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Objective: To determine the optimal quantitative magnetic resonance (MR) biomarker in neonatal encephalopathy following therapeutic hypothermia based on scan timing. Study design: This retrospective study included 98 neonates (35-41 weeks of gestation) with neonatal encephalopathy, who underwent therapeutic hypothermia; diffusion-weighted imaging and proton MR spectroscopy were performed at 24-96 hours (n = 56) and 7-14 days (n = 92) after birth, respectively, to estimate apparent diffusion coefficient (ADC) values, N-acetylaspartate and N-acetylaspartylglutamate (tNAA), lactate, and choline concentrations, and lactate/tNAA, tNAA/choline ratios in the deep gray matter. Adverse outcomes included death or neurodevelopmental impairment at 18-22 months of age. We used receiver operating characteristic curves to examine the prognostic accuracy of each MR biomarker. Results: Deep gray matter tNAA concentrations showed the best prognostic value, with an area under the curve (AUC) of 0.97 and 1.00 at 24-96 hours and 7-14 days after birth, respectively. At 24-96 hours of age, ADC values, lactate concentrations, and lactate/tNAA ratios showed prognostic value with AUCs of 0.90, 0.95, and 0.97, respectively. At 7-14 days of age, the AUCs of ADC values, lactate, and lactate/tNAA ratios were 0.61, 0.67, and 0.80, respectively; these were lower than those at 24-96 hours of age. Conclusions: During the first 2 weeks of life, the deep gray matter tNAA concentration was the most accurate quantitative MR biomarker. Although ADC values, lactate levels, and lactate/tNAA ratios also showed high prognostic value during 24-96 hours of life, only tNAA retained high prognostic value in the second week of life.

Purpose Enhanced acceleration selective arterial spin labeling (eAccASL) was introduced as non-enhanced and non-gated magnetic resonance angiography (MRA). This technique has not been applied to hand MRA. The objective of this study was to optimize the eAccASL for MRA of the hands and to investigate the factors for MRA visibility of the hands. Methods Twenty healthy volunteers were examined on a 1.5 T MR system. To evaluate arterial visualization, we compared four different acceleration-encoding (AENC) values (i.e., 0.12, 0.29, 0.58, and 0.87 m/s2). Image quality score regarding the MRA depiction of the proximal artery (range, 0–10), the distal artery (0–5), and venous contamination (0–5) was evaluated by three radiologists. We measured the peak to peak arterial blood flow velocity (Vpp) measured by phase contrast cine MRI and hand temperature as the factors for arterial visualization. Qualitative scores were compared with Friedman's tests. Spearman's correlation of qualitative scores with Vpp and hand temperature was performed to analyze influencing factors. Results For the distal arterial depiction, scores at AENC 0.12 (median, 9.0) and AENC 0.29 (8.0) were significantly better (both P 0.05). Conclusion eAccASL MRA of the hands was optimized by using low AENC values (0.12–0.29 m/s2). Venous contamination may increase with elevation of arterial blood flow.

The study aimed to determine whether magnetic resonance thoracic ductography (MRTD) is useful for preventing injury to the thoracic duct (TD) during thoracoscopic esophagectomy and for reducing the incidence of postoperative chylothorax. A total of 389 patients underwent thoracoscopic esophagectomy between September 2009 and February 2019 in Tokai University Hospital. Of them, we evaluated 228 patients who underwent preoperative MRTD (MRTD group) using Adachi’s classification and our novel classification (Tokai classification). Then, the clinicopathological factors of the MRTD group (n = 228) were compared with those of the non-MRTD group (n = 161), and comparative analyses were conducted after propensity score matching (PSM). The TD could be visualized by MRTD in 228 patients. The MRTD findings were divided into 9 classifications including normal findings and abnormal TD findings (Adachi classification vs Tokai classification; 5.3% vs 16.2%). After PSM, both groups consisted of 128 patients. The rate of postoperative chylothorax after thoracoscopic esophagectomy was significantly lower in the MRTD group (0.8%) than in the non-MRTD group (6.3%) (p = 0.036). In the multivariate analysis for risk factors for chylothorax, the independent prognostic factors were preoperative therapy and the presence of MRTD. This study revealed that MRTD was useful for preventing of chylothorax after thoracoscopic esophagectomy for esophageal cancer.

This study aimed to assess the feasibility for applying enhanced acceleration-selective arterial spin labeling (eAccASL) to non-electrocardiogram-gated and non-enhanced peripheral MRA. We compared eAccASL and background suppressed single shot turbo field echo (TFE)-triggered angiography non-contrast-enhanced sequence (BASS TRANCE) required electrocardiographic-gating in eight volunteers and three patients. In the volunteer study, eAccASL demonstrated a comparable arterial visualization compared with BASS TRANCE. In patient observation, the advantages with eAccASL were found in arterial visualization on the collateral vessels and without artifacts affected by arrhythmia events.

