Quantitative Analysis of Mobile Proteins in Normal Brain Tissue by Amide Proton Transfer Imaging: Age Dependence and Sex Differences.

PURPOSE: The aims of this study were to evaluate the relationship between age change and amide proton transfer (APT) signal in each region of the whole brain and to derive the standard value of APT signal in each brain region of normal adults. MATERIALS AND METHODS: Using the mDIXON 3-dimensional-APT sequence of the fast spin echo method, an APT image was obtained. In total, 60 patients (mean age, 49.8 ± 16.9 years) with no abnormal findings on magnetic resonance imaging data were included. For image analysis, registration parameters were created using the FMRIB Software Library 5.0.11, and then a region of interest was set in the Montreal Neurological Institute structural atlas for analysis. Statistical analyses were performed using the age-dependent and sex differences in APT signals from each brain region. RESULTS: No significant correlation was seen between APT signal and age and sex in all brain regions. CONCLUSION: Under the APT imaging parameter conditions used in this study, local brain APT signals in healthy adults are independent of age and sex.

Quantitative analysis of ovarian cysts and tumors by using T2 star mapping.

AIM: The aim of this study was to investigate the efficacy of T2 star (T2*) mapping in diagnosing ovarian cysts/ tumors. METHODS: Pelvic magnetic resonance examinations including T2*WI were performed before surgery in 35 patients. The region of interest, consisted of a 10 mm2 diameter circle, was set as much as possible inside ovarian tumors/cysts to measure T2*values, and mean T2* values were compared in ovarian cyst/tumor types, retrospectively. Diagnoses of 40 ovarian cysts/tumors were determined by pathological reports, in which 17 were endometriomas, 13 were mature cystic teratomas, 6 were mucinous cystadenomas and 4 were serous cystadenomas. RESULTS: The average T2* values of endometrioma was 56.8 ± 8.7 ms (mean ± SEM), which was significantly lower than that of mucinous cystadenoma (334.2 ± 58.5 ms, mean ± SEM) or serous cystadenoma (237.0 ± 45.4 ms, mean ± SEM). There was no difference in T2* values between endometrioma and mature cystic teratoma (64.1 ± 22.6 ms, mean ± SEM). Receiver operating characteristics curve analysis revealed that optimal cut-off value for differential diagnosis of endometrioma and mucinous or serous cystadenoma was 149.2 ms as T2* value, which has an area under the curve of 0.95 (sensitivity = 92.4%, specificity = 78.6%). CONCLUSION: T2* values were useful to diagnose various types of ovarian cyst/tumor.

Non-contrast enhanced 4D intracranial MR angiography based on pseudo-continuous arterial spin labeling with the keyhole and view-sharing technique.

PURPOSE: 4D dynamic MR angiography (4D-MRA) using pseudo-continuous arterial spin labeling (pCASL), combined with Keyhole and View-sharing (4D-PACK) for scan acceleration, is introduced. Its validity for arterial inflow dynamics visualization was investigated through comparison with 4D-pCASL and contrast inherent inflow enhanced multiphase angiography (CINEMA). METHODS: Six healthy volunteers were included in the study. The arterial transit time (ATT) in 4D-PACK was measured at multiple regions in middle cerebral artery (MCA), and Pearson's correlation coefficient with ATT in 4D-pCASL was calculated. The contrast-to-noise ratio (CNR) in 4D-PACK was measured in four MCA segments and compared with that in 4D-pCASL and CINEMA. Arterial visualization in 4D-PACK was assessed qualitatively in patients with moyamoya disease and arteriovenous malformation by comparing with CINEMA. RESULTS: 4D-PACK achieved a 36% scan time reduction compared with 4D-pCASL. The correlation coefficient for ATT measured by 4D-pCASL and 4D-PACK was greater than 0.96. The CNR was significantly higher using 4D-PACK compared with CINEMA in the M4 segment (P < 0.01). In patient examinations, the flow in the collateral artery or draining vein was better visualized in 4D-PACK compared with CINEMA. CONCLUSION: 4D-PACK accelerates 4D-pCASL, shows similar inflow dynamics as 4D-pCASL and shows better peripheral visualization compared with CINEMA. Magn Reson Med 80:719-725, 2018. © 2018 International Society for Magnetic Resonance in Medicine.

