Distinguishing CT and MR Imaging Features of Postprocedural Inflammation and Infectious Spondylodiscitis After Intradiscal Electrothermal Therapy

Purpose@#To investigate whether the signal or morphological changes in the adjacent bone or soft tissue after intradiscal electrothermal therapy (IDET) occur due to postprocedural inflammation or infectious spondylodiscitis. @*Materials and Methods@#Ten patients (female:male = 5:5; age range, 18–71 years; mean age: 36.5 years) who underwent lumbar IDET between January 2018 and December 2020 and complained of fever or pain were included in this study. The presence and extent of bone marrow and paraspinal soft tissue signal changes were evaluated using the first follow-up magnetic resonance imaging (MRI) after IDET. Signal changes in the treated discs and the presence and extent of epidural enhancement were evaluated. Additionally, we investigated the presence and margins of subchondral erosions in the vertebral body. @*Results@#Two radiologists analyzed the imaging findings by consensus. Six patients were diagnosed with postprocedural inflammation and four with infectious spondylodiscitis, which was confirmed by specimen culture after surgery. All 10 patients showed signal changes in the bone marrow of the vertebral bodies adjacent to the treated disc. Signal changes in the paraspinal soft tissue were observed in only five patients: three with infectious spondylodiscitis and two with postprocedural inflammation. In six patients with postprocedural inflammation, subchondral erosions had well-defined margins with a sclerotic rim and in four patients with infectious spondylodiscitis, subchondral erosions had ill-defined margins. Epidural enhancement showed an extensive pattern in all cases of infectious spondylodiscitis and localized patterns in cases of postprocedural inflammation. @*Conclusion@#MRI or computed tomography findings of well-defined subchondral erosions with a sclerotic rim and more localized signal changes in the paraspinal soft tissue or epidural space might aid in the differentiation of infectious spondylodiscitis and postprocedural inflammation in patients who underwent IDET.

Clinical Significance of Redundant Nerve Roots of the Cauda Equina in Spine MRI

Purpose@#This study aimed to evaluate the association of redundant nerve roots of the cauda equina (RNRCEs) with the degree and duration of symptoms in patients with lumbar spinal canal stenosis. @*Materials and Methods@#Between January 2017 and December 2018, 224 patients demonstrating central canal stenosis on lumbar spine MRI were included. Various imaging findings associated with spinal canal stenosis were investigated, as were the presence, level, type, and length of RNRCEs, and the presence of nerve root swelling. Clinically, the degree of symptoms and symptom changes after treatment were investigated. Multinomial logistic regression was used for statistical analysis. @*Results@#RNRCEs were present in 142 patients (63.4%). Most RNRCEs were observed above the level of stenosis (47.3%). RNRCE was associated with the number of stenoses and symptom duration (p < 0.05). The presence, level, type, and length of RNRCE and nerve root swelling significantly affected the severity of symptoms (p < 0.05). The type of treatment influenced symptom changes (p < 0.05). @*Conclusion@#The recognition and assessment of RNRCEs on spinal MRI are clinically important because the presence, level, type, and length of a RNRCE may be associated with the degree of symptoms and help predict the clinical outcome according to treatment methods.

Malignant Tenosynovial Giant Cell Tumor Presenting as an Extra-Articular Superficial Soft-Tissue Mass in a Knee

Malignant tenosynovial giant cell tumor (TsGCT) is a rare disease that can arise as a recurrent lesion or co-exist with a benign TsGCT lesion. Here we report a rare case of malignant TsGCT in a 73-year-old male with a history of lymphoma. The tumor appeared as a superficial soft-tissue mass in the subcutaneous fat tissue of the left knee.

