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Dive into the research topics where Na Ra Kim is active.

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Featured researches published by Na Ra Kim.


Korean Journal of Radiology | 2011

Time-Resolved 3D Contrast-Enhanced MRA on 3.0T: a Non-Invasive Follow-Up Technique after Stent-Assisted Coil Embolization of the Intracranial Aneurysm

Jin Woo Choi; Hong Gee Roh; Won-Jin Moon; Na Ra Kim; Sung Gyu Moon; Chung Hwan Kang; Young Il Chun; Hyun-Seung Kang

Objective To evaluate the usefulness of time-resolved contrast enhanced magnetic resonance angiography (4D MRA) after stent-assisted coil embolization by comparing it with time of flight (TOF)-MRA. Materials and Methods TOF-MRA and 4D MRA were obtained by 3T MRI in 26 patients treated with stent-assisted coil embolization (Enterprise:Neuroform = 7:19). The qualities of the MRA were rated on a graded scale of 0 to 4. We classified completeness of endovascular treatment into three categories. The degree of quality of visualization of the stented artery was compared between TOF and 4D MRA by the Wilcoxon signed rank test. We used the Mann-Whitney U test for comparing the quality of the visualization of the stented artery according to the stent type in each MRA method. Results The quality in terms of the visualization of the stented arteries in 4D MRA was significantly superior to that in 3D TOF-MRA, regardless of type of the stent (p < 0.001). The quality of the arteries which were stented with Neuroform was superior to that of the arteries stented with Enterprise in 3D TOF (p < 0.001) and 4D MRA (p = 0.008), respectively. Conclusion 4D MRA provides a higher quality view of the stented parent arteries when compared with TOF.


European Journal of Radiology | 2011

MR imaging of ulnar collateral ligament injury in baseball players: Value for predicting rehabilitation outcome

Na Ra Kim; Sung Gyu Moon; Sung Min Ko; Won-Jin Moon; Jin Woo Choi; Jin-Young Park

BACKGROUND To compare the MR findings of the ulnar collateral ligament (UCL) injury in baseball players between rehabilitation and reconstruction surgery. MATERIALS AND METHODS Thirty nine baseball players with clinical evidence of a UCL injury based on medial elbow pain and valgus instability were included. All patients received the rehabilitation treatment for more than six weeks. The elbow MR images of 27 patients not responding to rehabilitation treatment were reviewed that consequently had reconstruction surgery; in addition to 12 patients with improved symptoms with only rehabilitation treatment. The MR imaging was compared between the two treatment groups using the Pearsons chi-square test, and linear-by-linear association for the following features: the degree, signal intensity and site of the UCL injury on fat suppressed T2-weighted images. RESULTS High-grade partial tears and complete tears were more commonly seen in the group that had surgery (14 out of 27 patients, 52%; 8 out of 27 patients, 30%), and low-grade partial tears and intact continuity were more common in the group that had rehabilitation only (5 out of 12 patients, 42%; 5 out of 12 patients, 42%) (p=0.001). The injured UCL showed a fluid-like bright high or intermediate high signal intensity in the group that had surgery more frequently (14 out of 27 patients, 52%; 12 out of 27 patients, 44%), and intermediate high or low signal intensity was more frequent in the rehabilitation group (7 out of 12 patients, 58%; 3 out of 12 patients, 25%) (p=0.013). The UCL injury at the origin site was most commonly seen in both groups (23 out of 27 patients, 85%; 11 out of 12 patients, 92%, respectively) (p=0.496). CONCLUSION Preoperative MR imaging is useful for predicting the rehabilitation outcome of UCL injuries in baseball players.