Hyperecho PROPELLER-MRI: Application to rapid high-resolution motion-insensitive T2 -weighted black-blood imaging of the carotid arterial vessel wall and plaque.

PURPOSE: To demonstrate the usefulness of hyperecho and PROPELLER (HEP) for carotid arterial vessel wall imaging by using a quantitative comparison with conventional methods. PROPELLER is a motion-insensitive turbo spin-echo (TSE) sequence and has recently been utilized in magnetic resonance (MR) plaque imaging instead of double inversion recovery TSE (DIR-TSE). Wider blade-width, higher k-space density, and an improved blood suppression effect result in better image quality. In this study we introduce a new combination of HEP. MATERIALS AND METHODS: A total of 17 subjects were examined on a 3.0T system. We conducted quantitative comparisons for signal-to-noise ratio (SNR), contrast-to-noise-ratio, and image sharpness among HEP, DIR-TSE, and conventional PROPELLER (c-PROPELLER). Subsequently, images obtained with DIR-TSE, c-PROPELLER, and HEP were visually evaluated using a three-point scale by two board-certified radiologists. RESULTS: HEP showed high SNR similar to c-PROPELLER, good T2 contrast approximating DIR-TSE, and better blood suppression compared with the other two methods (P < 0.05). The image sharpness of HEP (2.55 ± 0.53) was higher than that of DIR-TSE (1.89 ± 0.33) and the absence of ghost or streak artifacts in HEP (2.89 ± 0.33) was better than that in both other methods (2.22 ± 0.83 for DIR-TSE and 2.00 ± 0.50 for c-PROPELLER) (P < 0.05). Furthermore, the degree of blood suppression, particularly in cases of slow or turbulent flow close to the atherosclerotic plaque, was identical for HEP (2.80 ± 0.45) and DIR-TSE (2.80 ± 0.45) but was significantly better than for c-PROPELLER (1.60 ± 0.55) (P < 0.05). CONCLUSION: This study demonstrates the usefulness of HEP in the carotid arteries. HEP can provide higher-resolution T2 -weighted black-blood imaging without flow- and/or motion-related artifacts, compared to conventional techniques. LEVEL OF EVIDENCE: 3 J. Magn. Reson. Imaging 2017;45:515-524.

Evaluation of Intracranial Arteriovenous Malformations With Four-Dimensional Arterial-Spin Labeling-Based 3-T Magnetic Resonance Angiography.

OBJECTIVE: We aimed to assess the usefulness of 3-T 4-dimensional (4D) arterial spin-labeling (ASL)-based magnetic resonance angiography (MRA) with color-coded time-of-arrival (TOA) maps for the evaluation of cerebral arteriovenous malformations (AVMs). METHODS: Our study included 6 patients with cerebral AVMs. They underwent 4D-ASL MRA at 3T and digital subtraction angiography. A pseudocontinuous arterial spin labeling protocol with look-locker sampling was used for spin labeling. Two independent readers reviewed the 4D-ASL MRA images with color-coded TOA maps for the nidus size, arterial feeders, and venous drainage. Two other readers consensually reviewed the digital subtraction angiography images. RESULTS: The cerebral AVMs were demonstrated on all 4D-ASL MRA images. In 5 high-flow AVMs, the color-coded TOA maps were especially useful for identifying the feeder/drainer. Intermodality agreement was excellent for the nidus size (κ = 1.0), very good for arterial feeders (κ = 0.88), and good for venous drainage (κ = 0.80). CONCLUSIONS: The 4D-ASL 3-T MRA with color-coded TOA maps is useful for assessing the gross angiographic characteristics of intracranial AVMs.

Usefulness of T2 star-weighted imaging in ovarian cysts and tumors.

