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Purpose: Tc-99m-Technegas-MAA single photon emission computed tomography (SPECT)-derived ventilation (V)/perfusion (Q) quotient SPECT was used to assess lung V-Q imbalance in patients with pulmonary emphysema. Methods: V/Q quotient SPECT and V/Q profile were automatically built in 38 patients with pulmonary emphysema and 12 controls, and V/Q distribution and V/Q profile parameters were compared. V/Q distribution on V/Q quotient SPECT was correlated with low attenuation areas (LAA) on density-mask computed tomography (CT). Parameters of V/Q profile such as the median, standard deviation (SD), kurtosis and skewness were proposed to objectively evaluate the severity of lung V-Q imbalance. Results: In contrast to uniform V/Q distribution on V/Q quotient SPECT and a sharp peak with symmetrical V/Q distribution on V/Q profile in controls, lung areas showing heterogeneously high or low V/Q and flattened peaks with broadened V/Q distribution were frequently seen in patients with emphysema, including lung areas with only slight LAA. V/Q distribution was also often asymmetric regardless of symmetric LAA. All the proposed parameters of V/Q profile in entire lungs of patients with emphysema showed large variations compared with controls; SD and kurtosis were significantly different from controls (P < 0.0001 and P < 0.001, respectively), and a significant correlation was found between SD and A-aDO2 (P < 0.0001). Conclusions: V/Q quotient SPECT appears to be more sensitive to detect emphysematous lungs compared with morphologic CT in patients with emphysema. SD and kurtosis of V/Q profile can be adequate parameters to assess the severity of lung V-Q imbalance causing gas-exchange impairment in patients with emphysema. [ABSTRACT FROM AUTHOR]

We performed high-field magnetization measurements, M( H), on the Ni5(TeO3)4Br2 by using a pulse magnet. The Ni2+ ions ( S = 1) of this compound form a two dimensional distorted spin frustrated system (distorted kagome lattice), and undergo a Neel transition at T N∼29 K, due to the anisotropy. Below T N, a complex spin arrangement which contains ten spin sub-lattices was suggested by neutron scattering and electron spin resonance studies. We observed a step-like transition at H c∼11 T when T< T N. By contrast, at T> T N, the field-dependent magnetization curves behaved like a straight line. The H c is close to those obtained by previous spin resonance studies of Ni5(TeO3)4Br2 and Ni5(TeO3)4Cl2 in which a spin-flop-like transition was proposed to explain the field-dependent resonance spectra. Interestingly, the observed change in magnetization (Δ M) at H c corresponds to nearly one-half of the magnetic moment of Ni2+ ion, suggesting that the observed step-like behavior possibly corresponds to a spin-flip-like transition (i.e. from antiferromagnetic state to ferrimagnetic state). In addition, in the high-field region ( H> H c), the M( H) curves did not show plateau behavior, but exhibited the straight lines having finite slopes without any sign of saturation up to 55 T. [ABSTRACT FROM AUTHOR]

We performed high-field magnetization measurements, M( H), on the Ni5(TeO3)4Br2 by using a pulse magnet. The Ni2+ ions ( S = 1) of this compound form a two dimensional distorted spin frustrated system (distorted kagome lattice), and undergo a Neel transition at T N∼29 K, due to the anisotropy. Below T N, a complex spin arrangement which contains ten spin sub-lattices was suggested by neutron scattering and electron spin resonance studies. We observed a step-like transition at H c∼11 T when T< T N. By contrast, at T> T N, the field-dependent magnetization curves behaved like a straight line. The H c is close to those obtained by previous spin resonance studies of Ni5(TeO3)4Br2 and Ni5(TeO3)4Cl2 in which a spin-flop-like transition was proposed to explain the field-dependent resonance spectra. Interestingly, the observed change in magnetization (Δ M) at H c corresponds to nearly one-half of the magnetic moment of Ni2+ ion, suggesting that the observed step-like behavior possibly corresponds to a spin-flip-like transition (i.e. from antiferromagnetic state to ferrimagnetic state). In addition, in the high-field region ( H> H c), the M( H) curves did not show plateau behavior, but exhibited the straight lines having finite slopes without any sign of saturation up to 55 T. [ABSTRACT FROM AUTHOR]