Arthroscopy | 2012

Is Arthroscopic Coracoplasty Necessary in Subcoracoid Impingement Syndrome

Jin-Young Park; Sang-Hoon Lhee; Kyung-Soo Oh; Na Ra Kim; Jung-Taek Hwang

PURPOSE The purpose of this study was to analyze the outcomes of arthroscopic coracoplasty in the treatment of subcoracoid impingement syndrome. METHODS We compared 23 shoulders that underwent arthroscopic coracoplasty for the treatment of subcoracoid impingement syndrome with 28 shoulders that did not undergo arthroscopic coracoplasty for the treatment of subcoracoid impingement syndrome, which comprised the control group. All the shoulders had subcoracoid and subacromial impingement syndrome with or without rotator cuff tear. Subcoracoid impingement was defined as a coracohumeral distance of less than 6 mm on the preoperative magnetic resonance image with anterior shoulder pain or tenderness. The 2 groups were further divided into several subgroups according to the size of concomitant rotator cuff tear, and a comparative analysis of functional outcomes after surgery among the subgroups was performed. RESULTS In the 2 groups, the overall functional outcomes improved after surgery. The study group showed a significant increase in internal rotation compared with that in the control group (P = .001) at the last follow-up. The large to massive rotator cuff tear subgroup of the study group showed a significant increase in internal rotation (P = .017). On the other hand, no significant difference was seen in the subgroups with small to medium rotator cuff tears including isolated subscapularis tears. The no rotator cuff tear subgroup of the study group showed a significant increase in internal rotation (P = .046). CONCLUSIONS Arthroscopic coracoplasty for subcoracoid impingement syndrome can provide a satisfactory outcome. In particular, a significant increase in internal rotation of the treated group was achieved after surgery in comparison with the untreated group, especially in the large to massive rotator cuff tear subgroup and in the no rotator cuff tear subgroup. LEVEL OF EVIDENCE Level III, retrospective comparative study.


Journal of Shoulder and Elbow Surgery | 2014

Revisit to scapular dyskinesis: three-dimensional wing computed tomography in prone position

Jin-Young Park; Jung-Taek Hwang; Kyung-Soo Oh; Seong-Jun Kim; Na Ra Kim; Myung-Joo Cha

BACKGROUND Three-dimensional (3D) wing computed tomography (CT) showed a high inter-rater reliability in assessing scapular dyskinesis. METHODS The 330 scapular movements of 165 patients were classified into 4 types by 7 blinded observers. Then, 3D wing CT was performed with patients prone, and 4 blinded observers measured 5 angles, consisting of upward rotation (UR) superior translation (ST), anterior tilting (AT), protraction (PRO), and internal rotation (IR). The inter-rater reliability (IRR) of 2 methods was calculated, and cutoff values were determined for the 5 angles on the 3D wing CT images. RESULTS The IRR was 0.783 for the observational method of scapular dyskinesis and 0.981 for 3D wing CT in the prone position. UR and ST angles were significantly larger in type 3 more than in the other types (P < .001, P < .001), and the AT angle showed a similar pattern in type 1 (P < .001). The PRO angle was significantly larger in types 1, 2, and 3 more than in type 4 (P < .001, P < .001, P = .013), and the IR angle was significantly larger in type 2 more than in the other types (P < .001). The cutoff values of the 5 angles were UR, 117°; ST, 90°; AT, 8°; PRO, 99°; and IR, 51°. The UR angle showed a significant correlation with glenohumeral internal rotation deficit (odds ratio, 0.436; P = .029) and the IR angle with MDI (odds ratio, 8.947; P = .048). CONCLUSION The patients with a high UR angle showed a low rate of glenohumeral internal rotation deficit and those with a high IR angle had a high rate of the MDI in affected shoulder by the determinant of the cutoff value of the 5 angles. LEVEL OF EVIDENCE Level III, development of diagnostic criteria with nonconsecutive patients, diagnostic study.


Skeletal Radiology | 2012

Acute coccydynia related to precoccygeal calcific tendinitis

Sung Gyu Moon; Na Ra Kim; Jin Woo Choi; Jeong Geun Yi

Symptomatic deposits of calcium hydroxyapatite have been reported in various sites other than the shoulders or hips. Sudden-onset coccydynia can lead to the discovery of calcific deposition in the precoccygeal region. We present the case of precoccygeal calcific tendinitis in a patient with acute coccydynia.


