Avascular Necrosis of the Capitate: MRI and Surgical Decision-Making of Two Case Reports

Avascular necrosis (AVN) is a rare disease occurring in the capitate of the wrist which is the third most common site of AVN among carpal bones. There are few reports on the MRI findings of AVN in the capitate bone. Besides, there is a paucity of reports showing the benefits of imaging for the choice of the treatment modality. We report two rare cases of capitate AVN requiring surgery.

Clinical Validation of a Deep Learning-Based Hybrid (Greulich-Pyle and Modified Tanner-Whitehouse) Method for Bone Age Assessment

Objective@#To evaluate the accuracy and clinical efficacy of a hybrid Greulich-Pyle (GP) and modified Tanner-Whitehouse (TW) artificial intelligence (AI) model for bone age assessment. @*Materials and Methods@#A deep learning-based model was trained on an open dataset of multiple ethnicities. A total of 102 hand radiographs (51 male and 51 female; mean age ± standard deviation = 10.95 ± 2.37 years) from a single institution were selected for external validation. Three human experts performed bone age assessments based on the GP atlas to develop a reference standard. Two study radiologists performed bone age assessments with and without AI model assistance in two separate sessions, for which the reading time was recorded. The performance of the AI software was assessed by comparing the mean absolute difference between the AI-calculated bone age and the reference standard. The reading time was compared between reading with and without AI using a paired t test. Furthermore, the reliability between the two study radiologists’ bone age assessments was assessed using intraclass correlation coefficients (ICCs), and the results were compared between reading with and without AI. @*Results@#The bone ages assessed by the experts and the AI model were not significantly different (11.39 ± 2.74 years and 11.35 ± 2.76 years, respectively, p = 0.31). The mean absolute difference was 0.39 years (95% confidence interval, 0.33– 0.45 years) between the automated AI assessment and the reference standard. The mean reading time of the two study radiologists was reduced from 54.29 to 35.37 seconds with AI model assistance (p < 0.001). The ICC of the two study radiologists slightly increased with AI model assistance (from 0.945 to 0.990). @*Conclusion@#The proposed AI model was accurate for assessing bone age. Furthermore, this model appeared to enhance the clinical efficacy by reducing the reading time and improving the inter-observer reliability.

Stress Fracture of the Capitate

Most capitate fractures occur in association with additional carpal injuries, particularly scaphoid fractures. Isolated fractures of the capitate account for only 0.3% of carpal injuries, and stress fractures are one form of this fracture. We report the case of a 20-year-old male who had a stress fracture of the capitate after serving as an honor guard in the military. Conventional radiographs and computed tomography of the right wrist revealed a minimally displaced fracture line located at the midcarpal aspect of the right capitate. A magnetic resonance imaging scan demonstrates a subarticular capitate fracture with diffuse bone marrow edema, small osteophytes, and irregularity of the midcarpal articular cartilage. We also review the carpal kinematics which possibly caused the stress fracture. Although stress fractures of the capitate are rare, they should also be accounted for with patients who perform repetitive motions of the wrist to a considerable extent.

The Association between the Magnetic Resonance Imaging Findings of Adhesive Capsulitis and Shoulder Muscle Fat Quantification Using a Multi-Echo Dixon Method

