Jang Gyu Cha

Subungual Tumors: Clinicopathologic Correlation with US and MR Imaging Findings

Various types of tumors can affect the subungual space, including benign solid tumors (glomus tumor, subungual exostosis, soft-tissue chondroma, keratoacanthoma, hemangioma, lobular capillary hemangioma), benign cystic lesions (epidermal and mucoid cysts), and malignant tumors (squamous cell carcinoma, malignant melanoma). Imaging plays an important role in the detection and differentiation of subungual tumors because of their small size, nonspecific clinical manifestations, and functional significance. Ultrasonography (US)-in particular, high-resolution US with color Doppler studies-provides useful information regarding tumor size, location, shape, and internal characteristics (cystic, solid, or mixed), but it is limited in the further characterization of tissue. Magnetic resonance (MR) imaging has an important role in categorizing tumors according to their anatomic location, pathologic origin, and signal characteristics. There is some overlap between the US and MR imaging features of subungual tumors; however, certain features can allow accurate diagnosis and expedite management when correlated with clinical and pathologic findings.

Comparison of high-resolution ultrasonography and computed tomography in the diagnosis of nasal fractures.

Objective. The purpose of this study was to compare the value of high‐resolution ultrasonography (HRUS) and computed tomography (CT) in the diagnosis of nasal fractures. Methods. Facial CT and HRUS examinations performed on 140 consecutive patients (103 male and 37 female; age range, 2–74 years; mean, 26 years) with nasal trauma between October 2004 and April 2007 were retrospectively evaluated. Sonograms were obtained with a hockey stick probe (15–7 MHz linear array transducer). All patients also underwent facial CT and conventional radiography. The nasal fracture detection rates for HRUS, CT, and conventional radiography were compared with the clinical and surgical diagnosis. Nasal fractures were classified into high‐ and low‐grade groups according to severity. They were also compared with the CT findings of all 280 lateral nasal bones and with HRUS findings as the reference standard. Results. The accuracy rates for HRUS, CT, and conventional radiography in detecting nasal fractures were 100%, 92.1%, and 78.6%, respectively. Compared with HRUS, CT revealed only 196 of 233 lateral nasal bone fractures; its accuracy was 80%. In high‐grade fractures, the accuracy of CT was 87%, but it decreased to 68% in low‐grade fractures. Conclusions. Compared with HRUS, CT had lower accuracy, especially in low‐grade nasal fractures. Thus, HRUS is a reliable diagnostic tool for the evaluation of nasal fractures.

High-Resolution Sonography for Nasal Fracture in Children

OBJECTIVE We describe the sonographic findings of nasal fracture in children, and we evaluate the diagnostic value of sonography as compared with conventional radiography and clinical findings to determine whether sonography can be a primary technique for evaluating nasal fracture in children. MATERIALS AND METHODS Conventional radiographs and sonographic scans were obtained in 26 consecutive children with nasal trauma who were seen at our hospital from March 2003 to March 2005. There were five girls and 21 boys, and their ages ranged from 1 year 9 months to 15 years 11 months (mean age, 9.9 years). The following sonographic scans (HDI-5000 unit with a 7-15-MHz linear array transducer) were used to evaluate the nasal bone at different levels: a midline longitudinal image; axial scans of the nasal bones at the upper, middle, and lower levels; images of the nasal septum; and transverse and longitudinal scans of both lateral walls. Ten children also underwent CT. RESULTS Conventional radiographs depicted 14 (54%) of 26 fractures. Sonographic scans were able to show all the fracture lines. One case was diagnosed as an old nasal fracture on the basis of a physical examination, even though a visible fracture line was seen on sonography. The sonographic findings of nasal fracture were disruption of the bone continuity with or without separation of the fractured segment (7/26), displacement of the bone segment as being depressed or overriding (20/26), associated septal deviation (7/26), and separation of the pyriform aperture of the maxilla and nasal bone (2/26). The associated findings were soft-tissue edema and hypoechoic hematoma near the fracture lines in 25 cases. The fractures involved both sides of the nasal bones in 11 of 26 cases, the midline part of the bones in six of 26 cases, and the unilateral paramedian or lateral part of the bones in 12 of 26 cases. Among the 10 CT scans, one CT scan did not depict the fracture, showing only soft-tissue swelling, and one scan showed fractures of the orbital floor and maxilla. CONCLUSION Sonography can be a primary diagnostic technique for evaluating nasal fracture in children. It inflicts no radiation, provides various imaging planes without positional change, and can be used to evaluate the cartilaginous septum. Potential pitfalls are the nasofrontal suture, the junction between the nasal bone and the pyriform aperture of the maxilla, the vascular groove, and the presence of an old fracture. CT can be used in addition to sonography in cases of suspected complex facial bone trauma.