Background Using conventional computed tomography (CT), the accurate diagnosis of lymph node (LN) metastasis of esophageal cancer is difficult. Purpose To examine dual-energy CT parameters to predict LN metastasis preoperatively in patients with esophageal cancer. Material and Methods Twenty-six consecutive patients who underwent dual-energy CT before an esophageal cancer surgery (19 patients with LN metastases) were analyzed. The included LNs had a short-axis diameter of ≥4 mm and were confirmed to be resected on postoperative CT. Their short-axis diameter, CT value, iodine concentration (IC), and fat fraction were measured on early- and late-phase contrast-enhanced dual-energy CT images and compared between pathologically confirmed metastatic and non-metastatic LNs. Results In total, 51 LNs (34 metastatic and 17 non-metastatic) were included. In the early phase, IC and fat fraction were significantly lower in the metastatic than in the non-metastatic LNs (IC = 1.6 mg/mL vs. 2.2 mg/mL; fat fraction = 20.3% vs. 32.5%; both P 0.05). Conclusion Using dual-energy CT images, IC and fat fraction are useful for diagnosing LN metastasis in patients with esophageal cancer.

DWI thermometry is affected by CSF pulsation. To achieve more accurate determination of intraventricular temperature, we compared conventional DWI (c-DWI), acceleration motion compensation DWI (aMC-DWI), and motion compensation DWI (MC-DWI) when using two different b values (commonly used b value [1000 s/mm2] and theoretically optimized b value according to the diffusion coefficient of the CSF [400 s/mm2]). Eight healthy volunteers were scanned using a 3.0-T magnetic resonance (MR) system. The temperature map was created using the diffusion coefficient from DWI with b = 1000 and 400 s/mm2, respectively. The intraventricular temperatures in the lateral ventricles (LV) with less CSF pulsation, and the third ventricle (TV), which has more CSF pulsation, were compared between three techniques using the Friedman test. We measured the body temperature in the axilla to compare it with the intraventricular temperature. With b = 1000 s/mm2, the intraventricular temperatures in TV for c-DWI were significantly higher (43.12 ± 2.86 °C) than those for the aMC-DWI (37.68 ± 1.66 °C; P

Rationale and Objectives Magnetic resonance thoracic ductography (MRTD) with balanced turbo field echo (bTFE) can visualize both the thoracic duct and its surrounding vessels. This study aimed to investigate the visibility of the terminal thoracic duct into the venous system in the subclavian region using MRTD with bTFE. Materials and Methods MRTD was performed with bTFE as a preoperative workup comprising respiratory gating on a 1.5-T magnetic resonance system for patients with esophageal cancer. The portion and the number of terminal thoracic ducts into the venous system and preterminal branching in the left subclavian region were assessed using MRTD in 132 patients. The confidence level of the visibility using MRTD was also evaluated. Results The most frequent terminal portion of the thoracic duct was the jugulovenous angle (92 patients, 69.7%), followed by the subclavian vein (27 patients, 20.5%) and the internal jugular vein (8 patients, 6.1%). Four patients also exhibited double entry of the thoracic duct into the venous system. The preterminal branching was single in 96 patients (72.7%) and multiple in 36 patients (27.3%). The confidence level of the visibility of the thoracic duct using MRTD was absolutely certain in 112 patients (84.8%) and was somewhat certain in 20 patients (15.2%). Conclusions MRTD with bTFE is a robust imaging modality to visualize the terminal portion of the thoracic duct into the venous system in the subclavian region.

Purpose To evaluate the influence of arm position on B1 and proton density fat fraction (PDFF) in the liver using chemical shift-encoded magnetic resonance imaging. Materials and methods Participants were 8 healthy volunteers without liver disease and 36 patients with presumed or proven fatty liver. We assessed two preliminary examinations in healthy subjects, i.e., arm position influence on B1 and the variability of the PDFF between two scans within a short period of time. To verify the changes in PDFF measurement, 36 patients with fatty liver were conducted to compare 2 different arm positions—the elevated arms and side arms positions. The measurement location was based on the Healey & Schroy classification. The Wilcoxon test was used to analyze the difference in B1 in between the elevated arms and side arms positions. The Bland-Altman analysis was used to assess the agreement between two measurements of PDFF: two same scans within a short period of time, and two scans with different arms positions. Results B1 was significantly different in all segments except for medial segment. The variability of the PDFF between two scans within a short period of time was small in all segments. Some patients had large fluctuations in all segments, although the mean differences in PDFF were small. Upper and lower limits of agreement were 2.064% to 2.871% and − 2.430% to −1.462%, respectively. The relative difference in the rate of PDFF changes as the median (interquartile range [IQR]) in the lateral, medial, anterior, and posterior segments between both the arms positions were 0.0% (9.4), 1.1% (7.3), 1.5% (8.2) and − 0.2% (10.3), respectively. Conclusions Arm position can significantly affect B1 and PDFF in the liver. Although the absolute change in PDFF between arm positions was not so large, the difference in arm positions can cause large relative PDFF fluctuations.

