C-Y Chang

National Yang Ming University, T’ai-pei, Taipei, Taiwan

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Publications (28)57.85 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: BACKGROUND AND PURPOSE:Flat detector CT has been increasingly used as a follow-up examination after endovascular intervention. Metal artifact reduction has been successfully demonstrated in coil mass cases, but only in a small series. We attempted to objectively and subjectively evaluate the feasibility of metal artifact reduction with various metallic objects and coil lengths.MATERIALS AND METHODS:We retrospectively reprocessed the flat detector CT data of 28 patients (15 men, 13 women; mean age, 55.6 years) after they underwent endovascular treatment (20 coiling ± stent placement, 6 liquid embolizers) or shunt drainage (n = 2) between January 2009 and November 2011 by using a metal artifact reduction correction algorithm. We measured CT value ranges and noise by using region-of-interest methods, and 2 experienced neuroradiologists rated the degrees of improved imaging quality and artifact reduction by comparing uncorrected and corrected images.RESULTS:After we applied the metal artifact reduction algorithm, the CT value ranges and the noise were substantially reduced (1815.3 ± 793.7 versus 231.7 ± 95.9 and 319.9 ± 136.6 versus 45.9 ± 14.0; both P < .001) regardless of the types of metallic objects and various sizes of coil masses. The rater study achieved an overall improvement of imaging quality and artifact reduction (85.7% and 78.6% of cases by 2 raters, respectively), with the greatest improvement in the coiling group, moderate improvement in the liquid embolizers, and the smallest improvement in ventricular shunting (overall agreement, 0.857).CONCLUSIONS:The metal artifact reduction algorithm substantially reduced artifacts and improved the objective image quality in every studied case. It also allowed improved diagnostic confidence in most cases.
    American Journal of Neuroradiology 01/2014; · 3.17 Impact Factor
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    ABSTRACT: BACKGROUND AND PURPOSE:Hyperperfusion syndrome is a devastating complication of carotid stent placement. The shortening of cerebral circulation time after stent placement is seen as a good indicator of the development of hyperperfusion syndrome. The purpose of our study was to evaluate whether patients with ipsilateral transverse sinus stenosis are prone to having shortened cerebral circulation time after stent placement, subsequently leading to the possible development of hyperperfusion syndrome.MATERIALS AND METHODS:Forty-nine patients with >70% unilateral carotid stenosis undergoing stent placement were recruited for analysis. Group A consisted of patients with a stenotic ipsilateral transverse sinus >50% greater than the diameter of the contralateral transverse sinus; the remaining patients were in group B. Quantitative DSA was used to calculate cerebral circulation time. Cerebral circulation time was defined as the time difference between the relative time to maximal intensity of ROIs in the proximal internal carotid artery and the internal jugular vein. ΔCCT was defined as cerebral circulation time before stent placement minus cerebral circulation time after stent placement. ΔCCT, white matter hyperintensity signals, and sulcal effacement in MR imaging were compared between the 2 groups.RESULTS:ΔCCT was significantly shorter in group A (0.65 ± 1.3) than in group B (-0.12 ± 1.4). Three patients had white matter hyperintensity signals in group A, and 1 developed hyperperfusion syndrome. Group B showed no MR imaging signs of hyperperfusion syndrome.CONCLUSIONS:Ipsilateral hypoplastic transverse sinus was associated with prolonged cerebral circulation time before stent placement and greatly shortened cerebral circulation time after stent placement. Inadequate venous drainage might play a role in impaired cerebral autoregulation and might influence the development of poststenting hyperperfusion syndrome.
    American Journal of Neuroradiology 01/2014; · 3.17 Impact Factor
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    ABSTRACT: To evaluate factors related to the technical and haemostatic outcomes of endovascular management in patients with head and neck cancers (HNC) associated with carotid blowout syndrome (CBS) of the external carotid artery (ECA). Between 2002 and 2011, 34 patients with HNC with CBS involving branches of the ECA underwent endovascular therapy. Treatment included embolization with microparticles, microcoils, or acrylic adhesives. Fisher's exact test was used to examine demographic features, clinical and angiographic severities, and clinical and imaging findings as predictors of endovascular management outcomes. Technical success and immediate haemostasis were achieved in all patients. Technical complications were encountered in one patient (2.9%). Rebleeding occurred in nine patients (26.5%). Angiographic vascular disruption grading from slight (1) to severe (4) revealed that the 18 patients with acute CBS had scores of 2 (2/18, 11.1%), 3 (3/18, 16.7%), and 4 (13/18, 72.2%). The 16 patients with impending and threatened CBS had scores of 1 (1/16, 6.25%), 2 (5/16, 31.25%), and 3 (10/16, 62.5%; p = 0.0003). For the 25 patients who underwent preprocedural computed tomography (CT)/magnetic resonance imaging (MRI) examinations within 3 months of treatment, the agreement between clinical and imaging findings reached the sensitivity, specificity, and kappa values for recurrent tumours (1, 0.7143, 0.7826), soft-tissue defect (0.9091, 0.3333, 0.2424), and sinus tract/fistula (0.4737, 0, 0.4286). Endovascular management for patients with CBS of the ECA had high technical success and safety but was associated with high rebleeding rates. We suggest applying aggressive post-procedural follow-up and using preprocedural CT/MRI to enhance the periprocedural diagnosis.