Utility of Sonographic Measurement of the Common Tensor Tendon in Patients With Lateral Epicondylitis

OBJECTIVE The purpose of this article is to evaluate prospectively the utility of sonographic measurements of the common extensor tendon for diagnosing lateral epicondylitis. SUBJECTS AND METHODS Forty-eight patients with documented lateral epicondylitis and 63 healthy volunteers were enrolled and underwent ultrasound of the elbow joint. The common extensor tendon overlying the bony landmark was scanned transversely, and the cross-section area and the maximum thickness were measured. Clinical examination was used as the reference standard in the diagnosis of lateral epicondylitis. Data from the patient and control groups were compared with established optimal diagnostic criteria for lateral epicondylitis using receiver operating characteristic curves. Qualitative evaluation with grayscale ultrasound was also performed on patients and healthy volunteers. RESULTS The common extensor tendon was significantly thicker in patients with lateral epicondylitis than in control subjects (p < 0.01). Tendon thickness greater than 4.2 mm (sensitivity, 78.4%; specificity, 95.2%; accuracy, 87.7%) and area larger than or equal to 32 mm(2) (sensitivity, 86.3%; specificity, 82.5%; accuracy, 84.2%) were highly predictive of lateral epicondylitis. For qualitative evaluation with gray-scale ultrasound, overall sensitivity, specificity, and accuracy values in the diagnosis of lateral epicondylitis were 76.5%, 76.2%, and 76.3%, respectively. CONCLUSION The quantitative sonographic measurements had an excellent diagnostic performance for lateral epicondylitis, as well as good or excellent interreader agreement. A common extensor tendon cross-section area greater than or equal to 32 mm(2) and a thickness of 4.2 mm correlated well with the presence of lateral epicondylitis. However, further prospective study is necessary to determine whether quantitative ultrasound with these cutoff values can improve the accuracy of the diagnosis of lateral epicondylitis.

Outcome of Thyroid Nodules Characterized as Atypia of Undetermined Significance or Follicular Lesion of Undetermined Significance and Correlation With Ultrasound Features and BRAFV600E Mutation Analysis

OBJECTIVE We aimed to establish the malignancy rate of thyroid nodules initially characterized as atypia of undetermined significance or follicular lesion of undetermined significance (AUS/FLUS) and whether they differ according to histologic subcategory. We also investigated the value of ultrasound features that predict malignancy and BRAF(V600E) mutation analysis and suggest strategies for the management of AUS/FLUS nodules. MATERIALS AND METHODS A total of 165 AUS/FLUS nodules were investigated. There are nine histologic subcategories of AUS/FLUS nodules. We compared the risk of malignancy in thyroid nodules according to the histologic subcategory using ultrasound findings and of those exhibiting the BRAF(V600E) mutation. RESULTS The malignancy rate of nodules with an initial diagnosis of AUS/FLUS was 55.2% (91/165). The malignancy rates by histologic subcategory were 0% in groups 1 (0/2), 2 (0/3), 4 (0/3), 7 (0/3), and 8 (0/1); 76.5% (13/17) in group 3; 83.1% (59/71) in group 5; and 29.2% (19/65) in group 9. The malignancy rate of nodules with suspicious ultrasound features was 79.3% (73/92), and the malignancy rate of nodules with indeterminate ultrasound features was 24.7% (18/73). AUS/FLUS nodules exhibiting taller-than-wide shape, illdefined margins, and microcalcifications or macrocalcifications showed significantly higher odds ratios. The likelihood of BRAF(V600E) mutation-positive nodules showing malignancy was 97.5% (39/40), whereas 39.7% (25/63) of BRAF(V600E) mutation-negative nodules were malignant (p < 0.05). CONCLUSION The malignancy rate of AUS/FLUS nodules in our study cohort was higher than previously reported. Nodules with suspicious features on ultrasound had a higher malignancy rate than did those with indeterminate features on ultrasound. The malignancy rate differed according to histologic subcategory; therefore, management of AUS/FLUS nodules should be tailored according to histologic subcategory.

