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This follow-up study was conducted over 30 years in a cadmium-polluted area of Japan. Urinary cadmium (U-Cd) concentration decreased by nearly half from 1986 to 2008 in men and women. However, it increased from 2008 to 2014 and maintained similar levels in 2016. Because renal atrophy may induce an increase in U-Cd, kidney volumes were determined using magnetic resonance imaging (MRI) scans in 2018. Based on the MRI results, we divided the participants into two groups, namely the normal group (n = 6, three men and three women) and the lesion group (n = 6, three men and three women). The level of urinary N-acetyl-β-d-glucosaminidase/creatinine (U-NAG/Cr) in the lesion group was significantly higher than in the normal group. The level of serum alkaline phosphatase (Al-P) was positively associated with U-Cd. Age and renal cortex volumes showed significantly negative associations. However, U-Cd and renal cortex and kidney volumes showed no significant associations. These results suggest that U-NAG and serum Al-P were sensitive biomarkers to reflect renal tubular dysfunction and bone damage caused by cadmium poisoning. Individuals chronically exposed to Cd should be observed carefully, due to the increased effect of aging on renal cortex volumes.

AIM To calculate the quantitative liver–portal vein contrast ratio (Q-LPC) cut-off value based on tumour detectability by using receiver operating characteristic (ROC) curves. MATERIALS AND METHODS Seventy-four patients with tumours (46 men and 28 women; age, 71 ± 8.1 years), who underwent liver magnetic resonance imaging (MRI) using gadolinium–ethoxybenzyl–diethylenetriamine pentaacetic acid (Gd–EOB–DTPA) were enrolled. Some patients were found to have multiple tumours. In total, 102 tumour images were evaluated for quantitative liver–spleen contrast ratio (Q-LSC) and Q-LPC 10 minutes after the administration of Gd–EOB–DTPA. Q-LPC and Q-LSC were compared to assess the cut-off values and usefulness. The ROC curve was evaluated using the method for continuously distributed test results, with a free scale of 50 mm. A score of ≥30 out of 50 points was considered good. Cut-off values of Q-LPC and Q-LSC were then calculated. The areas under the ROC curve (AUCs) were also examined and compared. RESULTS The AUC–ROC for Q-LPC was 0.858 (95% confidence interval [CI], 0.783–0.933). The cut-off value was determined to be at 1.462. Sensitivity was 0.747, and specificity was 0.852 at the cut-off value. The AUC–ROC for Q-LSC was 0.710 (95% CI, 0.597–0.822). The cut-off value was at 1.543, the sensitivity was 0.560, and the specificity was 0.778 at the cut-off value. A significant difference was noted between the AUCs (p=0.0016). CONCLUSION Q-LPC can be used for hepatobiliary phase MRI evaluation.

To evaluate the potential of diffusion kurtosis imaging (DKI) analysis with the breath-hold technique to assess the stage or classify hepatic fibrosis.Patients (n=67) suspected of having a disease of the hepatobiliary system examined by diffusion-weighted imaging (DWI) using a 3.0-T magnetic resonance imaging unit were enrolled in this study. To evaluate hepatic fibrosis, mean kurtosis, Mean apparent diffusion (MD) and apparent diffusion coefficient (ADC) values were compared between groups with varying fibrosis; F0-F1, F2-F3, and F4. The Steel-Dwass test was used for overall comparisons. Correlations between the fibrosis stage and mean kurtosis, MD or ADC values were assessed using Spearman's rank correlation. Discriminative capacities of DKI were evaluated using receiver operating characteristic (ROC) analysis.There were significant differences in ADC, MD and mean kurtosis values between non-cirrhosis and cirrhosis groups. Moreover, the mean kurtosis value was statistically different between the F0-F1 and F2-F3, F0-F1 and F4, and F2-F3 and F4 groups (all P0.05). MD value was statistically different between the F0-F1 and F4 groups, and F2-F3 and F4 groups (all P0.05). However, there was no significant difference in ADC values for all groups (all P0.05). In addition, mean kurtosis and MD values significantly correlated with the extent of hepatic fibrosis staging (Spearman's rank correlation coefficient, ρ=0.851 and -0.672; P0.0001). However, ADC values did not reveal a correlation with the extent of hepatic fibrosis staging (ρ=-0.227; P=0.078). According to the ROC analysis for the assessment of no fibrosis (F0), fibrosis (≥F1), and advanced fibrosis (≥F2) and liver cirrhosis, the DKI cut-off values were 0.923, 0.955, and 1.11, respectively.Using the DKI method with the breath-hold technique in the liver, the stage of hepatic fibrosis can be classified into normal and early hepatic fibrosis, substantial stages, and advanced hepatic fibrosis.

