Comparison of plain MRI and MR arthrography in the evaluation of lateral ligamentous injury of the ankle joint.

BACKGROUND: The purpose of this study was to determine the efficacy of plain magnetic resonance imaging (MRI) and magnetic resonance (MR) arthrography for detecting collateral ligamentous injury of the ankle joint. METHODS: Fifty patients (October 2001 to November 2003) suffering from ankle disability who underwent plain MRI and MR arthrographic studies were enrolled in this study. The diagnostic criteria for ligament disruption on plain MRI included nonvisualization, disruption, waviness of the ligament, or coexistent avulsion fracture. The MR arthrographic findings of ligament disruption were based on leakage of gadolinium contrast medium anterior to the anterior talofibular (ATaF) ligament following ATaF ligament disruption, and the contrast medium filling into the common peroneal tendon sheath after calcaneofibular (CF) ligament disruption. The 2 modalities were interpreted respectively and blindly. RESULTS: Seventeen patients received surgical intervention. There were 14 patients who had a torn ATaF ligament and 6 patients who suffered from CF ligament disruption proved by surgery. Limited detection of preoperative plain MRI survey, which showed 12 patients had torn ATaF and 2 patients had torn CF ligament, was noted. However, most patients with ligamentous injury were correctly diagnosed by MR arthrography preoperatively (only 1 case of CF injury was missed). The plain MRI alone had a higher incidence of false negative and false positive detection. MR arthrography was also valuable for evaluating the coexisting intra-articular pathologies of the ankle joint. CONCLUSION: For evaluating ankle disability, using plain MRI alone is not adequate for correctly detecting lateral collateral ligamentous injury of the ankle joint. MR arthrography improves the sensitivity and the accuracy for ATaF and CF ligament injuries. It also helps in assessing coexisting pathologic lesions of ankle joints, especially impingement syndromes and osteochondral lesions, and provides more information for therapeutic decision making.

The feasibility of low-dose CT for pulmonary metastasis in patients with primary gynecologic malignancy.

PURPOSE: To assess the feasibility of low-dose CT (LDCT) in the detection of pulmonary metastases in patients with primary gynecologic malignancies and also to compare the performance of chest digital radiography (DR) and LDCT for their delectability of pulmonary metastases, with use of standard-dose CT (SDCT) as the reference standard. MATERIALS AND METHODS: Thirty female patients with primary gynecologic malignancies (age range, 20-76 years; mean age, 50 years) underwent DR, noncontrast LDCT and contrast-enhanced SDCT, which were performed within an interval of 2 weeks. We used lung nodule, mediastinal lymphadenopathy (>10 mm in the short axis) and pleural changes (including effusion, irregular thickening, or nodularity) as the cardinal imaging findings of lung metastases. A five-point scoring system was designed to indicate the probability of lung metastasis from primary gynecologic malignancies. The five-point scores of DR, LDCT, and SDCT were analyzed by receiver operating characteristic (ROC) curve. RESULTS: SDCT probability scores of +2 and -2 were set to indicate true positive and true negative for pulmonary nodule, mediastinal lymphadenopathy, and pleural effusion, respectively. All the areas under the ROC curve of LDCT appeared to be larger than those of DR[pulmonary nodule: 0.96 [95% confidence interval (CI): 0.92-1.01] vs. 0.74 [95% CI: 0.57-0.91], 0.82 [95% CI: 0.70-0.95] vs. 0.61 [95% CI: 0.50-0.77]; mediastinal lymphadenopathy: 0.98 [95% CI: 0.93-1.03] vs. 0.90 [95% CI: 0.79-1.01], 0.94 [95% CI: 0.82-1.06] vs. 0.66 [95% CI: 0.44-0.88]; and pleural effusion: 0.98 [95% CI: 0.93-1.03] vs. 0.56 [95% CI: 0.29-0.82], 0.90 [95% CI: 0.74-1.05] vs. 0.46 [95% CI: 0.23-0.68]]. CONCLUSION: The performance of LDCT were comparable to those of SDCT and superior to those of DR for detection of pulmonary nodule, mediastinal lymphadenopathy, and pleural effusion. By using LDCT, there was no need of intravenous contrast injection and less radiation exposure. We propose a protocol including standard-dose abdominal CT and low-dose chest CT for the initial and follow-up stagings of primary gynecologic malignancy. The use of chest DR is unnecessary.

Metallic stenting for treatment of central venous obstruction in hemodialysis patients.