OBJECTIVE: To investigate the association between the magnetic resonance imaging (MRI) findings of adhesive capsulitis and shoulder muscle fat percentages using a multi-echo Dixon method. MATERIALS AND METHODS: Twenty-four patients with clinical diagnoses of adhesive capsulitis and either intact rotator cuffs or Ellman grade 1 partial tears as indicated by MRI scans were included. Two radiologists independently evaluated MRI scans of adhesive capsulitis as follows: presence or absence of axillary recess capsular and extracapsular hyperintensities; thickness of the coracohumeral ligament; thickness of abnormal rotator interval soft tissue; and thickness of glenoidal/humeral axillary recess capsules. Fat quantifications of the supraspinatus, infraspinatus, teres minor, subscapularis, teres major and posterior deltoid muscles were performed using multi-echo Dixon imaging at three locations. Inter-rater agreement was assessed. Differences in fat percentages were assessed and correlations between fat percentages and quantitative measurements were evaluated. RESULTS: The fat percentage of the supraspinatus was significantly higher in patients with extracapsular hyperintensity (present, 3.00 ± 1.74%; absent, 1.81 ± 0.80%; p = 0.022). There were positive correlations between the fat percentage of the teres minor and the thicknesses of the abnormal rotator interval soft tissue (r = 0.494, p = 0.014) and the glenoidal axillary recess capsule (r = 0.475, p = 0.019). After controlling for the effects of age, sex and clinical stage, the relationship between the teres minor fat percentage and the thickness of the abnormal rotator interval soft tissue was statistically significant (r = 0.384, p = 0.048). Inter-rater agreement was almost perfect for fat quantification (intraclass correlation coefficients [ICC] > 0.9) and qualitative analyses (k = 0.824), but were variable for quantitative measurements (ICC, 0.170–0.606). CONCLUSION: Several MRI findings of adhesive capsulitis were significantly related to higher fat percentages of shoulder muscles.

An Unusual Cause of Knee Pain: Periosteal Glomus Tumor of the Distal Femur

Glomus tumors are rare neoplasms that characteristically occur in subungual regions, but may also be found in other regions of the body. The clinical diagnosis of this tumor may be difficult if the tumor is located in an extradigital site. Most extradigital glomus tumors form in superficial locations. Herein, we present the case of a 34-year-old woman who experienced chronic knee pain with pinpoint tenderness resulting from a deep-seated periosteal glomus tumor of the distal femur. Extradigital glomus tumors should be considered in the differential diagnosis when characteristic clinical features and imaging findings indicative of glomus tumors are present, even if the tumor is located within deep tissues.

Ultrasonography of the lower extremity veins: anatomy and basic approach

Ultrasonography is an imaging modality widely used to evaluate venous diseases of the lower extremities. It is important to understand the normal venous anatomy of the lower extremities, which has deep, superficial, and perforating venous components, in order to determine the pathophysiology of venous disease. This review provides a basic description of the anatomy of the lower extremity veins and useful techniques for approaching each vein via ultrasonography.

Comparison of T1rho and T2 Mapping of Knee Articular Cartilage in an Asymptomatic Population

OBJECTIVE: To analyze subregional differences in T1rho (T1ρ) and T2 values and their correlation in asymptomatic knee cartilage, and to evaluate angular dependence with magic angles. MATERIALS AND METHODS: Six asymptomatic volunteers underwent knee MRI with T1ρ and T2 mapping. T1ρ and T2 values were measured by two radiologists independently, at nine subregions in the medial femoral condyle (MFC) cartilage, at angles of ± 0°, 15°, 35°, 55°, 75° respective to a vertical line (B0) bisecting the width of the distal femur, and at two locations in the patella. Subregional values of T1ρ and T2 were analyzed and significant differences in three divided portions of the MFC (anterior, central, and posterior) were statistically evaluated. Correlation between T1ρ and T2 and angular dependence with magic angles were also assessed for statistical significance. RESULTS: T1ρ values were lowest at +15° and highest at -55°. T2 values were lowest at +75° and highest at +35°. Both T1ρ and T2 were higher in superior patella than inferior patella. T1ρ showed significant differences in the three divided portions of the MFC, while T2 showed significant differences only between central and posterior portions. There was a weak correlation between T1ρ and T2 (r = 0.217, p = 0.127). T1ρ showed more angular dependence than T2. CONCLUSION: T1ρ and T2 showed different subregional values and angular dependence in asymptomatic knee cartilage with a weak correlation. Awareness of these differences will aid in assessment of cartilage in a specific subregion of the knee.

Detecting Peripheral Nerves in the Elbow using Three-Dimensional Diffusion-Weighted PSIF Sequences: a Feasibility Pilot Study

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.