Journal of Shoulder and Elbow Surgery | 2017

Stress ultrasound in baseball players with ulnar collateral ligament injuries: additional value for predicting rehabilitation outcome

Na Ra Kim; Sung Gyu Moon; Jin-Young Park; Jin Woo Choi; Kyung-Soo Oh

BACKGROUND The purpose of this study was to evaluate the additional value of stress ultrasound (US) for predicting rehabilitation outcome in baseball players with ulnar collateral ligament (UCL) injury. METHODS Stress US and magnetic resonance imaging (MRI) in 41 baseball players with UCL injury who received rehabilitation treatment for more than 6 weeks were retrospectively compared between the rehabilitation group (n = 23) and surgery group (n = 18). The MRI grade of UCL injury was assessed as intact continuity, low-grade partial tear, high-grade partial tear, and complete tear. To estimate sonographic joint laxity, we assessed 3 sonographic criteria as present or absent: ligamentous waviness, joint gapping, and intra-articular ring-down artifact. In addition, the presence of concomitant tenderness was checked during stress US. The diagnostic validity of MRI with and without stress US was analyzed as a predictor for the rehabilitation outcome. RESULTS The MRI grade was higher in the surgery group than in the rehabilitation group (P < .001). Sonographic joint laxity showing the ring-down artifact and concomitant tenderness with stress were significantly more frequent in the surgery group (P = .024 and P = .006, respectively). Sensitivity, specificity, and accuracy were 61.1%, 86.9%, and 75.6%, respectively, for MRI alone and 83.3%, 56.5%, and 68.2%, respectively, for the combination of MRI with joint laxity showing the ring-down artifact. For MRI in combination with joint laxity and concomitant tenderness, these values were 72.2%, 82.6%, and 78.0%, respectively. CONCLUSION The addition of stress US showing the ring-down artifact and concomitant tenderness was helpful for predicting the rehabilitation outcome of UCL injuries.


Journal of Shoulder and Elbow Surgery | 2016

Valgus extension overload syndrome in adolescent baseball players: clinical characteristics and surgical outcomes

Jin-Young Park; Hyun-Yul Yoo; Seok Won Chung; Seung Jun Lee; Na Ra Kim; Se-Young Ki; Kyung-Soo Oh

BACKGROUND Little is known about the clinical characteristics and surgical outcomes of valgus extension overload syndrome (VEOS) in adolescent athletes. We evaluated posteromedial compartment pathology, including combined lesions, and reported the surgical outcomes in adolescent baseball players. METHODS We retrospectively reviewed the medical records of 13 male adolescent baseball players (mean age, 15.4 years) who underwent arthroscopic olecranon tip resection (n = 9) or staged operations (arthroscopic olecranon tip resection, followed by medial collateral ligament reconstruction 2 weeks later; n = 4). The shape of the tip fragment was used to classify the olecranon into 2 types: type 1, dot-like fragment (n = 3); type 2, triangular-shape fragment (n = 10). Four outcome measures were analyzed: range of motion, visual analog scale (VAS) pain score, rate of return to play, and Conway scale score. RESULTS At a mean follow-up of 3.3 years (range, 2-6 years), the mean VAS pain score decreased from 4.1 preoperatively to 1.1 postoperatively (P < .05). Preoperative mean extension and supination were 4.2° and 70.0°, which improved to 1° (P < .05) and 76.2° (P < .05), respectively. The overall rate of return to play was 85% (11 of 13). On the Conway scale, 8 of 13 patients (62%) were classified as excellent. Patients who underwent isolated arthroscopic surgery reported less pain postoperatively and achieved a higher grade on the Conway scale than patients who underwent staged operations. CONCLUSIONS Arthroscopic resection of olecranon tip yielded favorable outcomes at a minimum of 2 years of follow-up. Patients with concomitant ulnar collateral ligament insufficiency had less optimal outcomes than those with isolated posteromedial impingement.