In acoustic-stimulated functional magnetic resonance imaging (fMRI), tasks are performed by subjects either during imaging in the presence of scanning noise or during non-imaging periods without scanning noise. Suitable syllables for voice tasks performed with MRI-compatible headphones are limited during the imaging period with scanning noise. However, suitable syllables for voice tasks during the non-imaging period, without scanning noise, are not yet known. This study aimed to identify suitable syllables for voice tasks during both imaging and non-imaging periods. The subjects were 12 healthy volunteers who were native Japanese speakers. On an answer sheet attached to a wooden board, they were asked to write down the syllables they perceived through MRI-compatible headphones during imaging and non-imaging periods. The rate of accuracy for the perception of syllables was calculated; optimally perceived syllables were defined by a rate of accuracy exceeding the 95% upper confidence limit (UCL). The accuracy of syllable perception was significantly higher (P < 0.01) during the non-imaging period (77.2 ± 5.6%) than during the imaging period (66.3 ± 5.0%). The 95% UCLs obtained from the rates of accuracy were 83.5% during imaging and 88.9% during the non-imaging period. The number of syllables for which the accuracy rate exceeded the 95% UCL was 28 during imaging and 33 during the non-imaging period. These syllables could be used for voice tasks in acoustic-stimulated fMRI during imaging or non-imaging periods.

OBJECTIVES: We aimed to determine whether diffusion kurtosis imaging (DKI) analysis with the breath-hold technique can replace liver function results obtained from laboratory tests. METHODS: Patients (n = 79) suspected of having a hepatobiliary disease, and control group without liver diseases (n = 15) were examined with non-Gaussian diffusion-weighted imaging using a 3.0 T magnetic resonance imaging unit. Based on the findings of DKI, various blood serum parameters, including the indocyanine green (ICG) retention rate 15 min after an intravenous injection of ICG (ICG-R15) and mean kurtosis values and Child–Pugh and albumin–bilirubin (ALBI) scores, were calculated. In total, 17 patients were tested using ICG-R15. For evaluating liver function, correlations between the mean kurtosis value and the Child–Pugh score, ALBI score, and ICG-R15 value as indicators of liver function obtained from blood data were assessed using Spearman’s rank correlation. In apparent diffusion coefficient as well, we assessed correlations with these indicators. RESULTS: The mean kurtosis value correlated with the Child–Pugh score (Spearman’s rank-correlation coefficient, ρ = 0.3992; p < 0.0001). Moreover, the mean kurtosis value revealed a correlation with the ICG-R15 value (Spearman’s rank-correlation coefficient, ρ = 0.5972; p = 0.00114). The correlation between the mean kurtosis value and the ALBI score was the poorest among these (Spearman’s rank-correlation coefficient, ρ = 0.3395; p = 0.0008). CONCLUSION: Liver function correlating with the Child–Pugh score and ICG-R15 value can be quantitatively estimated using the mean kurtosis value obtained from DKI analysis. DKI analysis with the breath-hold technique can be used to determine liver function instead of performing laboratory tests. ADVANCES IN KNOWLEDGE: Previous studies have not evaluated liver function in vivo using DKI.