Reducing Metallic Artifacts in Postoperative Spinal Imaging: Usefulness of IDEAL Contrast-enhanced T1- and T2-weighted MR Imaging—Phantom and Clinical Studies

PURPOSE To prospectively compare the effectiveness of iterative decomposition of water and fat with echo asymmetry and least-squares estimation (IDEAL) T2-weighted and contrast material-enhanced T1-weighted magnetic resonance (MR) imaging with that of a conventional MR imaging protocol in minimizing metallic artifacts in phantoms and in patients with metallic hardware after spinal surgery. MATERIALS AND METHODS Institutional review board approval and informed consent were obtained for this study. Coronal T1- and T2-weighted MR images of six titanium alloy pedicle screws in an oil bath containing tubes filled with diluted gadolinium contrast medium were obtained with frequency-selective fat saturation (FSFS) and IDEAL. Axial T2-weighted and contrast-enhanced T1-weighted MR imaging of the spine was performed with FSFS and IDEAL at 22 lumbar levels in 19 patients. Two musculoskeletal radiologists qualitatively analyzed the images in terms of the visualization of paravertebral muscle and the spinal canal region, uniformity of fat saturation, and noise. The paired images were rated by using a five-point scale. For the quantitative study with phantoms, the short- and long-axis lengths of metallic artifacts were determined on signal intensity profiles. RESULTS In the phantom study, metallic artifact size was markedly decreased in the IDEAL T2-weighted and contrast-enhanced T1-weighted images (P < .001). In the clinical study, IDEAL T2-weighted and contrast-enhanced T1-weighted images enabled significantly improved visualization of the dural sac (P < .001), spinal muscles (P < .05), uniformity of fat saturation (P < .001), and noise (P < .05). CONCLUSION IDEAL T2-weighted and contrast-enhanced T1-weighted MR imaging examinations effectively reduce the degree of tissue-obscuring artifacts produced by spinal fixation hardware and improve image quality compared with FSFS T2-weighted and contrast-enhanced T1-weighted MR imaging. SUPPLEMENTAL MATERIAL http://radiology.rsna.org/lookup/suppl/doi:10.1148/radiol.11101856/-/DC1.

Utility of Postmortem Autopsy via Whole-Body Imaging: Initial Observations Comparing MDCT and 3.0T MRI Findings with Autopsy Findings

Objective We prospectively compared whole-body multidetector computed tomography (MDCT) and 3.0T magnetic resonance (MR) images with autopsy findings. Materials and Methods Five cadavers were subjected to whole-body, 16-channel MDCT and 3.0T MR imaging within two hours before an autopsy. A radiologist classified the MDCT and 3.0T MRI findings into major and minor findings, which were compared with autopsy findings. Results Most of the imaging findings, pertaining to head and neck, heart and vascular, chest, abdomen, spine, and musculoskeletal lesions, corresponded to autopsy findings. The causes of death that were determined on the bases of MDCT and 3.0T MRI findings were consistent with the autopsy findings in four of five cases. CT was useful in diagnosing fatal hemorrhage and pneumothorax, as well as determining the shapes and characteristics of the fractures and the direction of external force. MRI was effective in evaluating and tracing the route of a metallic object, soft tissue lesions, chronicity of hemorrhage, and bone bruises. Conclusion A postmortem MDCT combined with MRI is a potentially powerful tool, providing noninvasive and objective measurements for forensic investigations.