    Clinical radiology 07/2013; · 1.65 Impact Factor
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    ABSTRACT: In acute ischemic stroke, the ability to estimate the penumbra and infarction core ratio helps to triage those who will potentially benefit from thrombolytic therapies. Flat-panel post-contrast DynaCT imaging can provide both vasculature and parenchymal blood volume within the angio room to monitor hemodynamic changes during the endovascular procedures. We report on an 80-year-old woman who suffered from an acute occlusion of the right distal cervical internal carotid artery. She was transferred to the angio room where in-room post-contrast flat-panel DynaCT imaging (syngo Neuro PBV IR) was performed to access the ischemic tissue, followed by successful mechanical thrombolytic therapy.
    Interventional Neuroradiology 12/2012; 18(4):463-468. · 0.77 Impact Factor
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    ABSTRACT: Primary spinal primitive neuroectodermal tumors (PNETs) are rare and classified into peripheral and central types because the treatment strategy and outcome are different. This study describes five cases of primary spinal peripheral type PNETs. Magnetic resonance imaging showed large extradural masses in the cervical and thoracic spine with bony invasion and paraspinal extension in four cases and a transdural mass in the sacral spinal canal in one case. We also briefly summarize the imaging characteristics of 36 peripheral type and six central type primary spinal PNETs in the literature.
    The neuroradiology journal. 11/2012; 25(5):604-9.
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    ABSTRACT: We report a 49-year-old right lobe liver transplant recipient, who developed a significant anastomotic stenosis of the right hepatic vein shortly thereafter. Shear wave elastography (SWE) was applied to investigate liver stiffness quantitatively. It showed increased stiffness in the anterior compared with the posterior segment of right lobe graft. The stenotic right hepatic venous anastomosis was then managed by angioplasty with stent placement. SWE after angioplasty showed a gradual decrease in stiffness of the anterior segment, which was almost equal to the posterior segment at 2 weeks thereafter. Our experience suggested that SWE may be a noninvasive tool to assess alterations in liver stiffness secondary to hepatic venous congestion after liver transplantation.
    Transplantation Proceedings 04/2012; 44(3):814-6. · 0.95 Impact Factor
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    ABSTRACT: The objective of this study was to explore the donor and recipient factors related to the spectral Doppler parameters of the transplant kidney in the early posttransplantation period. This retrospective study included 76 patients who underwent renal transplantation assessed using Doppler ultrasonography (US) on the first postoperative day. We compared spectral Doppler parameters (peak systolic velocity [PSV] and resistive index [RI]) of the segmental artery of the transplant kidney according to the type of renal transplant, level of serum creatinine (SCr) of donor prior to organ donation, and donor/recipient age. RI was significantly higher in deceased-donor kidney transplantation (DDKT) as compared with living-donor kidney transplantation (LDKT; 0.73 ± 0.10 vs 0.66 ± 0.11; P = .007). In the DDKT recipients, multivariate analysis showed donor SCr was the only factor affecting PSV (P = .023), whereas recipient age was the only factor affecting RI (P = .035). In the LDKT recipients, multivariate analysis showed recipient age was the only factor affecting both PSV (P = .009) and RI (P = .018). Spectral Doppler parameters in the early posttransplantation period are related to the type of renal transplant, donor renal function, and recipient age. These factors should be taken into consideration when interpreting the results of spectral Doppler US.
    Transplantation Proceedings 01/2012; 44(1):226-9. · 0.95 Impact Factor
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    ABSTRACT: The optimal steroid dosages in AECOPD are still under debate. Admission records of patients in our hospital from January to December 2008 due to a diagnosis of AECOPD were reviewed. More wheezing and tachypnea were noted in the patients with a maximal daily prednisolone dose more than 60 mg. The steroid dose was higher in AECOPD without pneumonia than those concurrent with pneumonia. Those who had concurrent pneumonia had a higher risk of nosocomial infections. The study reflects the heterogeneity of AECOPD and that steroid dosages were determined by the clinical evaluation of the severity of illness and bacterial infections.
