Steady-state Acquisition Magnetic Resonance Imaging Research Articles

Clinical Parameters Reflecting Globe/orbit Volume Imbalances in Japanese Acquired Esotropia Patients with High Myopia but without Abduction Limitations.

In high myopia, eye dislocation due to increased globe volume or tight orbital volume causes acquired esotro-pia. GOR (globe/orbit volume ratio), an indicator of the degree of progression of this pathology, was investi-gated the relationships among easily obtained clinical parameters. In this retrospective study, 20 eyes from 10 acquired esotropia patients with high myopia but without abduction limitations were examined. The mean age of the patients was 63.7 ± 8.2 years (mean ± standard deviation). Volumes were measured on the three-dimen-sional fast imaging employing steady-state acquisition magnetic resonance imaging images using the vol-ume-measurement function. Correlations between GOR and the displacement angle of the globe (DA), axial length (AL), and equatorial diameter (ED) were investigated. Mean DA, AL, ED, and GOR values were 107.5 ± 8.5°, 28.86 ± 1.92 mm, 25.00 ± 1.16 mm, and 0.36 ± 0.05, respectively. Only AL was correlated with GOR (p < 0.0001, R2 = 0.6649); DA (p = 0.30, R2 = 0.0633) and ED (p = 0.91, R2 = 0.0008) were not. AL was the only clinically available parameter to indicate globe/orbit volume imbalances in acquired esotropia with high myopia but without abduction limitation. AL may be important for the clinical assessment of the progression of this pathology.

Usefulness of three-dimensional fast imaging employing steady-state acquisition MRI of large vessel occlusion for detecting occluded middle cerebral artery and internal carotid artery before acute mechanical thrombectomy.

Objective Acute mechanical thrombectomy (AMT) in patients with acute ischemic stroke from large vessel occlusion (LVO) is performed without directly identifying the occluded vessels. In this study, we evaluated whether 1.5 T magnetic resonance imaging (MRI) with 3D-fast imaging employing steady-state acquisition (FIESTA) could visualize the occluded intracranial middle cerebral artery (MCA) and internal carotid artery (ICA) before AMT.Methods This retrospective study included 21 consecutive patients who underwent time-of-flight magnetic resonance angiography (TOF MRA) and 3D-FIESTA MRI immediately before AMT. The patients also underwent TOF MRA after AMT and achieved TICI 2b or 3 by AMT at our hospital between February 2018 and April 2019. When LVO in the anterior circulation was detected by TOF MRA, 3D-FIESTA MRI was additionally performed. Then, the occluded intracranial MCA and ICA, including their branches, were constructed on the workstation with volume rendering. The obtained images were fused with the TOF MRA images to create combined 3D images.Results The length and top-to-bottom distance of the affected M1 segment (calculated by the ipsilateral-to-contralateral ratio) were 1.29 and 1.17, respectively, on 3D-FIESTA MRI before AMT and 1.34 and 1.24, respectively, on TOF MRA after AMT. We assessed the number of M2 segments branching from the affected M1/M2 junction and visualized the affected anterior temporal artery. The 3D-FIESTA MRI before AMT and TOF MRA after AMT were consistent in all patients, except for two who moved vigorously during imaging.Conclusions Images acquired by 1.5T 3D-FIESTA MRI can visualize to predict the existing path of the occluded MCA and ICA before AMT in patients with LVO of the anterior circulation.

The rotating stretched curved planar reconstruction of 3D-FIESTA MR imaging for evaluating the anterior cruciate ligament of the knee joint

PurposeTo determine the feasibility of the rotating stretched curved planar reconstruction (CPR) of three-dimensional fast imaging with steady-state acquisition magnetic resonance imaging (3D-FIESTA MRI) for evaluating the anterior cruciate ligament of the knee joint. Materials and methodsMRI of 40 knee joints in healthy volunteers was performed on a 3.0-T MR scanner and a phased-array extremity coil. The protocol consisted of oblique sagittal spin echo (SE) T1WI, coronal FS-PDWI, axial FS-FSE-T2WI, and 3D-FIESTA sequences. The rotating stretched curved planar reconstructions (CPR) of the ACL at angles of 0°, 30°, 60°, 90°, 120°, 150°, and 180° were generated from images of 3D-FIESTA sequences. Signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) of the 3D-FIESTA were compared with those of the oblique sagittal SE T1WI sequence. The presence of the tibial attachment, midportion, femoral attachment, and double bundles of the ACL on the oblique sagittal SE T1WI and CPR of 3D-FIESTA MR imaging were divided into two categories: visible and not visible. ResultsThe ACL SNR efficiency of 3D-FIESTA sequences was significantly higher than that of oblique sagittal SE T1WI sequence (P < 0.05). The 3D-FIESTA sequences produced images with a significantly higher CNR between ACL and synovial fluid than did the oblique sagittal SE T1WI sequence (P < 0.05). CPR of 3D-FIESTA MRI generated an excellent visualization of the ACL. The CPR of 3D-FIESTA MRI was rated superior to oblique sagittal SE T1WI sequence in 60% and 65% of cases with regard to the tibial attachment and midportion of ACL, respectively (P < 0.05). CPR of 3D-FIESTA MR imaging was rated superior to oblique sagittal SE T1WI sequence in 80% and 85% of cases with regard to femoral attachment and double bundles of ACL, respectively (P < 0.05). ConclusionThe rotating stretched curved planar reconstruction of 3D-FIESTA sequences is significantly better than that of conventional 2D-MRI in evaluating the native ACL and its components, AM bundle and PL bundle, in healthy volunteers.