BACKGROUND: Central venous obstruction is a serious and common complication in hemodialysis patients. The recurrence rate is high after balloon dilation, while surgical repair is hazardous in these chronically ill patients. The aim of this study was to evaluate the efficacy of primary Wallstent placement for treatment of hemodialysis-related central venous obstructions. METHODS: Eighteen hemodialysis patients with symptomatic shunt dysfunction and arm swelling due to subclavian (n = 3) or innominate (n = 15) venous obstructions were treated at Kaohsiung Veterans General Hospital with primary Wallstent placement from November 1998 to August 2001. Technical success and complications were reported. Primary and secondary patency rates of stent and hemodialysis access were calculated by survival analysis with Kaplan-Meier method. RESULTS: A total of twenty-five Wallstents were deployed for central venous stenosis (n = 18) and occlusion (n = 7) in these 18 hemodialysis patients. The initial technical success rate was 100%. Fourteen episodes of re-obstruction developed during the observation period. Of them, seven episodes occurred within the stent, four episodes outside of but abutting to the peripheral end of the stent, and another three episodes of re-obstruction were attributed to delayed shortening of the Wallstent. Six of the 14 episodes were treated percutaneously with angioplasty alone, while seven episodes necessitated additional stent placement. No stent migration or other complications were encountered. Primary patency rates of stent and hemodialysis access at 3, 6, 12 and 18 months were 100 and 89%, 73 and 68%, 49 and 42%, and 16 and 0%, respectively. Secondary patency rates of stent and hemodialysis access each were both 100% after 3 months, 93 and 100% after 6 months, 85 and 91% after 12 months and, 68 and 72% after 24 months. CONCLUSIONS: Wallstents are safe to deploy, with excellent technical success for hemodialysis-related central venous obstructions. The Wallstent provides continued use of a hemodialysis access for a substantial period. However, repeated interventions may be necessary to maintain the patency.

Percutaneous stent-graft repair of a mycotic pulmonary artery pseudoaneurysm.

Ruptured mycotic pulmonary pseudoaneurysm is a lethal complication. Emergent surgical repair is usually recommended, but still associated with a high mortality rate. We present a patient in whom mycotic pulmonary pseudoaneurysm was a complication after surgical lobectomy 2 weeks earlier. This patient had suffered from repeated massive hemoptysis. After emergent surgical repair of the ruptured pulmonary artery stump, another episode of massive hemorrhage occurred. The pulmonary arteriogram revealed a segmental stenosis and a large, wide-necked, lobulated pseudoaneurysm at the left proximal pulmonary artery. We deployed a balloon-expandable stent-graft (48 mm in length mounted on a 12 mm x 40 mm angioplasty balloon) across the stenotic segment and the neck of the pulmonary pseudoaneurysm. Hemostasis was achieved immediately and, under a 4-week antibiotic treatment, patient was transferred to a local hospital for medical care. This case report demonstrates the benefit of minimally invasive endovascular therapy in a critically ill patient. A literature review of the etiology and management of mycotic pulmonary pseudoaneurysm is included.

Intra-abdominal gout mimicking pelvic abscess.

Gout is the most common crystal-induced arthritis. Gouty tophi typically deposit in the extremities, especially toes and fingers. We present an unusual case of intrapelvic tophaceous gout in a patient suffering from chronic gouty arthritis. CT and MRI of the abdomen and pelvic cavity disclosed calcified gouty tophi around both hips, and a cystic lesion with peripheral enhancement in the pelvic cavity along the course of the iliopsoas muscle. The intra-abdominal tophus mimicked pelvic abscess.

Isolated intraosseous gout in hallux sesamoid mimicking a bone tumor in a teenaged patient.

We are reporting an unusual case of isolated intraosseous tophus in medial hallux sesamoid presenting as tumor-like lesion in a teenage patient without prior history of gouty attack and underlying systemic disorders. The lesion manifested isointensity to surrounding muscles with internal low signal on spin echo (SE) T1-weighted images, and heterogeneous low signal intensity on fast spin echo (FSE) T2-weighted images. Computed tomography (CT) scan disclosed expansion and diffusely increased attenuation of the medial hallux sesamoid with focal cortical erosion and extraosseous extension of high attenuation content. The subsequent resection and pathology revealed intraosseous tophus deposition, which is particularly rare at this site and at this age. Imaging studies revealed some characteristic imaging features which can retrospectively be attributed to gouty tophus. When an expansile osteolytic lesion manifesting low signal intensity on T2-weighted image and internal calcifications on CT scan is encountered, the possibility of intraosseous tophus should be included in the list of differential diagnoses, even in a teenage patient without prior history of gout.