• Journal of the Korean Orthopaedic Association
• /
• v.53 no.6
• /
• pp.547-551
• /
• 2018

Three Stener-like lesions of the metacarpophalangeal joint of the fingers and a rupture of the first dorsal interosseous muscle mimicking the lesion in the index finger were observed. Two cases in the little fingers had a true Stener's lesion. In one case in the index finger, the ruptured ligament was retracted and located under the intact sagittal band, which was also observed by preoperative magnetic resonance imaging (MRI). Rupture of the first dorsal interosseous muscle was misdiagnosed preoperatively as a Stener's lesion in the index finger by ultrasonography. MRI should be an essential differential diagnostic exam for collateral ligament ruptures of the metacarpophalangeal joint of the fingers.

• Korean Journal of Radiology
• /
• v.22 no.5
• /
• pp.759-769
• /
• 2021

Objective: To evaluate the application of laplacian-regularized mean apparent propagator (MAPL)-MRI to brain glioma-induced corticospinal tract (CST) injury. Materials and Methods: This study included 20 patients with glioma adjacent to the CST pathway who had undergone structural and diffusion MRI. The entire CSTs of the affected and healthy sides were reconstructed, and the peritumoral CSTs were manually segmented. The morphological characteristics of the CST (track number, average length, volume, displacement of the affected CST) were examined and the diffusion parameter values, including fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD), radial diffusivity (RD), mean squared displacement (MSD), q-space inverse variance (QIV), return-to-origin probability (RTOP), return-to-axis probabilities (RTAP), and return-to-plane probabilities (RTPP) along the entire and peritumoral CSTs, were calculated. The entire and peritumoral CST characteristics of the affected and healthy sides as well as those relative CST characteristics of the patients with motor weakness and normal motor function were compared. Results: The track number, volume, MD, RD, MSD, QIV, RTAP, RTOP, and RTPP of the entire and peritumoral CSTs changed significantly for the affected side, whereas the AD and FA changed significantly only in the peritumoral CST (p < 0.05). In patients with motor weakness, the relative MSD of the entire CST, QIV of the entire and peritumoral CSTs, and the AD, MD, RD of the peritumoral CST were significantly higher, whereas the RTPP of the entire and peritumoral CSTs and the RTOP of the peritumoral CST were significantly lower than those in patients with normal motor function (p < 0.05 for all). In contrast, no significant changes were found in the CST morphological characteristics, FA, or RTAP (p > 0.05 for all). Conclusion: MAPL-MRI is an effective approach for evaluating microstructural changes after CST injury. Its sensitivity may improve when using the peritumoral CST features.

• Investigative Magnetic Resonance Imaging
• /
• v.18 no.2
• /
• pp.87-106
• /
• 2014

Purpose : To describe how a robust implementation of a radial 3D gradient-echo sequence with stack-of-stars sampling can be achieved, to review the imaging properties of radial acquisitions, and to share the experience from more than 5000 clinical patient scans. Materials and Methods: A radial stack-of-stars sequence was implemented and installed on 9 clinical MR systems operating at 1.5 and 3 Tesla. Protocols were designed for various applications in which motion artifacts frequently pose a problem with conventional Cartesian techniques. Radial scans were added to routine examinations without selection of specific patient cohorts. Results: Radial acquisitions show significantly lower sensitivity to motion and allow examinations during free breathing. Elimination of breath-holding reduces failure rates for non-compliant patients and enables imaging at higher resolution. Residual artifacts appear as streaks, which are easy to identify and rarely obscure diagnostic information. The improved robustness comes at the expense of longer scan durations, the requirement for fat suppression, and the nonexistence of a time-to-center value. Care needs to be taken during the configuration of receive coils. Conclusion: Routine clinical use of radial stack-of-stars sequences is feasible with current MR systems and may serve as substitute for conventional fat-suppressed T1-weighted protocols in applications where motion is likely to degrade the image quality.

• Investigative Magnetic Resonance Imaging
• /
• v.18 no.4
• /
• pp.362-365
• /
• 2014

Predominant involvement of a particular group of fingers due to a central nervous system lesion has been described as pseudoperipheral palsy. Two patients visited our hospital with isolated weakness of a particular group of fingers due to small cortical infarctions. A 51-year-old woman suddenly developed weakness in her left index and middle fingers. The brain MRI showed a small infarct in the right frontal cortex. A 67-year-old man was sudden difficulty using his chopsticks and had weakness in his right thumb and index finger. The brain MRI showed a small infarct in the left precentral cortex.

• Proceedings of the KOSOMBE Conference
• /
• v.1994 no.12
• /
• pp.43-46
• /
• 1994

A new spatial localization technique using high-order surface gradient coil (SGC) is proposed. Although the Spatial Selection with High-Order gradient (SHOT) can provide a 2-D selection with only one selective RF pulse, the high-order gradient produced by cylindrical-shape coils has not been clinically useful for clinical systems due to the large minimum selection size caused by the limited radial gradient intensity. However, by using the proposed high-order SGCs located near the imaging region, the size of volume selection can be reduced to a clinically useful 1-4 cm in diameter by applying stronger radial gradient with much less gradient driving power. A 40 cm-by-40 cm $r^{2}$ SGC has been designed and constructed, and phantom and volunteer studies have been performed. Experimental results using spatially localized MRI show good agreement to the theoretically predicted behavior.