AIM: The aim of this study was to investigate the prevalence of hypointensity on T2 star-weighted imaging (T2*WI), which is useful for detecting hemosiderin, in endometriomas and other ovarian tumors. The efficacy of detecting adhesions around ovarian tumors was also investigated. METHODS: Pelvic magnetic resonance (MR) examinations, including T2*WI, were carried out. The inclusion criteria were female patients with ovarian surgical treatments. One hundred seventeen patients with a total of 147 lesions were enrolled. Two radiologists retrospectively evaluated MR imaging (MRI) to predict ovarian pathology and the presence of adhesions. T2*WI hypointensity of the inside and outside along ovarian cysts/tumors was utilized to predict pathological diagnoses and the presence of adhesions, respectively. The kappa scores were calculated to measure interobserver agreement on MRI findings. The MRI interpretations were compared with the results of pathological investigation and surgical observations. RESULTS: Hypointensity inside along the cyst walls on T2*WI was observed in 100 out of 106 lesions of endometriomas (94.3%), and three out of 41 non-endometrial ovarian cysts/tumors (7.3%). Four different patterns of T2*WI were observed in ovarian cysts/tumors. The kappa score regarding T2*WI hypointensity inside along the cyst walls was 0.633. Using conventional routine pelvic MRI, the sensitivity for detecting adhesions around ovarian cysts was 84.5%. By adding T2*WI, the sensitivity improved to 91.4% (P < 0.01). With conventional methods to predict adhesions, the kappa score was 0.660. After adding T2*WI to the conventional methods, the kappa score was 0.767. CONCLUSION: Hypointensity on T2*WI was observed frequently in endometrioma. T2*WI also improved the sensitivity for detecting adhesions around ovarian cysts/tumors.

Collateral circulation via the circle of Willis in patients with carotid artery steno-occlusive disease: evaluation on 3-T 4D MRA using arterial spin labelling.

AIM: To evaluate whether 3-T four-dimensional (4D) arterial spin-labelling (ASL) -based magnetic resonance angiography (MRA) is useful for assessing the collateral circulation via the circle of Willis in patients with carotid artery steno-occlusive disease. MATERIALS AND METHODS: Institutional review board approval and prior written informed consent from all patients were obtained. The inclusion criteria were fulfilled by 13 patients with carotid artery steno-occlusive disease. All underwent 4D-ASL MRA at 3 T and digital subtraction angiography (DSA). The flow-sensitive alternating inversion recovery (FAIR) preparation scheme with look-locker sampling was used for spin labeling. At 300-ms intervals seven dynamic scans were obtained with a spatial resolution of 0.5×0.5×0.6 mm(3). The collateral flow via the circle of Willis was read on 4D-ASL MRA and DSA images by two sets of two independent readers each. κ statistics were used to assess interobserver and intermodality agreement. RESULTS: On DSA, collateral flow via the anterior communicating artery (AcomA) was observed in six patients, via the posterior communicating artery (PcomA) in four patients, and via both the AcomA and PcomA in three patients. With respect to the qualitative evaluation of 4D-ASL MRA images, interobserver agreement was excellent for all items (κ=1). 4D-ASL MRA and DSA consensus readings agreed on the type of collateral flow pattern in 10 of the 13 patients (77%). Intermodality agreement was good (κ=0.606; 95% confidence interval (CI): 0.215-0.997). CONCLUSION: 3 T 4D-ASL MRA may be a useful tool for the evaluation of the collateral circulation in patients with carotid artery steno-occlusive disease.

The superior ophthalmic vein: delineation with high-resolution magnetic resonance imaging.

OBJECTIVE: To delineate the superior ophthalmic vein (SOV) with high-resolution magnetic resonance (MR) imaging. METHODS: This retrospective study enrolled 302 consecutive outpatients, 101 patients, 51 males and 50 females, who underwent coronal T2-weighted imaging and 201 patients, 99 males and 102 females, who underwent three-dimensional (3D) phase-contrast (PC) MR angiography. RESULTS: Coronal T2-weighted imaging clearly delineated the intraorbital course of SOV on serial images in all 101 subjects. The SOV could be topographically divided into three segments in relation to the superior rectus muscle. The SOV crossed over the optic nerve at the level of the anterior ethmoidal foramina in 87% of right orbits and 71% of left orbits. The mean outer diameter of the SOV at the crossing point was 1.7 mm on both sides, but the SOVs were asymmetric in the same individual in 75% of the subjects. 3D PC MR angiography showed that the bilateral SOVs were symmetrical in 16% of subjects, larger in the right orbit in 18%, and larger in the left orbit in 13%, and were unidentified in 52%. The SOV showed a consistent lateral course to the ophthalmic artery. CONCLUSIONS: The SOV consistently courses lateral to the ophthalmic artery, but tends to show bilateral asymmetry in the outer diameter. The superior rectus muscle, anterior ethmoidal foramen, and anterior ethmoidal artery are valuable landmarks to identify the SOV during transcranial orbital surgery. Combination of high-resolution MR imaging and 3D PC MR angiography is useful for delineating the SOV.

