Guo Shu Huang

Differentiation of soft tissue benign and malignant peripheral nerve sheath tumors with magnetic resonance imaging

PURPOSE The objective of this study was to differentiate the magnetic resonance (MR) imaging appearance of benign peripheral nerve sheath tumors (PNSTs) from that of malignant PNSTs. MATERIALS AND METHODS Twenty-six patients who underwent MR imaging and had a histologic diagnosis of benign (schwannoma, n=16; neurofibroma, n=1) or malignant (n=9) PNST were retrospectively reviewed. The size, location, shape, margin, and signal intensities of the tumors on precontrast and gadolinium-enhanced MR imaging were analyzed. In each patient, the presence or absence of split fat, target, and fascicular signs was determined. RESULTS The mean size of the benign PNSTs (3.4 cm, S.D.=2.5 cm) was significantly smaller than that of the malignant tumors (8.2 cm, S.D.=3.1 cm) (P<.001). Seventeen (65.4%) of the 26 tumors were spindle shaped or ovoid (12 benign and 5 malignant tumors). Contiguity with specific nerves was identified in 15 (88.2%) of the 17 benign PNSTs but in none of the malignant tumors (P<.05). Well-defined margins were noted in all 17 benign PNSTs but in only 3 (33.3%) of the 9 malignant tumors (P<.001). Five (55.6%) of the 9 malignant PNSTs but none of the benign tumors showed signal intensity change in adjacent soft tissue (P<.05). There was no significant difference in signal intensity between the benign and malignant tumors on T(1)-weighted, T(2)-weighted, and contrast-enhanced MR images. The split fat and target signs were present more frequently in the benign PNSTs than in the malignant PNSTs (P<.05). CONCLUSIONS Benign and malignant PNSTs are often spindle shaped. Recognition of contiguity with adjacent nerves, a well-defined margin, and the presence of the split fat sign may suggest benignity. Imaging features suggestive of malignancy can be a larger size and an infiltrative margin.

Brain Injury After Acute Carbon Monoxide Poisoning: Early and Late Complications

OBJECTIVE The purposes of this article are to illustrate the variable CT and MRI features of carbon monoxide-induced brain injury and to discuss the underlying pathogenesis. CONCLUSION Carbon monoxide can produce different patterns of brain injury in the acute and delayed stages. CT and MRI are valuable in the delineation of disease extent and helpful for understanding the pathophysiologic mechanisms.

Tophaceous gout of the knee: revisiting MRI patterns in 30 patients.

Objective:To evaluate the locations and associated erosions of tophaceous gout in the knee and to reevaluate its characteristic magnetic resonance imaging features. Materials and Methods:We performed a retrospective review of the magnetic resonance (MR) images of the knees of 30 patients with histopathologically confirmed gouty tophi. Each tophaceous lesion was evaluated for location, morphology, signal intensity, and associated bone erosion or intraosseous involvement. Results:The tophaceous masses were commonly located on the medial aspect of the infrapatellar fat pad and anterior joint recess (n = 28, 87%), the space adjacent to the lateral rim of the lateral femoral condyle (n = 25, 78%), and the intercondylar fossae (n = 22, 69%). All tophaceous lesions showed similar signal characteristics (low–intermediate signal intensities on T1-weighted images, with heterogeneous signal intensities on T2-weighted images), and 3 morphologic patterns were observed: amorphous masses (n = 27), linear crystalline-like deposits (n = 6), and cystic lesions of the bursae around the knee (n = 3). Associated bone erosions occurred in the lateral rim of the lateral femoral condyle (n = 8), the roof of the intercondylar notch (n = 7), the tibial eminence (n = 5), and the medial and lateral rim of the tibial plateau (n = 3). Intraosseous tophi were seen in the tibial plateau (n = 3) and patella (n = 1). Conclusion:Knowledge of the common locations and associated erosions of tophaceous gout and its characteristic MR appearance may facilitate its correct diagnosis with magnetic resonance imaging, particularly in patients with no clinical symptom or only an isolated lesion on MR images.