• Journal of Biomedical Engineering Research
• /
• v.17 no.1
• /
• pp.19-24
• /
• 1996

The purpose of this paper is to design high-order (or radial) surface gradient coil (SGC), which can provide multi-dimensional spatial selection. Although the spatial Selection with High-Order gradienT (SHOT) can provide a 2-D selection with only one selective RF pulse, the high-order gradient pro- duced by conventional cylindrical-shape coils has not been clinically useful due to the large selection size caused by the limited radial gradient intensity. However, by using the proposed high-order SGCs located near the imaging region, the size of volume selection can be reduced to a clinically useflll size of 1-2 cm in diameter by applying stronger radial gradient field with much less gradient driving power. So far radial SGCs have been designed by using the field component method and may cause distortion in the selection shapes. In this paper, by using the target field approach for the coil design, selected volumes became almost circular. A 40 cm-by-40 cm $z^2$_surface gradient coil has been designed and implemented by using the target field approach. Phantom and volunteer studies have been performed Experimental results using spatially localized MRI show good agreement to the theoretically predicted behavior.

• Investigative Magnetic Resonance Imaging
• /
• v.20 no.2
• /
• pp.81-87
• /
• 2016

Purpose: To analyze the feasibility of three-dimensional (3D) diffusion-weighted (DW) PSIF (reversed FISP [fast imaging with steady-state free precession]) sequence in order to evaluate peripheral nerves in the elbow. Materials and Methods: Ten normal, asymptomatic volunteers were enrolled (6 men, 4 women, mean age 27.9 years). The following sequences of magnetic resonance images (MRI) of the elbow were obtained using a 3.0-T machine: 3D DW PSIF, 3D T2 SPACE (sampling perfection with application optimized contrasts using different flip angle evolution) with SPAIR (spectral adiabatic inversion recovery) and 2D T2 TSE (turbo spin echo) with modified Dixon (m-Dixon) sequence. Two observers used a 5-point grading system to analyze the image quality of the ulnar, median, and radial nerves. The signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) of each nerve were measured. We compared 3D DW PSIF images with other sequences using the Wilcoxon-signed rank test and Friedman test. Inter-observer agreement was measured using intraclass correlation coefficient (ICC) analysis. Results: The mean 5-point scores of radial, median, and ulnar nerves in 3D DW PSIF (3.9/4.2/4.5, respectively) were higher than those in 3D T2 SPACE SPAIR (1.9/2.8/2.8) and 2D T2 TSE m-Dixon (1.7/2.8/2.9) sequences (P < 0.05). The mean SNR in 3D DW PSIF was lower than 3D T2 SPACE SPAIR, but there was no difference between 3D DW PSIF and 2D T2 TSE m-Dixon in all of the three nerves. The mean CNR in 3D DW PSIF was lower than 3D T2 SPACE SPAIR and 2D T2 TSE m-Dixon in the median and ulnar nerves, but no difference among the three sequences in the radial nerve. Conclusion: The three-dimensional DW PSIF sequence may be feasible to evaluate the peripheral nerves around the elbow in MR imaging. However, further optimization of the image quality (SNR, CNR) is required.

• Archives of Hand and Microsurgery
• /
• v.23 no.4
• /
• pp.301-305
• /
• 2018

Hemangiomas are benign neoplasms of endothelial cells origin, rarely found in hand region. Authors report a 62-year-old female with capillary hemangioma of right index finger causing a neuropathic symptom via nerve compression. A space-occupying vascular lesion surrounding the radial digital nerve was revealed in magnetic resonance imaging (MRI), which was removed under microscopic assist. The digital nerve was decompressed consequently. The mass was firmly attached to both the digital nerve and digital artery, requiring a meticulous microscopic dissection to preserve the nerve and artery. Compression neuropathy caused by space-occupying lesions is rare and its diagnosis is often difficult. A microscopic surgical approach can be used to successfully relieve neuropathic pain after proper diagnosis established by diagnostic tools such as MRI as in this case.

• Journal of the Korean Society of Radiology
• /
• v.83 no.3
• /
• pp.582-596
• /
• 2022

To accurately interpret knee MRI, it is important not only to know the basic meniscal anatomy but also to distinguish it from that under pathological conditions. Thus, it would be helpful to know the normal meniscus variants (false positives) that could be mistaken for meniscal tears, and tears that could easily be missed and incorrectly diagnosed as normal (false negatives). False positives include synovial recesses, meniscal flounce, the relationship between the popliteus tendon and lateral meniscus, transverse ligament, the anterior root of the meniscus, and meniscofemoral ligament. False negatives include focal radial tears, flap tears, posterior root tears, meniscocapsular separation, and discoid meniscal tears. In this pictorial essay, we reviewed the imaging data obtained in the aforementioned cases.

• Journal of Acupuncture Research
• /
• v.20 no.6
• /
• pp.201-209
• /
• 2003

Objective : Recently, Seguele of Traffic Accident patients are increasing, especially cervical injury bring only severe sequela but also mortal damage to the patient. In treatment of the disease, the east medical treatment is another effective method. Methods : The patient resisted the west theraphy improved greatly in movement and sensation by acupuncture, moxibustion, herb medication and Physical treatment. In MRI, The treatment result is proved. Acupuncture on Stomach Meridian(足陽明胃經) referring to Naijing(內經) is thought effective. Results : Tetraplegia by Traffic Accident is considered as Wei Symptom in term of the east medicine, By means of radial and physical study of the patient treated by the east medicine, we are conviced that the east medicine is the excellent method Conclusions : Referring to the past documentary data, The only Treatment on this disease is Surgical operation, but the operation isn't the successful one because seg. of spinal cord injury is mortal. The east treatment, acupuncture, moxibustion herb medication and physical treatment isn't only effective but also satisfactory. In the future, The study on this disease by the east medicine should be made thoroughly.