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ABSTRACT: Background
Pseudoprogression is a treatment-related reaction with an increase in contrast-enhancing lesion size, followed by subsequent improvement. Differentiating tumor recurrence from pseudoprogression remains a problem in neuro-oncology.PurposeTo validate the added value of arterial spin labeling (ASL), compared with dynamic susceptibility contrast (DSC) perfusion magnetic resonance imaging (MRI) alone, in distinguishing early tumor progression from pseudoprogression in patients with newly diagnosed glioblastoma multiforme (GBM).Material and Methods
We retrospectively evaluated 117 consecutive patients with newly diagnosed GBM who underwent surgical resection and concurrent chemoradiotherapy (CCRT) as standard treatment modality. Sixty-two patients who developed contrast-enhancing lesions were assessed by both ASL and DSC perfusion MRI and classified into groups of early tumor recurrence (n = 34) or pseudoprogression (n = 28) based on pathologic analysis or clinical-radiologic follow-up. We used a qualitative analysis and semi-quantitative grade system on the basis of the tumor perfusion signal intensity into those equal to white matter (grade I), gray matter (grade II), and blood vessels (grade III) on ASL imaging. ASL grade was correlated with histogram parameters derived from DSC perfusion MRI.ResultsPseudoprogression was observed in 15 (53.6%) patients with ASL grade I, 13 (46.4%) with grade II, and 0 (0%) with grade III, with early tumor progression observed in seven (20.6%) patients with ASL grade I, 11 (32.3%) with grade II, and 16 (47.1%) with grade III (P = 0.0022). DSC perfusion histogram parameters differed significantly among ASL grades. ASL grade was an independent predictor differentiating pseudoprogression from early tumor progression (odds ratio, 4.73; P = 0.0017). On qualitative review, adjunctive ASL produced eight (12.9%) more accurate results than DSC perfusion MRI alone.ConclusionASL improves the diagnostic accuracy of DSC perfusion MRI in differentiating pseudoprogression from early tumor progression.
Acta Radiologica 04/2013; · 1.37 Impact Factor
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ABSTRACT: In recent years, mechanical thrombectomy using Solitaire stent retrieval has been tried for treating acute ischemic stroke with a large artery occlusion. We systematically reviewed published articles to appraise the evidence that supports the safety and efficacy of the mechanical thrombectomy in acute strokes with Solitaire stent.
Systematic searches using Medline and Scopus were performed for studies evaluating mechanical thrombectomy using a Solitaire stent in acute ischemic stroke. Articles were included if they were published since 2008, contained at least 5 subjects, and provided clinical results.
Thirteen articles (262 cases) were included in this review. The mean time of the procedures ranged from 37 to 95.6 minutes in 10 studies. The success of recanalization was achieved in 89.7% and the recanalization rate varied from 66.7% to 100% in all 13 studies. The overall rates of the symptomatic hemorrhagic complications and mortality were 6.8% and 11.1%, respectively. A favorable outcome of mRS 2 or under was 47.3%. Procedure-induced complications developed in 3.4%.
The present review suggested that mechanical thrombectomy using a Solitaire stent in acute ischemic stroke was effective in recanalizing the occluded artery. The rate of procedural complications was small.
Neurointervention. 02/2012; 7(1):1-9.
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ABSTRACT: VerifyNow antiplatelet assays were performed before and after stenting for various cerebral artery stenoses to determine the effect of the procedure itself to the function of dual antiplatelets given.
A total of 30 consecutive patients underwent cerebral arterial stenting procedure were enrolled. The antiplatelet pretreatment regimen was aspirin (100 mg daily) and clopidogrel (300 mg of loading dose followed by 75mg daily). VerifyNow antiplatelet assay performed before and right after stenting. The two test results were compared in terms of aspirin-reaction unit (ARU), P2Y12 reaction units (PRU), baseline (BASE), and percentage inhibition. We evaluated occurrence of any intra-procedural in-stent thrombosis or immediate thromboembolic complication, and ischemic events in 1-month follow-up.
