Synovial Lesions with Low Signal Intensities on T2-Weighted MR Image

Pigmented villonodular synovitis, synovial chondromatosis, long-standing rheumatoid arthritis, hemophilic arthropathy, chronic tophaceous gout, amyloid arthropathy, tuberculous arthritis, and hemangioma are the synovial diseases showing low signal intensity on T2-weighted image. Synovial deposition of hemosiderin, urate, and amyloid and fibrosis or caseous necrosis of hypertrophied synovium are known as the pathologic causes of T2 signal intensity. Because of the low incidence of the synovial lesions showing T2 low signal intensity, recognition of these diseases would be helpful for the exact diagnosis.

Synovial Lesions with Low Signal Intensities on T2-Weighted MR Image

Pigmented villonodular synovitis, synovial chondromatosis, long-standing rheumatoid arthritis, hemophilic arthropathy, chronic tophaceous gout, amyloid arthropathy, tuberculous arthritis, and hemangioma are the synovial diseases showing low signal intensity on T2-weighted image. Synovial deposition of hemosiderin, urate, and amyloid and fibrosis or caseous necrosis of hypertrophied synovium are known as the pathologic causes of T2 signal intensity. Because of the low incidence of the synovial lesions showing T2 low signal intensity, recognition of these diseases would be helpful for the exact diagnosis.

Comparison of Subchondral Fracture on Radiographs with MR Images in Evaluation of Osteonecrosis in LCP Patients

PURPOSE: To compare the subchondral fracture on plain radiography and MR image as a method for assessing osteonecrosis in Legg-Calve-Perthes(LCP) pateients. MATERIALS AND METHODS: We retrospetively reviewed 15 hip joint MR images and plain radiography which visualized subchondral fracture. With basis of the Salter-Thompson classification, extent of necrosis was graded group A to B, as follows; Group A= 50%. On PACS workstation, necrotic area of each MR image was measured to calculate the volume of necrotic portion: volume = necrotic area x slice thickness. Necrotic areas on MR images were graded group A to B and results were compared with that measured in Salter-Thompson classification. On follow up, bone resorption was measured and the extent was compared with subchondral fracture representing necrotic area and that on MR volume method respectively. RESULTS: In 9 joints of 15 hip joints (60%), the degree of necrosis in Salter-Thompson classification on plain radiographs was different from that on MR volume method. Based on plain radiographs by Salter-Thompson classification, the degree of necrosis was overestimated in 6 (67%) joints, and underestimated in 3(33%) joints compared with MR volume method. On follow up study, bone resorption was not correlated with necrotic extent of subchondral fracture and MR volume method. CONCLUSION: The extent of femoral head necrosis measured by subchondral fracture was different from that measured by MR and was not correlated with bone resorption on follow up. Therefore, usefulness of subchondral fracture as a prognostic factor may be limited.

A Case of Combined POEMS Syndrome and Multiple Myeloma with Positive M protein Only on Immunofixation

POEMS syndrome is a plasma cell proliferative disorder is characterized by the presence of peripheral neuropathy (P), organomegaly (O), monoclonal gammopathy (M), endocrinopathy or edema (E) and skin change (S). It can be rarely related to multiple myeloma. A 48-year-old man was admitted to our hospital due to paresthesia of both inguinal areas and weakness of both lower extremities. He had a history of Castleman's disease, and showed features of polyneuropathy, multiple osteoblastic lesions, hepatosplenomegaly, pretibial pitting edema, and papilledema. The serum and urine electrophoresis were negative, but urine immunofixagion could detect monoclonal protein. Plasmacytoma was confirmed through the biopsy for the osteoblastic lesions. We present a case of combined POEMS syndrome and multiple myeloma with positive M protein only on immunofixation in order to share our experience with physicians and specialists.