Intracranial dural arteriovenous fistulas: evaluation with 3-T four-dimensional MR angiography using arterial spin labeling.

PURPOSE: To evaluate whether 3-T four-dimensional (4D) arterial spin-labeling (ASL)-based magnetic resonance (MR) angiography is useful for the evaluation of shunt lesions in patients with intracranial dural arteriovenous fistulas (AVFs). MATERIALS AND METHODS: Institutional review board approval and prior written informed consent from all patients were obtained. Nine patients with intracranial dural AVF (seven men, two women; age range, 52-77 years; mean age, 63 years) underwent 4D ASL MR angiography at 3 T and digital subtraction angiography (DSA). Spin tagging was with flow-sensitive alternating inversion recovery with Look-Locker sampling. At 300-millisecond intervals, seven dynamic images with a spatial resolution of 0.5 × 0.5 × 0.6 mm(3) were obtained. The 4D ASL MR angiographic and DSA images were read by two sets of two independent readers each. Interobserver and intermodality agreement was assessed with the κ statistic. RESULTS: On all 4D ASL MR angiographic images, the major intracranial arteries were demonstrated at a temporal resolution of 300 milliseconds. Interobserver agreement was excellent for the fistula site (κ = 1.00; 95% confidence interval [CI]: 1.00, 1.00), moderate for the main arterial feeders (κ = 0.53; 95% CI: 0.08, 0.98), and good for venous drainage (κ = 0.77; 95% CI: 0.35, 1.00). Intermodality agreement was excellent for the fistula site and venous drainage (κ = 1.00; 95% CI: 1.00, 1.00) and good for the main arterial feeders (κ = 0.80; 95% CI: 0.58, 1.00). CONCLUSION: The good-to-excellent agreement between 3-T 4D ASL MR angiographic and DSA findings suggests that 3-T 4D ASL MR angiography is a useful tool for the evaluation of intracranial dural AVFs.

Venous lacunae presenting with unusual upward protrusion: an anatomic study using high-resolution magnetic resonance imaging.

PURPOSE: This study aims to investigate the distribution and anatomic features of venous lacuna presenting with unusual upward protrusion (VLUUP) using high-resolution magnetic resonance (MR) imaging. METHODS: This retrospective study included 59 consecutive outpatients who underwent MR imaging with gadolinium. Acquired imaging data were transferred to a workstation for analysis. RESULTS: The 30 male and 29 female subjects were aged from 10 to 76 years. A total of 46 VLUUPs located parasagittally were identified in 36 of the 59 patients, 24 on the right, and 22 on the left; 29 patients had one VLUUP, 4 patients had two, and 3 patients had three. Most VLUUPs (93 %) were distributed in the posterior third of the frontal region and the remainder (7 %) in the middle third. There were no VLUUP found in the anterior third of the frontal region or the parietal or occipital regions. The mean longitudinal and lateral dimensions of the VLUUPs and distance from the midline to the medial margin of the VLUUP were 9.7 mm (3.1-27.6), 6.9 mm (3.1-11.5), and 14.3 mm (1.6-43.5), respectively. CONCLUSIONS: The VLUUPs carry a higher risk of injury when making a bony window in or involving the parasagittal posterior frontal region. High-resolution MR imaging is useful for delineating the VLUUPs.

Calvarial diploic venous channels: an anatomic study using high-resolution magnetic resonance imaging.

