Kyung Jin Suh

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.

Non-Infectious Ischiogluteal Bursitis: MRI Findings

Objective We wished to report on the MRI findings of non-infectious ischiogluteal bursitis. Materials and Methods The MRI findings of 17 confirmed cases of non-infectious ischiogluteal bursitis were analyzed: four out of the 17 cases were confirmed with surgery, and the remaining 13 cases were confirmed with MRI plus the clinical data. Results The enlarged bursae were located deep to the gluteus muscles and postero-inferior to the ischial tuberosity. The superior ends of the bursal sacs abutted to the infero-medial aspect of the ischial tuberosity. The signal intensity within the enlarged bursa on T1-weighted image (WI) was hypo-intense in three cases (3/17, 17.6%), iso-intense in 10 cases (10/17, 58.9%), and hyper-intense in four cases (4/17, 23.5%) in comparison to that of surrounding muscles. The bursal sac appeared homogeneous in 13 patients (13/17, 76.5%) and heterogeneous in the remaining four patients (4/17, 23.5%) on T1-WI. On T2-WI, the bursa was hyper-intense in all cases (17/17, 100%); it was heterogeneous in 10 cases and homogeneous in seven cases. The heterogeneity was variable depending on the degree of the blood-fluid levels and the septae within the bursae. With contrast enhancement, the inner wall of the bursae was smooth (5/17 cases), and irregular (12/17 cases) because of the synovial proliferation and septation. Conclusion Ischiogluteal bursitis can be diagnosed with MRI by its characteristic location and cystic appearance.

Three-dimensional osseous micro-architecture of the distal humerus: Implications for internal fixation of osteoporotic fracture

BACKGROUND The purpose of this study is to analyze 3-dimensional structural parameters of cortical and trabecular bone in the distal humerus using quantitative CT and to find regional variations and differences according to age. METHODS We collected 14 cadaveric distal humeri with an average age of 58.4 years. The specimens were examined at 3 different levels: 1) distal trans-epicondylar section, 2) mid trans-olecranon fossa section, and 3) proximal supra-olecranon fossa section. RESULTS In the distal section, bone volume was the greatest in the anterior part of the lateral condyle and the least in the posterior part of the lateral condyle. Cortical thickness in the distal section was the thickest in the posterior medial and the thinnest in the anterior aspect followed by lateral aspect. The changes in cortical thickness with aging were obvious in the posterior side and trabecular bone on the medial condyle. CONCLUSION This study evaluated the differences in cortical and trabecular bone parameters in each different region of the distal humerus. We found a potential weakness of plate fixation in the posterolateral aspect of the distal condyle because of relative insufficient osseous micro-architecture, which may affect the treatment of osteoporotic distal humerus fractures especially in elderly patients.

CT and MRI findings of calcified spinal meningiomas: correlation with pathological findings.

ObjectiveThis study was designed to present characteristic CT and MR findings of calcified spinal meningiomas that correlate with pathological findings and to assess the efficacy of CT for the detection of calcifications within a mass in comparison to MRI.Materials and methodsBetween 1998 and 2009, 10 out of 11 patients who had pathologically confirmed psammomatous meningiomas showed gross calcifications on CT images and were included in this study. On CT scans of the 10 patients, the distribution pattern, morphology and number of calcifications within masses were evaluated. MRI was performed in seven patients and signal intensities of masses were assessed. The pathological results analyzed semi-quantitatively were compared with the density or the size of calcifications within a mass as seen on a CT scan.ResultsSeven of 10 masses were located at the thoracic spine level. Eight masses had intradural locations. The other two masses had extradural locations. Four masses were completely calcified based on standard radiographs and CT. Symptoms duration, the size of the mass and size or number of calcifications within a mass had no correlation. The location, size, and distribution pattern of calcifications within masses were variable. On MR images, signal intensity of calcified tumor varied on all imaging sequences. All the masses enhanced after injection of intravenous contrast material.ConclusionA calcified meningioma should be first suggested when extradural or intradural masses located in the spine contain calcifications regardless of the size or pattern as depicted on CT, especially in the presence of enhancement as seen on MR images.