Korean Journal of Radiology | 2015

Charcoal-Induced Granuloma That Mimicked a Nodal Metastasis on Ultrasonography and FDG-PET/CT after Neck Dissection

Jin Woo Choi; Won-Jin Moon; Nami Choi; Hong Gee Roh; Mi Young Kim; Na Ra Kim; Sung Gyu Moon; Hyun Woo Chung; So Dug Lim; Jung-Hyun Yang

Charcoal can be used for preoperative localization of metastatic lymph nodes in the neck. Charcoal remains stable without causing foreign body reactions during as hort period. However, foreign body reactions may develop if charcoal is left in situ for more than 6 months. We reported a case of charcoal granuloma mimicking local recurrence on fluorodeoxyglucose-positron emission tomography/computed tomography and ultrasonography in a 47-year-old woman who had cervical lymph node dissection due to metastatic invasive ductal carcinoma of the breast.


Spine | 2011

Cervical epidural lymphangioma presenting as a hemorrhagic cyst: a case report.

Seung Choul Lee; Sung Gyu Moon; Na Ra Kim; Woo Jin Choe; Won-Jin Moon

Study Design. A case report. Objective. We report a case of epidural lymphangioma in the cervical spine, and it manifested as a hemorrhagic cyst. Summary of Background Data. Intraspinal lymphangioma is an uncommon tumor with only a few cases reported in the literature. Epidural lymphangioma presenting as a hemorrhagic cyst is extremely rare. Methods. The patient chosen was a 43-year-old woman with the chief complaint of neck pain and right upper extremity numbness of 2-month duration. Results. Cervical spine magnetic resonance (MR) imaging revealed an epidural cystic mass extending to the right C6–C7 neural foramen. The mass showed fluid-fluid levels on T2-weighted image and high-signal intensity on diffusion-weighted image. Surgical resection and histologic analysis confirmed the diagnosis of epidural lymphangioma with internal hemorrhage. Conclusion. Epidural lymphangioma is a rare benign tumor. However, it should be included in the differential diagnosis of hemorrhagic cystic mass in the epidural space, which presented with fluid-fluid levels on MR imaging and high-signal intensity on diffusion weighted imaging.


Acta Orthopaedica | 2018

Automated detection and classification of the proximal humerus fracture by using deep learning algorithm

Seok Chung; Seung Seog Han; Ji Whan Lee; Kyung-Soo Oh; Na Ra Kim; Jong Pil Yoon; Joon Yub Kim; Sung Hoon Moon; Jieun Kwon; Hyo-Jin Lee; Young-Min Noh; Youngjun Kim

Background and purpose — We aimed to evaluate the ability of artificial intelligence (a deep learning algorithm) to detect and classify proximal humerus fractures using plain anteroposterior shoulder radiographs. Patients and methods — 1,891 images (1 image per person) of normal shoulders (n = 515) and 4 proximal humerus fracture types (greater tuberosity, 346; surgical neck, 514; 3-part, 269; 4-part, 247) classified by 3 specialists were evaluated. We trained a deep convolutional neural network (CNN) after augmentation of a training dataset. The ability of the CNN, as measured by top-1 accuracy, area under receiver operating characteristics curve (AUC), sensitivity/specificity, and Youden index, in comparison with humans (28 general physicians, 11 general orthopedists, and 19 orthopedists specialized in the shoulder) to detect and classify proximal humerus fractures was evaluated. Results — The CNN showed a high performance of 96% top-1 accuracy, 1.00 AUC, 0.99/0.97 sensitivity/specificity, and 0.97 Youden index for distinguishing normal shoulders from proximal humerus fractures. In addition, the CNN showed promising results with 65–86% top-1 accuracy, 0.90–0.98 AUC, 0.88/0.83–0.97/0.94 sensitivity/specificity, and 0.71–0.90 Youden index for classifying fracture type. When compared with the human groups, the CNN showed superior performance to that of general physicians and orthopedists, similar performance to orthopedists specialized in the shoulder, and the superior performance of the CNN was more marked in complex 3- and 4-part fractures. Interpretation — The use of artificial intelligence can accurately detect and classify proximal humerus fractures on plain shoulder AP radiographs. Further studies are necessary to determine the feasibility of applying artificial intelligence in the clinic and whether its use could improve care and outcomes compared with current orthopedic assessments.

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