Transiting Nerve Rootlet Abnormalities on MRI after Lumbar Laminectomy: Associations with Persistent Postoperative Pain

Objective@#To determine whether changes in the transiting nerve rootlet or its surroundings, as seen on MRI performed after lumbar hemilaminectomy, are associated with persistent postoperative pain (PPP), commonly known as the failed back surgery syndrome. @*Materials and Methods@#Seventy-three patients (mean age, 61 years; 43 males and 30 females) who underwent single-level partial hemilaminectomy of the lumbar spine without postoperative complications or other level spinal abnormalities between January 2010 and December 2018 were enrolled. Two musculoskeletal radiologists evaluated transiting nerve rootlet abnormalities (thickening, signal alteration, distinction, and displacement), epidural fibrosis, and intrathecal arachnoiditis on MRI obtained one year after the operations. A spine surgeon blinded to the radiologic findings evaluated each patient for PPP. Univariable and multivariable analyses were used to evaluate the association between the MRI findings and PPP. @*Results@#The presence of transiting nerve rootlet thickening, signal alteration, and ill-distinction was significantly different between the patients with PPP and those without, for both readers (p ≤ 0.020). Conversely, the presence of transiting nerve rootlet displacement, epidural fibrosis, and intrathecal arachnoiditis was not significantly different between the two groups (p ≥ 0.128). Among the above radiologic findings, transiting nerve rootlet thickening and signal alteration were the most significant findings in the multivariable analyses (p ≤ 0.009). @*Conclusion@#On MRI, PPP was associated with transiting nerve rootlet abnormalities, including thickening, signal alterations, and ill-distinction, but was not associated with epidural fibrosis or intrathecal arachnoiditis. The most relevant findings were the nerve rootlet thickening and signal alteration.

Spine Computed Tomography to Magnetic Resonance Image Synthesis Using Generative Adversarial Networks : A Preliminary Study

Objective@#: To generate synthetic spine magnetic resonance (MR) images from spine computed tomography (CT) using generative adversarial networks (GANs), as well as to determine the similarities between synthesized and real MR images. @*Methods@#: GANs were trained to transform spine CT image slices into spine magnetic resonance T2 weighted (MRT2) axial image slices by combining adversarial loss and voxel-wise loss. Experiments were performed using 280 pairs of lumbar spine CT scans and MRT2 images. The MRT2 images were then synthesized from 15 other spine CT scans. To evaluate whether the synthetic MR images were realistic, two radiologists, two spine surgeons, and two residents blindly classified the real and synthetic MRT2 images. Two experienced radiologists then evaluated the similarities between subdivisions of the real and synthetic MRT2 images. Quantitative analysis of the synthetic MRT2 images was performed using the mean absolute error (MAE) and peak signal-to-noise ratio (PSNR). @*Results@#: The mean overall similarity of the synthetic MRT2 images evaluated by radiologists was 80.2%. In the blind classification of the real MRT2 images, the failure rate ranged from 0% to 40%. The MAE value of each image ranged from 13.75 to 34.24 pixels (mean, 21.19 pixels), and the PSNR of each image ranged from 61.96 to 68.16 dB (mean, 64.92 dB). @*Conclusion@#: This was the first study to apply GANs to synthesize spine MR images from CT images. Despite the small dataset of 280 pairs, the synthetic MR images were relatively well implemented. Synthesis of medical images using GANs is a new paradigm of artificial intelligence application in medical imaging. We expect that synthesis of MR images from spine CT images using GANs will improve the diagnostic usefulness of CT. To better inform the clinical applications of this technique, further studies are needed involving a large dataset, a variety of pathologies, and other MR sequence of the lumbar spine.