Objective To determine the optimal quantitative magnetic resonance (MR) biomarker in neonatal encephalopathy following therapeutic hypothermia based on scan timing. Study design This retrospective study included 98 neonates (35-41 weeks of gestation) with neonatal encephalopathy, who underwent therapeutic hypothermia; diffusion-weighted imaging and proton MR spectroscopy were performed at 24-96 hours (n = 56) and 7-14 days (n = 92) after birth, respectively, to estimate apparent diffusion coefficient (ADC) values, N-acetylaspartate and N-acetylaspartylglutamate (tNAA), lactate, and choline concentrations, and lactate/tNAA, tNAA/choline ratios in the deep gray matter. Adverse outcomes included death or neurodevelopmental impairment at 18-22 months of age. We used receiver operating characteristic curves to examine the prognostic accuracy of each MR biomarker. Results Deep gray matter tNAA concentrations showed the best prognostic value, with an area under the curve (AUC) of 0.97 and 1.00 at 24-96 hours and 7-14 days after birth, respectively. At 24-96 hours of age, ADC values, lactate concentrations, and lactate/tNAA ratios showed prognostic value with AUCs of 0.90, 0.95, and 0.97, respectively. At 7-14 days of age, the AUCs of ADC values, lactate, and lactate/tNAA ratios were 0.61, 0.67, and 0.80, respectively; these were lower than those at 24-96 hours of age. Conclusions During the first 2 weeks of life, the deep gray matter tNAA concentration was the most accurate quantitative MR biomarker. Although ADC values, lactate levels, and lactate/tNAA ratios also showed high prognostic value during 24-96 hours of life, only tNAA retained high prognostic value in the second week of life.

The study aimed to evaluate the usefulness of prone-position computed tomography (CT) for predicting relevant thoracic procedure outcomes in minimally invasive esophagectomy (MIE) for thoracic esophageal cancer. A total of 59 patients underwent esophagectomy between May 2019 and December 2020 in Tokai University Hospital. Preoperative CT imaging was conducted with the patient in both the supine and prone positions, and the magnitude of change in the intramediastinal space was calculated. In the 56 patients (94.9%) who had undergone MIE, the effects of such a difference on the surgical outcomes were analyzed. A significant correlation of the magnitude of change in VE (distance between ventral aspect of the vertebral body and the midpoint of the esophagus) with the surgical outcome was revealed in the 17 patients (30.4%) in whom the magnitude of change in VE was over the 75th percentile. That is, in this subgroup, the magnitude of change in VE showed a negative correlation with the thoracic operation time (rs = − 0.57, p = 0.01) and blood loss during the thoracic procedure (rs = − 0.46, p = 0.01). Multivariate analysis identified a magnitude of change in VE ≥ 9 mm (OR = 0.14, p = 0.03) as an independent risk factor for postoperative pneumonia. This study indicates that preoperative prone-position CT imaging is useful for predicting the level of ease or difficulty of securing an adequate operative field, surgical outcomes, and the risk of postoperative pneumonia in MIE.

Background The utility of virtual monoenergetic imaging (VMI) for fine arteries has not been well clarified. Purpose To assess bronchial artery visualization using VMI and noise-optimized advanced VMI (VMI+). Material and Methods Eighty-seven patients with esophageal cancer underwent computed tomography (CT) using a third-generation dual-source system before surgery. Tube voltages were set to 90 kVp and 150 kVp, respectively. Images were reconstructed using VMI and VMI+ with energy levels of 40–120 keV (in 10-keV increments); composite images equivalent to CT images at 105 kVp were also generated. The CT attenuation value and contrast-to-noise ratio (CNR) of bronchial arteries using VMI and VMI+ were compared with those obtained using composite imaging. Two radiologists subjectively analyzed bronchial artery visualization with reference to the composite image. Results CT attenuation values for bronchial arteries using VMI at 40–60 keV and VMI+ at 40 keV and 50 keV were significantly higher than those obtained using composite imaging ( P Conclusion VMI and VMI+ at low voltages (40–50 keV) may be useful for bronchial artery visualization. VMI+ may be less effective for fine vessels as bronchial artery visualization.

Computed tomography (CT) has been widely used as an initial imaging modality for assessment of intracranial lesions or ruling out their presence...

The feasibility of the 3D dynamic improved motion-sensitized driven-equilibrium steady-state free precession (3D dynamic iMSDE SSFP) was evaluated for visualizing CSF motion and the appropriate parameters were determined. Both flow phantom and volunteer studies revealed that linear ordering and the shortest acquisition duration time were optimal. 3D dynamic iMSDE SSFP provides good quality imaging of CSF motion in the whole brain and enables visualization of flow in arbitrary planes from a single 3D volume scan.

To reduce the determination errors of CSF pulsation in diffusion-weighted image (DWI) thermometry, we investigated whether applying second-order motion compensation diffusion tensor imaging (2nd-MC DTI) and fractional anisotropy (FA) processing improves the measurement of intracranial cerebrospinal fluid (CSF) temperature. In a phantom study, we investigated the relationship between temperature and FA in artificial CSF (ACSF) to determine the threshold for FA processing. The calculated temperatures of ACSF were compared with those of water. In a human study, 18 healthy volunteers were scanned using conventional DTI (c-DTI) and 2nd-MC DTI on a 3.0 T magnetic resonance imaging (MRI) system. A temperature map was created using diffusion coefficients from each DWI with/without FA processing. The temperatures of intracranial CSF were compared between each DTI image using Welch’s analysis of variance and Games–Howell’s multiple comparisons. In the phantom study, FA did not exceed 0.1 at any temperature. Consequently, pixels exceeding the threshold of 0.1 were removed from the temperature map. Intracranial CSF temperatures significantly differed between the four methods (p p

