The spatial pattern of methacholine bronchoconstriction recurs when supine independently of posture during provocation but does not recur between postures

The location of lung regions with compromised ventilation (often called ventilation defects) during a bronchoconstriction event may be influenced by posture. We aimed to determine the effect of prone versus supine posture on the spatial pattern of methacholine-induced bronchoconstriction in six healthy adults (ages 21–41, 3 women) using specific ventilation imaging. Three postural conditions were chosen to assign the effect of posture to the drug administration and/or imaging phase of the experiment: supine methacholine administration followed by supine imaging, prone methacholine administration followed by supine imaging, and prone methacholine administration followed by prone imaging. The two conditions in which imaging was performed supine had similar spatial patterns of bronchoconstriction despite a change in posture during methacholine administration; the odds ratio for recurrent constriction was mean (SD) = 7.4 (3.9). Conversely, dissimilar spatial patterns of bronchoconstriction emerged when posture during imaging was changed; the odds ratio for recurrent constriction between the prone methacholine/supine imaging condition and the prone methacholine/prone imaging condition was 1.2 (0.9). Logistic regression showed that height above the dependent lung border was a significant negative predictor of constriction in the two supine imaging conditions ( P < 0.001 for each) but not in the prone imaging condition ( P = 0.20). These results show that the spatial pattern of methacholine bronchoconstriction is recurrent in the supine posture, regardless of whether methacholine is given prone or supine but that prone posture during imaging eliminates that recurrent pattern and reduces its dependence on gravitational height. NEW & NOTEWORTHY The spatial pattern of methacholine bronchoconstriction in the supine posture is recurrent and skewed toward the dependent lung, regardless of whether inhaled methacholine is administered while supine or while prone. However, both the recurrent pattern and the gravitational skew are eliminated if imaging is performed prone. These results suggest that gravitational influence on regional lung inflation and airway topography at the time of measurement play a role in determining regional bronchoconstriction in the healthy lung.

Remote transplantation of a third ventricle colloid cyst: case report

The authors report the case of a 15-year-old girl with a third ventricle colloid cyst. She presented with prolonged headache, nausea, vomiting, and loss of visual acuity with bilateral papilledema. Computed tomography and MRI revealed severe biventricular hydrocephalus with transependymal periventricular fluid and a minimally enhancing cystic mass of the third ventricle. The patient was diagnosed with a colloid cyst and obstructive hydrocephalus, and endoscopic resection with ablation of the cyst remnant was performed. While attempting to extricate the cyst from the patient's head, control of the cyst was lost and the cyst fell into the lateral ventricle beyond the surgeon's view. Postoperative imaging showed that the cyst had settled in the right occipital horn. After 3 years of follow-up, imaging suggests growth of the cyst in its new position without necrosis or displacement on prone imaging.