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.

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.

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.

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.

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.

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.

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.

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.

The assessment of myometrium perfusion in patients with uterine fibroid by arterial spin labeling MRI.

BACKGROUND: It has been suggested that an inadequate blood supply caused by uterine fibroids may lead to decreasing fertility. Therefore, a quantitative evaluation of blood flow in the uterus might be a good tool for infertility treatments. For the first step, the ability to perform arterial spin labeling (ASL)-MRI in pelvic organs was examined by measuring blood flow in the uterine muscle layer. RESULTS: Three normal volunteer women, seven patients with one uterine fibroid and four patients treated with GnRH analogue for uterine fibroids, were enrolled in this study. Perfusion of normal uterine myometrium was examined using non-enhanced ASL-MRI. The region of interest was set in the uterine muscle layer, with a point in the iliopsoas or gluteus muscle. The ASL perfusion index was calculated as (ASL value in uterus-ASL value in iliopsoas/gluteus muscle). The ASL perfusion indexes in the secretory phase of all 3 volunteers were significantly lower than the indexes in the proliferative phases (P < 0.05). In patients with fibroids, all three types of fibroids (subserosal, intramural and submucosal types) were included. In seven patients harboring a single uterine fibroid, the ASL perfusion indexes of myometrium on the fibroid-positive side increased 4.9 fold compared with that of the fibroid-negative side. With GnRH analogue treatment, ASL perfusion in myometrium decreased to 39% on average (P < 0.05). CONCLUSION: We utilized the ASL-MRI technique to evaluate perfusion of uterine myometrium. For clinical use, an inadequate blood supply caused by uterine fibroids is known to lead to decreasing fertility. The ASL-MRI technique might be useful to evaluate blood supply as a quantitative measurement of fertility in patients with uterine fibroids.

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.

Evaluation of Intracranial Vasculatures in Healthy Subjects with Arterial-Spin-Labeling-Based 4D-MR Angiography at 3T.

Contrast inherent inflow-enhanced multi-phase angiography combining multiple-phase flow-alternating inversion-recovery (CINEMA-FAIR) is an arterial-spin-labeling-based four-dimensional magnetic resonance angiography (4D-MRA) technique. Two neuroradiologists independently evaluated the depiction of the intracranial vasculatures in healthy subjects with 3T 4D-MRA using CINEMA-FAIR. Our results indicated that this technique can provide good visualization of the cerebral arteries with a high spatial and temporal resolution. It appears to have sufficient resolution for identifying flow difference in the anterior and posterior circulation in healthy subjects.

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.

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.

Volume isotropic simultaneous interleaved black- and bright-blood imaging: a novel sequence for contrast-enhanced screening of brain metastasis.

We introduced and optimized a novel sequence of fast (about 4 min), volumetric, high resolution, simultaneous bright- and black-blood imaging with sufficient T1 contrast between enhanced metastasis and surrounding brain parenchyma for their differentiation. This proposed sequence can be used for 3-dimensional volumetric T1-weighted bright- and black-blood imaging in contrast-enhanced studies and may be promising for detecting small brain metastases by improving differentiation between blood vessels and small brain metastases.

Cervical spondylosis: Evaluation of microstructural changes in spinal cord white matter and gray matter by diffusional kurtosis imaging.

INTRODUCTION: We investigated microstructural changes in the spinal cord, separately for white matter and gray matter, in patients with cervical spondylosis by using diffusional kurtosis imaging (DKI). METHODS: We studied 13 consecutive patients with cervical myelopathy (15 affected sides and 11 unaffected sides). After conventional magnetic resonance (MR) imaging, DKI data were acquired by using a 3T MR imaging scanner. Values for fractional anisotropy (FA), apparent diffusion coefficient (ADC), and mean diffusional kurtosis (MK) were calculated and compared between unaffected and affected spinal cords, separately for white matter and gray matter. RESULTS: Tract-specific analysis of white matter in the lateral funiculus showed no statistical differences between the affected and unaffected sides. In gray matter, only MK was significantly lower in the affected spinal cords than in unaffected spinal cords (0.60±0.18 vs. 0.73±0.13, P=0.0005, Wilcoxon's signed rank test). CONCLUSIONS: MK values in the spinal cord may reflect microstructural changes and gray matter damage and can potentially provide more information beyond that obtained with conventional diffusion metrics.

Improvement of T1 contrast in whole-brain black-blood imaging using motion-sensitized driven-equilibrium prepared 3D turbo spin echo (3D MSDE-TSE).

We demonstrated a new scheme for performing the T1-enhanced whole-brain black-blood imaging pulse sequence using motion-sensitized driven-equilibrium prepared 3-dimensional (3D) turbo spin echo (MSDE-TSE) with anti-driven-equilibrium post pulse. The use of an anti-driven-equilibrium pulse considerably improved the T1 contrast of MSDE-TSE black-blood images. This sequence can be used for whole-brain 3D volumetric T1-weighted black-blood imaging and may improve the accuracy of anatomical localization for certain brain lesions.

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.

Simple method for whole-brain volumetric T(1)-weighted turbo spin-echo imaging.

We propose a simple scheme of 3D turbo spin echo (TSE) with low-refocusing flip angles (RFAs) for obtaining sufficient T1-weighted contrast. The low RFA can easily lead spins into a pseudo-steady-state (PSS) condition, but a preparation scheme is required for smooth transition into static PSS. For obtaining T1 contrast, PSS preparation is the most important factor, and therefore we focused on the PSS preparation. To optimize the T1 contrast in the proposed sequence, we compared the following parameters: RFAs of 90° and 30°, and a PSS preparation scheme of "90° + α/2" and asymptotic preparation. Subsequently, to demonstrate the quality of the proposed sequence, we compared the image quality regarding conventional 3D TSE and 2D spin echo (SE). A combination of an RFA of 30° and the "90° + α/2" preparation scheme showed the highest T1 contrast. The optimized sequence provided higher contrast and sharper images compared to 3D TSE, and it showed contrast and a signal-to-noise ratio similar to those of 2D SE.