PURPOSE: To validate the feasibility of real time kinematography with four-dimensional (4D) dynamic functional wrist joint imaging using dual source CT. MATERIALS AND METHODS: Two healthy volunteers performed radioulnar deviation and pronation-supination wrist motions for 10 s and 4 s per cycle in a dual source CT scanner. Scan and reconstruction protocols were set to optimize temporal resolution. Cine images of the reconstructed carpal bone of the moving wrist were recorded. The quality of the images and radiation dosage were evaluated. RESULTS: The 4D cine images obtained during 4 s and 10 s of radioulnar motion showed a smooth stream of movement with good quality and little noise or artifact. Images from the pronation-supination motion showed noise with a masked surface contour. The temporal resolution was optimized at 0.28 s. CONCLUSION: Using dual source CT, 4D cine images of in vivo kinematics of wrist joint movement were obtained and found to have a shorter scan time, improved temporal resolution and lower radiation dosages compared with those previously reported.
Adult ; Artifacts ; Biomechanical Phenomena ; Carpal Bones/radiography ; Female ; Humans ; Nontherapeutic Human Experimentation ; Radiation Dosage ; Radiographic Image Interpretation, Computer-Assisted/methods ; Tomography, X-Ray Computed/*methods ; Wrist Joint/*physiology/*radiography

Ultrasonography (US) is noninvasive and offers real-time, low-cost, and portable imaging that facilitates the rapid and dynamic assessment of musculoskeletal components. Significant technological improvements have contributed to the increasing adoption of US for musculoskeletal assessments, as artificial intelligence (AI)-based computer-aided detection and computer-aided diagnosis are being utilized to improve the quality, efficiency, and cost of US imaging. This review provides an overview of classical machine learning techniques and modern deep learning approaches for musculoskeletal US, with a focus on the key categories of detection and diagnosis of musculoskeletal disorders, predictive analysis with classification and regression, and automated image segmentation. Moreover, we outline challenges and a range of opportunities for AI in musculoskeletal US practice.

The prevalence of cheek lymphoma, especially a mucosa-associated lymphoid tissue lymphoma (MALT), is very rare. Non-specific symptoms and image findings of cheek lymphoma may mimic benign entities and make it difficult to diagnose. In this case report, we present a case of MALT lymphoma of the cheek mimicking benign entities on computed tomography and magnetic resonance imaging.

The prevalence of cheek lymphoma, especially a mucosa-associated lymphoid tissue lymphoma (MALT), is very rare. Non-specific symptoms and image findings of cheek lymphoma may mimic benign entities and make it difficult to diagnose. In this case report, we present a case of MALT lymphoma of the cheek mimicking benign entities on computed tomography and magnetic resonance imaging.

BACKGROUND/AIMS: The Follicular Lymphoma International Prognostic Index (FLIPI) and FLIPI2 are well-known prognostic models for patients with follicular lymphoma (FL). However, their prognostic relevance has not been examined before in Korean patients with FL. METHODS: We reviewed clinical and laboratory information from our database of patients between 1995 and 2012. In total, 125 patients were stratified in three categories according to FLIPI or FLIPI2 scores: low-, intermediate-, and high-risk groups. We compared FLIPI and FLIPI2 in terms of progression-free survival (PFS) and overall survival (OS). RESULTS: Among the 125 patients, the prognostic value of FLIPI and FLIPI2 was evaluated in 73 patients who fulfilled the criteria of both prognostic models. Risk stratification by FLIPI and FLIPI2 showed significant differences in unfavorable parameters among each risk group, particularly between low- and intermediate-risk groups. The high-risk group b was significantly associated with poor PFS on both FLIPI and FLIPI2 (p < 0.05). However, the OS was significantly different only in the risk groups determined by FLIPI2 (p = 0.042). In a subgroup analysis of patients who received rituximab-containing chemotherapy, the risk stratification of both prognostic models showed a significant impact on PFS, especially in the low-risk group. CONCLUSIONS: FLIPI and FLIPI2 are appropriate prognostic models in Korean FL patients, especially for discriminating low-risk patients from intermediate- and high-risk groups.
Disease-Free Survival ; Drug Therapy* ; Humans ; Lymphoma, Follicular* ; Prognosis

