Search

Although the sensitive detection of putaminal iron deposition by T2*-weighted imaging (T2*-WI) is of diagnostic value for multiple system atrophy (MSA), the diagnostic significance of the pontine hot-cross bun (HCB) sign with increased ferritin-bound iron in the background remains unknown. We retrospectively evaluated the cases of 33 patients with cerebellar-form MSA (MSA-C) and 21 with MSA of the parkinsonian form (MSA-P) who underwent an MRI study with a 1.5-T system. Visualization of the HCB sign, posterior putaminal hypointensity and putaminal hyperintense rim on T2*-WI was assessed by two neurologists independently using an established visual grade, and were compared with those on T2-weighted imaging (T2-WI). The visual grade of pontine and putaminal signal changes was separately assessed for probable MSA (advanced stage) and possible MSA (early stage). T2*-WI demonstrated significantly higher grades of HCB sign than T2-WI (probable MSA-C, n = 27, p < 0.001; possible MSA-C, n = 6, p < 0.05; probable MSA-P, n = 13, p < 0.01). The visual grade of the HCB sign on T2*-WI in the possible MSA-C patients was comparable to that in the probable MSA-C patients. Although the HCB sign in MSA-P was of lower visual grade than in MSA-C even on T2*-WI, some patients showed evolution of the HCB sign preceding the appearance of the putaminal changes. These findings suggest that T2*-WI is of extreme value for detecting the HCB sign, which is often cited as a hallmark of MSA. The appearance of the HCB sign on T2*-WI might not only support but also improve the diagnosis of MSA.

To study the sexual dimorphism of human corpus cauosum (CC), we analyzed the midsaggital magnetic resonance imaging (MRI) morphometry in 67 adults aged (mean+/-s.d.) 36.82+/-9.35 years. Four specific angles of the CC were determined. All four angles in 34 females and 33 age-matched males showed a significant difference between females and males. These morphometric findings confirm a gender difference in the orientation of corpus callosum.

Hemodynamic factors are thought to play important role in the initiation, growth, and rupture of cerebral aneurysms. However, hemodynamic features in the residual neck of incompletely occluded aneurysms and their influences on recanalization are rarely reported. This study characterized the hemodynamics of incompletely occluded aneurysms that had been confirmed to undergo recanalization during long-term follow-up using computational fluid dynamic analysis. A ruptured left basilar-SCA aneurysm was incompletely occluded and showed recanalization during 11 years follow-up period. We retrospectively characterized on three-dimensional MR angiography. After subtotal occlusion, the flow pattern, wall shear stress (WSS), and velocity at the remnant neck changed during long-term follow-up period. Specifically, high WSS region and high blood flow velocity were found near the neck. Interestingly, these area of the remnant neck coincided with the location of aneurysm recanalization. High WSS and blood flow velocity were consistently observed near the remnant neck of incompletely occluded aneurysm, prone to future recanalization. It will suggest that hemodynamic factors may play important roles in aneurismal recurrence after endovascular treatment.

This study was undertaken to compare axial images of 99mTc-Technegas SPECT (Technegas) with those of 133Xe gas dynamic SPECT in patients with pulmonary emphysema. There were 20 patients, 19 males and 1 female. All patients except one ex-smoker were heavy smokers with a mean age of 68.1 years. For Technegas scintigraphy, the patients inhaled 505 MBq 99mTc-Technegas in several tidal volume breaths in the supine position without breath holding. For 133Xe gas scintigraphy, the patients inhaled 370 MBq 133Xe gas. 133Xe gas dynamic SPECT was performed in the equilibrium phase for the last minute of the 3 minute inhalation in a closed circuit, and in the washout phase for 6 minutes of inhalation in a semi-closed circuit, by means of a gamma camera with dual detectors (Picker model Prism 2000). Abnormal findings included heterogeneity, defects and hot spots on Technegas images and on retention images taken 3 minutes after 133Xe gas washout. In 2 of 20 patients, the degree of abnormal findings on Technegas images depended on the area of 133Xe gas retention in the washout phase. In 3 patients, the degree of abnormal findings on both Technegas SPECT and 133Xe gas dynamic SPECT images were equivalent. In the remaining 15 patients, more detailed findings and a greater area were shown by Technegas SPECT than 133Xe gas dynamic SPECT. We conclude that in patients with pulmonary emphysema Technegas SPECT can demonstrate ventilation impairment more easily than 133Xe gas dynamic SPECT.

Pulmonary emphysema can be diagnosed easily by X-ray CT (CT) as a low attenuation area. Recently Tc-99m-Technegas (Technegas) has been used for ventilation scintigraphy. The present study was undertaken to assess the usefulness of planar and SPECT images by using Technegas scintigraphy in patients with pulmonary emphysema. Technegas scintigraphy, CT and pulmonary function tests were performed in 20 patients (males, age 32–78 years). We classified the findings of Technegas images into 4 grades. Comparing planar and SPECT images of Technegas, more detailed findings were shown by SPECT than by planar images in mild cases (6 cases, 30%). In more severe cases, findings of SPECT and planar images were equivalent (14 cases, 70%). The degree of abnormal findings obtained by SPECT was equivalent to that obtained by CT in severe cases (6 cases, 30%). SPECT should be excluded in advanced stages as indicated by planar images.