Preoperative simulation of the thoracic duct using magnetic resonance thoracic ductography (MRTD) would enable a safe lymph node dissection near the thoracic duct and the prevention of chylothorax after an esophagectomy. The aim of this study was to determine whether MRTD is useful for preventing injury to the thoracic duct during surgery and for reducing the incidence of chylothorax after surgery. We evaluated 130 patients who underwent preoperative MRTD followed by a thoracoscopic esophagectomy for the treatment of thoracic esophageal cancer between August 2014 and April 2017 (MRTD group). These patients were then compared with 160 patients with esophageal cancer who underwent a thoracoscopic esophagectomy without preoperative MRTD (non-MRTD group). Four patients in the non-MRTD group developed Type IIIB chylothorax (International Consensus on Standardization), while none of the patients in the MRTD group developed Type III chylothorax. Some type of abnormal finding was found during MRTD in 24 patients (18.5%). Among them, 13 patients (10.0%) exhibited abnormal divergence, which was the most frequent finding, followed by 5 patients (3.8%) with window formation and 2 patients (1.5%) with stitch formation. The present study revealed the frequencies of abnormal findings of the thoracic duct and of patients with false-negative MRTD findings. Injury to the thoracic duct can be avoided through the use of appropriate care during procedures performed in patients with abnormal findings on preoperative MRTD.

Early volume analyses of the infantile brain may help predict neurodevelopmental outcome. However, brain volumes are not well understood in moderately preterm infants at term-equivalent age (TEA).This study retrospectively investigated the relationship between regional brain volumes and infant gestational age (GA) at birth in moderately preterm infants (30-35weeks' GA) on magnetic resonance imaging (MRI) at TEA.Forty infants scanned at TEA were enrolled. Regional brain volumes were estimated by manual segmentation on MRI, and their relationship with GA at birth was assessed.The regional volumes of the cerebral hemispheres and deep gray matter were larger (Spearman ρ=0.40, P=0.01, and Spearman ρ=0.48, P0.01, respectively), and volumes of the lateral ventricles were smaller (Spearman ρ=-0.32, P=0.04) in infants born at a later GA. The volumes of the cerebral hemispheres of the infants born at 30weeks' GA were significantly smaller than those born at 33 and 35weeks' GA (P0.05). No associations were found between the volume of the cerebellum and brainstem, and GA at birth (Spearman ρ=0.24, P=0.13, and Spearman ρ=0.24, P=0.14, respectively).The volumes of the cerebral hemispheres at TEA may be smaller in infants born at 30weeks' GA, whereas those of the cerebellum and brainstem may not be correlated with GA among moderately preterm infants.

Down syndrome (DS) is the most common chromosomal aberration, but the characteristics of the brainstem component in this condition during childhood (from newborn to preteen stages) have not been clarified.To evaluate the morphological features of the brainstem in DS on magnetic resonance imaging (MRI).MRIs for 32 children with DS (16 boys and girls each; age range, 0-11years) without major brain insults, and 32 age-matched controls (16 boys and girls each) were retrospectively analyzed. Height, width, and area of the midbrain, pons, and medulla oblongata were measured on sagittal T1-weighted images; these were compared in children with DS and age-matched controls. The ratios of the brainstem to the size of the posterior fossa (BS/PF index) were calculated; these were also compared in the children with DS and the control group.The width and area of the midbrain; height, width, area of the pons; and area of the medulla oblongata were significantly smaller in children with DS than in control children (P0.05); the area of the pons, particularly for the ventral part, showed the largest differences in the mean relative differences. The BS/PF indices of the height, width, and area of the pons were significantly smaller in children with DS than in the control group (P0.01). However, the BS/PF indices for the midbrain and the medulla oblongata did not differ between these two groups.Children with DS may have small brainstems, particularly in the pons; this may be a characteristic morphological feature of the brainstem on MRI in childhood including neonates.

Purpose To assess airway visibility in infants using pointwise encoding time reduction with radial acquisition (PETRA). Materials and methods PETRA was obtained in 37 infants (gestational age: 23-43 weeks; postconceptional age: 34-46 weeks) using 3T magnetic resonance imaging (MRI) without respiratory gating. The visibility of the branching point and the airway structures, including the trachea and bronchi, on PETRA was scored by two experienced pediatric radiologists using a four-point scale (0-3). The rates of good visibility (score 3 or 2) were calculated for each airway structure. Interrater agreement was evaluated by intraclass correlation coefficient (ICC). Results For readers 1 and 2, good visibility was achieved for the branching point of the main bronchi (76% and 95%, respectively), trachea (97% and 95%, respectively), right main bronchus (92% and 92%, respectively), and left main bronchus (97% and 84%, respectively). Lower rates of visibility were achieved for the lobar bronchi. There was substantial agreement (ICC: 0.61-0.79) between the two readers for all the airway structures, except for the branching point at the right upper/middle lobe bronchi, for which there was moderate agreement (ICC: 0.56). Conclusion PETRA has the potential for good airway visibility in infants, particularly for the trachea and main bronchi. Level of evidence 3 J. Magn. Reson. Imaging 2017;45:839-844.

