Chia Yuen Chen

Prominent Vessel Sign on Susceptibility-Weighted Imaging in Acute Stroke: Prediction of Infarct Growth and Clinical Outcome

Background and Purpose Predicting the risk of further infarct growth in stroke patients is critical to therapeutic decision making. We aimed to predict early infarct growth and clinical outcome from prominent vessel sign (PVS) identified on the first susceptibility-weighted image (SWI) after acute stroke. Materials and Methods Twenty-two patients with middle cerebral artery (MCA) infarction had diffusion-weighted imaging, SWI, MR angiography, and clinical evaluation using the National Institutes of Health Stroke Scale at 7–60 hours and 5–14 days after stroke onset. Late-stage clinical evaluation at 1 and 3 months used the modified Rankin Scale. The infarct area and growth were scored from 10 (none) to 0 (infarct or growth in all 10 zones) using the Alberta Stroke Program Early CT Score (ASPECTS) system. Results Infarct growth on the second MRI occurred in 13 of 15 patients with PVS on the first MRI and not in any patient without PVS (n=7; r=0.86, P<0.001). The extent of PVS was significantly correlated with infarct growth (r=0.82, P<0.001) and early-stage outcome (P=0.02). No between-group difference in late-stage clinical outcome was found. Conclusion PVS on the first SWI after acute MCA territory stroke is a useful predictor of early infarct growth. Extensive PVS within the large MCA territory is related to poor early-stage outcome and could be useful for clinical assessment of stroke.

Proton magnetic resonance spectroscopy-guided biopsy for cerebral glial tumors.

BACKGROUND AND PURPOSE Although application of proton magnetic resonance (MR) spectroscopy in the diagnosis of brain tumors has been reported, the role of this technique as guidance for targeting biopsy of brain tumors is not well established. The usefulness and limitations of predicting tumor proliferative activity and pathological grading of brain gliomas based on samples obtained from proton MR spectroscopy-guided stereotactic biopsy also remains unclear. The purpose of this study was to evaluate the usefulness of single-voxel MR spectroscopy-guided stereotactic biopsy for cerebral gliomas and to correlate the findings of MR spectroscopy with proliferative activity (measured by Ki-67 labeling index) of tumors and pathological diagnosis. METHODS Localized proton spectra were obtained before stereotactic/surgical biopsy in 7 patients with glioma (8 lesions). Metabolic values in the spectra were measured semiquantitatively and correlated with the Ki-67 labeling index and pathological grade of each surgical specimen. RESULTS MR spectroscopy-guided biopsy was effective in obtaining a representative specimen for accurate pathological diagnosis in all patients, including 1 patient with multifocal glioma and 2 with diffusely infiltrated gliomas (gliomatosis cerebri). Those lesions with higher choline complex/creatine ratio (Cho/Cr) and lower N-acetyl-L-aspartate/creatine values in MR spectroscopy were higher grade tumors. Higher Ki-67 labeling index (indicating higher proliferative activity of tumor) with higher Cho/Cr ratios in MR spectroscopy were significantly correlated with tumor grade. CONCLUSIONS MR spectroscopy-guided biopsy was effective in obtaining a representative specimen for accurate pathological diagnosis, and the Cho/Cr ratio of MR spectra and Ki-67 labeling index were reliable predictors of glioma grade.

MRI of epidermoid cyst of the conus medullaris

Study design:A case report of an epidermoid cyst in the conus medullaris with characteristic magnetic resonance imaging (MRI) findings.Objective:To describe an epidermoid cyst in the conus medullaris with characteristic MRI findings and point out these findings that correlated well with histologic findings.Setting:Taiwan.Case report:A 49-year-old man who suffered from pain and weakness in his right leg for 16 years. MRI showed a heterogeneous signal mass in the conus medullaris. The hyperintense signal area within the lesion may be attributed to the keratin content, whereas the hypointense signal area was related to calcification and soft-tissue component. The histologic findings were compatible with an epidermoid cyst.Conclusion:Epidermoid cysts in the conus medullaris must be considered in the differential diagnosis of mass lesions with long duration of related symptoms. The characteristic MRI findings are useful to differentiate epidermoid cysts from other tumors.

