OBJECTIVE Almost all small animal SPECT is performed with pinhole collimators (PH), including single-PH (SPH) and multi-PH (MPH). In the clinical study, not only PH but also parallel-hole collimator (PAH) is often used in planar and SPECT imaging. However, there have been no comparative studies on image quality with various collimators on the small animal imaging. This study compared the basic ...

Echo planar imaging was initially introduced as a technique to reduce the magnetic resonance imaging exam to a single shot (snap-shot) acquisition, much like a conventional radiograph. This vision, of course, created a good deal of speculation about the clinical impact of an echo planar imaging-equipped magnetic resonance imaging device. From completing the entire magnetic resonance exam in a m...

Pulmonary embolism (PE) is a preventable cause of morbidity and mortality which needs prompt recognition. Ventilation-perfusion (V/Q) scan is a well-established diagnostic test for evaluation of suspected PE. We report a 32-year-old woman with history of rheumatologic disease and acute dyspnea, who was referred for V/Q scintigraphy. The planar images revealed multiple mismatched defects through...

Understanding the mechanism of coupling between neuronal events and hemodynamic responses is important in non-invasive functional imaging of the brain. The stimulus frequency dependence of hemodynamic responses has been studied using a rat somatosensory cortex model; most results for short stimulus durations reveal peak frequencies at which the hemodynamic response is maximized. However, such p...

Neuronal oscillations produce oscillating magnetic fields. There have been trials to detect neuronal oscillations using MRI, but the detectability in in vivo is still in debate. Major obstacles to detecting neuronal oscillations are (i) weak amplitudes, (ii) fast oscillations, which are faster than MRI temporal resolution, and (iii) random frequencies and on/off intervals. In this study, we pro...

Nyquist ghosts are an inherent artifact in echo planar imaging acquisitions. An approach to robustly eliminate Nyquist ghosts is presented that integrates two previous Nyquist ghost correction techniques: temporal domain encoding (phase labeling for additional coordinate encoding: PLACE and spatial domain encoding (phased array ghost elimination: PAGE). Temporal encoding modulates the echo plan...