Summary Background and purpose Iterative reconstruction (IR) offers noise reduction and improved image quality of computed tomography (CT). Our aim was to assess the imaging quality of non-contrast helical CT of the head in children using IR. Materials and methods This study recruited 78 consecutive children aged ≤5 years (range: from 3 months to 5 years; mean: 1.7 years) who underwent an emergent non-enhanced helical CT of the head with no abnormal findings. The acquired data were reconstructed using filtered back projection (FBP) and sinogram-affirmed IR (SAFIRE) with strength levels of 2 (IR2) and 4 (IR4). The imaging quality of FBP, IR2 and IR4 was scored by two experienced neuroradiologists in terms of the contrast between the gray–white matter junction and artifacts from the skull at the level of the semioval center, basal ganglia and fourth ventricle. FBP, IR2 and IR4 scores were compared at each slice level. The signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were calculated for FBP, IR2 and IR4 and were compared among the three reconstruction algorithms. Results The score of IR2 and IR4 was significantly higher than that of FBP in terms of both the contrast between the gray–white matter junction and artifacts from the skull at each slice level (P Conclusions IR may improve the image quality of helical CT of the head in children.

We evaluated the visibility of the thoracic duct by fast balanced turbo field echo with extended k-space sampling (bTFEe). The thoracic duct of 10 healthy volunteers was scanned by bTFEe using a 1.5-T magnetic resonance imaging (MRI), which was acquired in approximately 2 minutes. Three-dimensional (3D) turbo spin-echo (TSE) was obtained for comparison. The thoracic duct including draining location of the venous system was overall well visualized on bTFEe, compared to TSE.

Purpose To assess arterial visibility on 4D time-of-flight (4D-TOF) by temporal magnetization transfer contrast pulse (t-MTC) and temporal tilted optimized nonsaturating excitation (t-TONE). 3D-TOF magnetic resonance angiography (MRA) is used for the noninvasive assessment of the intracranial arteries. However, it does not provide temporal information for diagnosing hemodynamics. To noninvasively obtain more detailed hemodynamics-related information, we developed a novel time-resolved MRA without the arterial spin labeling technique, termed 4D-TOF MRA using saturation pulse. Materials and Methods On a 3.0T MRI, three techniques were compared to optimize the visibility of the arteries above the circle of Willis; 1) simple 4D-TOF, 2) 4D-TOF with t-MTC, and 3) 4D-TOF with t-MTC and t-TONE. Eight healthy volunteers were scanned with these three sequences. The contrast changes between the background tissue and the arteries in temporal phases were assessed and compared quantitatively and qualitatively. Results The contrast between the background and the arteries for 4D-TOF with t-MTC and t-TONE was significantly higher than those for the other methods in delayed phases (P < 0.001).The qualitative assessment showed that 4D-TOF with t-MTC and with t-MTC and t-TONE provided better visualization of the intracranial artery than simple 4D-TOF (P < 0.001). Conclusion 4D-TOF with t-TONE and t-MTC enabled observation of the intracranial hemodynamics. Optimized 4D-TOF provides high-quality images without image subtraction, and good visibility of the intracranial arteries even in the prolonged observation time. J. Magn. Reson. Imaging 2016;43:1320–1326.

The thoracic duct, a terminal lymph vessel, is thought to dilate after the intake of a fatty meal. However, this physiological change has not been well explored in vivo. Therefore, the present study aimed to assess serial changes in the thoracic duct after the intake of a fatty meal using magnetic resonance thoracic ductography (MRTD). Eight healthy volunteers were subjected to one MRTD scan before a fatty meal and eight serial MRTD scans every hour thereafter. The cross-sectional areas of the thoracic duct were estimated using MRTD measurements of the diameters of the thoracic duct at the upper edge of the aortic arch, the tracheal bifurcation, the mid-point between the tracheal bifurcation and the left part of the diaphragm and the left part of the diaphragm. The change-rates in these areas were calculated before and after the fatty meal intake, and the maximal change-rate and timing of its achievement were determined for each subject. The summed change-rates in the four portions of the thoracic duct ranged from -40.1 to 81.3%, with maximal change-rates for each subject ranging from 22.8 to 81.3% (mean, 50.4%). Although individual variations were observed, most subjects (88.9%) exhibited a maximal change-rate at 4-6 h after meal intake, with subsequent decreases at 7-8 h. In conclusion, MRTD revealed a tendency toward thoracic duct enlargement at 4-6 h after the intake of a fatty meal, followed by contraction.

We assessed labeling region selectivity on time-spatial labeling inversion pulse (Time-SLIP) with pencil beam pulse (PB Time-SLIP) for the use of visualizing cerebrospinal fluid (CSF) flow dynamics. We compared the selectivity of labeling to the third and fourth ventricles between PB Time-SLIP and conventional Time-SLIP (cTime-SLIP) in eight volunteers and one patient using a 1.5T MRI. PB Time-SLIP provided more selective labeling in CSF than cTime-SLIP, particularly in complex anatomical regions.