Objective: To clarify the difference of (18)F-FDG uptake kinetics between FDG-avid metastatic lymph nodes (LNs) in patients with non-small-cell lung cancer (NSCLC) and FDG-avid benign LNs associated with various etiologies on dual-time point PET/CT scan, and to determine the optimal parameter for differentiation. Methods: The subjects were 134 FDG-avid metastatic LNs in 67 patients with NSCLC and 62 FDG-avid benign LNs in 61 patients with various lung disorders including NSCLC. PET/CT scan was performed at 2 time points (at 60 min and at 120 min) after intravenous injection of 4.4 MBq/kg (18)F-FDG. The maximum standardized uptake value (SUVmax) on early and delayed scans and the percent change of SUVmax (%DeltaSUVmax) were measured at each FDG-avid LN. The optimal parameter for differentiation was determined by the receiver-operating characteristic analysis. Results: Delayed SUVmax was increased compared with early SUVmax in 114 (85.0%) FDG-avid metastatic LNs and 42 (67.7%) FDG-avid benign LNs, with significant higher delayed SUVmax than early values (7.0 +/- 5.0 vs. 5.9 +/- 3.4; P < 0.0001, and 3.0 +/- 1.3 vs. 2.8 +/- 1.0; P < 0.05, respectively). Early and delayed SUVmax and %DeltaSUVmax in metastatic LNs were significantly higher than those in benign LNs (P < 0.0001). The optimal parameter for the differentiation was the combined use of early SUVmax > 3.0 or delayed SUVmax > 4.0, yielding sensitivity of 88.8%, specificity of 80.6%, accuracy of 86.2%, negative predictive value of 76.9%, and positive predictive value of 90.6%. It provided better results than the use of early SUVmax > 3.0 alone (P = 0.019) or the optimal parameter for %DeltaSUVmax (>5%) (P = 0.012). However, 12 (19.3%) benign LNs were indistinguishable from metastatic LNs. Conclusions: Although dual-time point PET/CT scan enhances the difference of FDG uptake between FDG-avid metastatic and benign LNs and improves the differentiation when compared with a single scan, biopsy procedure may be still required for accurate assessment of LN status in patients with NSCLC and possible etiologies showing intensive FDG uptake in benign LNs. [ABSTRACT FROM AUTHOR]

Objective: The aim of this study is to clarify the difference of F-18 FDG uptake kinetics between FDG-avid non-small-cell lung cancer (NSCLC) and benign lesions associated with various etiologies on dual-time point PET/CT scan, and to determine the optimal parameter for differentiation. Materials and Methods: The materials were 76 FDG-avid solitary NSCLC in 76 patients and 57 FDG-avid solitary benign lesions associated with various etiologies in 61 patients. FDG PET/CT scan was performed at 60 and 120 min after intravenous injection of 4.4 MBq/kg F-18 FDG. The maximum standardized uptake value (SUVmax) on early and delayed scans and the percent change of SUVmax (%DeltaSUVmax) between the two time points were measured. The optimal differential parameter was determined by receiver-operating characteristic curve analysis and evaluation of diagnostic accuracy. Results: The mean +/- SD of early SUV max, delayed SUVmax and %DeltaSUVmax were 8.3 +/- 5.2, and 10.2 +/- 6.5, and 21.9% +/- 18.9 in FDG-avid NSCLC, and 3.8 +/- 3.2, 4.0 +/- 3.7, and 11.3% +/- 26.0 in FDG-avid benign lesions, respectively. Delayed SUVmax in NSCLC was significantly higher than early SUVmax (P < 0.0001); while not different in benign lesions. Percent change of SUVmax in NSCLC was also significantly higher than that in benign lesions (P < 0.01). The optimal parameter for the differentiation was delayed SUVmax > 5.5 and yielded sensitivity of 77.6%, specificity of 80.7% and accuracy of 78.9%, which provided better differentiation than the use of %DeltaSUVmax or the traditional parameter of early SUVmax > 2.5. However, 11 (19.2%) benign lesions were indistinguishable from NSCLC. Conclusion: Although delayed PET/CT scan enhances the difference of FDG uptake between FDG-avid NSCLC and benign lesions, and the use of delayed SUVmax > 5.5 appears to improve the differentiation of these hypermetabolic lesions compared with an early scan, careful interpretation and management for correct differentiation are still required. [ABSTRACT FROM AUTHOR]