Salivary Glands: Echo-Planar versus PROPELLER Diffusion-weighted MR Imaging for Assessment of ADCs

PURPOSE To compare the image distortion and the quantification variation in parotid gland apparent diffusion coefficients (ADCs) on periodically rotated overlapping parallel lines with enhanced reconstruction (PROPELLER) versus echo-planar diffusion-weighted (DW) magnetic resonance (MR) images and to investigate the relationship between parotid gland ADC and parotid gland fat content. MATERIALS AND METHODS This prospective study was approved by a local institutional review board. Written informed consent was obtained from all 33 enrolled healthy volunteers (15 men, 18 women; mean age, 36.4 years +/- 11.8 [standard deviation]). All participants underwent 1.5-T non-fat-saturated and fat-saturated PROPELLER DW MR imaging as well as 1.5-T nonaccelerated and twofold-accelerated echo-planar DW MR imaging. Image distortion on the DW images was qualitatively scored, and parotid ADC was quantitatively analyzed. The correlation between parotid ADC and parotid fat content was evaluated by using linear regression analysis. Wilcoxon signed rank and t tests were used for statistical analysis, with Bonferroni correction applied for multiple comparisons. RESULTS Echo-planar DW images showed distortion, which was completely eliminated on the PROPELLER DW images. The mean parotid ADCs measured with non-fat-saturated PROPELLER (0.670 x 10(-3) mm(2) +/- 0.149), nonaccelerated echo-planar (0.892 x 10(-3) mm(2) +/- 0.128), twofold-accelerated echo-planar (1.088 x 10(-3) mm(2) +/- 0.124), and fat-saturated PROPELLER (1.307 x 10(-3) mm(2) +/- 0.217) DW imaging differed significantly from one another (P < .001 for all comparisons). Parotid ADC had a significant negative correlation with parotid fat content (x) measured at non-fat-saturated PROPELLER DW imaging: ADC = -0.0087x + 1.1173 (r = 0.80, P < .001). CONCLUSION PROPELLER DW imaging pulse sequences can yield distortion-free images for parotid ADC measurements and enable quantitative evaluation of the relationship between parotid ADC and parotid fat content. SUPPLEMENTAL MATERIAL http://radiology.rsna.org/lookup/suppl/doi:10.1148/radiol.2531082228/-/DC1.

Tenosynovial lipoma arborescens of the ankle in a child

Lipoma arborescens is a rare entity of the synovium and frequently occurs in the joints. Lipoma arborescens involving the synovial sheaths of the tendons is exceedingly rare. We report a case of a 12-year-old girl with lipoma arborescence affecting the synovial sheaths of the peroneal, posterior tibialis, and flexor tendons. Identification of the typical features of fat tissues in the proliferative synovium on MRI may help in making a correct diagnosis. The clinical presentation and MRI findings are described, and the entity is briefly reviewed.

Eosinophilic fasciitis in a military recruit: MRI evaluation with clinical correlation

Abstract. Eosinophilic fasciitis (EF) is an uncommon connective tissue disease. We report a patient with EF who presented with episodic swelling and stiffness of his legs and forearms in combination with peripheral eosinophilia. Imaging studies of the legs and forearms, including computed tomography (CT) and magnetic resonance imaging (MRI), clearly demonstrated the characteristic finding of fascial thickening. The complete clinical imaging and pathological findings are described in this report. Cross-sectional imaging is useful in diagnosing EF and in the appropriate clinical scenario may be helpful in differentiating EF from other connective tissue diseases.

Volume-Dependent Overestimation of Spontaneous Intracerebral Hematoma Volume by the ABC/2 Formula

Background: Although the ABC/2 formula has been widely used to estimate the volume of intracerebral hematoma (ICH), the formula tends to overestimate hematoma volume. The volume-related imprecision of the ABC/2 formula has not been documented quantitatively. Purpose: To investigate the volume-dependent overestimation of the ABC/2 formula by comparing it with computer-assisted volumetric analysis (CAVA). Material and Methods: Forty patients who had suffered spontaneous ICH and who had undergone non-enhanced brain computed tomography scans were enrolled in this study. The ICH volume was estimated based on the ABC/2 formula and also calculated by CAVA. Based on the ICH volume calculated by the CAVA method, the patients were divided into three groups: group 1 consisted of 17 patients with an ICH volume of less than 20 ml; group 2 comprised 13 patients with an ICH volume of 20 to 40 ml; and group 3 was composed of 10 patients with an ICH volume larger than 40 ml. Results: The mean estimated hematoma volume was 43.6 ml when using the ABC/2 formula, compared with 33.8 ml when using the CAVA method. The mean estimated difference was 1.3 ml, 4.4 ml, and 31.4 ml for groups 1, 2, and 3, respectively, corresponding to an estimation error of 9.9%, 16.7%, and 37.1% by the ABC/2 formula (P<0.05). Conclusion: The ABC/2 formula significantly overestimates the volume of ICH. A positive association between the estimation error and the volume of ICH is demonstrated.