Knowledge of MRI findings in pediatric cerebral infarction is limited. To determine whether cortical necrosis and network injury appear in the acute phase in post-stroke children and to identify anatomical location of acute network injury and the ages at which these phenomena are seen. Images from 12 children (age range: 0–9 years; neonates [

BACKGROUND AND PURPOSE: T1-weighted pointwise encoding time reduction with radial acquisition (PETRA) sequences require limited gradient activity and allow quiet scanning. We aimed to assess the usefulness of PETRA in pediatric brain imaging. MATERIALS AND METHODS: We included consecutive pediatric patients who underwent both MPRAGE and PETRA. The contrast-to-noise and contrast ratios between WM and GM were compared in the cerebellar WM, internal capsule, and corpus callosum. The degree of myelination was rated by using 4-point scales at each of these locations plus the subcortical WM in the anterior frontal, anterior temporal, and posterior occipital lobes. Two radiologists made all assessments, and the intra- and interrater agreement was calculated by using intraclass correlation coefficients. Acoustic noise on MPRAGE and PETRA was measured. RESULTS: We included 56 patients 5 days to 14 years of age (mean age, 36.6 months) who underwent both MPRAGE and PETRA. The contrast-to-noise and contrast ratios for PETRA were significantly higher than those for MPRAGE (P < .05), excluding the signal ratio for cerebellar WM. Excellent intra- and interrater agreement were obtained for myelination at all locations except the cerebellar WM. The acoustic noise on PETRA (58.2 dB[A]) was much lower than that on MPRAGE (87.4 dB[A]). CONCLUSIONS: PETRA generally showed better objective imaging quality without a difference in subjective image-quality evaluation and produced much less acoustic noise compared with MPRAGE. We conclude that PETRA can substitute for MPRAGE in pediatric brain imaging.

To assess airway visibility in infants using pointwise encoding time reduction with radial acquisition (PETRA).PETRA was obtained in 37 infants (gestational age: 23-43 weeks; postconceptional age: 34-46 weeks) using 3T magnetic resonance imaging (MRI) without respiratory gating. The visibility of the branching point and the airway structures, including the trachea and bronchi, on PETRA was scored by two experienced pediatric radiologists using a four-point scale (0-3). The rates of good visibility (score 3 or 2) were calculated for each airway structure. Interrater agreement was evaluated by intraclass correlation coefficient (ICC).For readers 1 and 2, good visibility was achieved for the branching point of the main bronchi (76% and 95%, respectively), trachea (97% and 95%, respectively), right main bronchus (92% and 92%, respectively), and left main bronchus (97% and 84%, respectively). Lower rates of visibility were achieved for the lobar bronchi. There was substantial agreement (ICC: 0.61-0.79) between the two readers for all the airway structures, except for the branching point at the right upper/middle lobe bronchi, for which there was moderate agreement (ICC: 0.56).PETRA has the potential for good airway visibility in infants, particularly for the trachea and main bronchi.3 J. Magn. Reson. Imaging 2017;45:839-844.

Hydranencephaly is a fetal central nervous system disorder in which most of the cerebral hemispheres are damaged and largely replaced with cerebrospinal fluid. We present susceptibility-weighted imaging findings in an infant with hydranencephaly, who showed foci of signal loss mainly at the peripheral portion of the thalamus and falx cerebri. Although the exact cause of hydranencephaly has not been established, these findings suggest previous hemorrhage and parenchymal destructive changes.

The authors report on a case of histiocytic sarcoma (HS) in a pediatric patient presenting with a solitary tumor in the cerebellum, with the aim of providing insight into primary HS in the CNS, which is especially rare. A 17-month-old Japanese girl presented with a 2-week history of progressive gait disturbance. Brain MRI revealed a 4.7 × 4.3 × 4.3–cm well-demarcated solitary mass in the right hemisphere of the cerebellum, initially suggestive of medulloblastoma, ependymoma, or anaplastic astrocytoma. On intraoperative inspection the cerebellar tumor showed intensive dural attachment and was subtotally removed. Histological and immunohistochemical findings were consistent with HS. The patient subsequently received chemotherapy, and her preoperative neurological symptoms improved. Primary HS in the CNS usually demonstrates an aggressive clinical course and is currently considered to have a poor prognosis. The possibility of this rare tumor should be included in the differential diagnosis of localized cerebellar tumors in the pediatric age group.

In this study, we report 2 pediatric cases of nuclear protein of the testis (NUT) midline carcinoma (NMC) suggestive of pulmonary origin: case 1 was a 14-year-old Japanese boy and case 2 was a 7-year-old Japanese girl. Initial symptoms of both cases were prolonged cough and chest pain, and the case 2 patient also complained of lumbago and lumbar mass due to bone metastases. Imaging studies revealed that pulmonary tumors from both patients were located at the hilar region of the lower lobe. Biopsies of the tumors showed undifferentiated carcinoma in case 1 and combined undifferentiated and squamous cell carcinoma in case 2. Despite intensive treatment with chemotherapy and radiation, progression of neither tumor was controlled, and both patients died of the tumors at 1 year (case 1) and 4 months (case 2) after onset of disease. Both tumors were diffusely positive for p63 and NUT expression and were partially positive for various cytokeratins. Reverse transcription polymerase chain reaction analysis and subsequent direct sequencing revealed that the bromodomain-containing protein 4-NUT chimeric gene was present in tumor tissue of both patients, leading to a diagnosis of NMC. The tumor cells of case 1 were also positive for thyroid transcription factor-1 expression, but those of case 2 were negative. Histologic examination of the surgically removed lung tumor of case 1 indicated that the origin of the tumor was basal cells of the bronchiolar epithelia.