Common variable immunodeficiency (CVID) is a heterogeneous disorder characterized by recurrent bacterial infections, hypogammaglobulinemia and low to normal numbers of circulating B cells. Mutations in the ICOS, TACI and CD19 genes have recently been identified in <10% of CVID patients. We, herein, describe two novel CD19 gene disruptions in an 8-year-old Japanese boy, who had been clinically diagnosed as having CVID at the age of 5 years. Flow-cytometric analysis demonstrated absence of CD19 and reduced CD21 expression on CD20-postive peripheral blood B cells. Mutation analysis of CD19 revealed a mutation in the splice acceptor site of intron 5 (IVS5-1G>T) of the maternal allele, resulting in skipping of exon 6, and a truncated protein product. The paternal allele was disrupted by a gross deletion encompassing at least the ATP2A1, CD19 and NFATC2IP genes. The patient had a small number of IgD− CD27+ memory B cells, in which somatic mutation were detected. His B cells showed substantial proliferation upon stimulation, but reduced IgG and IgA production in vitro. These findings extend the mutation spectrum of the CD19 deficiency to four, and confirm the homogeneity of the CD19 deficiency as a unique type of CVID.Genes and Immunity (2007) 8, 663–670; doi:10.1038/sj.gene.6364431; published online 20 September 2007 [ABSTRACT FROM AUTHOR]

The flare catalogue of the Yohkoh mission is compiled and linked to this article as an electronic supplement. For showing flare characteristics over wide energy range concisely, we provide the images of Hard X-ray Telescope (HXT) and the Soft X-ray Telescope (SXT), and the spectra of Hard X-ray Spectrometer (HXS) and Gamma-Ray Spectrometer (GRS) with the Wide Band Spectrometer (WBS) time profiles. The energy versus pulse height (PH) data channels in HXS and GRS are re-calibrated by using the data of the whole mission period. Secular gain changes are recognized in HXS, and the characteristics of power-law flare spectra simultaneously observed by HXT and HXS confirms the trend. The GRS gains are different for the flare observations during the previous maximum and for the current maximum. The total of 33 γ -ray events are observed, and for 12 of them γ-ray flare spectra are obtained. [ABSTRACT FROM AUTHOR]

This article focuses on a study that was conducted to analyze the 4-nonylphenol (NP), 4-nonylphenol mono- and diethoxylates and other 4-alkylphenols in water and shellfish from rivers flowing into Lake Biwa, Japan. Water and shellfish samples were collected from the Fujima and Shintori rivers once every month from June 1999 to March 2000. The two rivers flow into Lake Biwa. For water samples, NP, NP1EO (nonylphenol monoethoxylate) and NP2EO (nonylphenol diethoxylate) were detected all the year round at high frequency (59/60) in the two rivers. 4-tert-butylphenol, 4-tert-octylphenol, bisphenol A were detected at lower concentrations and at lower frequency (16/60). Composition of NP, NP1EO and NP2EO was 21%, 45% and 34% in Fujima river water and 19%, 55% and 26% in Shiratori river water.

The HXS and GRS detectors on Yohkoh observed the 14 July 2000, X5.7 flare, beginning at ∼ 10:20 UT, ∼ 4 min before the peak in soft X-rays. The hard X-rays and γ-rays peaked ∼ 3 min later at ∼ 10:27 UT. Solar γ-ray emission lasted until ∼ 10:40 UT. Impact of high-energy ions at the Sun is revealed by the γ-ray lines from neutron capture, annihilation radiation and de-excitation that are visible above the bremsstrahlung continuum. From measurement of these lines we find that the flare-averaged spectrum of accelerated protons is consistent with a power law ge10 MeV with index 3.14±0.15 and flux 1.1×1032 protons MeV−1 at 10 MeV. We estimate that there were ∼1.5×1030 erg in accelerated ions if the power law extended without a break down to 1 MeV; this is about 1% of the energy in electrons > 20 keV from measurements of the hard X-rays. We find no evidence for spectral hardening in the hard X-rays that has been suggested as a predictor for the occurrence of solar energetic particle (SEP) events. This was the third largest proton event above 10 MeV since 1976. The GRS and HXS also observed γ-ray lines and continuum produced by the impact of SEP on the Earth's atmosphere beginning about 13 UT on 14 July. These measurements show that the SEP spectrum softened considerably over the next 24 hours. We compare these measurements with proton measurements in space. [ABSTRACT FROM AUTHOR]