The Efficacy of Unenhanced MR Imaging for the Diagnosis of Acute Appendicitis: A Performance Comparison Versus Abdominal Ultrasonography

PURPOSE: To evaluate the efficacy of unenhanced MR imaging compared to the diagnostic accuracy, advantage, and limitations of abdominal ultrasonography in the diagnosis of acute appendicitis. MATERIALS AND METHODS: The study included 40 patients suspected of having acute appendicitis and who were subjected to an unenhanced MR image, as well as an abdominal ultrasonography. A T1 FLASH in an axial image, a chemical shift-selective fat suppressed T2 HASTE in an axial image, as well as a T2 HASTE in an axial and coronal image were obtained as unenhanced MR images. The diagnosis was established based on a surgical or clinical follow-up of the unenhanced MR results, which were then statistically compared to the ultrasonographic results. RESULTS: The surgical or clinical follow-up results revealed that 25 patients were positively diagnosed with appendicitis. Of these, 7 patients had symptoms of acute appendicitis with no pathologic diagnoses, whereas the 8 remaining patients were diagnosed with another condition. The sensitivity and accuracy of the unenhanced MR imaging was 92% and 90%, compared to ultrasonography which was 68% and 72.5% accurate, respectively. The differences in sensitivity and accuracy between the two methods were found to be statistically significant (p < .05, chi-square test). Based on these results, unenhanced MR imaging was superior to sonography for the diagnosis of appendicitis. CONCLUSION: Unenhanced MR imaging may be a useful modality for the diagnosis of acute appendicitis, especially for suboptimal or nondiagnostic sonographies, as well as patients that are particularly sensitive to radiation exposure.

MR Findings of Flexor Hallucis Longus Dysfunction

PURPOSE: To find the MR findings and evaluate the usefulness of MR in flexor hallucis longus(FHL) dysfunction. MATERIALS AND METHODS: From 1992 to 2003, fourty patients were found to have surgically confirmed FHL dysfunction. 24 cases of 22 patients who had performed MR were included in this study. We analyzed the signal intensity of FHL tendon and muscle, tendon sheath, sheath effusion, and bone lesions, retrospectively. RESULTS: Non-specific, increased sheath effusion of FHL tendon was seen in 12 cases (50%). Large amount of sheath effusion(grade 3) was observed in 5 cases (21%). The signal intensity of FHL tendon was normal in all cases. High signal intensity at the FHL muscle, proximal to musculotendinous junction was seen in 1 case (4%). One case (4%) of marrow edema of the talus and another one case (4%) of osteochondritis dissecans of the talus was seen. CONCLUSION: Non-specific, increased sheath effusion of FHL tendon was observed on MR in FHL dysfunction patients. Therfore, MR has a limited role in diagnosis of FHL dysfunction and is useful to exclude other bone and tendon diseases causing medial ankle pain.

Enteroscopy-guided Contrast Radiography of Small Bowel Lesions

PURPOSE: To introduce the method of enteroscopy-guided contrast radiography (ECR) and evaluate the diagnostic value of ECR for those patients with small bowel lesions. MATERIALS AND METHODS: From Aug 2004 to Dec 2005, 43 double-balloon enteroscopy (DBE) examinations were performed in 32 patients with suspected small bowel diseases. Among them, DBE revealed abnormal finding in 24 patients, and ECR was then performed in 13 of these 24 patients. RESULTS: ECR demonstrated abnormal findings in 11 among the 13 patients. In the cases of tumors and bezoar, the ECR images were very helpful for the surgical planning. However, for the evaluation of inflammatory lesions, DBE showed more accurate results and ECR could not demonstrate small or shallow ulcerative lesions. CONCLUSION: ECR can be helpful for surgical planning or determination of treatment effect in the cases of small bowel lesions that require surgical treatment or follow-up study.

Imaging of the Brachial Plexus

MR (magnetic resonance) imaging of the brachial plexus is challenging because of the complex and tangled anatomy of the brachial plexus and the multifariouness of pathologies that can put on it. Improvements in imaging techniques, including the availability of high resolution MR image systems and high channels multidetector computed tomography (CT), have led to more accurate diagnoses and improved serve for treatment planning. For the purpose of imaging and treatment of the brachioplexopathy, it is considerate to divide traumatic and nontraumatic diseases affecting the brachial plexus. MRI is the current gold standard imaging modality for nontraumatic brachial plexopathy. CT myelography is the preferred for the diagnosis of nerve root avulsions affecting the brachial plexus. Other modalities, such as CT, ultrasonography and positron emission tomography, have a limited role in the evaluation of brachial plexus pathology. High-quality, high-resolution MRI remains the main tool for imaging the brachial plexopathy.