Correlation between Ultrasonography Findings and Electrodiagnostic Severity in Carpal Tunnel Syndrome: 3D Ultrasonography

BACKGROUND AND PURPOSE: To determine the correlation between the cross-sectional area (CSA) of the median nerve measured at the wrist using three-dimensional (3D) ultrasonography (US) and the electrophysiological severity of carpal tunnel syndrome (CTS). METHODS: We prospectively examined 102 wrists of 51 patients with clinical CTS, which were classified into 3 groups according to the electrodiagnostic (EDX) findings. Median nerve CSAs were measured using 3D US at the carpal tunnel inlet and at the level of maximal swelling. RESULTS: Ten wrists were negative for CTS. Of the 92 CTS-positive wrists, 23, 30, and 39 were classified as having mild, moderate, and severe CTS, respectively. The median nerve CSA differed significantly between the severe- and moderate-CTS groups (p=0.0007 at the carpal tunnel inlet and p<0.0001 at the maximal swelling site). There was a correlation between median nerve CSA and EDX parameters among those wrists with severe and mild CTS (p<0.0001 at both sites). CONCLUSIONS: The median nerve CSA as measured by 3D US could provide additional information about the severity of CTS, as indicated by the strong correlation with standard EDX findings.

Xanthoma Simulating Plantar Fibromatosis on Sonography

Xanthomas are local collections of lipid-laden macrophages and collagen, which are usually associated with impaired lipoprotein metabolism. Xanthomas occur frequently in the skin, subcutis, or tendon, and occasionally in the plantar fascia. Small numbers of xanthomas have been surgically confirmed in the plantar fascia and their sonographic appearance has not been described in the literature. We present sonographic findings of a pathologically proven plantar fascia xanthoma, which was initially mistaken as plantar fibromatosis.

Lipoma-like Liposarcoma with Osteosarcomatous Dedifferentiation of the Chest Wall: A Case Report

We report a case of liposarcoma with osteosarcomatous dedifferentiation of the chest wall in a 58-year-old man, which had been initially mistaken as myositis ossificans. CT and MRI demonstrated a soft tissue mass consisting of two components: a non-lipomatous area with amorphous calcification/ossification and a well-encapsulated fatty component. Based on local excision in the non-lipomatous area, myositis ossificans was initially diagnosed. As the mass was gradually enlarging, however, wide excision including the fatty component was performed and histological assessment revealed lipoma-like, well-differentiated liposarcoma with high-grade osteosarcomatous dedifferentiation. Here, we describe the radiological-pathological features of this rare neoplasm.

Evaluation of the Chondromalacia Patella Using a Microscopy Coil: Comparison of the Two-Dimensional Fast Spin Echo Techniques and the Three-Dimensional Fast Field Echo Techniques

OBJECTIVE: We wanted to compare the two-dimensional (2D) fast spin echo (FSE) techniques and the three-dimensional (3D) fast field echo techniques for the evaluation of the chondromalacia patella using a microscopy coil. MATERIALS AND METHODS: Twenty five patients who underwent total knee arthroplasty were included in this study. Preoperative MRI evaluation of the patella was performed using a microscopy coil (47 mm). The proton density-weighted fast spin echo images (PD), the fat-suppressed PD images (FS-PD), the intermediate weighted-fat suppressed fast spin echo images (iw-FS-FSE), the 3D balanced-fast field echo images (B-FFE), the 3D water selective cartilage scan (WATS-c) and the 3D water selective fluid scan (WATS-f) were obtained on a 1.5T MRI scanner. The patellar cartilage was evaluated in nine areas: the superior, middle and the inferior portions that were subdivided into the medial, central and lateral facets in a total of 215 areas. Employing the Noyes grading system, the MRI grade 0-I, II and III lesions were compared using the gross and microscopic findings. The sensitivity, specificity and accuracy were evaluated for each sequence. The significance of the differences for the individual sequences was calculated using the McNemar test. RESULTS: The gross and microscopic findings demonstrated 167 grade 0-I lesions, 40 grade II lesions and eight grade III lesions. Iw-FS-FSE had the highest accuracy (sensitivity/specificity/accuracy = 88%/98%/96%), followed by FS-PD (78%/98%/93%, respectively), PD (76%/98%/93%, respectively), B-FFE (71%/100%/93%, respectively), WATS-c (67%/100%/92%, respectively) and WATS-f (58%/99%/89%, respectively). There were statistically significant differences for the iw-FS-FSE and WATS-f and for the PD-FS and WATS-f (p < 0.01). CONCLUSION: The iw-FS-FSE images obtained with a microscopy coil show best diagnostic performance among the 2D and 3D GRE images for evaluating the chondromalacia patella.