Purpose: In magnetic resonance imaging of the brain, BLADE is used to compensate for head motion. The technique focuses mainly on acquisition of T2-weighted or contrast-enhanced T1-weighted images in adults; its utility for nonenhanced T1-weighted imaging in children is not well established. We compared the quality of T1-weighted fluid-attenuated inversion recovery brain imaging with BLADE (T1-FLAIR-BLADE) to that of conventional spin-echo T1-weighted imaging (T1-SE) in pediatric patients who cannot stay still during MR imaging. Materials and Methods: Our investigation included a volunteer study and a retrospective clinical study. Six healthy adult volunteers underwent scanning to compare the contrast of T1-SE, T1-weighted fluid-attenuated inversion recovery imaging (T1-FLAIR), and T1-FLAIR-BLADE at both 1.5 and 3 tesla. Comparison was based on scores assigned independently by 2 blinded observers and by calculated contrast-to-noise ratio. The clinical study included 20 children who underwent both T1-SE and T1-FLAIR-BLADE at either 1.5 (n=9) or 3 T (n=11). On each sequence, 2 blinded observers independently scored visualization of the cerebral gyri and contrast between gray and white matter. We compared scores between sequences separately for 1.5 and 3T using Wilcoxon signed-rank tests. Results: At both 1.5 and 3T, contrast was better using T1-FLAIR and T1-FLAIR-BLADE than T1-SE in volunteers, and overall scores were significantly higher with T1-FLAIR-BLADE (P

Purpose: To assess the anatomic variation and age-related changes of phase shifts in the neonatal cerebral venous system at susceptibility-weighted imaging (SWI). Materials and Methods: Thirty-five neonates who had undergone SWI and who did not have any intracranial or systemic abnormalities were retrospectively assessed. Phase shifts in the veins in the deep gray matter and in the cortical veins in the frontal, rolandic, and parietal areas were measured and compared. Correlations between phase ratio (ratio of the phase shift in the vein in the deep gray matter to that in the cortical veins) and gestational age at birth, gestational age at magnetic resonance imaging (MRI), and age after birth were assessed. Results: Phase shift in the veins in the deep gray matter was significantly higher than those in the cortical veins (P < 0.01). Among the cortical veins, the venous phase shift in the rolandic area was significantly higher than those in the frontal and parietal areas (P < 0.01). There was a negative correlation between the phase ratio and the gestational age at MRI (Spearman ρ = −0.35, P = 0.04). Conclusion: An anatomical variation in phase shifts was identified in the neonatal venous system. The observed reduction in phase shift differences between the veins in the deep gray matter and those in the cortex as gestational age at MRI increased may reflect brain development. J. Magn. Reson. Imaging 2011;. © 2011 Wiley Periodicals, Inc.

Bowel contents and peripheral nerves often show high signal intensity at diffusion-weighted imaging (DWI) of the abdomen and pelvis, obscuring or mimicking pathology. This study introduced and compared short tau inversion recovery (STIR) with single-axis DWI to the usual combination of spectral fat suppression (SFS) with trace DWI in the suppression of bowel contents and peripheral nerves. Five volunteers underwent both STIR with single-axis DWI and SFS with trace DWI of the abdomen and pelvis. Images were evaluated by two observers with respect to the suppression of signal of bowel contents and peripheral nerves using four-point grading scales (4=poor suppression; 3=moderate suppression; 2=good suppression; 1=excellent suppression). Mean scores (±S.D.) regarding the suppression of bowel contents were 1.60±0.55 and 1.40±0.89 for STIR with single-axis DWI and 3.40±0.55 and 3.00±1.00 for SFS with trace DWI for observers 1 and 2, respectively. Mean scores regarding the suppression of peripheral nerves were 1.20±0.45 and 1.20±0.45 for STIR with single-axis DWI and 2.40±0.89 and 2.80±0.84 for SFS with trace DWI for observers 1 and 2, respectively. In conclusion, STIR with single-axis DWI is superior to SFS with trace DWI in the suppression of bowel signal and peripheral nerves.

Introduction Punctate white matter lesions (PWML) are recognized with magnetic resonance imaging (MRI) as hypersignal on T1-weighted imaging and hyposignal on T2-weighted imaging. Our aim was to assess how often a hemorrhagic component was present in PWML using susceptibility-weighted imaging (SWI). Methods Seventeen preterm (gestational age, 25–34 weeks) and seven full-term infants (age at MRI, 37–42 weeks) with PWML were included. Seven preterm infants had sequential MRIs. PWML were diagnosed with conventional MRI and compared with SWI, where signal loss is suggestive of hemorrhage. The pattern of associated brain lesions was taken into account, and the percentage of lesions with signal loss on SWI was calculated for each infant. Results A significantly higher percentage of signal loss on SWI (median, 93.9%) was found among infants with germinal matrix and intraventricular hemorrhage as the primary diagnosis (n = 8) compared to those with a primary diagnosis of white matter injury (n = 14; median, 14.2%; p

(18)F-FDG PET is an established functional imaging modality for the evaluation of human disease. Diffusion-weighted MRI (DWI) is another rapidly evolving functional imaging modality that can be used to evaluate oncologic and nononcologic lesions throughout the body. The information provided by (18)F-FDG PET and DWI can be complementary, because the 2 methods are based on completely different biophysical underpinnings. This article will describe the basic principles, clinical applications, and limitations of DWI. In addition, the available evidence that correlates and compares (18)F-FDG PET and DWI will be reviewed.

