Application of collimator broad correction three dimensional ordered subsets expectation maximization for regional cerebral blood flow measurement

Autoradiography (ARG) has been used for quantitative analysis of the cerebral blood flow using ¹²³I-IMP, and the regional cerebral blood flow (rCBF) can be assessed more accurately with scatter and attenuation correction. Currently, the filtered back projection (FBP) method is generally used for image reconstruction. However, we anticipate obtaining more accurate rCBF by the ordered subsets expectation maximization method with collimator broad correction three dimensional ordered subsets expectation maximization (3D-OSEM). In the present study, we optimized the processing conditions to quantify rCBF using the 3D-OSEM method and compared them with the FBP method. Regarding the method, we determined the subsets and iteration, compared rCBF values using a profile curve, and compared them with the rCBF values obtained by the XeCT (Xenon-enhanced computed tomography)/CBF method. We found that in the 3D-OSEM method using 90 direction collection and 1.72 mm/pixel, the most accurate image was obtained around subset 9 and iteration 10. In addition, as compared to the profile curve and the XeCT/CBF method, the thalamus rCBF was high in the 3D-OSEM method with a good correlation with that of the XeCT/CBF. Accordingly, we concluded that the 3D-OSEM method can improve the decrease in rCBF due to blurring of the distance between the source (i.e., a structure located in the central part of the brain such as the thalamus and the collimator).     

Novel method for quantitative evaluation of cardiac amyloidosis using 201TlCl and 99mTc-PYP SPECT

Objective

The degree of myocardial technetium-^99m-pyrophosphate (^99mTc-PYP) accumulation in cardiac amyloidosis is conventionally evaluated by the PYP score. This method involves qualitative visual evaluation on two-dimensional images. Here, we performed three-dimensional quantitative analysis using software developed in our laboratory.

Methods

We performed dual myocardial imaging using thallium-²⁰¹-chloride (²⁰¹Tl-Cl) and ^99mTc-PYP in cases of suspected cardiac amyloidosis and calculated the PYP accumulation rates of all myocardial pixels showing ^99mTc-PYP accumulation. We defined this procedure as quantitative evaluation of the degree of ^99mTc-PYP accumulation in the myocardium. Patients were divided into two groups with and without a diagnosis of cardiac amyloidosis, and we examined the PYP accumulation rates in both groups. In addition, we examined the PYP scores of the two groups by conventional qualitative evaluation.

Results

The PYP scores of the cardiac amyloidosis group were significantly higher than those of the other group. The PYP accumulation rates of the cardiac amyloidosis group were significantly higher than those of the other group. There were significant differences in the PYP accumulation rate and PYP score between the two groups. There was considered to be a threshold between the two groups in the case of the PYP accumulation rate.

Conclusions

When the threshold of the PYP score was defined as 3+ and that of the PYP accumulation rate as 41.5?%, the sensitivity of the PYP score and PYP accumulation rate was 84.6?%. However, the specificity of the PYP accumulation rate was higher than that of the PYP score. Quantitative evaluation by the PYP accumulation rate of the degree of ^99mTc-PYP accumulation in the myocardium may be useful in the diagnosis of cardiac amyloidosis.     

A case of Bordetella trematum and Kerstersia gyiorum infections in a patient with congestive dermatitis

Bordetella trematum and Kerstersia gyiorum are rare gram-negative bacilli that are not frequently detected in human infections. In this report, we describe a case of a 48-year-old man who presented to our hospital with an infected wound on his leg. Discharges from the cracks of the granulation were collected and evaluated in our microbiology laboratory. Gram staining of the specimen showed polymorphonuclear leukocytes and abundant gram-negative bacilli. Three types of colonies were isolated on blood agar and were identified as B. trematum and Alcaligenes faecalis using VITEK MS. Moreover, K. gyiorum and B. trematum were identified and confirmed via 16S ribosomal RNA (rRNA) gene sequencing. The patient successfully recovered following application of meropenem antibacterial therapy and surgical debridement. This is the first reported case of complex wound infection caused by both B. trematum and K. gyiorum. Identification of B. trematum has recently been made possible by routine bacterial identification using matrix-assisted laser desorption-ionization time-of-flight mass spectrometry (MALDI-TOF MS). However, K. gyiorum isolation is still rare, and species identification requires 16S rRNA sequencing. Thus, this case highlighted the importance of using multiple methods, such as MALDI-TOF MS and 16S rRNA gene sequencing, for identification of rarely isolated species from clinical specimens.     

Radiographic and CT features of radiation-induced organizing pneumonia syndrome after breast-conserving therapy

Purpose  

To investigate radiographic and computed tomography features of radiation-induced organizing pneumonia syndrome after breast-conserving surgery.     

Human herpesvirus-6 (HHV-6)-associated hemophagocytic syndrome

Virus-associated hemophagocytic syndrome (VAHS) is characterized by histiocytic proliferation and phagocytosis triggered by virus infections. Viruses in the herpes group, especially the Epstein-Barr virus (EBV), are well known to cause VAHS; however, the relationship between this syndrome and human herpesvirus-6 (HHV-6) infection has rarely been reported. In this study, we describe a 23-month-old girl who exhibited typical manifestations of VAHS associated with HHV-6 infection. To the best of our knowledge, this case is the fifth reported case in the English literature.     