Primary Squamous Cell Carcinoma of the Thyroid Gland With Eggshell Calcification Sonographic and Computed Tomographic Findings

Primary squamous cell carcinoma (SCC) of the thyroid gland is an extremely rare neoplasm with fewer than 55 reported cases. 1 The cancer, which resembles anaplastic carcinoma, tends to be advanced at presentation, with rapid progression and a poor prognosis. 2 Calcification is a common finding on thyroid imaging. Microcalcification is known to be associated with thyroid malignancy. 3 Eggshell or peripheral calcification was once thought to be an indicator that a tumor is benign, with few exceptions. Cases of papillary cell carcinoma, anaplastic carcinoma, and follicular cell carcinoma with this calcified pattern have been reported. 3 - 8 However, from review of the literature in English, no thyroid SCC with eggshell calcification has been reported. Here we report a case of primary SCC of the thyroid gland with eggshell calcification and its sonographic, computed tomographic (CT), and pathologic findings.

Predicting Mortality in Patients With “Malignant” Middle Cerebral Artery Infarction Using Susceptibility-Weighted Magnetic Resonance Imaging: Preliminary Findings

AbstractTo evaluate malignant middle cerebral artery (MCA) infarction (defined as space-occupying edema in more than 50% to 75% of the MCA territory) on magnetic resonance imaging (MRI) with susceptibility-weighted imaging (SWI) sequence and assess the usefulness of SWI findings, diffusion-weighted imaging (DWI) findings, and apparent diffusion coefficient (ADC) as predictors of clinical outcome.Data from 16 patients with large MCA infarction previously admitted to our institution between December 2009 and October 2012 were retrospectively collected and analyzed. Within 7 days after stroke onset, 1 neurologist and 1 neuroradiologist estimated the area of infarction on DWI/ADC and extent of prominent vessel sign (PVS) on SWI images using the Stroke Program Early MR Score (SPEMRS). The PVS on SWI was defined as a local prominence of hypointense vessels with either increased vessel number or diameter in the target area, when compared with the number or diameter of the contralateral MCA territory vessels.Six patients died and 10 survived. Although the DWI/ADC-SPEMRS and clinical profiles were similar between the nonsurvivor and survivor groups, SWI-SPEMRS was significantly lower in the nonsurvivor group (P < 0.001).The area of deoxygenation on SWI in patients with malignant MCA infarction can predict mortality. Lower SWI-SPEMRS is a potentially better predictor of poor outcome than lower DWI-SPEMRS. A larger prospective study is needed to clarify the role of SWI as a therapeutic guide in malignant MCA.

Malignant fibrous histiocytoma of the heart: a case report

Malignant fibrous histiocytoma (MFH) in the heart is rare.We present a case of a 38-year-old woman with histologically confirmed MFHs in the left atrium, liver and bone.The patient presented with shortness of breath and right shoulder pain. A plain radiograph showed an osteolytic lesion at the neck of the humerus on the right side. A computed tomography (CT) scan of the chest showed a lobulated tumour occupying the cardiac left atrium and a large heterogeneously enhancing mass in the liver and osteolytic metastasis in the thoracic spine.The patient underwent complete resection of the cardiac tumour, and histology showed a high-grade pleomorphic sarcoma – an MFH. Biopsy of the lesions on the right shoulder and in the liver also showed the same histologic diagnosis.

Topogram-based tube current modulation of head computed tomography for optimizing image quality while protecting the eye lens with shielding

Background Multiple rounds of head computed tomography (CT) scans increase the risk of radiation-induced lens opacification. Purpose To investigate the effects of CT eye shielding and topogram-based tube current modulation (TCM) on the radiation dose received by the lens and the image quality of nasal and periorbital imaging. Material and Methods An anthropomorphic phantom was CT-scanned using either automatic tube current modulation or a fixed tube current. The lens radiation dose was estimated using cropped Gafchromic films irradiated with or without a shield over the orbit. Image quality, assessed using regions of interest drawn on the bilateral extraorbital areas and the nasal bone with a water-based marker, was evaluated using both a signal-to-noise ratio (SNR) and contrast-noise ratio (CNR). Two CT specialists independently assessed image artifacts using a three-point Likert scale. Results The estimated radiation dose received by the lens was significantly lower when barium sulfate or bismuth-antimony shields were used in conjunction with a fixed tube current (22.0% and 35.6% reduction, respectively). Topogram-based TCM mitigated the beam hardening-associated artifacts of bismuth-antimony and barium sulfate shields. This increased the SNR by 21.6% in the extraorbital region and the CNR by 7.2% between the nasal bones and extraorbital regions. The combination of topogram-based TCM and barium sulfate or bismuth-antimony shields reduced lens doses by 12.2% and 27.2%, respectively. Conclusion Image artifacts induced by the bismuth-antimony shield at a fixed tube current for lenticular radioprotection were significantly reduced by topogram-based TCM, which increased the SNR of the anthropomorphic nasal bones and periorbital tissues.