BACKGROUND: The calvarial diploic venous channels (CDVCs) are well-known intraosseous structures, but their distribution and anatomofunctional implications are not fully understood. OBJECTIVE: To investigate the architecture of CDVCs using high-resolution magnetic resonance (MR) imaging. METHOD: This prospective study enrolled 43 male and 37 female outpatients who underwent a 3.0-T MR imaging equipped by a 32-channel head coil. T1-weighted imaging covering the whole cranial vault was performed after gadolinium injection. In addition, one-piece orbitozygomatic craniotomy was performed in three cadaveric heads to observe the interruption of the CDVCs. RESULTS: The CDVCs showed irregular contours and peculiar branching patterns with four common major pathways: the pteriofrontparietal (PFP), frontoorbital (FO), occipitoparietal (OP), and occipitocervical (OC) routes. The proximal PFP coursed as a single trunk and divided into several branches at the level of the frontal eminence. The orbital part of the FO continued to the subcutaneous vein via the supraorbital rim. The PFP and the pterional part of the FO fused proximally with the sphenoparietal sinus and descended as the middle meningeal vein. The OP coursed in the superoinferior direction and connected the junction part of the transverse-sigmoid sinus to the parietal superior sagittal sinus. The OC occurred as a single trunk in the median occipital bone, drained extracranially, and joined the suboccipital venous channels. CONCLUSIONS: The CDVCs seem to be a relatively consistent network functioning not only as conduits connecting the intracranial dural sinuses but also as pathways to the extracranial venous systems. High-resolution MR imaging is useful for investigating the CDVCs.

An anatomic study of the inferior oblique nerve with high-resolution magnetic resonance imaging.

OBJECTIVE: To investigate anatomic features of the inferior oblique nerve (IObN) by high-resolution magnetic resonance (MR) imaging and cadaveric dissection. METHODS: This study enrolled 100 consecutive outpatients, who underwent 3.0 T MR imaging equipped by the 32-channel head coil. The T2-weighted imaging data of IObN were extracted for analysis and compared with the findings of microsurgical dissection in 14 orbits. RESULTS: 50 male and 50 female subjects allotted to the imaging study were aged from 11 to 78 years. In 94 % sides, the IObN was found to separate from the inferior rectus muscle (IRM) at the level just behind to the posterior pole of the bulb. At the midpoint of the IObN part coursing along the orbital floor and above or adjacent to the infraorbital nerve and artery complex, the mean distance from the lateral margin of the IRM was 1.0 mm on the right and 0.9 mm on the left. The IObN showed upward direction change just below the belly of the inferior oblique muscle and innervated to it at the equator level in 78 sides on the right and 89 on the left. Dissected specimens revealed the consistent morphological findings of the IObN. CONCLUSIONS: The IObN seems to be a relatively consistent structure. Anatomic information on the IObN and surrounding structures that are provided by high-resolution MR imaging can be a help for safe surgery.

Evaluation of contrast and denoising effects related to imaging parameters of compressed sensitivity encoding in contrast-enhanced magnetic resonance imaging.

To acquire reference data for setting an appropriate compressed sensitivity encoding (CS) for brain lesion detectability, the effects of contrast and noise on contrast-enhanced magnetic resonance imaging (MRI) were evaluated. Gadobutrol at various concentrations and manganese chloride tetrahydrate were used as a phantom. Various CS factors (0-10) and denoising levels (weak, medium, and strong) were assessed. The contrast amount decreased from CS7 in non-denoised images for 0.5-2 mmol/L solutions but slightly decreased from CS7 with denoising. The noise amount significantly increased with an increasing CS factor. Generally, there was a significant difference in the denoising level and rate across all CS factors in the case of the 2 and 0 mmol/L solutions. When the CS factor was increased without denoising, the integrated noise power spectrum (NPS) increased and decreased in the high-frequency and low-frequency areas, respectively. These data can be used to establish settings based on the degree of denoising.

Type-B monogalactosyldiacylglycerol synthases are involved in phosphate starvation-induced lipid remodeling, and are crucial for low-phosphate adaptation.

Mono- and digalactosyldiacylglycerol (MGDG and DGDG, respectively) constitute the bulk of membrane lipids in plant chloroplasts. Mutant analyses in Arabidopsis have shown that these galactolipids are essential for chloroplast biogenesis and photoautotrophic growth. Moreover, these non-phosphorous lipids are proposed to participate in low-phosphate (Pi) adaptations. Under Pi-limited conditions, a drastic accumulation of DGDG occurs concomitantly with a large reduction in membrane phospholipids, suggesting that plants substitute DGDG for phospholipids during Pi starvation. Previously, we reported that among the three MGDG synthase genes (MGD1, MGD2 and MGD3), the type-B MGD2 and MGD3 are upregulated in parallel with DGDG synthase genes during Pi starvation. Here, we describe the identification and characterization of T-DNA insertional mutants of Arabidopsis type-B MGD genes. Under Pi-starved conditions, the mgd3-1 mutant showed a drastic reduction in DGDG accumulation, particularly in the root, indicating that MGD3 is the main isoform responsible for DGDG biosynthesis in Pi-starved roots. Moreover, in the roots of mgd2 mgd3 plants, Pi stress-induced accumulation of DGDG was almost fully abolished, showing that type-B MGD enzymes are essential for membrane lipid remodeling in Pi-starved roots. Reductions in fresh weight, root growth and photosynthetic performance were also observed in these mutants under Pi-starved conditions. These results demonstrate that Pi stress-induced membrane lipid remodeling is important in plant growth during Pi starvation. The widespread distribution of type-B MGD genes in land plants suggests that membrane lipid remodeling mediated by type-B MGD enzymes is a potent adaptation to Pi deficiency for land plants.

