Turbo spin-echo-based enhanced acceleration-selective arterial spin labeling without electrocardiography or peripheral pulse unit triggering and contrast enhancement for lower extremity MRA.

PURPOSE: Lower extremity magnetic resonance angiography (MRA) without electrocardiography (ECG) or peripheral pulse unit (PPU) triggering and contrast enhancement is beneficial for diagnosing peripheral arterial disease (PAD) while avoiding synchronization failure and nephrogenic systemic fibrosis. This study aimed to compare the diagnostic performance of turbo spin-echo-based enhanced acceleration-selective arterial spin labeling (eAccASL) (TSE-Acc) of the lower extremities with that of turbo field-echo-based eAccASL (TFE-Acc) and triggered angiography non-contrast enhanced (TRANCE). METHODS: Nine healthy volunteers and a patient with PAD were examined on a 3.0 Tesla magnetic resonance imaging (MRI) system. The artery-to-muscle signal intensity ratio (SIR) and contrast-to-noise ratio (CNR) were calculated. The arterial visibility (1: poor, 4: excellent) and artifact contamination (1: severe, 4: no) were independently assessed by two radiologists. Phase-contrast MRI and digital subtraction angiography were referenced in a patient with PAD. Friedman's test and a post-hoc test according to the Bonferroni-adjusted Wilcoxon signed-rank test were used for the SIR, CNR, and visual assessment. p < 0.05 was considered statistically significant. RESULTS: No significant differences in nearly all the SIRs were observed among the three MRA methods. Higher CNRs were observed with TSE-Acc than those with TFE-Acc (anterior tibial artery, p = 0.014; peroneal artery, p = 0.029; and posterior tibial artery, p = 0.014) in distal arterial segments; however, no significant differences were observed upon comparison with TRANCE (all p > 0.05). The arterial visibility scores exhibited similar trends as the CNRs. The artifact contamination scores with TSE-Acc were significantly lower (but within an acceptable level) compared to those with TFE-Acc. In the patient with PAD, the sluggish peripheral arteries were better visualized using TSE-Acc than those using TFE-Acc, and the collateral and stenosis arteries were better visualized using TSE-Acc than those using TRANCE. CONCLUSION: Peripheral arterial visualization was better with TSE-Acc than that with TFE-Acc in lower extremity MRA without ECG or PPU triggering and contrast enhancement, which was comparable with TRANCE as the reference standard. Furthermore, TSE-Acc may propose satisfactory diagnostic performance for diagnosing PAD in patients with arrhythmia and chronic kidney disease.

The relationship between cadmium exposure and renal volume in inhabitants of a cadmium-polluted area of Japan.

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-ß-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.

Diffusion kurtosis imaging in the assessment of liver function: Its potential as an effective predictor of liver function.

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.

Identification of syllables best recognized in acoustic-stimulated functional magnetic resonance imaging.

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.

Diffusion kurtosis imaging with the breath-hold technique for staging hepatic fibrosis: A preliminary study.

PURPOSE: To evaluate the potential of diffusion kurtosis imaging (DKI) analysis with the breath-hold technique to assess the stage or classify hepatic fibrosis. MATERIALS AND METHODS: 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. RESULTS: 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 P<0.05). MD value was statistically different between the F0-F1 and F4 groups, and F2-F3 and F4 groups (all P<0.05). However, there was no significant difference in ADC values for all groups (all P>0.05). 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; P<0.0001). 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. CONCLUSION: 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.

[Effects of region of interest settings in signal-to-noise ratio measurement of clinical images using arrays of multiple receiver coils].

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.

Involvement of hypoxia-inducible factor-1alpha and vascular endothelial growth factor in the mechanism of development of chronic subdural hematoma.

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 of the breast.

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.

Noninvasive estimation of intracranial compliance in idiopathic NPH using MRI.

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.

Subtraction SPECT for parathyroid scintigraphy based on maximization of mutual information.

UNLABELLED: Our objective was to investigate the feasibility of subtraction for SPECT images of (99m)Tc-MIBI double-phase parathyroid scintigraphy. METHODS: Fourteen patients with hyperparathyroidism were enrolled in the present study. Histopathologically, excised tissue specimens showed hyperplasia in 11 patients and adenoma in 3 patients. Both ultrasonography and (99m)Tc-sestamibi (MIBI) SPECT images were obtained from all patients. As standard lines to ensure that patient positioning remained identical between the different phases, we used the cross-marker produced by a pair of laser pointers, the orbitomeatal line, and the vertical midline through the patient's nose. Data processing was performed with software that enables image registration by maximization of mutual information. The results of subtraction SPECT imaging were compared with those of ultrasonography. RESULTS: The registration of double-phase SPECT images was successful in all patients when the salivary glands were excluded from the image reconstruction region. The overall sensitivities of scintigraphy and ultrasonography were 90.9% (40/44) and 70.5% (31/44), respectively, with respective specificities of 83.3% (10/12) and 75.0% (9/12). Scintigraphy and ultrasonography showed accuracies of 92.8% (52/56) and 71.4% (40/56), respectively. CONCLUSION: The new technique used in the present study allowed the subtraction for SPECT images. The sensitivity of parathyroid lesion detection using this technique was superior to that of ultrasonography.