Giant Synovial Chondromatosis of the Knee Mimicking a Parosteal Osteosarcoma: A Case Report / 대한골관절종양학회지

Synovial chondromatosis is a benign nodular cartilaginous proliferation arising in the synovium of joints. The radiolographic features of this condition are variable. Rarely, it would be confused with malignancy such as chondrosarcoma, osteosarcoma or synovial sarcoma. We report a case of primary synovial chondromatosis of the posterior aspect of the proximal tibia mimicking a parosteal osteoarcoma on the radiography, which showed a homogeneously radiopaque juxtacortical mass. However, subsequent computed tomography (CT) showed multiple intra-articular masses containing chondroid mineralization, suggesting synovial chondromatosis.

A Primary Extragonadal Teratoma of the Proximal Humerus

A extragonadal malignant teratoma of the extremity is a rare pheonemenon. We describe a extremely rare case of malignant teratoma of the left proximal humerus in a 14-yr-old female. Radiologic evaluations, including magnetic resonance imaging, suggested a malignant bone tumor, but a pathological examination revealed an immature bony teratoma. Bone scintigraphy and positron emission tomography computed tomography scan showed increased uptake of proximal humerus but no other abnormal lesion.

Mucoid Degeneration of Anterior Cruciate Ligament: Correlation between MR Imaging and Pathologic Findings in Patients with Osteoarthritis of the Knee

PURPOSE: To evaluate the mucoid degeneration (MD) of the anterior cruciate ligament (ACL) of the knee by correlation of MRI findings with pathology, in the patients with osteoarthritis (OA). MATERIALS AND METHODS: This study included 17 patients (mean 68.8 years old) who underwent preoperative MRI. In proton density-weighted sagittal and coronal images ACLs were evaluated for the thickness and signal intensity (SI). Total knee replacement arthroplasty was performed and the pathologic findings of ACL were evaluated. MD was classified as 3 grades according to the degenerated amount in microscopy. Thickness and SI was evaluated as normal or increased on MRI. RESULTS: All of the 4 patients who showed thickened ACL showed increased SI on MRI. All of the 8 patients with increased SI of the ACL on MRI had MD in the ACL. However, remained 9 patients also had MD, in spite of their normal thickness and SI on MRI. Calcification was seen in 5 patients. CONCLUSION: Eight cases who showed ACL thickening or increased SI on MRI were well correlated with MD, however, because the other nine cases who showed normal thickness and normal SI of ACL on MRI also showed MD in pathology, normal MRI finding should not exclude the possibility of MD of ACL.

A Case of Femoral Artery Thrombosis Following Cardiac Cathetherization Treated with Recombinant Tissue Plasminogen Activator in Neonate

Femoral artery thrombosis is an uncommon but potentially serious complication following pediatric cardiac catheterization. Treatment options of thrombosis include intravenous heparin infusion, thrombolytic therapy such as streptokinase, urokinase and tissue plasminogen activator, and surgical thrombectomy. These treatments have varying degrees of success and complication. We report successful use of recombinant tissue plasminogen activator for management of femoral artery thrombosis in neonate following transcatheter balloon valvuloplasty of pulmonary valvular stenosis.

Unusual Location of Central Nervous System Langerhans Cell Histiocytosis: Case Report

Langerhans cell histiocytosis of the central nervous system (CNS) usually involves the hypothalamic-pituitary axis, and T1-weighted MR images normally demonstrate infundibular thickening and/or a mass lesion in the hypothalamus and the absence of a posterior pituitary "bright spot". We recently encountered a case of CNS Langerhans cell histiocytosis with no posterior pituitary "bright spot" and with lesions involving the cerebellum and basal ganglia but not the hypothalamic-pituitary axis.