Objectives: To evaluate the hemodynamics of bladder tumors, we developed a method to calculate change in R 1 value (ΔR 1) from T 1-dynamic contrast-enhanced fast spin-echo magnetic resonance imaging (T 1DCE-FSE-MRI). Materials and methods: On a 1.5-T MR system, T 1DCE-FSE-MRI was performed. This study was applied to 12 patients with urinary bladder tumor, i.e. urothelial carcinoma. We compared ΔR 1-time and ΔSI-time between a peak in the ΔR 1-time and ΔSI-time curve occurred during the first pass within 60 s. Next, we assessed the slope of increase for 180 s after CA injection (Slope 0-180). Results: The mean slope of the first pass was significantly higher for bladder tumors on both the ΔR 1-time and the ΔSI-time curve compared with normal bladder walls. Moreover, a significant difference was apparent between bladder tumors and normal bladder walls on the mean Slope 0-180 in the ΔR 1-time curve. However, no significant difference in the mean Slope 0-180 was observed on the ΔSI-time curve between bladder tumors and normal bladder walls. Conclusion: T 1DCE-FSE-MRI offers three advantages: quantitative analysis; high-quality (i.e., artifact-free) images; and high temporal resolution even for SE images. Use of ΔR 1 analysis with T 1DCE-FSE-MRI allows more detailed information on the hemodynamics of bladder tumors to be obtained and assists in differentiation between bladder tumors and the normal bladder wall. © 2011 Elsevier Ireland Ltd. All rights reserved., Thesis of Kanazawa, Yuki / 金澤 裕樹 博士学位論文(金沢大学 / 大学院医薬保健学総合研究科)

Normal-pressure hydrocephalus (NPH) is characterized by a clinical triad of ataxia, incontinence, and dementia, as well as dilated ventricles but normal cerebrospinal fluid (CSF) pressures. In patients with NPH, CSF shunt placement is effective for improving these symptoms (1). NPH has attracted attention as one of the few treatable causes of dementia. Diagnosis of idiopathic NPH (INPH) without a known cause of communicating hydrocephalus, including subarachnoid hemorrhage or meningitis, is particularly difficult (2). Moreover, to clarify the cause of NPH, accurately diagnose NPH, and identify appropriate patients for shunt surgery, several tests have been proposed, including cisternography, the CSF tap test, resistance measures, external lumbar drainage, and intracranial pressure recording, in addition to clinical findings and conventional imaging diagnosis with x-ray computed tomography or magnetic resonance (MR) imaging (3–6). It has also been reported (7) that a single standard for the prognostic evaluation of patients with INPH was lacking and that supplemental tests could increase the predictive accuracy of the prognosis. The CSF tap test is a particularly reliable examination, but it is invasive and has low sensitivity. It has been proposed that MR imaging CSF flow studies can be used to noninvasively obtain information about intracranial mechanical properties in INPH (eg, intracranial compliance) (2,8–12). However, the diagnostic utility of this latter method is still not established.Arterial inflow into the cranium induces venous and CSF outflow and displacement of the intracranial spinal cord during the cardiac cycle, resulting in pulsatile brain motion (12–14). Brain pulsation (ie, bulk motion) reportedly can give rise to artifactual phase dispersion and may lead to overestimation of the apparent diffusion coefficient (ADC) (15,16). Brockstedt et al (17) reported that ADC was not changed significantly during the cardiac cycle with the single-shot echo-planar imaging (EPI) sequence widely used in diffusion MR imaging. However, they analyzed only two delay times (100 and 400 msec) between the R peaks in the cardiac cycle. To more completely analyze ADC changes during the cardiac cycle, our own group has previously evaluated the temporal change in ADC during the entire cardiac cycle by using an electrocardiographically (ECG)-triggered single-shot diffusion EPI sequence to minimize bulk motion effect. As a result, we revealed in a previous study that white matter ADC changed significantly over the cardiac cycle and that such changes were synchronized with the arterial inflow (volume loading) at systole (18). We further hypothesize that changes in ADC during the cardiac cycle are related to the biomechanical properties of intracranial tissues; hence, observed temporal changes in ADC in diseases such as INPH that are characterized by low intracranial compliance (12) may well be different than those in other diseases. Therefore, the purpose of our study was to determine whether temporal changes in ADC over the cardiac cycle were different in patients with INPH as compared with patients with ex vacuo ventricular dilatation and healthy control subjects.

