Anatomical variants of anterior communicating artery complex. A study by Computerized Tomographic Angiography.

Advances in imaging techniques have led to the identification of normal variations and abnormalities of cerebral arteries. Although the anterior communicating artery complex (ACAC) variations are usually asymptomatic, their description is essential in the radiologic report, since they can have clinical relevance. The aim of this study is to describe arterial anomalies of the ACAC and their prevalence. A retrospective observational descriptive analysis of ACAC variations in Computerized Tomographic Angiography (CTA) was performed. All CTA (426 studies) obtained in our center from 2015 to 2017 were included. Presence of aneurysm was recorded and its relationship with arterial variants was analyzed with a Chi-square test. The most common variants found in our study are linked to the A1 segment (42.3%) of the anterior cerebral artery (ACA): absence: 10.6%, hypoplasia: 31.2%, fenestration: 0.5%. A2 segment variants were present in 15.3% (absence: 0.2%; hypoplasia 8.5%; Azygos artery: 1.4%; triple ACA: 5.2%). Anterior Communicanting Artery was typical in 92.5%, absent in 4.7%, double/fenestrated in 0.9%, triple in 0.2%, X-shape in 1.2% and Y-shape in 0.2%. Aneurysms were present in 10.7%. Anterior circulation aneurysm involved the 50% of patients with aneurysm. Although the 60.9% of them showed artery variants, they did not reach statistical significance (p = 0.6). In conclusion, the Anterior Communicating Artery Complex presents variations in its anatomy. The most common anterior circulation vascular variants are the hypoplasia and the absence of the A1 segment. There does not appear to be a clear association between intracranial aneurysms and anatomical variations.

Early Detection of Hyperprogressive Disease in Non-Small Cell Lung Cancer by Monitoring of Systemic T Cell Dynamics.

Hyperprogressive disease (HPD) is an adverse outcome of immunotherapy consisting of an acceleration of tumor growth associated with prompt clinical deterioration. The definitions based on radiological evaluation present important technical limitations. No biomarkers have been identified yet. In this study, 70 metastatic NSCLC patients treated with anti-PD-1/PD-L1 immunotherapy after progression to platinum-based therapy were prospectively studied. Samples from peripheral blood were obtained before the first (baseline) and second cycles of treatment. Peripheral blood mononuclear cells (PBMCs) were isolated and differentiation stages of CD4 lymphocytes quantified by flow cytometry and correlated with HPD as identified with radiological criteria. A strong expansion of highly differentiated CD28- CD4 T lymphocytes (CD4 THD) between the first and second cycle of therapy was observed in HPD patients. After normalizing, the proportion of posttreatment/pretreatment CD4 THD was significantly higher in HPD when compared with the rest of patients (median 1.525 vs. 0.990; p = 0.0007), and also when stratifying by HPD, non-HPD progressors, and responders (1.525, 1.000 and 0.9700 respectively; p = 0.0025). A cut-off value of 1.3 identified HPD with 82% specificity and 70% sensitivity. An increase of CD28- CD4 T lymphocytes ≥ 1.3 (CD4 THD burst) was significantly associated with HPD (p = 0.008). The tumor growth ratio (TGR) was significantly higher in patients with expansion of CD4 THD burst compared to the rest of patients (median 2.67 vs. 0.86, p = 0.0049), and also when considering only progressors (median 2.67 vs. 1.03, p = 0.0126). A strong expansion of CD28- CD4 lymphocytes in peripheral blood within the first cycle of therapy is an early differential feature of HPD in NSCLC treated with immune-checkpoint inhibitors. The monitoring of T cell dynamics allows the early detection of this adverse outcome in clinical practice and complements radiological evaluation.