To clarify the relationship between thallium-201 chloride kinetics and proliferative activity in brain tumours, a single-photon emission tomographic (SPET) study was performed and the results correlated with monoclonal antibody MIB-1 staining of the tumour tissue. [sup 201] Tl SPET was performed 10 min (early scan) and 2 h (delayed scan) after intravenous administration of [sup 201] Tl (111 MBq) in 34 intra-axial tumours including 24 malignant tumours, and in 27 extra-axial tumours including one malignant tumour. Tumour [sup 201] Tl kinetic parameters [early and delayed uptake ratios (ER and DR, respectively), retention index (RI), and the ratio of tumour delayed activity to early activity (Td/Te)] were compared with tumour tissue MIB-1 labelling indices (MIB-1 LI) representative of tumour cell proliferative activity. In the intra-axial tumours, ER and DR and MIB-1 LI were significantly higher in the malignant tumours than in the benign tumours. ER and DR were significantly correlated with MIB-1 LI (P<0.01 and P<0.05, respectively), but RI and Td/Te were not. In the extra-axial benign tumours, ER was as high as that in the intra-axial malignant tumours, while MIB-1 LI was equal to that in the intra-axial benign tumours. There were no significant correlations between any [sup 201] Tl kinetic parameters and MIB-1 LI. This study indicates that [sup 201] Tl ER may be the most reliable parameter for predicting the proliferative activity of intra-axial tumours. [ABSTRACT FROM AUTHOR]

We have found a new type of three-dimensional quantized Hall effect (QHE) in layered semiconductors Bi2−xSnxTe3 (x≤0.0125) single crystals. The Hall resistivity is not expressed in a universal relation applicable for a conventional QHE and depends appreciably on the doped Sn concentration x. The flat Hall plateaus are visible at higher Landau levels but are rather suppressed at lower regions. The calculated Landau levels of the upper valence band (UVB) with the best-fit band parameters are in excellent agreement with the experiments, including spin splitting. For Bi2−xSnxTe3, the Sn-originated impurity band (IB) has resonant nature and enhances the density of states at the Fermi level of UVB. The charge transfer occurs between the quantized UVB and the resonant IB or the lower valence band (LVB) for Bi2−xSnxTe3 or Bi2Te3, respectively, and the Landau levels are enhanced appreciably. We have revealed that the quasi-localized states are formed in quantized three-dimensional density of state spectra. We have proposed a possible model for the present QHE, which is a modification of Mani's model, where the quasi-localized state is formed at the disorder-originated tail of each Landau level. In the quasi-localized regime, the IB or LVB are responsible for the carrier reservoir to regulate the Hall resistivity. [ABSTRACT FROM AUTHOR]

Single crystals of a new diluted magnetic semiconductor Bi[sub 2 – ][sub x]Fe[sub x]Te[sub 3] (0≤x≤0.08) were grown. For all crystals, the transition into a ferromagnetic state with easy axis parallel to the C[sub 3] axis was observed at temperature T[sub c] increasing with iron concentration and reaching 12 K at x = 0.08. An increase in the Seebeck coefficient, anomalous Hall effect, and resistivity jump at T = T[sub c] were also observed. The frequency of the de Haas–van Alphen oscillations decreases with increasing x, indicating the donor properties of Fe. © 2001 MAIK “Nauka / Interperiodica”. [ABSTRACT FROM AUTHOR]

A 3-year-old child presented with severe type-7 adenoviral pneumonia, after the resolution of diffuse pulmonary infiltrates of the pneumonia. Xenon-133 ventilation and Tc-99-m macroaggregated albumin (MAA) perfusion studies revealed a localized airflow obstruction and matched perfusion defect, and marked air trapping in the remaining lungs, and these abnormalities were not detected and not suspected even with CT. Thereafter, in a relatively short period, the child developed persistent bronchiectatic changes and pulmonary hyperinflation throughout the lungs. However, the scintigraphic findings were not significantly changed. This is the first description of radionuclide scintigraphic findings which clearly showed an irreversible long-term functional effect of adenoviral pneumonia. [ABSTRACT FROM AUTHOR]

