Gwang Woo Jeong

Blood-oxygenation-level-dependent functional magnetic resonance imaging for evaluating cerebral regions of female sexual arousal response.

OBJECTIVES To evaluate, for the first time, the cerebral regions associated with female sexual arousal evoked by visual stimulation using noninvasive blood-oxygenation-level-dependent (BOLD) functional magnetic resonance imaging (fMRI). METHODS A total of 6 healthy right-handed female volunteers (mean age 33 years, range 25 to 41) underwent fMRI on a 1.5-T MR scanner, in which the BOLD technique was used to create fMR images reflecting local brain activities. Real-time visual stimulation was performed with alternatively combined erotic and nonerotic films to identify the activated brain regions associated with sexual response. The perceived sexual arousal response was assessed using a scale ranging from 1 (no change) to 5 (maximal increase). RESULTS The mean score for perceived sexual arousal by erotic visual stimulation was 2.7 on the 5-point scale and was unchanged by nonerotic stimulation. During the visual task, the occipital cortex was activated by both the erotic and the nonerotic films; however, the following cerebral areas were significantly (P <0.05) activated, varying from 4 of 6 to 6 of 6 women: inferior frontal lobe, cingulate gyrus, insula gyrus, corpus callosum, thalamus, caudate nucleus, globus pallidus, and inferior temporal lobe. CONCLUSIONS This study is the first to evaluate noninvasive BOLD-fMRI in identifying cerebral regions associated with sexual arousal response evoked by visual stimulation in women.

Outcomes of manual aspiration thrombectomy for acute ischemic stroke refractory to stent-based thrombectomy

Background and purpose The optimal treatment for patients with acute stroke refractory to stent-based thrombectomy (SBT) is unclear. This study aimed to report clinical outcomes of manual aspiration thrombectomy (MAT) for the treatment of acute ischemic stroke refractory to SBT. Methods We retrospectively analyzed clinical and angiographic data of 30 patients who underwent MAT with a Penumbra reperfusion catheter because of refractory occlusion after SBT with a Solitaire stent as first-line endovascular therapy. Refractory occlusion was defined by a lack of successful revascularization (defined as Thrombolysis In Cerebral Infarction ≥2b) after five retrieval attempts. A good outcome was defined as a modified Rankin scale score of ≤2 at 3 months. Results Successful revascularization was achieved in 83.3% (25/30) of the patients who underwent MAT after failed SBT. There was no arterial rupture or dissection or symptomatic intracranial hemorrhage. Two embolic occlusions in a new arterial territory and five subarachnoid hemorrhages occurred, neither of which caused neurological worsening. At the 3-month follow-up, 36.7% (11/30) of patients exhibited a good outcome. The mortality rate was 6.7% (2/30) at 3 months. Conclusions This study suggests that MAT with the Penumbra reperfusion catheter can further increase the revascularization rate without serious complications in patients with acute stroke with refractory occlusions after SBT with a Solitaire stent.

Intravoxel incoherent motion diffusion-weighted imaging for monitoring chemotherapeutic efficacy in gastric cancer