Evaluation of the facial nerve and internal auditory canal cross-sectional areas on three-dimensional fast imaging employing steady-state acquisition magnetic resonance imaging in Bell’s palsy

Background/aim: This study aimed to evaluate the facial nerve (FN) and internal auditory canal (IAC) on three-dimensional fast imaging employing steady-state acquisition (3D-FIESTA) magnetic resonance imaging (MRI) to define possible structural differences in cases of Bell's palsy (BP). Materials and methods: Fifty-six patients presenting with BP were included in this study. The measurements of the diameters and the cross-sectional areas (CSAs) of the FNs and IACs obtained on 3D-FIESTA MRI both on the affected and unaffected sides of all patients were compared. Results: A significant difference was found between affected and unaffected sides of the patients in terms of the mean CSA of the FN and IAC (P < 0.001). The CSAs of the FN were larger and the CSAs of the IAC were smaller on the affected sides than the equivalents on the unaffected sides of the patients, respectively. The difference in terms of the ratios of IAC CSA to FN CSA between affected and unaffected sides of the patients was also found to be statistically significant (P < 0.001). Conclusion: We have found that FN and IAC size differ on the affected sides of patients with BP. These anatomical differences may contribute to the risk for this disease.

Diagnosis of demyelinating brain lesion simulating brain tumors on fast imaging employing steady-state acquisition magnetic resonance imaging.

Background:A single inflammatory demyelinating brain lesion sometimes mimics a brain tumor on conventional magnetic resonance imaging (MRI), and thus poses a considerable diagnostic challenge. We assessed the usefulness of a new MRI technique, fast imaging employing steady-state acquisition (FIESTA), for the diagnosis of inflammatory demyelinating disease (IDD).Methods:Three patients (2 males, 1 female) with a histopathologically proven inflammatory demyelinating brain lesion which mimicked a brain tumor on MRI were evaluated with a post-contrast three-dimensional FIESTA sequence before biopsy and treatment. Those images were compared with the images of intra-axial brain tumors (n = 147).Results:Preoperative FIESTA showed an iso- or slightly hyperintense distinct intralesional structure that appeared reticulate or broad-line in patients with IDD. These structures traversed a hyperintense demyelinating lesion in the deep grey matter (DGM) and were connected to the surrounding extralesional area, which appeared to be dense fibers between DGM. Such distinct intralesional structures were not observed in most brain tumors.Conclusion:Reticulate or broad-line-like intralesional structures on FIESTA may, therefore, be suggestive of IDD rather than indicate a brain tumor.

An intradural arachnoid cyst of the thoracic spinal cord detected by fast imaging employing steady-state acquisition magnetic resonance imaging

An intradural arachnoid cyst of the thoracic spinal cord detected by fast imaging employing steady-state acquisition magnetic resonance imaging

Does a small posterior fossa increase nerve vascular conflict in trigeminal neuralgia?

Magnetic resonance imaging (MRI) can be helpful in visualizing neurovascular conflict (NVC) of the trigeminal nerve in patients with trigeminal neuralgia (TN), but the relationship between these two events is controversial. To investigate whether posterior fossa volume is a predisposing factor for NVC in TN. We conducted a case-control study of clinically diagnosed idiopathic TN of 30 patients aged 30-79 years and 30 age- and sex-matched controls. We compared the volume of the posterior fossa and subarachnoid space using fast-imaging employing steady-state acquisition MRI and the iPlan® programme of BrainLab. The posterior fossa volumes in controls and patients with TN were 168.97 cm(3) and 167.63 cm(3), respectively. A small pontomesencephalic cistern volume was more frequent in TN. However, neither the cisternal nor parenchymal portions of the posterior fossa were different between patients with TN and controls, and no significant volume difference was observed in this study. Although the hypothesis that small posterior fossa volume influences TN was feasible, we did not find any volumetric differences (including the cisternal and parenchymal volumes).However, small pontomesencephalic cistern volumes were more frequent in patients with TN.

Usefulness of fast imaging employing steady-state acquisition magnetic resonance images for appropriate fenestration in a recurrent convexity arachnoid cyst

It is difficult for convexity arachnoid cysts to determine where the cyst should be fenestrated because there is no large cistern around the cyst. We successfully fenestrated a recurrent convexity arachnoid cyst during a second surgery because of the information provided by preoperative fast imaging employing steady-state acquisition (FIESTA) magnetic resonance (MR) imaging. A 19-year-old woman experienced a progressive headache and was diagnosed with an arachnoid cyst in the right temporal lobe, for which she underwent membranectomy. However, the cyst was gradually enlarging for 2 years after the first surgery and the patient’s headache recurred. FIESTA MR images revealed the membrane between the cyst and the distal sylvian fissure. This membrane was dissected and resected to connect to the cistern in the second surgery.