A Case of Dialysis-related Amyloidosis of the Hip and Cervical Spine: Imaging Findings

Dialysis-related amyloidosis is a complication of long-term hemodialysis and it is characterized by the accumulation of beta2-microglobulin in the osteoarticular structures. We describe here the imaging findings of a case of dialysis-related amyloidosis involving the hip and cervical spine in a 62-year-old woman who received long-term dialysis. We focus here on the CT and MR imaging findings of the cervical spine and we include a review of the relevant literatures.

MR Imaging Findings of Acute Gouty Arthritis

PURPOSE: The purpose of this study was to describe the clinical and MR imaging features of acute gouty arthritis and to define the characteristic findings that would be helpful for differentiating acute gouty arthritis from septic arthritis. MATERIALS AND METHODS: The authors retrospectively studied seven patients who suffered from acute gouty arthritis. The MR imaging findings were analyzed by two musculoskeletal radiologists who focused on joint effusion, subchondral bone erosion, bone marrow edema, synovial thickening (regular and even, or irregular and nodular), and the soft tissue changes (edema or abscess). The clinical records of the patients were reviewed with regard to age and gender, the clinical presentation and the laboratory findings (serum uric acid, WBC, erythrocyte sedimentation rate, C-reactive protein and synovial fluid culture). RESULTS: The patients consisted of six men and one woman whose mean age was 41 years (age range: 24-65 years). The joints involved were the knee (n=6), and ankle (n=1). Two patients had medical histories of gouty attacks that involved the first metatarsophalangeal joint. In six cases, the serum uric acid level during acute attacks was elevated. In all the patients, the affected joint became swollen, hot, erythematous and extremely tender, and this was accompanied by a high ESR and a high C-reactive protein level at the time of presentation. The results of Gram stain and culture of the synovial fluid were negative. In all patients, the MR images showed large amounts of joint effusion, thick irregular and nodular synovial thickening and soft tissue edema without subchondral bone erosions and soft tissue abscess. In one case, subchondral bone marrow edema of the medial femoral condyle was present. In five cases, there were multiple low signal foci in the joint on the spin-echo T2-weighted MR image. CONCLUSION: Even though the MR imaging findings of acute gouty arthritis are nonspecific, it should be considered as a possible diagnosis when a large amount of joint effusion, irregular and nodular synovial thickening and soft tissue edema without subchondral bone erosion, bone marrow edema or soft tissue abscess are seen in the knee or ankle joint, and especially if this is accompanied by the clinical and laboratory features of infection.

Metastatic Spinal Epidural Leiomyoma: A Case Report

We report here on a case of a spinal extradural leiomyoma in a 67-year-old woman, and this tumor was in a very unusual location for a leiomyoma. Because the patient underwent hysterectomy for a uterine leiomyoma 20 years ago, we can speculate that the spinal lesion was a metastatic leiomyoma.