MR imaging findings of high-voltage electrical burns in the upper extremities: correlation with angiographic findings:

Background A high-voltage electrical burn is often associated with deep muscle injuries. Hidden, undetected deep muscle injuries have a tendency for progressive tissue necrosis, and this can lead to major amputations or sepsis. MRI has excellent soft tissue contrast and it may aid in differentiating the areas of viable deep muscle from the areas of non-viable deep muscle. Purpose To describe the MR imaging findings of a high-voltage electrical burn in the upper extremity with emphasis on the usefulness of the gadolinium-enhanced MRI and to compare the MR imaging findings with angiography. Material and Methods We retrospectively reviewed the imaging studies of six patients with high-voltage electrical burns who underwent both MRI and angiography at the burn center of our hospital from January 2005 to December 2009. The imaging features were evaluated for the involved locations, the MR signal intensity of the affected muscles, the MR enhancement pattern, the involved arteries and the angiographic findings (classified as normal, sluggish flow, stenosis or occlusion) of the angiography of the upper extremity. We assessed the relationship between the MR imaging findings and the angiographic findings. Results The signal intensities of affected muscles were isointense or of slightly high signal intensity as compared with the adjacent unaffected skeletal muscle on the T1-weighted MR images. Affected muscles showed heterogenous high signal intensity relative to the adjacent unaffected skeletal muscle on the T2-weighted images. The gadolinium-enhanced T1-weighted images showed diffuse inhomogeneous enhancement or peripheral rim enhancement of the affected muscles. The angiographic findings of the arterial injuries showed complete occlusion in three patients, severe stenosis in two patients and sluggish flow in one patient. Of these, the five patients with complete occlusion or severe stenosis on angiography showed non-perfused and non-viable areas of edematous muscle on MRI. On the other hand, one patient with sluggish flow on angiography showed a perfused and viable area of edematous muscle on MRI. Conclusion Gadolinium-enhanced MRI is a useful non-invasive imaging modality to detect the site and extent of hidden, undetected deep muscle injuries in a group of patients with high-voltage electrical burns of the upper extremities.

Spectrum of superficial nerve-related tumor and tumor-like lesions: MRI features

Superficial soft-tissue masses arising from skin appendages, metastasis, and inflammatory lesions have been widely reported. However, nerve-related superficial mass-like lesions other than peripheral nerve sheath tumors are less commonly described. High resolution magnetic resonance imaging (MRI) is an excellent non-invasive tool for the evaluation of such lesions. In this article, the authors discuss the entire spectrum of these lesions and also outline a systemic diagnostic approach.

Lead-Induced Impairments in the Neural Processes Related to Working Memory Function

Background It is well known that lead exposure induces neurotoxic effects, which can result in a variety of neurocognitive dysfunction. Especially, occupational lead exposures in adults are associated with decreases in cognitive performance including working memory. Despite recent advances in human neuroimaging techniques, the neural correlates of lead-exposed cognitive impairment remain unclear. Therefore, this study was aimed to compare the neural activations in relation to working memory function between the lead-exposed subjects and healthy controls. Methodology/Principal Findings Thirty-one lead-exposed subjects and 34 healthy subjects performed an n-back memory task during MRI scan. We performed fMRI using the 1-back and 2-back memory tasks differing in cognitive demand. Functional MRI data were analyzed using within- and between-group analysis. We found that the lead-exposed subjects showed poorer working memory performance during high memory loading task than the healthy subjects. In addition, between-group analyses revealed that the lead-exposed subjects showed reduced activation in the dorsolateral prefrontal cortex, ventrolateral prefrontal cortex, pre supplementary motor areas, and inferior parietal cortex. Conclusions/Significance Our findings suggest that functional abnormalities in the frontoparietal working memory network might contribute to impairments in maintenance and manipulation of working memory in the lead-exposed subjects.

Desmoplastic fibroma of bone in a toe: radiographic and MRI findings.

Desmoplastic fibroma is a rare benign primary bone tumor that is histologically similar to the soft tissue desmoid tumor. It most often involves the mandible, large long bone or iliac bone. Desmoplastic fibroma in a toe has been extremely rarely reported. Authors report a rare case of desmoplastic fibroma of bone occurring in the distal phalanx of a foot, with descriptions of the radiographic and MRI findings, correlation of the radiologic and pathologic findings, and discussion on the differential diagnosis of the tumor.

Nuchal-type fibroma of the buttock: magnetic resonance imaging findings

Nuchal-type fibroma, first described in 1988 by Enzinger and Weiss, is a rare fibrous growth occurring predominantly in the interscapular and paraspinous regions. It is typically located in the subcutaneous tissue of the posterior neck but may occur in extranuchal soft tissue sites such as the upper back, shoulder, and facial regions. In this article, we describe the magnetic resonance imaging findings of a nuchal-type fibroma that involved the buttock in a 45-year-old woman, and we review and discuss the literature on the subject.

A case of scapulothoracic dissociation with brachial plexus injury: magnetic resonance imaging findings.

Scapulothoracic dissociation is defined as violent lateral or rotational displacement of the shoulder girdle from its thoracic attachments with severe neurovascular injury. We describe the radiographic and associated magnetic resonance (MR) imaging findings of a case of scapulothoracic dissociation with brachial plexus injury in a 17-year-old man, and include a review of the relevant literature.