AIM To assess intravoxel incoherent motion diffusion-weighted imaging (IVIM-DWI) for monitoring early efficacy of chemotherapy in a human gastric cancer mouse model. METHODS IVIM-DWI was performed with 12 b-values (0-800 s/mm(2)) in 25 human gastric cancer-bearing nude mice at baseline (day 0), and then they were randomly divided into control and 1-, 3-, 5- and 7-d treatment groups (n = 5 per group). The control group underwent longitudinal MRI scans at days 1, 3, 5 and 7, and the treatment groups underwent subsequent MRI scans after a specified 5-fluorouracil/calcium folinate treatment. Together with tumor volumes (TV), the apparent diffusion coefficient (ADC) and IVIM parameters [true water molecular diffusion coefficient (D), perfusion fraction (f) and pseudo-related diffusion coefficient (D(*))] were measured. The differences in those parameters from baseline to each measurement (ΔTV%, ΔADC%, ΔD%, Δf% and ΔD(*)%) were calculated. After image acquisition, tumor necrosis, microvessel density (MVD) and cellular apoptosis were evaluated by hematoxylin-eosin (HE), CD31 and terminal-deoxynucleotidyl transferase mediated nick end labeling (TUNEL) staining respectively, to confirm the imaging findings. Mann-Whitney test and Spearmans correlation coefficient analysis were performed. RESULTS The observed relative volume increase (ΔTV%) in the treatment group were significantly smaller than those in the control group at day 5 (ΔTVtreatment% = 19.63% ± 3.01% and ΔTVcontrol% = 83.60% ± 14.87%, P = 0.008) and day 7 (ΔTVtreatment% = 29.07% ± 10.01% and ΔTVcontrol% = 177.06% ± 63.00%, P = 0.008). The difference in ΔTV% between the treatment and the control groups was not significant at days 1 and 3 after a short duration of treatment. Increases in ADC in the treatment group (ΔADC%treatment, median, 30.10% ± 18.32%, 36.11% ± 21.82%, 45.22% ± 24.36%) were significantly higher compared with the control group (ΔADC%control, median, 4.98% ± 3.39%, 6.26% ± 3.08%, 9.24% ± 6.33%) at days 3, 5 and 7 (P = 0.008, P = 0.016, P = 0.008, respectively). Increases in D in the treatment group (ΔD%treatment, median 17.12% ± 8.20%, 24.16% ± 16.87%, 38.54% ± 19.36%) were higher than those in the control group (ΔD%control, median -0.13% ± 4.23%, 5.89% ± 4.56%, 5.54% ± 4.44%) at days 1, 3, and 5 (P = 0.032, P = 0.008, P = 0.016, respectively). Relative changes in f were significantly lower in the treatment group compared with the control group at days 1, 3, 5 and 7 follow-up (median, -34.13% ± 16.61% vs 1.68% ± 3.40%, P = 0.016; -50.64% ± 6.82% vs 3.01% ± 6.50%, P = 0.008; -49.93% ± 6.05% vs 0.97% ± 4.38%, P = 0.008, and -46.22% ± 7.75% vs 8.14% ± 6.75%, P = 0.008, respectively). D* in the treatment group decreased significantly compared to those in the control group at all time points (median, -32.10% ± 12.22% vs 1.85% ± 5.54%, P = 0.008; -44.14% ± 14.83% vs 2.29% ± 10.38%, P = 0.008; -59.06% ± 19.10% vs 3.86% ± 5.10%, P = 0.008 and -47.20% ± 20.48% vs 7.13% ± 9.88%, P = 0.016, respectively). Furthermore, histopathologic findings showed positive correlations with ADC and D and tumor necrosis (r s = 0.720, P < 0.001; r s = 0.522, P = 0.007, respectively). The cellular apoptosis of the tumor also showed positive correlations with ADC and D (r s = 0.626, P = 0.001; r s = 0.542, P = 0.005, respectively). Perfusion-related parameters (f and D(*)) were positively correlated to MVD (r s = 0.618, P = 0.001; r s = 0.538, P = 0.006, respectively), and negatively correlated to cellular apoptosis of the tumor (r s = -0.550, P = 0.004; r s = -0.692, P < 0.001, respectively). CONCLUSION IVIM-DWI is potentially useful for predicting the early efficacy of chemotherapy in a human gastric cancer mouse model.

The Usefulness of Air Insufflation Helical CT in Colorectal Cancer

Purpose: In patients with colorectal carcinoma, helical CT using air as a contrast agent provides axial images and a three-dimensional CT colonogram similar to that provided by barium enema. The purpose of this study was to assess the usefulness of air insufflation helical CT in colorectal cancer patients. Materials and Methods: Thirty-three patients with colorectal carcinoma confirmed by surgery underwent air insufflation helical CT scanning after the infusion of air through the anus. In eleven who underwent barium studies, CT colonograms were also obtained. Two radiologists, who reached a consensus, analysed the detection rate, location and staging of the tumors; staging was based on the modified Dukes (Astler-Coller) classification. Results: Using axial helical CT, the detection rate was 97%; staging was correct in 23 of the 33 patients, with an overall accuracy of 70%. Pathologic correlation was correct in 30 of the 33 cases (three were overestimated), and sensitivity, specificity and accuracy were 100%, 50%, and 91%, respectively. With regard to the involvement of lymph nodes, pathologic correlation was correct in 25 of the 33 patients; four were overestimated and four were underestimated. Sensitivity, specificity and accuracy were 69%, 80%, and 76%, respectively. The detection rate of CT colonography was 100%, but because in one case there was a discrepancy between CT colonography and barium enema as to the shape of the carcinoma, the agreement rate was 91%. Conclusion: Air insufflation helical CT, which provides a higher detection rate and more precise staging of colorectal carcinoma than the use of positive contrast materials and three dimensional depiction of tumor location, is helpful for the evaluation of colorectal carcinoma.