Improved selective visualization of internal and external carotid artery in 4D-MR angiography based on super-selective pseudo-continuous arterial spin labeling combined with CENTRA-keyhole and view-sharing (4D-S-PACK).

PURPOSE: Four-dimensional magnetic resonance angiography (4D-MRA) based on super-selective pseudo-continuous arterial spin labeling, combined with Keyhole and View-sharing (4D-S-PACK) was introduced for scan-accelerated vessel-selective 4D-MRA. Label selectivity and visualization effectiveness were assessed. METHODS: Nine healthy volunteers were included in the study. The label selectivity for the imaging of internal carotid artery (ICA) and external carotid artery (ECA) circulation was assessed qualitatively. The contrast-to-noise ratio (CNR) in 4D-S-PACK was measured in four middle cerebral artery (MCA) and superficial temporal artery (STA) segments and compared with that in contrast-inherent inflow-enhanced multi-phase angiography combined with the vessel-selective arterial spin labeling technique (CINEMA-select). Vessel-selective arterial visualization in 4D-S-PACK was assessed qualitatively in a patient with dural arteriovenous fistula and compared with digital subtraction angiography (DSA) and non-vessel selective 4D-PACK. RESULTS: 4D-S-PACK vessel selectivity was judged to be at a clinically acceptable level in all cases except one ECA-targeted label. The CNR was significantly higher using 4D-S-PACK compared with CINEMA-select in MCA and STA peripheral segments (p < 0.001). In patient examination, territorial flow visualization in feeding artery and draining vein circulation on 4D-S-PACK were comparable with that on DSA and the identification of such responsible vessels was easier on 4D-S-PACK than on 4D-PACK. CONCLUSION: 4D-S-PACK showed high vessel-selectivity and higher visualization effectiveness compared with CINEMA-select. One clinical case was performed and ICA and ECA territorial flow was successfully visualized separately, suggesting clinical usefulness.

Isozyme-specific modes of activation of CTP:phosphorylcholine cytidylyltransferase in Arabidopsis thaliana at low temperature.

Arabidopsis thaliana increases cellular phosphatidylcholine (PC) content during cold acclimation by up-regulating PC biosynthesis. The A. thaliana genes CCT1 and CCT2 encode CTP:phosphorylcholine cytidylyltransferases (CCTs; EC 2.7.7.15), which regulate PC biosynthesis via the CDP-choline pathway. We isolated the T-DNA-tagged knockout mutants cct1 and cct2 of A. thaliana (Wassilevskaja; WS). CCT activity in cct1 and cct2 plants accounted for 29 and 79% to the cellular CCT activity of WS plants, respectively. When plants were exposed to 2 degrees C for 7 d, CCT activity increased in both cct1 and cct2 plants, and immunoblot analyses revealed that cct1 contained an increased level of CCT2 protein whereas cct2 exhibited little increase in CCT1 level. For each mutant grown at 23 degrees C, CCT activity was mainly enriched in the particulate (15,000 x g pellet) and microsomal (150,000 x g pellet) fractions from rosette leaf homogenates. After exposure to cold, the particulate and microsomal fractions of cct1 plants had higher total CCT activity due to increased levels of CCT2; in contrast, the levels of CCT1 in cct2 plants remained unchanged in particulate and microsomal fractions despite a significant increase in the total CCT activity. We conclude that the CDP-choline pathway of A. thaliana is up-regulated at low temperature via isogene-specific modes: enhanced expression of CCT2 and post-translational activation/inactivation of CCT1 in membranes. PC levels were similarly maintained in both mutants and WS plants after 14 d at 2 degrees C, suggesting that either of the CCT genes is sufficient for PC biosynthesis at low temperature.