Intervertebral Disk Degeneration Related to Reduced Vertebral Marrow Perfusion at Dynamic Contrast-Enhanced MRI

OBJECTIVE The purpose of this study was to use dynamic contrast-enhanced MRI to ascertain the relation between intervertebral disk degeneration and lumbar vertebral marrow blood perfusion. SUBJECTS AND METHODS We recruited 25 patients (50 vertebral bodies) who underwent dynamic contrast-enhanced MRI of the lumbar spine. The peak signal enhancement of each vertebral body was calculated from the time signal after curve fitting of a pharmacokinetic model. We controlled for other variables that might have affected blood perfusion by assessing two vertebral bodies in each patient. The 25 patients were divided into three groups. In group 1, one of the vertebral bodies (L1 or L3) evaluated was between two adjacent normal disks and the other was between two adjacent degenerated disks. In group 2, each of the two vertebral bodies evaluated was between two normal disks. In group 3 each of the two vertebral bodies evaluated was between two degenerated disks. RESULTS Without normalization by minimization of other variables, there were no statistically significant differences in original peak enhancement values among groups 1, 2, and 3 (p = 0.179). After normalization, the peak enhancement in group 1 (0.846 +/- 0.060) was significantly lower than that in group 2 (0.988 +/- 0.047) (p = 0.003) or group 3 (0.973 +/- 0.081) (p = 0.008). CONCLUSION After normalization, lumbar vertebral marrow perfusion correlated well with intervertebral disk degeneration evaluated with dynamic contrast-enhanced MRI. Blood perfusion was 14% less in the vertebral body marrow between two degenerated disks than in vertebral marrow between two normal disks.

Effects of (-)-epigallocatechin-3-gallate on cyclooxygenase 2, PGE2, and IL-8 expression induced by IL-1β in human synovial fibroblasts.

The objective of this study was to examine the effects of (−)-epigallocatechin-3-gallate (EGCG) on cyclooxygenase 2 (COX-2), prostaglandin E2 (PGE2), and interleukin 8 (IL-8) expression induced by IL-1β in human synovial fibroblasts. Cells were enzymatically isolated from synovial tissue taken from patients undergoing joint replacement surgery for osteoarthritis. Reverse transcriptase-polymerase chain reaction, immunocytochemistry, and western blotting were used to assess the COX-2 gene and protein expression with the associated mechanisms. PGE2 and IL-8 secretion into the culture medium was assayed by enzyme-linked immunosorbent assay. COX-2 upregulation in synovial fibroblasts induced by IL-1β was significantly suppressed by EGCG in a dose-dependent manner. PGE2 and IL-8 secretion was also induced by IL-1β stimulation and significantly suppressed by EGCG. The mechanism was associated with the phosphorylation of IKKβ. EGCG may inhibit the expression of inflammatory mediators, such as COX-2, PGE2, and IL-8, induced by IL-1β in human synovial fibroblasts. EGCG may be of value in the treatment of synovial inflammation.

Pyogenic liver abscess treated by percutaneous catheter drainage: MDCT measurement for treatment outcome

OBJECTIVE To analyze multidetector computed tomographic (MDCT) parameters in patients with pyogenic liver abscess (PLA), and to identify which parameters can be predicted percutaneous catheter drainage (PCD) treatment outcome. MATERIALS AND METHODS Clinical, laboratory and MDCT findings of 175 patients with PLA who had undergone PCD were retrospectively reviewed. All abscesses shown on MDCT were evaluated for size, margin, attenuation values, location, number of large (>3cm) abscesses, presence of a cystic component, presence of gas, and the shortest length to the liver capsule. Univariate and multivariate analyses of the MDCT parameters that affect PCD treatment outcome was performed. For continuous data of MDCT parameters (abscess size and the shortest length), we used receiver-operating-characteristic (ROC) curve to determine the optimal cut-off values. RESULTS PCD was failed in 32 patients and the overall failure rate was 18.28%. Multivariate analysis revealed that PCD failure was predicted by the presence of gas (odds ratio [OR], 42.67), a large abscess (OR 1.21), low minimal attenuation values (OR 1.02), wide range of attenuation values (OR 1.01), a shorter length to the liver capsule (OR 0.09) and lack of a cystic component (OR 0.09) of the PLA. ROC curve showed that the shortest length less than 0.25cm and an abscess size greater than 7.3cm were the optimal cut-off values predicting PCD treatment failure. CONCLUSION Among these MDCT parameters, gas formation within PLA was the most important predictor for PCD failure. Surgical intervention might be considered early in high-risk patients of PCD failure.