Construct validity of a new computer-assisted cognitive assessment battery in normal adults

A computer-assisted battery for neuropsychological tests (CNT) has been designed to screen adults for cognitive impairment. The aim of this study was to gather evidence for the construct validity of CNT and also investigate the relationship between CNT and conventional neuropsychological tests. Subjects were 45 healthy adults (21 men and 24 women), who ranged in age from 20 to 70 years (mean = 33.5, SD = 1.9) with no history of substance abuse, or of psychotic or neurological disorders. The CNT in our study consists of six subtests designed to assess various components of driving, such as digit span, visual scanning, visual and verbal memory, complex reaction time, and vigilance. Mini-mental state test, Kana-hiroi test, word fluency, the auditory-verbal learning test and Raven's colored progressive matrices were also performed as conventional neuropsychological tests. Results showed there were high correlations between each CNT subtests and conventional neuropsychological tests. A factor analysis (with varimax rotation) identified 4 factors with eigen values greater than 1, which accounted for over 70% of the variance. CNT was able to estimate each factor related to cognitive function such as learning and memory, attention, judgment, and visual scanning selectively. CNT may thus be a useful tool for detection of cognitive impairment, although this test has important limitations. Broader applications of these tests will require extensive population-based validation.     

Fiberoptic observation of thrombosis and thrombolysis in isolated human coronary arteries

Coronary arteries isolated from cadavers autopsied within 7 hours after death were perfused with canine arterial blood, and the processes of thrombus formation at the segments stenosed with atheroma and the thrombolytic effects of urokinase were investigated by angioscopy. Ten minutes of blood perfusion caused thin mural thrombi localized at the stenotic or nonstenotic segments. During 30 minutes of blood perfusion, the thin mural thrombi of the outlet or inlet of the segment grew into a doughnut-shaped thrombus. Also, the thin mural thrombi in the stenotic segment grew into a streamer-like thrombus and drifted downstream. These thrombi grew in size with increasing perfusion time and finally obstructed the stenotic segment. Globular thrombi close to the outlet also were formed in a few preparations. Unlike the thrombi at the stenotic segment, the mural thrombi in the nonstenotic segments did not grow into massive thrombi. The thrombi were reduced in size within 10 minutes of perfusion with 320 U/ml or more of urokinase. During thrombolysis, sandstorm-like dispersion of the blood cells occurred, small fragments detached from the mother thrombus and flew downstream, or the fibrin core of the thrombus was exposed. The results indicate the usefulness of angioscopy for the dynamic and serial investigation of thrombosis and thrombolysis.     

The validity of anaerobic threshold determination by a Douglas bag method compared with arterial blood lactate concentration

Summary Using an open circuit system (Douglas bag method), measurement of the anaerobic threshold (AT) was performed on ten healthy male college students during an incremental exercise test on a bicycle ergometer in an attempt to determine the validity of this method as compared with arterial blood lactate AT measurement.Blood samples were taken from either the radial or brachial artery through a Teflon catheter (3 ml/each time) every minute until the subject's maximal exercise tolerance was reached. Blood lactate was analyzed by the enzymatic method.Differences in work rate, O₂, % O_{2 max}, _E, HR, and R at AT _LA (AT determined by the increase in blood lactate) and at AT _GE (gas exchange AT based on the non-linear increases in _E, CO₂, and other respiratory parameters), respectively, were all found to be statistically insignificant. There was a significant correlation (r=0.866, p<0.01) between AT _LA and AT _GE when expressed in O₂ values (l/min). There was also a significant correlation between AT _LA and O_{2 max} (r=0.778, p<0.01). These results indicate that the commonly used Douglas bag method could provide a valid non-invasive measure of anaerobic threshold.     

G2A plays proinflammatory roles in human keratinocytes under oxidative stress as a receptor for 9-hydroxyoctadecadienoic acid

G2A is a stress-inducible G protein-coupled receptor for oxidized free fatty acids, such as 9-hydroxyoctadecadienoic acid (HODE). As skin is routinely and pathologically exposed to many oxidative stresses such as UV radiation, chemical agents, and inflammation that might induce both G2A expression and production of G2A ligands, we examined G2A function in human keratinocytes. G2A was expressed in human epidermis, normal human epidermal keratinocytes (NHEK), and an immortalized human keratinocyte cell line (HaCaT). 9(S)-HODE evoked intracellular calcium mobilization and secretion of cytokines, including IL-6, IL-8, and GM-CSF in NHEK cells. These responses became prominent in HaCaT cells by overexpression of G2A. 9(S)-HODE inhibited proliferation of NHEK cells by suppressing DNA synthesis and arresting the cell cycle in the G0/1-phase. On the other hand, 13(S)-HODE, another major oxidative product from linoleate, showed little or no effect on either cytokine secretion or on proliferation in NHEK cells. A small interfering RNA designed to downregulate G2A caused suppression of 9(S)-HODE-induced inhibitory effects on proliferation of NHEK cells. UVB and H(2)O(2) induced G2A expression and caused oxidation of linoleate to produce 9-HODE in HaCaT cells. These results suggest that 9-HODE-G2A signaling plays proinflammatory roles in skin under oxidative conditions.