Clinical Efficacy of Real-Time Sonoelastography for the Follow-Up of Congenital Sternocleidomastoid Muscle Torticollis

PURPOSE@#To evaluate the clinical efficacy of real-time sonoelastography (RTS) for the follow-up of congenital muscular torticollis, based on measurements of muscle elasticity.@*MATERIALS AND METHODS@#Thirty-four infants (23 male, 11 female) with congenital sternocleidomastoid (SCM) muscle torticollis underwent ultrasonography and elastography between November 2012 and December 2014. We evaluated the thickness, morphology (mass-like, fusiform, or overall thickened shape), and echogenicity of the SCM muscle on grayscale images and color patterns (homogeneous blue, mixed green < 50% and ≥ 50%, and green to red) on elastography. Strain ratios were measured using Q-lab software. A clinician classified the degree of neck rotation and side flexion deficits using a 5-point grade system based on angles of neck rotation and side flexion. Correlations between the ultrasonography and clinical findings were evaluated by statistical analysis.@*RESULTS@#Twenty-two infants had right and 12 had left SCM torticollis, respectively. Linear regression analysis showed that involved/contralateral SCM thickness differences, morphology, elasticity color scores, and strain ratios of the affected SCM muscles were significantly correlated with neck rotation and side flexion deficit scores (p < 0.05). The elasticity color score of the affected SCM muscle was the most significant factor.@*CONCLUSION@#RTS might provide a reliable means for evaluating and monitoring congenital muscular torticollis.

Prognostic Indicators of Extremity Liposarcoma / 대한정형외과학회잡지

Purpose@#The aim of this retrospective study was to define the prognostic factors for liposarcoma to aid in the selection of effectivetreatments. @*Materials and Methods@#This study analyzed 41 cases out of 45 cases diagnosed with and treated for liposarcoma 2002 to 2015; 4 casesof well-differentiated liposarcoma were excluded. The effects of sex, age, site, stage, and histological classification on survival wereanalyzed retrospectively. For 28 cases diagnosed with myxoid liposarcoma, additional analysis was performed after the inclusion of roundcell components. @*Results@#The mean age at diagnosis was 52.05 years (range 25–82 years) and the average follow-up period was 63.7 months. The diseasefreesurvival rate was 43.2%. Most factors, including sex and age, were not significantly associated with the survival rate. On the otherhand, the stage (Musculoskeletal Tumor Society stage) was significantly associated with the survival rate. The survival rate of patients withmyxoid liposarcoma was 69% and the local recurrence and metastasis results varied according to the presence of round cells. @*Conclusion@#The stage of liposarcoma and the sex of the patient were found to be effective factors for prognosis. When planning thetreatment for liposarcoma, the treatment outcome for liposarcoma differs according to several prognostic factors.

Treatment of Enchondroma in the Hands and Feet / 대한정형외과학회잡지

Purpose@#The purpose of this study was to suggest an appropriate treatment method by comparing nonsurgical treatment and surgical treatment for enchondroma in the hands and feet. @*Materials and Methods@#Seventy four cases with enchondroma of the hands and feet from January 1996 to March 2017 were selected to evaluate the functional outcomes. Thirty cases were treated with nonsurgical treatment, and 44 cases were treated with surgical treatment, such as curettage only or curettage with a bone graft. The mean follow-up period was 18.1 months. The functional results were analyzed using the Wilhelm and Feldmeier formula. @*Results@#The mean age was 38 years, and the age range was between eight and 69 years. According to the Wilhelm and Feldmeier formula, the mean score of hand enchondroma was 3.09±0.85 and 3.20±0.91 in the non-operative and operative group, respectively. The mean scores of the foot except for the grip strength were 2.57±0.79 and 2.75±0.50, respectively. No significant difference was observed according to the functional results. Among the 18 cases of enchondroma with pathological fractures, nine cases were treated non-surgically and nine cases were treated by surgically. In all 18 cases, complete bone healing was observed at the final follow-up. @*Conclusion@#Relatively satisfactory results were obtained in both surgical and nonsurgical treatment and there was no significant difference in functional outcomes. In cases of enchondroma in the hands and feet, nonsurgical treatment can also be a good treatment option.

A Rare Manifestation of Solitary Primary Bone Lymphoma of the Finger: a Case Report

Primary extranodal bone lymphoma involving the peripheral extremities is extremely rare. Here, we report a definitive case of diffuse large B-cell lymphoma involving the phalangeal bone of the 3rd finger. Systemic evaluation revealed the lesion as the only site of lymphoma involvement.