The median Pre-ARU was 418 (range, 350-586). For clopidogrel the medians of the pre-BASE, PRU, and percent inhibition were 338 (279-454), 256 (56-325), and 27% (0-57%). The medians of the post-ARU, BASE, PRU, and percent inhibition after stenting were 469 (range, 389-573), 378 (288-453), 274 (81-370), and 26% (0-79%). There was a significant increase of ARU (p=0.045), BASE (p=0.026), and PRU (p=0.018) before and after stenting. One immediate thromboembolic event was observed in poor-response group after stenting. There was no in-stent thrombosis and ischemic event in 1-month follow-up.
We observed a significant increase of platelet reactivity to dual antiplatelet therapy right after stenting procedure for various cerebral arterial stenoses.
Neurointervention. 02/2012; 7(1):23-6.
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ABSTRACT: The middle cerebral artery (MCA) "susceptibility sign" on T2*-weighted imaging has been reported to indicate acute thrombotic occlusion. We evaluated the serial progression of this susceptibility sign on follow-up MRI and its effect on recanalization and clinical outcome after intraarterial thrombolysis.
Thirty-three acute ischemic stroke patients who were treated with intraarterial thrombolysis and underwent MRI within 6 hours of symptom onset were enrolled in this study. All study participants had either M1 or M2 occlusion on digital subtraction angiography before thrombolysis and underwent follow-up MRI 2-3 days after thrombolysis. Recanalization status was evaluated using the thrombolysis in myocardial infarction (TIMI) flow grade on digital subtraction angiography immediately after thrombolysis. The serial progression of the susceptibility sign on follow-up T2*-weighted imaging was compared with the MR angiographic findings. Baseline clinical parameters and clinical outcome were also reviewed.
A positive MCA susceptibility sign on the initial T2*-weighted imaging was detected in 16 (48%) of the 33 patients. The mean TIMI grade was higher in the patients with a positive sign on imaging than in those without the sign (2.3 vs 1.0, respectively; p < 0.005). In the risk factor analysis, a history of atrial fibrillation was significantly higher in the patients with the MCA susceptibility sign than in those with negative findings for the sign (13/16 [81%] vs 4/17 [24%], respectively). In 14 of the 16 patients with the positive sign, the sign disappeared on follow-up MRI, and that finding (i.e., disappearance of the sign) was well correlated with complete recanalization on follow-up MR angiography in 12 patients. Multivariate logistic regression analysis showed that this sign was not associated with a favorable functional outcome 30 days after thrombolytic treatment.
The MCA susceptibility sign can be indicative of acute thromboembolic occlusion and can be used to predict the immediate effectiveness of intraarterial thrombolysis. However, the appearance of this sign was not associated with a favorable clinical outcome after thrombolysis in our small series study.
American Journal of Roentgenology 12/2006; 187(6):W650-7. · 2.78 Impact Factor
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ABSTRACT: The purpose of our study was to assess whether cerebral microbleeds are related to early hemorrhagic transformation after thrombolytic therapy for hyperacute ischemic stroke.
The cases of 279 patients with suspected ischemic stroke who underwent MRI including T2*-weighted images were retrospectively evaluated. The inclusion criteria were as follows: imaging performed within 6 hr after symptom onset, presence of territorial infarct of anterior circulation, no history of intracerebral hemorrhage, thrombolytic treatment, and available follow-up MR images. Microbleeds were classified according to number as follows: absent (grade 1, 0 bleeds), mild (grade 2, 1-2 bleeds), moderate (grade 3, 3-10 bleeds), and severe (grade 4, > 10 bleeds). The prevalence and severity of early hemorrhagic transformation after thrombolysis were assessed on follow-up images.
Among 279 patients, 65 patients (37 men, 28 women; mean age, 67 years) met the inclusion criteria. Microbleeds were found in 25 patients. Early hemorrhagic transformation occurred in nine of 40 patients without microbleeds (grade 1) and in eight of 25 patients with microbleeds: two of 12 patients with grade 2, three of eight patients with grade 3, and three of five patients with grade 4 microbleeds. The presence of symptomatic hemorrhage did not correlate with the number of microbleeds. Results of multivariate logistic regression analysis showed that the presence of microbleeds was not associated with hemorrhagic transformation after thrombolytic treatment.
