by two reviewers who rated WMHs following the "age-related white matter changes (ARWMC)" scale. 107 adult HIV-positive patients receiving lumbar punctures for clinical reasons were included. 70 patients (66.6%) were diagnosed with WMHs. Average WMH scores were higher in treated [7 (1-11)] vs. naïve individuals [3 (0-6)] (p = 0.008). Higher WHMs scores were observed in patients with chronic renal impairment along with chronic hepatitis (naïve) and longer HIV duration (treated participants). No consistent associations between plasma, CSF biomarkers and WMHs scores were found. 45 patients underwent full neurocognitive tests and WMHs scores were non-significantly higher in patients diagnosed with HAND [6.5 (0.5-8.3) vs. 1.5 (0-7), p = 0.165]; screening (IHDS and FAB), visuo-spatial (Corsi's) and auditory-verbal memory (disillabic words repetition) tests scored worse in patients with higher WMHs. In our population of HIV-positive patients with low CD4 nadir and partial CD4 cell recovery the burden of WMHs was associated with the duration of HIV infection and with commonly observed comorbidities (such as renal and hepatic impairment). Given the association with worse neurocognition, further studies on tailored interventions are needed.

Cytomegalovirus central nervous system compartmentalization in a patient presenting with AIDS.

Cytomegalovirus (CMV) central nervous system involvement is uncommon and hardly diagnosed because it can mimic many different conditions. We here present a case of an HIV-positive patient with neurological signs and symptoms (headache, asthenia, confusion, hallucinations, ataxia) with concurrent opportunistic diseases (neurotoxoplasmosis, disseminated Kaposi's sarcoma, disseminated CMV infection). CMV CNS involvement was not initially considered given the observed multiple comorbidities: antiviral treatment duration was probably not adequate given the end-organ disease. Concomitantly, plasma CMV DNA was undetectable while cerebrospinal fluid viral load was 31,340 copies/ml. Ganciclovir treatment followed by oral valganciclovir maintenance was associated with the slow disappearance of symptoms, the improvement of MRI images and the persistent undetectability of CMV DNA. The case here reported highlights the challenges of diagnosing CMV encephalitis in HIV-positive patients (with several cerebral comorbidities), the incomplete knowledge of the appropriate treatment for such a disease and the possibility of CMV replication in the cerebrospinal fluid despite undetectable plasma CMV DNA.