Vascular endothelial growth factor (VEGF), a potent inducer of angiogenesis and vascular permeability in diverse physiological and pathological conditions, may be involved in the pathophysiology of chronic subdural hematoma (CSDH). The present study investigated the source and mechanisms for the induction of VEGF in CSDH by measuring the concentration of VEGF in the hematoma of 102 patients (122 hematomas) using the enzyme-linked immunosorbent assay technique. The relationship between the VEGF concentration in hematoma and the intrahematoma membranous structure confirmed by preoperative T(2)(*)-weighted magnetic resonance image was examined in 46 of these patients. VEGF and hypoxia-inducible factor-1alpha (HIF-1alpha) expression was immunohistochemically studied and microvessel density (MVD) in the outer membrane was identified using anti-CD31 antibody in 30 patients. VEGF and HIF-1alpha were positive in the outer membranes of all 30 patients. VEGF expression was significantly correlated to HIF-1alpha expression (r(s) = 0.651, p = 0.0084) and VEGF concentration in the hematoma (r(s) = 0.654, p = 0.0013). VEGF concentration in layered hematomas, which have intrahematoma membranous structure, was significantly higher than in non-layered hematomas (p < 0.01). Although MVDs of the outer membranes were comparable to those described in tumors, there was no significant relationship with VEGF expression. The present study suggests that VEGF in CSDH, which may be induced in the neomembrane by HIF-1 release, may give rise to the excessive development of fragile microvessels and hyperpermeability, resulting in the enlargement of CSDH.

Pleomorphic adenoma is a very rare benign tumor of the breast. Only 70 cases have been reported in the world literature. Recently, we encountered a case of pleomorphic adenoma of the breast and thus present here the mammographic and ultrasonographic findings with the pathology of this rare breast tumor. The patient was a 76-year-old Japanese woman with a right breast mass. The mammography showed a 1.5-cm, lobulated high-density mass with partially ill-defined margins. Ultrasonography revealed an irregularly shaped mass with partially ill defined borders, hypoechoic and heterogeneous internal echoes, and posterior acoustic enhancement. These findings suggested an invasive carcinoma. Awareness of this type of tumor will help in correct diagnosis, in spite of the rarity of this disease.

Conventional diagnostic X-ray units are used for radiographic imaging in many countries. For obtaining entrance surface doses, a numerical dose determination method has been applied in Japan. Although this technique is effective, it has to account for errors, particularly fluctuations, due to the beam quality and output of X-ray tubes. As a part of our quality control procedures, we recorded the entrance surface air kerma, tube voltage, and half-value layer measurements made for four diagnostic X-ray tubes over a 103-week period. The entrance surface air kerma for one of the four X-ray tubes had increased significantly by 11.4 % over 1 year from its initial setting, whereas the tube voltages and half-value layers did not deviate significantly from their initial values. Medical physicists and radiological technologists should be aware of this fluctuation for diagnostic X-ray tubes and take it into consideration when calculating the entrance surface air kerma. © 2014 Japanese Society of Radiological Technology and Japan Society of Medical Physics., 発行後1年より全文公開

In many clinical imaging procedures using arrays of multiple receiver coils, a uniform sensitivity process is performed using the sensitivity distribution from the body coil. This causes the noise to be uneven, and background noise cannot be used when measuring the signal-to-noise ratio (SNR). The SNR of clinical images with sensitivity correction using arrays of multiple receiver coils sets the region of interest (ROI) in the region where the signal is uniform, and is limited to the identical ROI method where measurements are taken with noise from the identical region. When SNR is measured with the identical ROI method, uneven noise caused by sensitivity correction as well as the signal strength distribution within the ROI of the object is reflected in the noise. Therefore, evaluation must be performed in as localized a position as possible. Measurement error becomes small on images with higher resolution, and if ROI larger than 10×10 pixels can be set in a region of even signal, SNR measurement of clinical images with less underestimation may be possible.

The pathophysiology of idiopathic normal pressure hydrocephalus (I-NPH) is still unclear and the diagnosis is sometimes difficult. The aim of this study was to assess the biophysics of I-NPH by measuring intracranial compliance using cine MRI.The study included patients with I-NPH (I-NPH group, n = 13), brain atrophy or asymptomatic ventricular dilation (VD group, n = 10), and healthy volunteers (control group, n = 13). Net blood flow (bilateral internal carotid and vertebral arteries and jugular veins) and cerebrospinal fluid (CSF) flow in the subarachnoid space at the C2 cervical vertebral level were measured using phase-contrast cine MRI. CSF pressure gradient (PG(p-p)) and intracranial volume changes (VC(p-p)) during a cardiac cycle were calculated.The compliance index (CI=VC(p-p)/PG(p-p)) in the I-NPH group was significantly lower than in the control and VD groups, whereas no difference was found between the control and VD groups. CI values of I-NPH patients after the tap test were larger than those before. These results clearly show that the intracranial compliance of I-NPH is relatively low compared to that of brain atrophy or normal subject. The increase of CI after a tap test also supports this finding.It is possible to estimate intracranial compliance as CI non-invasively using cine MRI. CI could become a useful method for the diagnosis of I-NPH.