Purpose: A phantom study was conducted to evaluate the feasibility of body contour definition with Compton scatter photons from external sources of technetium-99m pertechnetate (Tc-99m) to create a fusion image of CT and SPECT images.Methods: External sources of 1 mCi (37 MBq) Tc-99m were placed on each collimator, and body-contour SPECT images were obtained with an energy window of 100 keV +/- 25% for detecting 90 degrees and 180 degrees Compton scatter photons of Tc-99m from the body surface in water-filled cylindrical and hexagonal phantoms, and in a chest phantom with a Tc-99m-avid simulated lung nodule and multimethod surface markers. In the chest phantom, each transaxial SPECT slices was registered with the corresponding CT slice by using image-matching soft ware. A summation of the registered images yielded a three-dimensional (3-D) fusion image of this phantom.Results: This method clearly visualized the body contour on all the SPECT slices in all the phantoms except for the complex hexagonal phantom. There was no significant difference between the known and SPECT-measured diameters of the cylindrical phantom. The fit of CT and SPECT images of the chest phantom was achieved with a mean alignment error of 5% in visual inspection, which was improved to 0.2% after correction of the magnification of the SPECT images according to the resultant dimensional differences. The 3-D fusion image of this phantom effectively visualized the anatomic location of the lung nodule and surface markers.Conclusion: This simple method effectively provided boundary information on the cold phantoms. Although further improvements in the registration technique with CT images are desirable, the body-contour SPECT image obtained by this method has the potential for accurately creating a 3-D fusion image with CT images, and is a feasible way of anticipating the anatomical localization of a target tissue. [ABSTRACT FROM AUTHOR]

Oncogenic and anti-apoptotic Bcl-2 is expressed much less in estrogen receptor α (ERα) negative breast cancers, which show more malignant phenotypes, than ERα-positive, indicating that some other Bcl-2 family member(s) are involved in the apoptotic balance of the cancer cells. We first analyzed mRNA expression of pro-apoptotic Bak and Bax along with that of anti-apoptotic Bcl-2 and Bcl-x[sub L], using breast cancer specimens of 27 patients. Bak mRNA was expressed much less in ERa negative breast cancers, along with reduced expression of Bcl-2. Immunostaining of sections of 108 patients confirmed the observation. Next, stable transformants of MCF-7 cells with sense Bak expression vector showed fewer colonies in soft agar compared with the parental cells, while stable introduction of antisense Bak vector enhanced colony formation at lower estradiol concentrations. The reduction of Bak may play important roles in malignant development of breast cancer to acquire estrogen independency, counteracting the reduced Bcl-2. [ABSTRACT FROM AUTHOR]

The fermentation characteristics of Saccharomyces cerevisiae strains which overexpress a constitutive OLE1 gene were studied to clarify the relationship between the fatty acid composition of this yeast and its ethanol productivity. The growth yield and ethanol productivity of these strains in the medium containing 15% dextrose at 10 °C were greater than those of the control strains under both aerobic and anaerobic conditions but this difference was not observed under other culture conditions. During repeated-batch fermentation, moreover, the growth yield and ethanol productivity of the wild-type S. cerevisiae increased gradually and then were similar to those of the OLE1-overexpressing transformant in the last batch fermentation. However, the unsaturated fatty acid content (77.6%) of the wild-type cells was lower than that (86.2%) of the OLE1-recombinant cells. These results suggested that other phenomena caused by the overexpression of the OLE1 gene, rather than high unsaturated fatty acid content, are essential to ethanol fermentation by this yeast. [ABSTRACT FROM AUTHOR]

A 28-year-old woman with a deformed thorax and kyphoscoliosis associated with Klippel-Feil syndrome developed respiratory failure with pulmonary hypertension. Pulmonary 133Xe ventilation and 99mTc-MAA perfusion scintigraphies showed maldistributions of lung ventilation and perfusion, and noticeably delayed 133Xe washout from the lungs. Dynamic breathing MR imaging showed poor and/or asynchronous respiratory movements of the chest wall and diaphragm. These findings indicate that the perfusion-ventilation imbalance, the decreased ventilatory turnover, and expiratory flow from the alveolar space partly derived from the impaired respiratory mechanics may be responsible for the respiratory complications in this patient. [ABSTRACT FROM AUTHOR]

