Jeong Jin Seo

Contrast Enhancement and Contrast Extravasation on Computed Tomography After Intra-Arterial Thrombolysis in Patients With Acute Ischemic Stroke

Background and Purpose— The goal of this study was to determine the CT findings and clinical consequences of contrast enhancement and contrast extravasation on CT scans obtained after intra-arterial thrombolytic therapy for treatment of acute ischemic stroke. Methods— Sixty-two patients were treated with intra-arterial thrombolysis. All patients underwent nonenhanced CT scans immediately and 24 hours after thrombolytic therapy. Contrast enhancement was defined as a hyperdense lesion that disappeared on a 24-hour follow-up CT scan. Contrast extravasation was defined as a hyperdense lesion with maximum Hounsfield unit >90 that persisted on a follow-up CT scan. We evaluated the differences in the clinical and radiological data between 3 groups: contrast enhancement, contrast extravasation, and control groups. Results— Contrast enhancement was found in 14 of 62 patients (22.6%); contrast extravasation was seen in 7 (11.3%). Compared with the control group, the contrast enhancement group had a lower recanalization grade (64.3% versus 34.1%, P =0.048) and a lower incidence of hemorrhagic transformation (14.3% versus 43.9%, P =0.047). The contrast extravasation group had a higher incidence of both hemorrhage (100% versus 43.9%, P =0.006) and symptomatic hemorrhage (100% versus 14.6%, P <0.001) than the control group. Poor outcomes were more frequent in the contrast extravasation group (100% versus 38.9%, P =0.003) than the control group. Conclusions— Contrast enhancement on CT scans obtained after intra-arterial thrombolysis is usually not associated with hemorrhagic complications. However, contrast extravasation is highly associated with parenchymatous hematoma and should be considered a negative prognostic sign.

Dissection of the V4 segment of the vertebral artery: clinicoradiologic manifestations and endovascular treatment

Intracranial vertebral artery (VA) dissection has three clinical presentations: ischemia, hemorrhage, and mass effect. Imaging findings of intracranial VA dissections vary according to clinical presentation. Irregular stenosis or occlusion of the VA is the most common finding in patients with posterior fossa infarction, whereas a dissecting aneurysm is the main feature in those with acute subarachnoid hemorrhage. A chronic, giant, dissecting aneurysm can cause mass effect on the brain stem or cranial nerves, as well as distal embolism. Magnetic resonance imaging is useful for detection of intramural hematomas and intimal flaps, both of which are diagnostic of VA dissection. Multidetector computed tomography angiography is increasingly used for diagnosis of VA dissection. Catheter angiography is still beneficial for evaluation of precise endoluminal morphology of the dissection before surgical or endovascular intervention. Endovascular treatment is now considered a major therapeutic option for patients with a ruptured dissecting aneurysm or a chronic dissecting aneurysm. Anticoagulation therapy is currently considered the initial treatment of choice in patients with posterior circulation ischemic symptoms. Endovascular treatment, such as stent-assisted angioplasty or coil occlusion at the dissection site, can be performed in selected patients with posterior fossa ischemic symptoms.

Bilateral paramedian thalamic contrast enhancement on CT after Intra-arterial thrombolysis.

A 58-year-old woman presented with an acute embolic occlusion of the distal basilar artery. She underwent angioplasty and intra-arterial thrombolysis. Angiography performed after recanalization revealed a single perforating thalamic artery. A nonenhanced CT scan carried out immediately after the procedure revealed hyperdense lesions in the bilateral paramedian portions of the thalami, which disappeared on the 24-hour follow-up CT scan. Three months later, the patient improved to functional independence, but had some memory dysfunction and vertical gaze palsy. This case suggests that contrast enhancement or extravasation can occur in the thalamus after intra-arterial thrombolysis performed to recanalize a basilar artery occlusion.

Luteinized fat in Krukenberg tumor: MR findings

Abstract. To our knowledge, there is no description of the fat-containing Krukenberg tumor. We report on a case of Krukenberg tumor associated with luteinized fat, which showed hyperintensity on T1-weighted MR image. The diagnosis was surgically confirmed. Hyperintense portion of the Krukenberg tumor on T1-weighted image showed diminished signal intensity on fat-saturated, T1-weighted images. Krukenberg tumor should be considered in the differential diagnosis of ovarian masses when fat signal is seen.

Multidetector-row CT Angiography of Hepatic Artery: Comparison with Conventional Angiography

Purpose: To determine the usefulness of three-dimensional CT angiography using multidetector-row CT (MDCT) for delineating the arterial anatomy of the liver. Materials and Methods: Hepatic arterial three-dimensional CT angiography was performed using MDCT (Lightspeed Qx/I; GE Medical Systems, Milwaukee, Wis., U.S.A.) in 45 patients with HCC undergoing conventional angiography for transcatheter hepatic arterial chemoembolization. The scanning parameters during the early arterial phase were 2.5 mm slice thickness, 7.5 mm rotation of table speed, and a pitch of 3. Images were obtained by one radiologist using maximum intensity projection from axial CT images obtained during the early arterial phase. Two radiologists blinded to the findings of conventional angiography independently evaluated the hepatic arterial anatomy and the quality of the images obtained. Results: Compared with conventional angiography, reader A correctly evaluated the hepatic arterial anatomy depicted at three-dimensional CT angiography. Reader Bs evaluation was correct in 40 of 45 patients. Interobserver agreement was good (kappa value, 0.73), and both readers assessed the quality of three-dimensional CT angiography as excellent. Conclusion: Three-dimensional CT angiography using MDCT was accurate for delineating the arterial anatomy of the liver, and interobserver agreement was good. The modality may provide, prior to conventional angiography, valuable information regarding a patients hepatic arterial anatomy.

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.

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.

Colonic wall abnormalities on enhanced CT: Differentiation between inflammatory and neoplastic diseases

The computed tomographic(CT) findings of fourteen patients with inflammatory disease and 28 with neoplasm, who had an abnormal colonic wall thickening, were retrospectively studied to establish CT criteria for each disorder in differentiating inflammatory from neoplastic lesions. According to homogeneity, density and contour of mural thickening and peric이ic inf1ammatory change in enhanced CT scans, we classified colonic wall abnormalities into 6 patterns: 1) multilayering with inner and outer hyperand nùddle hypodensities, 11) homogeneously hyperdense with pericolic inf1ammatorγ change, 111) heterogeneously hyperdense with peric이ic inf1ammatory change , 1끼 homogeneously hyperdense with lobulated contour, V) heterogeneously hypodense with lobulated contour and V1) heterogeneously mixed densities with irregular lobulated contour. Type 1,II,and 111 were distinctively identified in inf1ammatory disease , type 1V, V in neoplasm, and type V1 in both diseases. We conclude that enhanced CT could be helpfl비 in the initial diagnosis andj or suggestion of abnormal colonic wall diseases and differentiation of inflammatorγ from neoplastic diseases.