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Fifteen male freedivers underwent repetitive 3T pseudocontinuous ASL and ³¹P-/¹H-MR spectroscopy before, during, and after a 5-minute breath-hold (split into early and late phases) and gave temporally matching venous blood gas samples. The spatial coefficient of variation of CBF (by arterial spin-labeling) decreased during the early breath-hold phase whereas CBF remained almost stable during this phase and increased in the late phase. Cerebrovascular reactivity differed between the anterior and the posterior circulation during all phases. The cerebral energy metabolism of trained freedivers withstands severe hypoxic hypercarbia in prolonged breath-hold due to a complex cerebrovascular hemodynamic response.

Twenty patients with MR imaging negative for temporal lobe epilepsy who underwent preoperative evaluation and 10 healthy controls were scanned using PET/MR imaging with simultaneous acquisition of PET and arterial spin-labeling. On the basis of the standard uptake value and CBF, receiver operating characteristic analysis and a logistic regression model were used to evaluate the predictive value for the localization. Complete concordance was noted in lateralization and localization among the PET, arterial spin-labeling, and histopathologic findings in 12/20 patients based on visual assessment. PET/MR imaging–based multiparametric imaging involving arterial spin-labeling may increase the clinical value of localizing the epileptogenic zone by providing concordant and complementary information.

A group of 59 patients with untreated histologically proved T2–T4 oropharyngeal squamous cell carcinoma were retrospectively analyzed. Human papillomavirus status was determined by viral DNA detection on tissue samples. MR imaging protocol included T2-weighted, contrast-enhanced T1-weighted, and DWI sequences. Parametric maps of ADC were obtained from DWI sequences. Texture analysis was performed on T2 and volumetric-interpolated brain examination sequences and on ADC maps. ADC was significantly lower in oropharyngeal squamous cell carcinoma positive for human papillomavirus compared with oropharyngeal squamous cell carcinoma negative for it. ADC and smoking status allowed noninvasive prediction of human papillomavirus status with a good accuracy.

An intention-to-treat single-center cohort (n= 592) was re-evaluated for all patients in whom no reperfusion could be achieved (n = 63). Baseline characteristics were compared between patients with and without reperfusion failures. After qualitative review of all cases with reperfusion failures, a classification system was proposed and relative frequencies were reported. Reasons for reperfusion failure in stent-retriever thrombectomy are heterogeneous. The failure to establish intracranial or cervical access is almost as common as stent-retriever failure after establishing intracranial access. Systematic reporting standards of reasons may help to further estimate relative frequencies and thereby guide priorities.