PURPOSE: To evaluate meniscofibular ligament (MFibL) at the posterolateral corner of the knee joint on the magnetic resonance arthrography (MRA) with 70degrees knee flexion. MATERIALS AND METHODS: The MRA of the knee joint was performed at 70degrees knee flexion. Eighteen patients (19 knee joints) underwent scanning of sagittal, coronal, and axial fat-suppressed T1 weighted images (T1FS), and coronal fat-suppressed T2 weighted images. Sagittal three-dimensional (3D) gradient echo (GRE) images were also obtained. Retrospective review of 19 knee MRA studies was independently performed by two musculoskeletal radiologists. The statistical significance was proved by chi-square test. RESULTS: The MFibL ligament was optimally demonstrated on the far lateral sagittal 3D GRE and T1FS MRA images. The MFibL appeared as a curvilinear or straight hypointense band of variable thickness, extended from the posterolateral meniscus to upper anteromedial aspect of the fibular head. The MFibL was demonstrated with scale 2 (more than a half length of the ligament) by both reviewers in 73.68% (n=14/19) of the knee 3D GRE images and 89.47% (n=17/19) of the knee T1FS images. The visualization on T1FS and that on GRE were not statistically different from each other (p>0.05). The interobserver agreements were significantly good on both 3D GRE and T1FS images in detecting the ligament (kappa values, 0.642 and 0.683, respectively). CONCLUSION: The MFibL is well visualized on the far lateral sagittal MRA at 70degrees knee flexion, which could potentially be useful in recognizing structures in the posterolateral corner of the knee, including the MFibL.
Adult ; Female ; Humans ; Knee Joint/*pathology ; Ligaments/*pathology ; Magnetic Resonance Imaging/*methods ; Male ; Middle Aged ; Young Adult

PURPOSE: The purpose of this study was to find and categorize the various magnetic resonance imaging (MRI) findings of spinal metastases that correlate with the type of primary cancer. MATERIALS AND METHODS: We retrospectively reviewed gadolinium-enhanced magnetic resonance images of 30 patients with 169 spinal metastatic lesions from lung cancer (n = 56), breast cancer (n = 29), colorectal cancer (n = 20), hepatocellular carcinoma (HCC) (n = 17), and stomach cancer (n = 47). The size, location, extent of invasion, signal intensity, margin, enhancement pattern, and osteoblastic or osteolytic characteristics of each metastatic tumor were analyzed. RESULTS: The metastatic lesions from HCC were larger than those from the other primary tumors (P < 0.05) except for colorectal cancer (P = 0.268). Well-defined metastatic tumor margins were more frequently seen in lung cancer and breast cancer (P < 0.01). All but HCC showed a tendency to invade the vertebral body rather than the posterior elements (P < 0.02). Colorectal cancer and HCC showed a tendency toward extraosseous invasion without statistical significance. HCC showed a characteristic enhancement pattern of 'worms-in-a-bag'. Rim enhancement with a sclerotic center was only seen in spinal metastases from stomach cancer. CONCLUSION: Despite many overlapping imaging features, spinal metastases of various primary tumors display some characteristic MRI findings that can help identify the primary cancer.
Breast Neoplasms ; Carcinoma, Hepatocellular ; Colorectal Neoplasms ; Humans ; Lung Neoplasms ; Magnetic Resonance Imaging ; Magnetic Resonance Spectroscopy ; Neoplasm Metastasis ; Osteoblasts ; Retrospective Studies ; Spine ; Stomach ; Stomach Neoplasms

