Effect of Poly(Lactide-Co-Glycolide) Nanoparticles on Local Retention of Fluorescent Material: An Experimental Study in Mice

Kang, Yeonah,Lee, Eugene,Lee, Joon Woo,Kim, Sung Rae,Kang, Myung Joo,Choi, Young Wook,Ahn, Joong Mo,Kang, Yusuhn,Kang, Heung Sik unknown 2018 KOREAN JOURNAL OF RADIOLOGY Vol.19 No.5

<P><B>Objective</B></P><P>Poly(lactide-co-glycolide) (PLGA) nanoparticles are promising materials for the development of new drug-releasing systems. The purpose of this study was to evaluate the <I>in vivo</I> retention time of materials loaded in nanoparticles as compared with that of the material alone by <I>in vivo</I> imaging in nude mice.</P><P><B>Materials and Methods</B></P><P>Mice (n = 20) were injected with 0.1 mL fluorescent material 1,1′-dioctadecyl-3,3,3′,3′ tetramethylindotricarbocyanine iodide (DiR)-loaded PLGA nanoparticles (200 nm) into the right paraspinal muscle, and the same volume of pure DiR solution was injected into the left paraspinal muscle. Fluorescence images were obtained using an <I>in vivo</I> optical imaging system. Fluorescent images were taken 1 day after the injection, and seven more images were taken at 1-week intervals. Image analysis was done with ImageJ program, and one region of interest was chosen manually, which corresponded to the highest signal-intensity area of fluorescence signal intensity.</P><P><B>Results</B></P><P>After 7 weeks, 12 mice showed a right-sided dominant signal, representing the DiR loaded PLGA nanoparticles; 5 mice showed a left-side dominant signal, representing the free DiR solution; and 3 mice showed no signal at all beginning 1 day after the injection. During the 7-week period, the mean signal intensities of the free DiR solution and DiR-loaded PLGA nanoparticles diverged gradually. On day 1, the mean signal intensity of free DiR solution was significantly higher than that of DiR-loaded PLGA (<I>p</I> < 0.001). Finally, by week 7, DiR-loaded PLGA express significantly high signal intensity compared with free DiR solution (<I>p</I> = 0.031).</P><P><B>Conclusion</B></P><P>The results of the current study suggested that therapeutic agents bound to PLGA nanoparticles may exhibit prolonged retention times.</P>

Gliomas: Histogram analysis of apparent diffusion coefficient maps with standard- or high-b-value diffusion-weighted MR imaging--correlation with tumor grade.

Kang, Yusuhn,Choi, Seung Hong,Kim, Young-Jae,Kim, Kwang Gi,Sohn, Chul-Ho,Kim, Ji-Hoon,Yun, Tae Jin,Chang, Kee-Hyun Radiological Society of North America 2011 Radiology Vol.261 No.3

<P>To explore the role of histogram analysis of apparent diffusion coefficient (ADC) maps based on entire tumor volume data in determining glioma grade and to evaluate the diagnostic performance of ADC maps at standard (1000 sec/mm(2)) and high (3000 sec/mm(2)) b values.</P>

Systemic effects of fluoroscopically guided epidural steroid injection with dexamethasone

Kang, Woo Young,Lee, Joon Woo,Lee, Eugene,Kang, Yusuhn,Ahn, Joong Mo,Kang, Heung Sik The Korean Pain Society 2019 The Korean Journal of Pain Vol.32 No.3