    International journal of clinical pharmacology and therapeutics 11/2011; 49(11):705-8. · 1.20 Impact Factor
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    ABSTRACT: We aimed to summarize the imaging findings of 25 patients with gefitinib-related interstitial lung disease (ILD), and identify the factors related to prognosis of gefitinib-related ILD in patients with non-small-cell-lung cancer. Diagnosis of gefitinib-induced ILD by at least two chest radiologists was based on a review and analysis of the chest radiography and CT findings plus clinical data in the medical records. All patients were diagnosed with Stage III - IV non-small-cell carcinoma (adenocarcinoma (n = 24), bronchioalveolar cell carcinoma (n = 1)) and essential clinical data such as gefitinib as first-line use and survival status were recorded and analyzed to determine whether these were prognosis predictors. The imaging findings were classified into four patterns according to the previous largest study in Japan. The 25 chest radiographs were classified as Pattern A (n = 8), Pattern B (n = 3), Pattern C (n = 6), and pattern D (n = 8). Likewise the 23 CT images were classified as pattern A (n = 8; 34.8%), B (n = 3; 13%), C (n = 5; 21.7%), and D (n = 7; 30.4%). The mortality rate was significantly higher in patients with pattern D than in patients with the other patterns. Pattern D imaging findings were also significantly correlated with non first-line use of gefitinib (p = 0.007). We found an increase in mortality rate in patients with gefitinib associated ILD/pattern D compared to other radiological patterns. Familiarity with these imaging patterns can facilitate early and accurate diagnosis and help physicians gauge clinical prognosis of gefitinib-related ILD.
    International journal of clinical pharmacology and therapeutics 10/2011; 49(10):587-93. · 1.20 Impact Factor
  • C-Y Chang, S-C Lin, W-H Su, C-M Ho, Y-S Jou
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    ABSTRACT: Common genetic alteration in cancer genomes is implicated for embracing an aberrant cancer gene participated in tumor progression. In this study, we identified a somatic mutated LIM and cysteine-rich domains-1 (LMCD1) as a putative metastatic oncogene in human hepatocellular carcinoma (HCC) using integrated genomic approaches. In addition to revealing genomic amplification and gene upregulation, we identified recurrent E135K (3/48 cases) mutations in HCC tissues and K237R mutation in the PLC/PRF/5 HCC cell line. Expression of mutant LMCD1 E135K or K237R reduced the stress fiber assembly, increased cortical actin accumulation and induced lamellipodial extension. Consistently, these mutations enhanced cell migration and showed activation of the Rac1-signaling pathway. Inhibition of the LMCD1/Rac1 pathway by an LMCD1 short-hairpin RNA (shLMCD1) or the Rac1 inhibitor NSC23766 suppressed the mutation-mediated lamellipodial protrusion and cell migration. In PLC/PRF/5 cells with endogenous K237R mutation, cell migration was enhanced by estrogen-induced LMCD1 expression but reversed by shLMCD1 treatment. Moreover, overexpression of LMCD1 E135K mutation significantly promoted systemic lung metastasis in a murine tail vein injection model. Together, our results suggest that LMCD1 mutations are potential oncogenic events in HCC metastasis to promote cell migration through the Rac1-signaling pathway.
    Oncogene 09/2011; 31(21):2640-52. · 7.36 Impact Factor
  • C-Y Chang, Y-C Lai, S-C Chang
    QJM: monthly journal of the Association of Physicians 08/2011; 105(9):907-9. · 2.36 Impact Factor
  • QJM: monthly journal of the Association of Physicians 06/2011; 105(7):701-3. · 2.36 Impact Factor
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    ABSTRACT: Collateral networks between the external carotid artery and internal carotid arteries become crucial for cerebral perfusion after occlusion of internal carotid arteries. We report the first case of a patient who received percutaneous transluminal angioplasty and stenting in a collateral vessel between the external and internal carotid artery for treatment of radiation induced severe stenosis of the internal carotid artery in the context of a contralateral internal carotid artery occlusion.
    Interventional Neuroradiology 03/2011; 17(1):22-6. · 0.77 Impact Factor
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    ABSTRACT: Chemical pleurodesis is an effective treatment for persistent air leakage and secondary pneumothorax. We report the case of a 57-year-old man who presented with pneumothorax and was treated by tube thoracostomy. Because of malpositioning of the chest tube, the minocycline that was administered for pleurodesis was injected into the lung parenchyma instead, which induced chemical pneumonitis. A review of literature indicated that this is the first report of minocycline-associated chemical pneumonitis and its successful treatment.