Diagnosis and Prediction of Clinical Outcomes in Patients with Acute Lacunar Infarction: Usefulness of Perfusion MR Imaging

Purpose: To correlate the findings of perfusion-weighted imaging (PWI) with clinical outcomes in patients with acute lacunar infarction. Materials and Methods: Eleven patients (7 males and 4 females) with acute lacunar infarction who were examined within 50 (mean, 29) hours of the onset of symptoms underwent conventional MRI, diffusion-weighted imaging (DWI) and PWI. Gadolinium (0.2 mmol/kg) was injected at a rate of 2 ml/sec, and PWI was performed using a gradient-echo EPI pulse sequence and the following parameters: TR/TE, 2000/60; flip angle, 90 degree; matrix size, 128128. Relative cerebral blood volume (rCBV) maps were derived from gadolinium bolus perfusion-weighted images where rCBV ratios between infarcted areas were detected by DWI, and contralateral control areas were obtained. In each case, the resulting rCBV ratio at a lesion site was compared with the clinical outcome determined on the basis of the difference between National Institute Health Stroke Scale (NIHSS) scores at admission and discharge. Results: With the aid of the time-intensity curve obtained at PWI, the rCBV maps revealed a hypoperfused area in 10 of 11 patients, and there was positive correlation (r=0.81) with clinical outcome. Conclusion: Although PWI has a lower detection rate than DWI, it may be a useful modality for helping determine prognosis in cases of acute lacunar infarction.

Virtual Endoscopy Using Spiral CT in Patients with Carcinomas of the Hypopharynx and Larynx

Purpose: To compare the usefulness of virtual endoscopy using spiral CT with that of laryngoscopy in the detection and evaluation of laryngeal and pharyngeal carcinomas. Materials and Methods: Twenty-four patients with pathologically proven laryngeal and pharyngeal carcinomas underwent laryngoscopy and virtual endoscopy using spiral CT. Eleven of the carcinomas were supraglottic, five were glottic, and eight were hypopharyngeal. Source images obtained by spiral CT were transmitted to an independent workstation and virtual endoscopic images were obtained using Navigator software. These were graded according to their quality (good, fair, bad), and were interpreted by two radiologists who were blinded to the conventional endoscopic findings. These latter were subsequently compared with the virtual endoscopic findings in terms of similarity to laryngoscopic examination and detectability of lesions. Results: The overall image quality of virtual endoscopy was good in 16 cases (67%), fair in eight (33%), and bad in no case. Among the 11 supraglottic carcinomas, image quality was good in seven cases (64%), and fair in four (36%). In four of the five glottic carcinomas (80%) quality was good, and in one case (20%) it was fair, while among the eight hypopharyngeal carcinomas, quality was good in five cases (63%), and fair in three (37%). Overall, detection of the lesion was possible in 23 cases (96%). Due to the small size of the lesion, the Conclusion: Virtual endoscopy using spiral CT is a safe and noninvasive method, and also successfully detects laryngeal and pharygenal lesions, with good image quality. For the evaluation of laryngeal and hypopharyngeal carcinoma, its use may complement that of axial CT.

Comparison between Spiral CT and MR Imaging in Evaluation of Focal Hepatic Masses

Purpose: The main aim of this study was to compare spiral CT and MR imaging in the detection and charac-terization of focal hepatic masses. Materials and Methods: Seventy-nine patients with 155 focal hepatic masses confirmed pathologically, or radi-ologically and clinically [hepatocellular carcinoma(HCC) (n =52), hemangioma (n=36), cysts (n =35), metas-tasis (n =27), intrahepatic cholangiocarcinoma (n =5)], underwent two- or three-phase spiral CT, and T1-, T2- weighted, and dynamic contrast-enhanced MR imaging. The detection and characterization of focal hepatic masses by these modalities were evaluated and compared. Results: The detection rates of spiral CT and MR imaging, respectively, were as follows: HCC, 81%(42/52) and 94%(49/52); hemangioma, 75%(27/36) and 100%(36/36); cysts, 80%(28/35) and 100%(35/35); metastasis, 67%(18/27) and 100%(27/27); and intrahepatic cholangiocarcinoma, 100%(5/5) and 100%(5/5). MR imaging was superior to spiral CT in mass detection of HCC, hemangioma, cysts, and metastasis (p