Background: Epidural steroid injections (ESIs) have been widely used in managing spinal pain. Dexamethasone has recently emerged as a useful drug in this setting, relative to particulate steroids, although the associated systemic effects have not been fully elucidated. This study aimed to investigate the incidences and types of systemic effects after fluoroscopically guided ESI with dexamethasone. Methods: This retrospective study included 888 ESIs with dexamethasone (fluoroscopically guided at the cervical and lumbosacral levels) performed on 825 patients during January to June 2017. Data regarding systemic effects were collected via telephone interviews using a standardized questionnaire at 2 weeks after the procedure. Data on patient demographic, clinical, and procedural characteristics were collected and analyzed to identify factors that were associated with systemic effects. All statistical analyses were performed using the chi-squared test. Results: Among the 825 patients, 40 patients (4.8%) experienced systemic effects during the 2-week follow-up period. The most common systemic effect was facial flushing (12 patients, 1.5%), which was followed by urticaria (7 patients, 0.8%) and insomnia (7 patients, 0.8%). A history of spine surgery was significantly associated with the occurrence of systemic effects (P = 0.036). Systemic effects were significantly more common for injections at the cervical level than at the lumbar level (P = 0.019). Conclusions: Approximately 4.8% of the patients who underwent ESI with dexamethasone experienced minor and transient systemic effects. These effects were more common in patients who had undergone a previous spine surgery or received a cervical ESI.

Accuracy of Preoperative MRI with Microscopy Coil in Evaluation of Primary Tumor Thickness of Malignant Melanoma of the Skin with Histopathologic Correlation

Kang, Yusuhn,Choi, Jung-Ah,Chung, Jin-Haeng,Hong, Sung Hwan,Kang, Heung Sik The Korean Society of Radiology 2013 KOREAN JOURNAL OF RADIOLOGY Vol.14 No.2

<P><B>Objective</B></P><P>The purpose of this study was to evaluate the accuracy of a preoperative MRI with microscopy coils in determining the primary tumor thickness of malignant melanoma with histopathologic correlation.</P><P><B>Materials and Methods</B></P><P>Eleven patients with histopathologically confirmed malignant melanoma were included in this study. MR images of the tumors were obtained with a 47-mm microscopy coil on 1.5T MR scanners and were evaluated by two radiologists, who assessed the thickness of the primary tumor on T2-weighted images (T2WI) and gadolinium-enhanced T1-weighted images with fat suppression (Gd-T1WI) and compared the results with the histopathologic findings as the reference standard. Correlations between tumor thickness on MRI and histopathologic examination were assessed using concordance correlation coefficients (CCCs). Inter- and intraobserver variabilities of tumor measurements were also assessed by intraclass correlation coefficient (ICC).</P><P><B>Results</B></P><P>Among the 11 cases included in the study, 10 cases from the same number of patients were managed with surgical excision and one case was confirmed with punch biopsy. The primary tumor thickness measured on T2WI showed better correlation with histopathologic results, as compared with measurements taken on Gd-T1WI: the CCC of measurements on T2WI ranged from 0.64 to 0.78, indicating a substantial agreement, whereas the CCC of measurements on Gd-T1WI ranged from 0.50 to 0.61, indicating a moderate to substantial agreement. Inter- and intraobserver agreements of readers 1 and 2 were excellent for both T2WI and Gd-T1WI, with ICC ranging from 0.86 to 0.99.</P><P><B>Conclusion</B></P><P>MR imaging with microscopy coils may be an accurate technique in the preoperative assessment of tumor thickness in malignant melanoma, especially on T2-weighted images.</P>

Efficacy and outcome predictors of fluoroscopy-guided facet joint injection for spondylolysis

Kang, Woo Young,Lee, Joon Woo,Lee, Eugene,Kang, Yusuhn,Ahn, Joong Mo,Kang, Heung Sik Springer-Verlag 2018 Skeletal radiology Vol.47 No.8

Systemic effects of fluoroscopically guided epidural steroid injection with dexamethasone

Woo Young Kang,Joon Woo Lee,Eugene Lee,Yusuhn Kang,Joong Mo Ahn,Heung Sik Kang 대한통증학회 2019 The Korean Journal of Pain Vol.32 No.3