Metastatic Bone Tumors with Sunburst Periosteal Reaction

PURPOSE: The purpose of this study was to describe the clinical and imaging features of metastatic bone tumors with sunburst periosteal reaction and to define the characteristic findings which would be helpful for differentiating metastatic bone tumors from primary malignant bone tumors. MATERIALS AND METHODS: The authors retrospectively reviewed the cases of nine patients with pathologically confirmed metastatic bone tumors with sunburst periosteal reaction, for which imaging studies (plain radiographs [n=9], radioisotope [RI] scans [n=4], magnetic resonance [MR] images [n=6], and computed tomographic [CT] scans [n=4]) were performed. The imaging studies of each lesion were analyzed by two musculoskeletal radiologists focusing on the metastatic site, patterns of bone response, signal intensity characteristics and pattern of contrast enhancement on MR. The clinical records of the patients were reviewed with regard to the age and sex of the subjects, the clinical presentation, and the origin of the primary tumors. RESULTS: The cases consisted of six men and three women, whose mean age was 62 years (age range, 50-88 years). The primary tumors were adenocarcinoma of the stomach [n=4], adenocarcinoma of the lung [n=2], adenocarcinoma of the prostate [n=1], hepatocellular carcinoma of the liver [n=1], and adenocarcinoma of unknown origin [n=1]. The sites of metastatic involvement exhibiting sunburst periosteal reaction were the scapula [n=2], proximal humerus [n=2], rib [n=1], iliac bone [n=1], tibia [n=1], spine [n=1], and proximal phalanx [n=1]. In all patients, the imaging findings showed osteolytic [n=3] or osteoblastic [n=6] lesions with sunburst periosteal reaction. In six cases, the lesions were iso-intense on the T1-weighted images and heterogeneously hyperintense on the T2-weighted images. The gadolinium-enhanced T1-weighted images showed a nearly homogenous enhancement of the lesions without any central necrotic portion. CONCLUSION: Although metastatic bone tumor exhibiting sunburst periosteal reaction is rare, it should be included along with primary malignant bone tumors in the differential diagnosis of bone lesions with sunburst periosteal reaction, especially in older patients with or without a known primary malignancy.

A Case of Pilomatricoma in the Upper Arm: Sonographic and MR Imaging Findings

Pilomatricoma is an uncommon benign skin neoplasm arising from the hair matrix. The radiologic features of this uncommon tumor have occasionally been described in the literature however, to the best of our knowledge, there have been no reports in Korea on the sonographic and MR imaging findings of pilomatricoma involving the upper arm. In this article, we describe the imaging findings of a case of pilomatricoma involving the upper arm, with the emphasis being placed on the sonographic and MR imaging findings and a review of the literature.

Calcific Tendinitis of the Rectus Femoris: A Case Report / 대한정형외과학회잡지

The most common anatomic location of calcific tendinitis is the suprasupinatus muscle of the shoulder joint. However, it is known to develop in any joint including the hip, knee, wrist, and elbow. Around the hip joint, it occurs usually in areas such as the gluteus maximus tendon, the gluteus medius tendon, and the bursa between the gluteus medius and the greater trochanter. The occurrence of calcific tendinitis in the rectus femoris is very rare. We hereby report three cases of calcific tendinitis, which developed in the rectus femoris.

MR Findings of Chondroblastoma with Emphasis on Enhancement Pattern

PURPOSE: To analyze the MR findings of chondroblastoma and peritumoral bone marrow, focussing on the enhancement pattern. MATERIALS AND METHODS: Enhanced MR images obtained from 23 patients with pathologically proven chondroblastoma were retrospectively reviewed by three radiologists. The enhancement pattern was classified as one of three types: homogeneous, heterogeneous, or peripheral rim, while peritumoral bone marrow enhancement was assigned one of four grades. Correlation between the enhancement pattern and T2 signal intensity of a tumor was analyzed by Fisher's exact test. RESULTS: The enhancement pattern was homogeneous in ten cases, heterogeneous in six, and involved the peripheral rim in seven. In 11 cases, peritumoral bone marrow enhancement was observed. Among the ten instances of homogeneous enhancement the signal intensity seen at T2WI was homogeneously iso or low in six cases, homogeneously high in two, and heterogeneous in two. Among the seven cases in which there was peripheral rim enhancement, the signal intensity observed at T2WI was homogeneously high in three, fluid-fluid level in three, and homogeneously iso or low in one. CONCLUSION: At MR imaging, chondroblastoma shows variable signal intensities and enhancement patterns. The peripheral rim enhancement observed at T2WI correlated with homogeneously high signal intensity or fluid-fluid levels.

Spontaneous Total Necrosis of Hepatocellular Carcinoma

We describe a case of spontaneous total necrosis of hepatocellular carcinoma (HCC). Contrast-enhanced CT scanning revealed a hypoattenuating mass during both the hepatic arterial and portal venous phase. During the latter, subtle capsular enhancement was noted. Ultrasonography demonstrated the presence of a hypoechoic mass with a peripheral hyperechoic rim. The patient underwent tumorectomy, and a totally necrotic mass was found. Microscopic examination revealed necrotic tissue with HCC ghost cells, suggesting spontaneous total necrosis of HCC.

