ABSTRACT
Ocular abnormalities have apparent effects on brain activation. However, neuroimaging data about the ocular characteristics of healthy participants are still lacking to be compared with data for patients with ocular pathology. The objective of this multiple participants’ functional magnetic resonance imaging (fMRI) studies was to investigate the brain activation characteristics of healthy participants when they view stimuli of various shapes, pattern and size. During the fMRI scans, the participants view the growing ring, rotating wedge, fl ipping hour glass/bow tie, quadrant arc and full checker board stimuli. All stimuli have elements of black-and-white checkerboard pattern. Statistical parametric mapping (SPM) was used in generating brain activation via fi xed-effects (FFX) and conjunction analyses. The stimuli of various shapes, pattern and size produce different brain activation with more activation concentrated in the left hemisphere. These results are supported by the conjunction analysis which indicated that the left pre-central, post-central, superior temporal and occipital gyrus as well as the left cingulate cortices were involved when the participants viewed each given stimulus. Differential activation analysis showed activation with high specifi city in the occipital region due to the stimuli of various shapes, pattern and size. The activation in the right middle temporal gyrus was found to be signifi cantly higher in response to moving stimuli as compared to stationary stimuli. This confi rms the involvement of the right middle temporal gyrus in the observation of movements. The black-and-white checkerboard stimuli of various shapes, pattern and size, stationary and moving was found to 1) activate visual as well as other cortices in temporal and parietal lobes, 2) cause asymmetry in brain function and 3) exhibit functional integration characteristics in several brain areas.
Subject(s)
Photic StimulationABSTRACT
This was a case of a 35-year-old man with mediastinal mass requiring computed tomography [CT]-guided biopsy for tissue diagnosis. A posterior approach with an 18-gauge biopsy needle was used to obtain tissue sample. Post biopsy, patient condition deteriorated and multiphase CT study detected active bleeding in arterial phase at the biopsy site with massive hemothorax. Subsequent angiography showed arterial bleeder arising from the apical branch of the right pulmonary artery. Selective endovascular embolization with NBCA [n-Butyl cyanoacrylate] was successful. Patient survived the complication. The case highlighted a rare complication in a common radiology procedure and the value of the interventional radiology unit in avoiding a fatal outcome
Subject(s)
Humans , Male , Mediastinal Neoplasms , Radiology, Interventional , Mediastinal Neoplasms/diagnosis , Tomography, X-Ray Computed , Biopsy , Embolization, TherapeuticABSTRACT
Background: Reversible focal lesions in the splenium of the corpus callosum (SCC) or reversible splenial lesion syndrome are rare and little is known about their pathophysiology. Case summary: The authors describe a case of a 65-year-old female who presented with fever, abnormal behaviour and mild hypernatremia. She was on neuropsychiatric treatment for bipolar disorder but denied any history of seizure. After an extensive workout to exclude infection, a clinical diagnosis of neuroleptic malignant syndrome (NMS) was made. Initial magnetic resonance imaging (MRI) of the brain showed a lesion in the SCC characterized by high-signal intensity on T2-weighted and FLAIR sequences with reduced signal intensity on T1-weighted sequence. Diffuse weighted imaging (DWI) showed restricted diffusion. There was no enhancement following Gadolinium administration. The follow-up MRI 8 weeks later showed complete resolution of the SCC lesion. Conclusion: While the pathophysiology of reversible SCC lesions is still unclear, this case highlights the need to consider NMS in the differential diagnosis of reversible splenial lesion of the corpus callosum.