Small and large numbers of microbleeds are not independent risk factors for early hemorrhagic transformation and symptomatic hemorrhage after thrombolytic therapy for hyperacute ischemic stroke. Additional studies with large groups of subjects are needed to confirm our conclusion.
American Journal of Roentgenology 05/2006; 186(5):1443-9. · 2.78 Impact Factor
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ABSTRACT: The purpose of our study was to evaluate the usefulness of contrast-enhanced sonography for prostate cancer detection in patients with an indeterminate prostate-specific antigen (PSA) level (4-10 ng/mL) and negative findings on digital rectal examination.
Forty-eight patients underwent gray-scale, color Doppler, and contrast-enhanced sonography examinations and then sonographically guided biopsy. Contrast-enhanced sonography was performed using Levovist at a mechanical index of 1.1-1.4. The performances of the three methods for cancer detection were compared according to biopsy site and patient.
Sensitivity by biopsy site was greater on contrast-enhanced sonography (68%) than on gray-scale (39%) and color Doppler (41%) sonography (p > or = 0.05), whereas the specificity and overall accuracy by biopsy site (82% and 77% for gray-scale sonography, 84% and 79% for color Doppler sonography, and 83% and 81% for contrast-enhanced sonography, respectively) were not different for the three methods (p > 0.05). The concordance score for sonography and biopsy results by patient was not different for gray-scale (6.4 +/- 1.8), color Doppler (6.3 +/- 0.6), and contrast-enhanced sonography (6.5 +/- 0.7) (p = 0.281).
Contrast-enhanced sonography could improve only the sensitivity for cancer detection in analysis by biopsy site but did not improve the overall performance of sonography in patients with an indeterminate PSA level and negative digital rectal examination.
American Journal of Roentgenology 05/2006; 186(5):1431-5. · 2.78 Impact Factor
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ABSTRACT: The objective of our study was to compare the diagnostic accuracy of virtual cystoscopy, multiplanar reformation, and source CT images for lesion detection in the contrast material-filled bladder.
Two observers independently evaluated 47 patients (28 men and 19 women; mean age +/- SD, 59 +/- 16 years) with virtual cystoscopy, multiplanar reconstruction, and source CT images acquired with contrast material-filled bladder using an MDCT scanner (detector array, 4 x 1.25 mm; beam pitch, 0.75). Agreement between the two observers was evaluated for the three reconstruction methods using kappa statistics. Using the conventional cystoscopic findings as a reference, we compared the results of the three reconstruction techniques both by bladder site and by patient using the McNemar test.
The interobserver agreement for the number of positive sites was excellent for virtual cystoscopy (kappa = 0.816), fair for multiplanar reconstruction (kappa = 0.461), and good for source CT images kappa = 0.676). For both observers, the sensitivity for lesion detection by bladder site was significantly greater with virtual cystoscopy (observer 1, 95%; observer 2, 90%) than with multiplanar reconstruction (78% and 60%) and source CT (68% and 65%) images (p < 0.05), whereas the specificity by bladder site and the sensitivity and specificity by patient did not differ with the three methods (p > 0.05). For determining the presence or absence of lesion at each site, virtual cystoscopy was more accurate than multiplanar reconstruction and source CT images for both observers (p < 0.05).
Virtual cystoscopy is more accurate than multiplanar reconstruction and source CT images for the detection of lesions in the bladder.
American Journal of Roentgenology 10/2005; 185(3):689-96. · 2.78 Impact Factor
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ABSTRACT: To determine the diagnostic accuracy of CT arthrography and virtual arthroscopy in the diagnosis of anterior cruciate ligament and meniscus pathology.
Thirty-eight consecutive patients who underwent CT arthrography and arthroscopy of the knee were included in this study. The ages of the patients ranged from 19 to 52 years and all of the patients were male. Sagittal, coronal, transverse and oblique coronal multiplanar reconstruction images were reformatted from CT arthrography. Virtual arthroscopy was performed from 6 standard views using a volume rendering technique. Three radiologists analyzed the MPR images and two orthopedic surgeons analyzed the virtual arthroscopic images.