PURPOSE: To compare the image quality and ligament traceability in ankle images obtained using Volume Isotropic Turbo Spin Echo Acquisition (VISTA) MRI with and without fat suppression. MATERIALS AND METHODS: The signal-to-noise ratios (SNRs) in images from a phantom and from the ankle of a volunteer were compared. Ten ankles from 10 non-symptomatic volunteers were imaged for comparisons of contrast ratio (CR) and ligament traceability. All examinations were performed using VISTA sequences with and without fat suppression on a 3T MRI scanner. The SNRs were obtained from images with subjects and without subjects (noise-only). Contrast ratios from images of the 10 ankles were acquired between fluid and tendon (F-T), F-cartilage (C), F-ligament (L), fat (f)-T, f-C and f-L. Two musculoskeletal radiologists independently scored the traceability of 7 ligaments, in sagittal, axial and coronal images respectively, based on a 4-point scale (1 as not traceable through 4 as clearly traceable). The Wilcoxon signed-rank test was used to compare the CR. Fisher's exact test and Pearson's chi-squared test were used to compare the ligament traceability. RESULTS: The SNRs did not differ significantly between the two sequences except in bone marrow. VISTA SPAIR showed the higher CR only in F-T (p = 0.04), whereas VISTA showed higher CR in f-T (p = 0.005), f-C (p = 0.005) and f-L (p = 0.005). The calcaneofibular ligament traceability with VISTA was superior to that obtained with VISTA SPAIR (p < 0.05) in all planes. CONCLUSION: VISTA showed significant superiority to VISTA SPAIR in tracing CFL due to the superior CR between fat and ligament.
Animals ; Ankle ; Bone Marrow ; Ligaments ; Magnetic Resonance Spectroscopy ; Magnetics ; Magnets ; Signal-To-Noise Ratio ; Tendons

OBJECTIVE: To optimize the dose of contrast agent and the level of energy for dual-energy computed tomography (DECT) arthrography of the shoulder joint and to evaluate the benefits of the optimized imaging protocol. MATERIALS AND METHODS: Dual-energy scans with monochromatic spectral imaging mode and conventional single energy scans were performed on a shoulder phantom with 10 concentrations from 0 to 210 mg/mL of iodinated contrast medium at intervals of 15 or 30 mg/mL. Image noise, tissue contrast, and beam hardening artifacts were assessed to determine the optimum dose of contrast agent and the level of monochromatic energy for DECT shoulder arthrography in terms of the lowest image noise and the least beam hardening artifacts while good tissue contrast was maintained. Material decomposition (MD) imaging for bone-iodine differentiation was qualitatively assessed. The optimized protocol was applied and evaluated in 23 patients. RESULTS: The optimal contrast dose and energy level were determined by the phantom study at 60 mg/mL and 72 keV, respectively. This optimized protocol for human study reduced the image noise and the beam-hardening artifacts by 35.9% and 44.5%, respectively. Bone-iodine differentiation by MD imaging was not affected by the iodine concentration or level of energy. CONCLUSION: Dual-energy scan with monochromatic spectral imaging mode results in reduced image noise and beam hardening artifacts.
Analysis of Variance ; Artifacts ; Contrast Media/*diagnostic use ; Female ; Humans ; Male ; Middle Aged ; Phantoms, Imaging ; Shoulder Joint/pathology/*radiography ; Signal-To-Noise Ratio ; *Tomography, X-Ray Computed

Magnetic resonance imaging (MRI) is an essential modality for the diagnosis of musculoskeletal system defects because of its higher soft-tissue contrast and spatial resolution. With the recent development of MRI-related technology, faster imaging and various image plane reconstructions are possible, enabling better assessment of three-dimensional musculoskeletal anatomy and lesions. Furthermore, the image quality, diagnostic accuracy, and acquisition time depend on the MRI protocol used. Moreover, the protocol affects the efficiency of the MRI scanner. Therefore, it is important for a radiologist to optimize the MRI protocol. In this review, we will provide guidance on patient positioning; selection of the radiofrequency coil, pulse sequences, and imaging planes; and control of MRI parameters to help optimize the MRI protocol for the six major joints of the musculoskeletal system.