Practical Application of Iterative Decomposition of Water and Fat with Echo Asymmetry and Least-Squares Estimation (IDEAL) Imaging in Minimizing Metallic Artifacts

Iterative decomposition of water and fat with echo asymmetry and the least-squares estimation (IDEAL) is a recently developed method for robust separation of fat and water with very high signal-to-noise-ratio (SNR) efficiency. In contrast to conventional fat-saturation methods, IDEAL is insensitive to magnetic field (B0 and B1) inhomogeneity. The aim of this study was to illustrate the practical application of the IDEAL technique in reducing metallic artifacts in postoperative patients with metallic hardware. The IDEAL technique can help musculoskeletal radiologists make an accurate diagnosis particularly in musculoskeletal imaging by reducing metallic artifacts, enabling the use of contrast enhancement, improving SNR performance, and providing various modes of MR images with one scan parameter.

Comparison of MRI T2 Relaxation Changes of Knee Articular Cartilage before and after Running between Young and Old Amateur Athletes

Objective To compare changes in T2 relaxation on magnetic resonance (MR) images of knee articular cartilage in younger and older amateur athletes before and after running. Materials and Methods By using a 3.0-T MR imager, quantitative T2 maps of weight-bearing femoral and tibial articular cartilages in 10 younger and 10 older amateur athletes were acquired before, immediately after, and 2 hours after 30 minutes of running. Changes in global cartilage T2 signals of the medial and lateral condyles of the femur and tibia and regional cartilage T2 signals in the medial condyles of femoral and tibia in response to exercise were compared between the two age groups. Results Changes in global cartilage T2 values after running did not differ significantly between the age groups. In terms of the depth variation, relatively higher T2 values in the older group than in the younger group were observed mainly in the superficial layers of the femoral and tibial cartilage (p < 0.05). Conclusion Age-related cartilage changes may occur mainly in the superficial layer of cartilage where collagen matrix degeneration is primarily initiated. However, no trend is observed regarding a global T2 changes between the younger and older age groups in response to exercise.

Comparison of Three-Dimensional Isotropic and Two-Dimensional Conventional Indirect MR Arthrography for the Diagnosis of Rotator Cuff Tears

Objective To compare the accuracy between a three-dimensional (3D) indirect isotropic T1-weighted fast spin-echo (FSE) magnetic resonance (MR) arthrography and a conventional two-dimensional (2D) T1-weighted sequences of indirect MR arthrography for diagnosing rotator cuff tears. Materials and Methods The study was approved by our Institutional Review Board. In total, 205 patients who had undergone indirect shoulder MR arthrography followed by arthroscopic surgery for 206 shoulders were included in this study. Both conventional 2D T1-weighted FSE sequences and 3D isotropic T1-weighted FSE sequence were performed in all patients. Two radiologists evaluated the images for the presence of full- or partial-thickness tears in the supraspinatus-infraspinatus (SSP-ISP) tendons and tears in the subscapularis (SSC) tendons. Using the arthroscopic findings as the reference standard, the diagnostic performances of both methods were analyzed by the area under the receiver operating characteristic curve (AUC). Results Arthroscopy confirmed 165 SSP-ISP tendon tears and 103 SSC tendon tears. For diagnosing SSP-ISP tendon tears, the AUC values were 0.964 and 0.989 for the 2D sequences and 3D T1-weighted FSE sequence, respectively, in reader I and 0.947 and 0.963, respectively, in reader II. The AUC values for diagnosing SSC tendon tears were 0.921 and 0.925, respectively, for reader I and 0.856 and 0.860, respectively, for reader II. There was no significant difference between the AUC values of the 2D and 3D sequences in either reader for either type of tear. Conclusion 3D indirect isotropic MR arthrography with FSE sequence and the conventional 2D arthrography are not significantly different in terms of accuracy for diagnosing rotator cuff tears.