Background: Epidural steroid injections (ESIs) have been widely used in managing spinal pain. Dexa-methasone has recently emerged as a useful drug in this setting, relative to particulate steroids, although the associated systemic effects have not been fully elucidated. This study aimed to investigate the incidences and types of systemic effects after fluoroscopically guided ESI with dexamethasone.Methods: This retrospective study included 888 ESIs with dexamethasone (fluoroscopically guided at the cervical and lumbosacral levels) performed on 825 patients during January to June 2017. Data regarding systemic effects were collected via telephone interviews using a standardized questionnaire at 2 weeks after the procedure. Data on patient demographic, clinical, and procedural characteristics were collected and analyzed to identify factors that were associated with systemic effects. All statistical analyses were performed using the chi-squared test.Results: Among the 825 patients, 40 patients (4.8%) experienced systemic effects during the 2-week follow-up period. The most common systemic effect was facial flushing (12 patients, 1.5%), which was followed by urticaria (7 patients, 0.8%) and insomnia (7 patients, 0.8%). A history of spine surgery was significantly associated with the occurrence of systemic effects (P = 0.036). Systemic effects were significantly more com-mon for injections at the cervical level than at the lumbar level (P = 0.019).Conclusions: Approximately 4.8% of the patients who underwent ESI with dexamethasone experienced minor and transient systemic effects. These effects were more common in patients who had undergone a previous spine surgery or received a cervical ESI.

Maximum standardized uptake value of foot SPECT/CT using Tc-99m HDP in patients with accessory navicular bone as a predictor of surgical treatment

Bae, Sungwoo,Kang, Yusuhn,Song, Yoo Sung,Lee, Won Woo Williams & Wilkins Co 2019 Medicine Vol.98 No.2

<P><B>Abstract</B></P><P>Quantitative bone SPECT/CT (single-photon emission computed tomography/computed tomography) using Tc-99m hydroxymethylene diphosphonate is emerging as a useful imaging modality for skeletal diseases. Accessory navicular bone (ANB) has been evaluated by bone scintigraphy only qualitatively and semiquantitatively. However, a truly objective quantitative assessment of ANB is lacking. Here, we measured the maximum standardized uptake value (SUVmax) of the ANB and investigated its usefulness as an imaging biomarker for ANB.</P><P>Consecutive quantitative bone SPECT/CT studies that had been performed on the foot were retrospectively analyzed. One hundred five patients (male:female = 44:61; median age = 32.0 [range, 11–81] years old; 31 negative controls without ANB and 74 patients with ANB [7 unilateral and 67 bilateral]) and their 210 feet were investigated. The ANBs were classified into types I, II, III (Geist classification), and 0 (contralateral navicular of unilateral ANB). Type II ANBs were subclassified into II-1 (with bony abnormality) or II-0 (without bony abnormality). The treatment modality was observation, conservative treatment, or surgical removal. The associations between the SUVmax and clinical findings, including surgery, were investigated.</P><P>Patients with type II-1 ANB had the highest SUVmax among all ANB types (<I>P</I> < .001). The SUVmax of symptomatic ANB was greater than that for asymptomatic ANB (<I>P</I> < .001), and the SUVmax for the surgically resected ANB group was also significantly higher than that for the observation only or conservative treatment group (<I>P</I> < .001). Subtype II-1 had a significantly higher SUVmax compared with subtype II-0 (<I>P</I> < .001). Logistic regression analyses in type II ANB showed that young age (<I>P</I> = .020) and SUVmax (<I>P</I> = .031) were significant predictors for surgery. Receiver operating characteristic curve and survival analyses revealed an optimal SUVmax cutoff of 5.27 g/mL for predicting final surgical treatment.</P><P>SUVmax derived from quantitative bone SPECT/CT was strongly associated with symptom, surgical treatment, and a known high-risk type of ANB. Risk stratification for final surgical treatment of ANB can be achieved using the SUVmax from quantitative bone SPECT/CT.</P>

Focal Bone Marrow Lesions

Seung Jae J. Kim,Yusuhn Kang,Dae Ha Kim,Jae Young Lim,Joo Hyun Park,Joo Han Oh 대한견주관절의학회 2019 대한견주관절학회지 Vol.22 No.1

Ultrasound diathermy is widely used for the treatment of musculoskeletal disorders and other soft tissue injuries. Its use as a therapeutic modality is believed to be safe, with very few reported complications. Here, we report two patients who developed focal bone marrow abnormalities after receiving ultrasound diathermy. Both patients’ magnetic resonance (MR) evaluations revealed linear subchondral bone lesions of the superolateral humeral head similar to those in osteonecrosis. The patients’ symptoms subsequently improved, and available follow-up MR evaluation revealed near complete resolution of bone lesions. These findings suggest that ultrasound diathermy, and its interaction with bone tissue through thermal mechanisms, can cause focal bone marrow abnormalities. Furthermore, the bone marrow abnormalities seem to be transient, resolving upon cessation of ultrasound diathermy, therefore osteonecrosis should be differentiated from this temporal lesion.