Background The pathophysiology of idiopathic normal pressure hydrocephalus (I-NPH) is still unclear and the diagnosis is sometimes difficult. The aim of this study was to assess the biophysics of I-NPH by measuring intracranial compliance using cine MRI. Methods The study included patients with I-NPH (I-NPH group, n = 13), brain atrophy or asymptomatic ventricular dilation (VD group, n = 10), and healthy volunteers (control group, n = 13). Net blood flow (bilateral internal carotid and vertebral arteries and jugular veins) and cerebrospinal fluid (CSF) flow in the subarachnoid space at the C2 cervical vertebral level were measured using phase-contrast cine MRI. CSF pressure gradient (PG(p-p)) and intracranial volume changes (VC(p-p)) during a cardiac cycle were calculated. Findings The compliance index (CI=VC(p-p)/PG(p-p)) in the I-NPH group was significantly lower than in the control and VD groups, whereas no difference was found between the control and VD groups. CI values of I-NPH patients after the tap test were larger than those before. These results clearly show that the intracranial compliance of I-NPH is relatively low compared to that of brain atrophy or normal subject. The increase of CI after a tap test also supports this finding. Conclusions It is possible to estimate intracranial compliance as CI non-invasively using cine MRI. CI could become a useful method for the diagnosis of I-NPH.

We developed a novel system for imaging and qualitative analysis of surface vessels using near infrared (NIR) radiation with tuned aperture computed tomography (TACT®), even if the NIR cannot transmit through thick regions. NIR-sensitive CCD camera was surrounded by sixty light emitting diodes (alternating wavelengths of 700 nm and 810 nm), and could only detect the NIR from the subcutaneous tissue. We obtained multiple near infrared projections of surface vessels at each wavelength in accordance with the optical aperture theory within one second. Then, we created tomograms using the TACT program, and determined the venous oxygenation index (VOI), which reflected the oxygen saturation level, calculated from the image signals at each wavelength. This system produced thinner NIR tomograms under 0.5 mm. The change in VOI after load test calculated from NIR tomograms was more sensitive than that from NIR images without tomography. Our novel system makes it possible to non-invasively obtain NIR tomograms and accurately analyze changes in oxygen saturation.

The aim of this study is to clarify biophysics of normal pressure hydrocephalus (NPH) based on non-invasive intracranial compliance measurement using magnetic resonance imaging (MRI). Patients with NPH after subarachnoid hemorrhage (NPH group, n = 5), brain atrophy or asymptomatic ventricular dilation (VD group, n = 5), and healthy volunteers (control group, n = 12) were included in this study. Net blood flow (bilateral internal carotid and vertebral arteries, and jugular veins) and cerebrospinal fluid (CSF) flow in subarachnoid space at the C2 level of cervical vertebra were measured using phase-contrast cine MRI. CSF pressure gradient and intracranial volume changes during a cardiac cycle were calculated based on Alperin’s method. Compliance index (Ci = delta V/delta P) was obtained from the maximum pressure gradient and volume changes. Pressure volume response (PVR) was measured in the NPH group during a shunt operation. Ci in the NPH group was the lowest among the three studies groups. No difference was found between the control and VD groups. There was a linear correlation between Ci and PVR. In conclusion, intracranial compliance can be determined by cine MRI non-invasively. It is well known that NPH has relatively low intracranial compliance, this non-invasive method can be used for the diagnosis of NPH.

To clarify intracranial dynamical properties in normal pressure hydrocephalus (NPH), we assessed a spectral phase transfer function (PTF) calculated from the driving vascular pulsation and cerebrospinal fluid (CSF) flow in the aqueduct. Because the PTF is thought to change in accordance with the degree of pressure damping.