Usefulness of CT Angiogra p hy after Metallic Stent Implantation of the Internal Carotid Artery

Purpose : To evaluate the usefulness of CT angiography in Patients with implantation of metallic stent for stenosed internal carotid artery. Materials and Methods : Seven patients with atherosclerotic stenosis of the internal carotid artery underwent metallic stent implantation. All were male and their ages ranged from 36 to 69 years. A total of seven stents were placed in the internal carotid artery in five patients and in the carotid bifurcation in two. Spiral CT scans were obtained and CT angiographic images were reconstructed using MPR or curved MPR techniques at a workstation. The interval between CT and conventional angiography did not exceed six days except in one pa-tient, in whom it was 61days. CT and conventional angiography were compared for stent position with respect to the carotid bifurcation, stent deformation, intraluminal filling defect, and luminal caliber and outflow. Luminal patency of the implanted stent was measured according to NASCET(North American Symptomatic Carotid Endarterectomy Trial) criteria, and statistically processed (p>.05). The presence or absence of in-trastent thrombus and vascular wall calcification was determined using axial source images. Results : In all patients, CT angiographic findings matched those obtained by conventional angiography. Complications such as migration or deformation of an implanted stent, intraluminal filling defect, change of lu-minal caliber or outflow of implanted stent were not observed in any patient. In two studies in which Wilcoxon signed rank test was used, degree of stent expansion correlated closely(p=0.237). Axial source im-ages showed that in no patient was an intrastent thrombus present, though in five, vascular wall calcification of internal carotid arteries outside the stent was noted. Conclusion : CT angiography is useful for the assessment of positional change, occlusion, and luminal patency of a stent-implanted internal carotid artery.

MR Imaging with Fluid Attenuated Inve rsion Recovery Sequence of Childhood Adrenoleukodystrophy: Comparisonwith T2 Weighted Spin Echo Imaging

Purpose : The purpose of this study was to evaluate the usefulness of FLAIR(Fluid Attenuated InversionRecovery) MR imaging in childhood adrenoleukodystrophy by comparing with those of T2-weighted FSE imaging, and tocorrelate MRI finidings with clinical manifestations. Materials and Methods : Axial FLAIR images(TR/TE/TI=10004/123/2200) and T2-weighted FSE images(TR/TE=4000/104) of brain in six male patients(age range :6-17 years, mean age : 10.2 years) with biochemically confirmed adrenoleukodystrophy were compared visually by tworadiologists for detection, conspicuity, and the extent of lesion. Quantitatively, we compared lesion/CSFcontrast, lesion/CSF contrast to noise ratio(CNR), lesion/white matter(WM) contrast, and lesion/WM CNR betweenFLAIR and T2 weighted image. We correlated MR findings with clinical manifestations of neurologic symptoms andevaluated whether MRI could detect white matter lesions in neurologically asymptomatic patients. Results : Visualdetection of lesions was better with FLAIR images in 2 of the 6 cases and it was equal in the remainders. Visualconspicuity and detection of the extent of lesion were superior on FLAIR images than T2-weighted images in all 6cases. In the quantitative assessment of lesions, FLAIR was superior to T2-weighted image for lesion/CSF contrastand lesion/CSF CNR, but was inferior to T2 weighted image for lesion/WM contrast and lesion/WM CNR. In one case,FLAIR images distinguished the portion of encephalomalacic change from lesions. MR findings ofadrenoleukodystrophy were correlated with clinical manifestations in symptomatic 4 cases, and also detected whitematter lesions in asymptomatic 2 cases. Conclusion : MR imaging with FLAIR sequence provided images that wereequal or superior to T2-weighted images in the evaluation of childhood adrenoleukodystrophy. MRI findings werewell correlated with clinical manifestations and could detect white matter lesions in neurologically asymptomaticadrenoleukodystrophy patients.