This study retrospectively investigated the good parameters on thallium-201 chloride (201Tl) SPECT for early assessment of the therapeutic effects in patients with non-small cell lung cancer. Based on tumor response as determined by chest CT scan about 9 weeks after the end of irradiation with adjuvant chemotherapy, the subjects were divided to the responder group (tumor regression > 50%, n = 13) and non-responder group (tumor regression < 50%, n = 13). 201Tl SPECT was performed before and at the halfway through the course of therapy (average tumor dose, 27.4 Gy +/- 4.5) in all the patients. SPECT was conducted twice 15 min (early scan) and 120 min (delayed scan) after intravenous injection of 148 MBq (4 mCi) of 201Tl. Tumor-to-contralateral normal lung tissue count ratios on both scans were calculated as early and delayed uptake ratios (EUR and DUR), and a retention index (RI) was also derived from these ratios. In the responder group, a significant decrease in DUR and RI halfway through the therapy was observed compared to pretreatment (2.6 +/- 0.6 vs. 3.5 +/- 1.0; p < 0.01, and -2.3% +/- 25.5 vs. 37.4% +/- 17.8; p < 0.001, respectively), even though EUR did not change significantly (N.S.). By contrast, in the non-responder group, there were no significant changes in any of these parameters (N.S.). When comparing DUR and RI for the two groups halfway through the therapy, DUR and RI were significantly lower in the responder group (both; p < 0.01), but no significant difference was noted in EUR (N.S.), and the percent reduction in tumor size did not correlate with the percent decrease in DUR or RI (N.S.). These results indicate that the extent of decrease in DUR and RI after therapy can be a useful parameter for early assessment of the therapeutic effects in patients with non-small cell lung cancer. [ABSTRACT FROM AUTHOR]

Since acute disseminated intravascular coagulation (DIC) often contributes to a fatal outcome in patients with systemic lupus erythematosus (SLE), prediction of its development is important to prevent the occurrence of such an event. To analyze the risk factor(s) contributing to the development of acute DIC in SLE, we carried out a retrospective study of a series of 129 SLE patients, eight of whom developed DIC during the course of this disease, to assess which of the easily assessable parameters, present at the time of first medical examination, were of predictive significance. The important individual variables, determined by univariate analysis, were male sex, leukopenia, and infection. These factors were placed in a multivariate logistic regression model, and only one factor, infection at first medical examination, was found to have predictive significance for the development of acute DIC in SLE patients. The prevention and control of infection in SLE patients might have implications for preventing the development of acute DIC. [ABSTRACT FROM AUTHOR]

An observation of horizontal air showers of sizes from 10 to 10 particles (1 to 100 TeV in energy) has been performed. For showers of sizes up to ∼2.10, the size spectrum and zenith angle distributions are observed to be consistent with expectation. Some deviation appears in both the size spectrum and angle distributions for showers above ∼2.10, which suggests that they may be due to a short-lived muon parent particle. [ABSTRACT FROM AUTHOR]

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Two resolution schemes for the impossibility theorems on the Gibbard-Kelly claims of libertarian rights, which are rather contrasting with each other, are proposed and their implications discussed. The first scheme asserts that there exists a collective choice rule satisfying the Pareto principle and the Gibbard-Kelly libertarian claims if there exists at least one socially unconcerned individual. The second scheme asserts existence of an eligible collective choice rule if there exists at least one liberal individual. [ABSTRACT FROM AUTHOR]

We have assembled data from patients with fever of unknown origin who underwent gallium scintigraphy during the past 5 years in order to obtain a more current sampling of patients, and evaluated the role of gallium scintigraphy retrospectively. Of the 36 patients studied, gallium scintigraphy was positive and contributed to the detection of the foci or fever origins in 17 (47.2%). The ratio of neoplastic diseases with myeloproliferative and with lymphoproliferative disorders was relatively high compared with previous reports. However, gallium scintigraphy did not contribute to the diagnosis of collagen disease. With the ability to detect both inflammatory and neoplastic lesions, gallium scintigraphy was useful in detecting the foci of fevers of unknown origin. [ABSTRACT FROM AUTHOR]

This paper describes abnormal brain perfusion unexpectedly demonstrated by Tc-99m MAA total-body imaging in two children with intracardiac right-to-left shunt (RLS) associated with complex congenital heart disease. One child was a 12-year-old girl with asplenia cardiac syndrome and multiple cerebral infarctions caused by thromboembolism in the internal carotid artery, and the other child was a 6-month-old boy who developed focal cerebral infarction following shunt operation. In both children, the total-body imaging depicted the brain due to RLS, where radioactivity decreased unilaterally in the cerebral hemisphere. In the first patient, radioactivity also decreased in the contralateral cerebellum, suggesting the crossed cerebellar diaschisis phenomenon. These abnormalities in brain perfusion were confirmed by Tc-99m HMPAO brain SPECT. Careful review of the distribution of the radiotracer in the depicted brain on Tc-99m MAA total-body imaging may provide important information regarding brain perfusion in some patients with a high risk of stroke complication associated with RLS. [ABSTRACT FROM AUTHOR]