CYBERKNIFE STEREOTACTIC RADIOTHERAPY FOR SPINAL TUMORS

For para- and intraspinal tumors, precise spinal cord delineation is critical for CyberKnife (Accuray, Inc., Sunnyvale, CA) stereotactic radiotherapy. We evaluated whether computed tomographic (CT) myelography is superior to magnetic resonance imaging (MRI) for accurate spinal cord delineation. Treatment parameters and short-term outcome and toxicity are also presented. The planning CT scan, the gadolinium-enhanced, T1-weighted, 3-dimensional (3D) fast imaging employing steady-state acquisition MRI scan, and the CT myelogram were fused before volume-of-interest delineation. The planning target volume margin was less than 1 mm using the Xsight Spine tracking system (Accuray). We present data from 11 heavily pretreated patients who underwent CyberKnife stereotactic radiosurgery between November 2006 and January 2008. Spatial resolution was 0.46 and 0.93 mm/pixel for CT myelography and 3D-fast imaging employing steady-state acquisition MRI, respectively. The contrast between cerebrospinal fluid and spinal cord was excellent with CT myelography. A transient postmyelography headache occurred in 1 patient. The mean gross tumor volume was 51.1 mL. The mean prescribed dose was 34 Gy in 4 fractions (range, 2-7 fractions) with 147 beams (range, 79-232 beams) to the 75% reference isodose line (range, 68-80%), covering 95% (range, 86-99%) of the gross tumor volume with a mean conformity index of 1.4 (range, 1.1-1.8). No short-term toxicity on the spinal cord was noted at 1- to 6-months of follow-up. CT myelography was more accurate for spinal cord delineation than 3D-fast imaging employing steady-state acquisition MRI (used for its myelographic effect), particularly in the presence of ferromagnetic artifacts in heavily pretreated patients or in patients with severe spinal compression. Because other MRI sequences (T2 and gadolinium-enhanced T1) provide excellent tumor characterization, we suggest trimodality imaging for spinal tumor treatment to yield submillimetric delineation accuracy. Combined with CyberKnife technology, CT myelography can improve the feasibility of dose escalation or reirradiation of spinal tumors in selected patients, thereby increasing local control while avoiding myelopathy. Further follow-up and prospective studies are warranted.

Preoperative Assessment of Microvascular Compression of Cranial Nerve IX and X Using 3D Fast Imaging Employing Steady-state Acquisition Magnetic Resonance Imaging in Glossopharyngeal Neuralgia

Preoperative Assessment of Microvascular Compression of Cranial Nerve IX and X Using 3D Fast Imaging Employing Steady-state Acquisition Magnetic Resonance Imaging in Glossopharyngeal Neuralgia

Three-dimensional Fast Imaging Employing Steady-state Acquisition Magnetic Resonance Imaging for Stereotactic Radiosurgery of Trigeminal Neuralgia

The aim of this study was to demonstrate the use and applications of the three-dimensional fast imaging employing steady-state acquisition (3-D-FIESTA) magnetic resonance imaging sequence in targeting and planning for stereotactic radiosurgery of trigeminal neuralgia. A 3-D-FIESTA sequence for visualization of cranial nerves in the cranial base was added to the routine magnetic resonance imaging scan to enhance the treatment planning for trigeminal neuralgia. T1-weighted images, 1 mm thick, were directly compared with the FIESTA sequence for the exact visualization of the trigeminal entry zone and surrounding vasculature. The target accuracy was evaluated by image fusion of computed tomographic and magnetic resonance imaging scans. The anatomy visualized with the FIESTA sequence was validated by direct inspection of the gross anatomic specimens of the trigeminal complex. A total of 15 consecutive patients, 10 women and 5 men, underwent radiosurgery for essential trigeminal neuralgia between April and July, 2003. The mean age of the patients was 65.2 years (range, 24-83 yr). Nine patients had right-sided symptoms. Four patients had had previous surgery (two microvascular decompression, one percutaneous rhizotomy, and one radiofrequency thermocoagulation). The 3-D-FIESTA sequence successfully demonstrated the trigeminal complex (root entry zone, trigeminal ganglion, rootlets, and vasculature) in 14 patients (93.33%). The 3-D-FIESTA sequence also allowed visualization of the branches of the trigeminal nerve inside Meckel's cavity. This exact visualization correlated precisely with the anatomic specimens. In one patient (6.66%), it was not possible to demonstrate the related vasculature. However, the other structures were clearly visualized. The 3-D-FIESTA sequence is used in this study for demonstration of the exact anatomy of the trigeminal complex for the purpose of radiosurgical planning and treatment of trigeminal neuralgia. With such imaging techniques, radiosurgical targeting of specific trigeminal nerve branches may be feasible. It has not been possible previously to target individual branches of the trigeminal nerve.