Aim: Congenital extrahepatic portosystemic shunt (CEPS) is a rare anomaly in which the enteric blood bypasses the liver and drains into the systemic veins through various venous shunts. Patients with CEPS often have liver tumors and complications such as cardiac or other anomalies, but portosystemic encephalopathy and gastrointestinal bleeding occur only occasionally. The clinical problems differ for each individual with CEPS, and establishing a prognosis can be very difficult. Methods: We reviewed the clinical features of 136 reported cases of CEPS and classified these cases according to their portosystemic shunts. Results: We classified portal blood flow directly into the inferior vena cava (IVC) as type A (88 cases), portal blood flow into the renal vein as type B (36 cases), and portal blood flow into the iliac vein via an inferior mesenteric vein as type C (12 cases). Type A patients were complicated with cardiac anomalies at a higher rate than other types. Type C patients had lower prevalences of cardiac anomalies and portosystemic encephalopathy than the other types, but the prevalence of gastrointestinal bleeding was significantly higher (P

Introduction The aim of this study was to introduce and assess a new magnetic resonance (MR) technique for selective peripheral nerve imaging, called “subtraction of unidirectionally encoded images for suppression of heavily isotropic objects” (SUSHI). Methods Six volunteers underwent diffusion-weighted MR neurography (DW-MRN) of the brachial plexus, and seven volunteers underwent DW-MRN of the sciatic, common peroneal, and tibial nerves at the level of the knee, at 1.5 T. DW-MRN images with SUSHI (DW-MRNSUSHI) and conventional DW-MRN images (DW-MRNAP) were displayed using a coronal maximum intensity projection and evaluated by two independent observers regarding signal suppression of lymph nodes, bone marrow, veins, and articular fluids and regarding signal intensity of nerves and ganglia, using five-point grading scales. Scores of DW-MRNSUSHI were compared to those of DW-MRNAP using Wilcoxon tests. Results Suppression of lymph nodes around the brachial plexus and suppression of articular fluids at the level of the knee at DW-MRNSUSHI was significantly better than that at DW-MRNAP (P

Microsusceptibility changes in the brain are well known to correspond with microbleeds or micrometal fragments in adults, but this phenomenon has not been explored well in children. To assess imaging and clinical characteristics of children with multiple foci of microsusceptibility changes using susceptibility-weighted imaging (SWI). Between 2006 and 2008, 12 children with multiple foci of microsusceptibility on SWI without corresponding abnormal signal on conventional MRI were identified and were retrospectively assessed. The locations of foci of microsusceptibility included the cerebral white matter, basal ganglia, brainstem and cerebellar white matter, without any clear systematic anatomic distribution. CT (n = 5) showed no calcification at the locations corresponding to the microsusceptibility on SWI. Conventional MR imaging showed white matter volume loss (n = 5), delayed myelination (n = 2), acute infarction (n = 1), chronic infarction (n = 1), meningitis (n = 1), slight signal abnormality in the white matter (n = 1) and no abnormal findings (n = 1). Follow-up SWI (n = 3) showed no change of the microsusceptibility foci. Interestingly, all children had a history of heart surgery under extracorporeal circulation for congenital heart disease. Multiple foci of microsusceptibility can be seen in the brain on SWI in children with congenital heart disease who underwent heart surgery with extracorporeal circulation.

Hyperthermia using implants is a cancer treatment in which cancer tissue is heated to over 42.5 °C to selectively kill the cancer cells. In this study, a resonant circuit was used as an implant, and a weak magnetic field of RF pulses from a magnetic resonance imaging (MRI) device was used as an excitation source. We report here how the temperature of the resonant circuit was controlled by changing the excitation frequency of the MRI. As a result, the temperature rise of the resonant circuit was successfully found to depend on its position in the MRI device. This significant result indicates that the temperature of the resonant circuit can be controlled only by adjusting the excitation position. Accurate temperature control is therefore expected to be possible by combining this control technique with the temperature measurement function of MRI equipment.

Objective To introduce and assess a new way of performing whole-body magnetic resonance imaging (MRI) using a non-integrated surface coil approach as available on most clinical MRI systems worldwide. Methods Ten consecutive asymptomatic subjects prospectively underwent whole-body MRI for health screening. Whole-body MRI included T1-, T2- and diffusion-weighted sequences, and was performed using a non-integrated surface coil to image four different stations without patient repositioning. The four separately acquired stations were merged, creating seamless coronal whole-body T1-, T2- and diffusion-weighted images. Anatomical alignment, image quality at the boundaries of adjacent stations, and overall image quality of all stations were qualitatively assessed. Results The average time (±SD) taken to change the surface coil from one station to the next station was 53.8 (±7.1) s. The average total extra examination time ± SD was 2 min 41.4 s (±15.3 s). Anatomical alignment, image quality at the boundaries of adjacent stations, and overall image quality of all stations of T1-, T2- and diffusion-weighted whole-body MRI were overall graded as “good” to “excellent”. Conclusion This study shows that a time-efficient and high-quality whole-body MRI examination can easily be performed by using a non-integrated sliding surface coil approach. Electronic supplementary material The online version of this article (doi:10.1007/s00330-009-1674-1) contains supplementary material, which is available to authorized users.