MR Imaging Findings of Gliosarcoma: Report of Three Cases

Gliosarcoma is a rare primary brain tumor composed of neoplastic glial cells and a sareomatous spindle-cell element. We report three cases of gliosarcoma, and describe their MR findings, which in many respects are very similar to those of malignant astrocytomas. Gliosarcomas are, however, more peripherally located, abutting and/or invading the dura mater, and at T2-weighted imaging their signal intensity is lower than is usually the case with malignant astrocyomas. Despite its rarity, the possibility of gliosarcoma should be considered when MR findings of this nature are apparent.

Sonographic Evaluation of Breast Nodules: Comparison of Conventional, Real-Time Compound, and Pulse-Inversion Harmonic Images

OBJECTICE: To compare the use of conventional, real-time compound, and pulse-inversion harmonic imaging in the evaluation of breast nodules. MATERIALS AND METHODS: Fifty-two breast nodules were included in this study, conducted between May and December 2000, in which conventional, real-time compound, and pulse-inversion harmonic images were obtained in the same plane. Three radiologists, each blinded to the interpretations of the other two, evaluated the findings, characterizing the lesions and ranking the three techniques from grade 1, the worst, to grade 3, the best. Lesion conspicuity was assessed, and lesions were also characterized in terms of their margin, clarity of internal echotexture, and clarity of posterior echo pattern. The three techniques were compared using Friedman's test, and interobserver agreement in image interpretation was assessed by means of the intraclass correlation coefficient. RESULTS: With regard to lesion conspicuity, margin, and internal echotexture of the nodules, real-time compound imaging was the best technique (p < 0.05); in terms of posterior echo pattern, the best was pulse-inversion harmonic imaging (p < 0.05). Real-time compound and pulse inversion harmonic imaging were better than conventional sonography in all evaluative aspects. Interobserver agreement was greater than moderate. CONCLUSION: Real-time compound and pulse-inversion harmonic imaging procedures are superior to conventional sonography in terms of both lesion conspicuity and the further characterization of breast nodules. Real-time compound imaging is the best technique for evaluation of the margin and internal echotexture of nodules, while pulse-inversion harmonic imaging is very effective for the evaluation of the posterior echo patterns.

Nodular Hepatocellular Carcinoma: Findings of Single-Level Dynamic CT During Hepatic Arteriography

PURPOSE: To evaluate the hemodynamics of nodular hepatocellular carcinoma (HCC) using single-level dynamic CT during hepatic arteriography (CTHA) according to the size of the nodule. MATERIALS AND METHODS: Forty 40 patients with nodular HCC confirmed histologically or radiologically underwent single-level dynamic CTHA. Contrast media was injected via the hepatic artery for 20 seconds at a rate of 1.2 ml/sec. Images were obtained prior to this and thereafter at 3-second intervals until 30 seconds after the start of injection, and additional images at 45 and 60 seconds. The CTHA findings were retrospectively reviewed, and cases were assigned to one of three groups, according to the size of the tumor [ 5 cm (group III, n =16)]. We focused on onset time of contrast enhancement (CE), peak CE time and density, and duration of plateau. The patterns of CE were classified as homogeneous, heterogeneous, peripheral, or "nodule in nodule ". RESULTS: The onset time of CE was 3 seconds and mean peak CE time was 18.8 seconds. A plateau was noted in all groups (mean duration, 6.8 seconds). Mean peak CE time and density were 16.5 seconds and 294.1 HU in group I, 18.5 seconds and 324.1 HU in group II, and 20.1 seconds and 114.0 HU in group III. The most frequent pattern of CE (83%) was homogeneous, and this was found in group I. The small HCC group (group I) showed a faster mean peak CE time than the large group (group III) (p < 0.05), and this latter showed a lower peak CE density than the other groups (p < 0.05). In groups II and III, "nodule in nodule "(72%) and heterogeneous patterns (69%) were, respectively, the most frequent findings. CONCLUSION: Single-level dynamic CTHA is useful in evaluating the hemodynamics of HCC.