    International journal of clinical pharmacology and therapeutics 01/2011; 49(1):49-50. · 1.20 Impact Factor
  • Y-F Wei, C-Y Chang, S-C Chang
    QJM: monthly journal of the Association of Physicians 01/2011; 105(2):203-4. · 2.36 Impact Factor
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    ABSTRACT: We report a patient with traumatic carotid-cavernous fistula associated with an isolated internal carotid artery in whom, after trans-arterial balloon embolisation, premature balloon detachment occurred with balloon migration to the supraclinoid carotid artery, leading to total occlusion of the blood flow. The carotid flow was eventually restored by direct puncture of the detached balloon via the optic canal and by deploying a coronary stent to fix the balloon in the vascular wall. The fistula was eventually occluded by using detachable coils. He was discharged with a mild hemiparesis and decreased acuity in the left eye.
    Acta Neurochirurgica 05/2009; 152(2):321-4. · 1.55 Impact Factor
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    ABSTRACT: Perfusion of renal transplants may be altered by various pathological conditions. This study assessed cortical perfusion of renal transplants during acute rejection episodes using power Doppler quantification. Forty-eight renal transplant patients with clinical indications for biopsy were included in this study. Power Doppler ultrasonography (US) of these renal transplants was performed prior to biopsy. Power Doppler image intensity in the proximal outer cortex of renal transplants was quantified by image analysis software. The results of power Doppler quantification were compared with the clinical data and histological findings. Biopsies were classified into three groups based on Banff diagnostic categories: group 1 (no acute rejection; 26 patients), group 2 (acute cell-mediated rejection alone; 12 patients), and group 3 (acute antibody-mediated rejection with/or without acute cell-mediated rejection; 10 patients). The power Doppler intensity of the outer renal cortex was 1.98 +/- 1.50 dB for group 1, 1.38 +/- 0.86 dB for group 2, and 0.81 +/- 0.66 dB for group 3. Statistically, there was a significant difference between group 1 and group 3 (1.98 vs 0.81 dB, P = .01) but not between group 1 and group 2 (1.98 vs 1.38 dB, P = .34). In conclusion, the status of cortical perfusion of renal transplants can be determined noninvasively by quantified power Doppler US. Accordingly, acute antibody-mediated rejection is associated with significantly decreased cortical perfusion, which, we propose, is due to this distinct pathological process.
    Transplantation Proceedings 10/2008; 40(7):2330-2. · 0.95 Impact Factor
  • Clinical radiology 09/2008; 63(8):948-51. · 1.65 Impact Factor
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    ABSTRACT: Coil herniation into the parent artery after detachment is an uncommon complication of embolization of the intracranial aneurysm. We report our experience with stent reconstruction of the lumen and flow of the internal carotid artery (ICA) after coil herniation during embolization for intracranial ICA aneurysms and the possible mechanisms of coil herniation. A series of 216 consecutive patients was treated by endovascular coil embolizations for intracranial aneurysms. Of these patients, there were 9 (4 men, 5 women; 32-68 years of age) complicating with coil herniation into the ICA and undergoing stent deployment to reconstruct the ICA lumen (n = 8) or both lumen and flow (n = 1). Wide-neck aneurysms were found in 8 and narrow-neck, in 1. Aneurysms were in the posterior communicating artery (n = 5) and the paraophthalmic (n = 3) and cavernous portions (n = 1) of the ICA. Self-expandable stents were deployed in the ICA in 6; balloon-mounted stents were selected in 3. The causes of coil herniation appeared to be coil instability after detachment (n = 6), excessive embolization (n = 1), microcatheter-related problems (n = 1), or being pushed by subsequent coil embolization (n = 1). Endovascular stent placement to reconstruct the lumen and/or flow of the ICA was technically successful in all 9 patients; 1 needed a second stent due to further coil migration. No significant procedure-related complications were found. Clinical follow-up was 8-35 months. Coil herniation occasionally occurs during endovascular embolization of ICA aneurysms because of coil instability after detachment, excessive embolization, microcatheter-related problems, or pushing by subsequent coil embolization. In this small series, stent placement was safe and effective in the reconstruction of the arterial lumen and/or restoration of flow past a herniated coil mass.
    American Journal of Neuroradiology 09/2008; 29(10):1951-5. · 3.17 Impact Factor
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    The British journal of radiology 02/2007; 80(949):e15-8. · 2.11 Impact Factor

Publication Stats

226 Citations
57.85 Total Impact Points

Institutions

  • 2006–2013
    • National Yang Ming University
      T’ai-pei, Taipei, Taiwan
  • 2002–2012
    • Taipei Veterans General Hospital
      • Division of Radiology
      T’ai-pei, Taipei, Taiwan
  • 2011
    • National Defense Medical Center
      • Graduate Institute of Life Sciences
      Taipei, Taipei, Taiwan
    • Far Eastern Memorial Hospital
      • Department of Internal Medicine
      T’ai-pei, Taipei, Taiwan
    • National Taiwan University Hospital
      • Department of Internal Medicine
      Taipei, Taipei, Taiwan