Sclerosing Peritonitis with Gross Calcification: Case Report

Sclerosing peritonitis is an uncommon complication of continuous ambulatory peritoneal dialysis (CAPD) and can lead to small bowel dysfunction involving abdominal pain, progressive loss of ultrafiltration, and small intestinal obstruction. Peritoneal thickening, in which calcification can develop, often starts as a small plaque which gradually becomes larger. We report a case of CAPD-related calcifying peritonitis.

Anterior Interosseous Nerve Syndrome with Varient Nerve Innervation: A Case Report

Anterior interosseous nerve syndrome is characterized by weakness of the flexor pollicis longus, the flexor digitorum profundus and the pronator quadratus in the presence of normal sensation. Although MR imaging findings of anterior interosseous nerve syndrome has been reported in a few articles, we report herein a case of anterior interosseous nerve syndrome involving more than usual muscles innervated by anterior interosseous nerve, caused by varient nerve innervation.

Perfusion MR Imaging in Gliomas: Comparison with Histologic Tumor Grade

OBJECTIVE: To determine the usefulness of perfusion MR imaging in assessing the histologic grade of cerebral gliomas. MATERIALS AND METHODS: In order to determine relative cerebral blood volume (rCBV), 22 patients with pathologically proven gliomas (9 glioblastomas, 9 anaplastic gliomas and 4 low-grade gliomas) underwent dynamic contrast-enhanced T2*-weighted and conventional T1- and T2-weighted imaging. rCBV maps were obtained by fitting a gamma-variate function to the contrast material concentration versus time curve. rCBV ratios between tumor and normal white matter (maximum rCBV of tumor / rCBV of contralateral white matter) were calcu-lated and compared between glioblastomas, anaplastic gliomas and low-grade gliomas. RESULTS: Mean rCBV ratios were 4.90'+/-1.01 for glioblastomas, 3.97'+/-0.56 for anaplastic gliomas and 1.75'+/-1.51 for low-grade gliomas, and were thus sig-nificantly different; p < .05 between glioblastomas and anaplastic gliomas, p <.05 between anaplastic gliomas and low-grade gliomas, p < .01 between glioblas-tomas and low-grade gliomas. The rCBV ratio cutoff value which permitted dis-crimination between high-grade (glioblastomas and anaplastic gliomas) and low-grade gliomas was 2.60, and the sensitivity and specificity of this value were 100% and 75%, respectively. CONCLUSION: Perfusion MR imaging is a useful and reliable technique for esti-mating the histologic grade of gliomas.

Human Brain Mapping of Language-Related Function on 1.5T Magnetic Resonance System: Focused on Motor Language Function

PURPOSE: To investigate the feasibility of functional MR imaging of motor language function and its usefulnessin the determination of hemispheric language dominance. MATERIALS AND METHODS: In order to activate the motorcenter of language, six subjects(5 right-handed, 1 left-handed; 3 males, 3 females) generated words. They wererequested to do this silently, without physical articulation, in response to English letters presented visually.Gradient-echo images (TR/TE/flip angle, 80/60/40o; 64x128 matrix; 10mm thickness) were obtained in three axialplanes including the inferior frontal gyrus. Functional maps were created by the postprocessing of gradient-echoimages, including subtraction and statistics. Areas of activation were topographically analyzed and numbers ofactivated pixels in each region were compared between right and left sides. The reproducibility of functional mapswas tested by repetition of functional imaging in the same subjects. RESULTS: Statistically significant activationsignals were demonstrated in five of six subjects, in whom the distribution of those signals was predominantly inboth frontal lobes. Hemispheric lateralization of activation, when activated pixels were compared between bothinferior frontal gyri, was in all cases on the left. In four subjects, functional maps were reproduced in asimilar fashion. CONCLUSION: Our results suggest that functional MR imaging can depict the activation of motorlanguage function in the brain and can be used as a useful non-invasive method for determining the hemisphericdominance of language.