Soft Tissue Metastasis in Patients with Primary Malignancies; Magnetic Resonance Imaging and Clinical Evaluations

PURPOSE@#The purpose of this study was to evaluate the clinical and magnetic resonance imaging (MRI) findings of soft tissue metastases distinct from benign soft tissue lesions.@*MATERIALS AND METHODS@#We retrospectively analyzed the MRI findings of soft tissue lesions found incidentally in patients with primary carcinoma and those without primary carcinoma from 2002–2015. To evaluate the features of soft tissue metastases distinct from benign soft tissue lesions, patients with benign soft tissue lesions were randomly selected and statistically analyzed for the distinctive features of the two groups.@*RESULTS@#A total of 47 patients (mean age 46.2 years) and 36 controls (mean age 46.2 years) were enrolled. Thirty six of the 47 patients were diagnosed with soft tissue metastasis, most commonly as the primary cancer (31%). The most common site of soft tissue metastasis was the lower extremities (36%) followed by the upper extremities (31%). Soft tissue metastasis was statistically significantly different from benign soft tissue lesions according to patient age, lesion size, margin, presence of degenerative changes in lesions, and presence of edema around the mass.@*CONCLUSION@#If the incident soft tissue lesion shows malignant features on MRI in patients with primary carcinoma or in patients over 40 years of age, the radiologist should consider the possibility of metastatic cancer.

Calcifying Aponeurotic Fibroma of the Knee: a Case Report with Radiographic and MRI Finding

Calcifying aponeurotic fibroma (CAF) is an uncommon benign tumor and a locally aggressive fibroblastic lesion. It commonly affects the palmar side of the hand and fingers, and the soles of the feet. The typical clinical manifestations are known as a poorly circumscribed, slow-growing, and asymptomatic firm mass. Most CAFs usually reveal low to intermediate or isointensity on T1-weighted images, and strong heterogeneous enhancement. However, various signal intensities on T2-weighted images have been reported depending on the degree of hypocellularity or the amount of calcification or collagen within the tumor. This report provides the radiographic and MRI finding of CAF arising in uncommon site, the knee region, of a 19-year-old male who presented with a painful and palpable mass.

Therapeutic Approach to Humeral Pathologic Fracture Caused by Benign Bone Tumor / 대한정형외과학회잡지

PURPOSE: The purpose of this study is to suggest an appropriate therapeutic approach by making a comparison between conservative therapy and surgical therapy for a pathologic fractures of the humerus caused by benign bone tumor. MATERIALS AND METHODS: We selected 15 cases with a pathologic fracture of the humerus caused by benign bone tumor from January 2000 to April 2014 to evaluate the fracture union period and remission of primary bone tumor. Eight cases were treated with conservative therapy, and 7 cases by surgical therapy. The mean age was 13.1 years, and the age range was between 1 year and 19 years; there were 8 male cases and 7 female cases. The mean follow-up period was 24.9 months, with a range from 4 months to 72 months. We evaluated the remission of primary benign tumor in accordance with the ‘Modified Neer classification’ system. RESULTS: There was no statistically significant difference in age, sex, and mean follow-up period between the two groups. The pathologic fracture was united in all cases without secondary displacement. There was no statistically significant difference in the fracture union period (p=0.164) and remission of primary benign tumor (p=0.931) between the two groups. CONCLUSION: We suggest that both conservative and surgical therapies can be a treatment for pathologic fracture of the humerus caused by benign bone tumor.

Subperiosteal Osteoid Osteoma of the Knee: Case Report

Osteoid osteoma, a frequent lesions of bone, is usually intraosseous but occasionally subperiosteal. We describe the case of a 19-year-old male with knee pain caused by subperiosteal osteoid osteoma. Radiologic evaluation was performed with radiographic, computed tomography (CT), ultrasonographic (US) and magnetic resonance imaging (MRI). But the preoperative diagnosis of osteoid osteoma was delayed because of unusual imaging findings and atypical symptom. After excisional biopsy, histological examination confirmed the diagnosis of osteoid osteoma. The lesion was treated successfully with CT-guided radiofrequency ablation.