Reduction of respiratory ghosting motion artifacts in conventional two-dimensional multi-slice Cartesian turbo spin-echo: which k-space filling order is the best?

The two-dimensional Cartesian turbo spin-echo (TSE) sequence is widely used in routine clinical studies, but it is sensitive to respiratory motion. We investigated the k-space orders in Cartesian TSE that can effectively reduce motion artifacts. The purpose of this study was to demonstrate the relationship between k-space order and degree of motion artifacts using a moving phantom. We compared the degree of motion artifacts between linear and asymmetric k-space orders. The actual spacing of ghost artifacts in the asymmetric order was doubled compared with that in the linear order in the free-breathing situation. The asymmetric order clearly showed less sensitivity to incomplete breath-hold at the latter half of the imaging period. Because of the actual number of partitions of the k-space and the temporal filling order, the asymmetric k-space order of Cartesian TSE was superior to the linear k-space order for reduction of ghosting motion artifacts.

Cylindrical Inversion Pulse for the Reduction of Cardiac Motion Artifacts in Contrast-enhanced Breast MRI.

We proposed a simple technique for reduction of cardiac-related motion artifacts on contrast-enhanced images in the breast by using cylindrical regional-suppression technique (CREST) that can directly suppress the heart signals. The purpose of this study was to select the optimal scan parameters and to evaluate the feasibility in the breast. We demonstrated that the optimized CREST could dramatically reduce the cardiac-related flow artifacts without any penalty to the acquisition time, signal-to-noise ratio and contrast-enhanced lesion-to-parenchyma contrast.

Differentiation of hypointense nodules on gadoxetic acid-enhanced hepatobiliary-phase MRI using T2 enhanced spin-echo imaging with the time-reversed gradient echo sequence: An initial experience.

PURPOSE: To optimize the flip angle (FA) of the T2 enhanced spin-echo imaging using the time reversed gradient echo (T2FFE) and evaluate its utility for differentiating hypointensity nodules in the hepatobiliary phase (HBP) of gadoxetic acid-enhanced (Gd-EOB) MRI. MATERIALS AND METHODS: First, FA optimization of the T2FFE in the HBP was investigated by comparing signal-to-noise ratio (SNR) among different FAs using phantoms. The liver-to-muscle contrast ratios (CRLiver-Muscle) and image quality among three FAs (20°, 50° and 80°) were compared using images of 10 patients. Next, the utility of the T2FFE with an optimized FA for differentiating hypointensity nodules in the HBP was assessed by comparing the lesion-to-liver contrast ratio (CRLesion-Liver) among cysts, hemangiomas, hepatocellular carcinomas, and metastatic tumors in 32 patients. RESULTS: SNR increased as FA increased, but leveled off at FAs of 50° and greater. The FA of 50° showed significantly better image quality scores than that of 80° (p<0.05). After employing an FA of 50°, the CRLesion-Liver value indicated that the T2FFE depicted benign lesions as hyperintense and most malignant lesions as hypointense in relation with the liver parenchyma (p<0.05). CONCLUSION: The T2FFE in the HBP of Gd-EOB-MRI is useful for differentiating benign and malignant liver lesions.

[Clinical usage of parallel imaging of head three-dimensional MR image for analysis of VSRAD: a comparison of imaging statistical analytic results in SENSE acquisition method shortening acquisition time versus conventional acquisition method].

Voxel-based Specific Regional Analysis System for Alzheimer's Disease (VSRAD) has developed recently as an adjunctive diagnostic tool for early Alzheimer-type dementia (ATD), using three-dimensional (3D) MRI with statistical parametric mapping (SPM), and for the objective evaluation of brain atrophy. However, it takes more than five minutes to acquire MRI data by the 3D gradient echo method (3D FFE), resulting in low-throughput performance and motion artifact. These problems interrupt the application of daily MRI study. In this study, we recruited 20 patients suspected of having ATD who then underwent continuous 3D FFE MRI studies with and without the SENSE method. It was found that the VSRAD results of MRI data with SENSE were nearly to equal to those without SENSE, in spite of the prediction of a decline in source-to-noise ratio due to the reduction factor in the SENSE method.