Quantitative assessment of steroid amount in the tissue after epidural steroid injection: a new rabbit model

Cho, Jungheum,Lee, Joon Woo,Lee, Eugene,Kang, Yusuhn,Cho, Ha Ra,Kim, Dong Yoon,Ho, Myoung Jin,Kang, Myung Joo,Choi, Yong Seok The Korean Pain Society 2019 The Korean Journal of Pain Vol.32 No.4

Background: To develop a rabbit epidural steroid injection (ESI) model for analyzing steroid retention in the tissue, and to assess the difference in steroid retention in the model according to the location and time elapsed after ESI. Methods: Fluoroscopy-guided ESI was performed using the interlaminar approach between the lowest two lumbar segments in 13 female New Zealand white rabbits. Four rabbits were allocated to each of three different groups according to the time of sacrifice: 3, 7, and 15 days post-ESI; the remaining rabbit was sacrificed immediately post-ESI to obtain baseline data. After sacrifice, two segments were harvested: the lowest two lumbar vertebrae and another two lumbar vertebrae immediately above these. The residual steroid amount (RSA) and residual steroid concentration (RSC) in the collected spinal columns were analyzed. A linear mixed model was used to compare RSAs and RSCs between the injected and adjacent segments, and among the number of days until sacrifice; P < 0.05 was considered statistically significant. Results: Both RSA and RSC of the injected segment were significantly higher than those of the adjacent segment (P < 0.001, both). The RSA and RSC significantly decreased over time (P = 0.009 and P = 0.016, respectively). Conclusions: The developed rabbit ESI model verified that significantly more steroid was retained at the injected segment than at the adjacent segment and the residual steroid decreased over time. This model could be useful not only for comparing current steroid medications, but also for developing new, better steroid formulations.

Percutaneous Sacroplasty : Effectiveness and Long-Term Outcome Predictors

Lee, Jaehyung,Lee, Eugene,Lee, Joon Woo,Kang, Yusuhn,Ahn, Joong Mo,Kang, Heung Sik The Korean Neurosurgical Society 2020 Journal of Korean neurosurgical society Vol.63 No.6

Objective : To evaluate the effectiveness and long-term outcome predictors of percutaneous sacroplasty (PSP). Methods : This single-center study assessed 40 patients with sacral insufficiency fractures using the short-axis technique under C-arm flat-panel detector computed tomography (CT). Two radiologists reviewed the patients' magnetic resonance and CT images to obtain imaging findings before PSP and determine technical success, respectively. The short-term outcomes were visual analog scale score changes and opioid usage reductions. Long-term outcomes were determined using telephone interviews and the North American Spine Society (NASS) patient-satisfaction index at least one year after PSP. Results : Technical success was achieved without any significant complications in 39 patients (97.5%). Telephone interviews were possible with 12 patients and failed in 10 patients; death was confirmed in 18 patients. Fifteen patients (50%) re-visited the hospital and received conservative treatment, including spinal injections. Nine patients reported positive satisfaction (NASS patient-satisfaction index 1 or 2), while the negative satisfaction group (NASS patient-satisfaction index 3 or 4, n=3) showed a higher incidence of compression fractures at the thoracolumbar spine level (66.7% vs. 22.2%) and previous spinal injection history (66.7% vs. 33.3%). The poor response group also showed higher incidences of facet joint arthrosis (100% vs. 55.6%), central canal stenosis (100% vs. 22.2%), neural foraminal stenosis (33.3% vs. 22.2%), scoliosis (100% vs. 33.3%), and sagittal malalignment (100% vs. 44.4%). Conclusion : PSP was effective for sacral insufficiency fractures and showed good long-term outcomes. Combined compression fractures in the thoracolumbar spine and degenerative lumbar pathologies could be possible poor outcome predictors.