Magnetic Resonance Imaging Findings of Early Spondylodiscitis: Interpretive Challenges and Atypical Findings

MR findings of early infectious spondylodiscitis are non-specific and may be confused with those of other conditions. Therefore, it is important to recognize early MR signs of conditions, such as inappreciable cortical changes in endplates, confusing marrow signal intensities of vertebral bodies, and inflammatory changes in paraspinal soft tissues, and subligamentous and epidural spaces. In addition, appreciation of direct inoculation, such as in iatrogenic spondylodiscitis may be important, because the proportion of patients who have undergone recent spine surgery or a spinal procedure is increasing. In this review, the authors focus on the MR findings of early spondylodiscitis, atypical findings of iatrogenic infection, and the differentiation between spondylodiscitis and other disease entities mimicking infection.

Imaging Features of Madelung's Disease: Case Report

Madelung's disease, or benign symmetric lipomatosis, is an uncommon disorder that is characterized by massive symmetrical deposits of adipose tissue in the upper trunk, neck and head, and is usually associated with alcohol abuse; as such, patients usually complain of cosmetic issues. Historically, Madelung's disease is usually encountered in men between 30 and 60 years of age, and is more prevalent in the Mediterranean population. In this case study, we describe a rare case of Madelung's disease, in an Asian patient who presented with symmetrically located bilateral masses in the anterior neck, which grew progressively larger over a period of seven years.

Diagnostic Value of MRI in Schwannoma / 대한골관절종양학회지

PURPOSE: To diagnose soft tissue tumor, such as lipoma and Schwannoma, magnetic resonance imaging (MRI) is sufficient in most cases. However, various characteristics are found in MRI images of Schwannoma, thus other type of tumors are often misdiagnosed as Schwannoma with MRI images. In this study, we evaluate the diagnostic value of specific MRI findings of Schwannoma. MATERIALS AND METHODS: From January 2002 to May 2013, 104 patients who are suspected as Schwannoma rith MRI images are included in data, and the final diagnosis is confirmed with biopsy. Patients are divided into group 1 and group 2 who are confirmed as Schwannoma and other disease with biopsy, respectively. RESULTS: 92 patients were diagnosed as Schwannoma (group 1) and 12 patients were diagnosed as other disease (group 2). We investigate the diagnostic value of specific MRI findings of Schwannoma. 41 patients of group 1 (45%) and 0 patients of group 2 (0%) showed target sign, 47 patients of group 1 (51%) and 2 patients of group 2 (17%) showed fascicular sign, 44 patients of group 1 (48%) and 5 patients of group 2 (42%) showed fat split sign, 28 patients of group 1 (30%) and 1 patients of group 2(9%) showed nerve entering and exiting sign, and 8 patients of group 1 (9%) and 6 patients of group 2 (50%) showed none of four specific findings on their MRI images. 52 patients of group 1 (57%) and 5 patients of group 2 (42%) have tumors on the pathway of nerve. Target sign could be considered as the best diagnostic value of the sign we investigate (p<0.05). CONCLUSION: Although specific MRI findings have powerful diagnostic value, patients are often misdiagnosed as Schwannoma with MRI findings. Therefore, if patients who are suspected as Schwannoma based on MRI findings have no target sign on their MRI images, we should consider the possibility of other disease.

Soft Tissue Masses Showing Low Signal Intensity on T2-weighted Images: Correlation with Pathologic Findings

OBJECTIVE: The aims of this article are to differentiate soft tissue masses showing low signal intensity on T2-weighted images (T2WIs) according to the histopathologic findings. CONCLUSION: To know relatively small numbered soft tissue masses with low signal intensities on T2WIs adding characteristic location, morphology, signal intensities on other sequences might be helpful for differential diagnosis of mostly nonspecific soft tissue tumors on MRI.