The sensitivity and specificity of CT arthrography for the diagnosis of anterior cruciate ligament abnormalities were 87.5%-100% and 93.3-96.7%, respectively, and those for meniscus abnormalities were 91.7%-100% and 98.1%, respectively. The sensitivity and specificity of virtual arthroscopy for the diagnosis of anterior cruciate ligament abnormalities were 87.5% and 83.3-90%, respectively, and those for meniscus abnormalities were 83.3%-87.5% and 96.1-98.1%, respectively.
CT arthrography and virtual arthroscopy showed good diagnostic accuracy for anterior cruciate ligament and meniscal abnormalities.
Korean Journal of Radiology 5(1):47-54. · 1.54 Impact Factor
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ABSTRACT: Alveolar soft-part sarcoma (ASPS) of the head and neck is an extremely rare malignancy. Although the clinical and imaging features of this tumor have been reported, a periodic review of unusual tumors is useful. The purpose of this study was to describe the clinical and imaging features of ASPS of the head and neck.
Between January 1990 and May 2004 at our institution, five head and neck ASPS were diagnosed in five patients (two male and three female patients; age range, 4-22 years). Clinical and imaging findings were reviewed retrospectively. Imaging studies consisted of contrast material-enhanced CT (in four patients), MR imaging (in four patients), and digital subtraction angiography (in two patients).
The locations of the tumor were tongue in two cases, larynx in one case, buccal space in one case, and paravertebral space in one case. This tumor appeared as a large lobulating-contoured mass with high signal intensity and flow voids on T2-weighted images and showed strong enhancement on contrast-enhanced CT and MR images. Preoperative angiography showed high vascularity. Wide surgical excisions were performed in four cases. Mean follow-up periods were 16 months (range, 6-30 months), and no recurrence was noted except for the laryngeal case.
ASPS should be included in the differential diagnosis of head and neck tumor when a slow-growing, large mass with high signal intensity and flow voids on T2-weighted images and strong enhancement on contrast-enhanced CT or MR image is seen, particularly in young female patients.
American Journal of Neuroradiology 26(6):1331-5. · 2.93 Impact Factor
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ABSTRACT: Hyperdense lesions can frequently be observed on the CT obtained immediately after intra-arterial (IA) thrombolysis, and it is sometimes difficult to differentiate contrast extravasation from the hemorrhagic lesions. The purposes of this study are to classify the hyperdense lesions according to their morphologic features and to track the outcome of those lesions.
Among the 94 patients who suffered with anterior circulation ischemic stroke and who were treated with IA thrombolysis, 31 patients revealed hyperdense lesions on the CT obtained immediately after the procedure. The lesions were categorized into four types according to their volume, shape, location and density: cortical high density (HD), soft HD, metallic HD and diffuse HD. The follow-up images were obtained 3-5 days later in order to visualize the morphologic changes and hemorrhagic transformation of the lesions.
Among the 31 patients with HD lesions, 18 (58%) showed hemorrhagic transformation of their lesion, and six of them were significant. All the cortical HD lesions (n = 4) revealed spontaneous resolution. Seven of the soft HD lesions (n = 13) showed spontaneous resolution, while the rest of the group showed hemorrhagic transformation. Among them the hemorrhage was significant in only two patients (2/6) who did not achieve successful recanalization. All the metallic HD lesions (n = 10) resulted in hemorrhagic transformation; among them, three cases (30%) with a maximum CT value more than 150 HU (Hounsfield unit) subsequently showed significant hemorrhagic transformation on the follow-up CT. There were four diffuse HD lesions, and two of them showed hemorrhagic transformation.
The parenchymal hyperdense lesions observed on the CT obtained immediately after IA thrombolysis in ischemic stroke patients exhibited varying features and they were not always hemorrhagic. Most of the soft HD lesions were benign, and although all of the metallic HD lesions were hemorrhagic, some of them were ultimately found to be benign.
Korean Journal of Radiology 7(4):221-8. · 1.54 Impact Factor
