Language Lateralization by Functional MRI: A Comparison with Wada Test-preliminary Results

PURPOSE: To evaluate the usefulness of functional MR imaging (fMRI) for the determination of languagedomi-nance and to assess differences in language lateralization according to activation task or activated area. MATERIALS AND METHODS: Functional maps of the language area were obtained during word generation tasks (noun andverb) and a reading task in ten patients (9 right handed, 1 left handed) who had undergone the Wada test. MRexaminations were performed using a 1.5T scanner and the EPI BOLD technique. The SPM program was employed for thepostprocessing of images and the threshold for significance was set at p<0.001 or p<0.01. A lateralization indexwas calculated from the number of activated pixels in three hemispheric re-gions (whole hemisphere, frontal lobe,and temporoparietal lobe), and the results were compared with those of Wada tests. The results for lateralizationof language area were compared among stimulation tasks and regions and used for calculation of lateralizationindices. RESULTS: During the Wada test, nine patients were left dominant and one patient was right dominant forlan-guage. Language dominance based on activated signals in each hemisphere was consistent with the results of theWada test in 87.5% (verb and noun generation tasks) and 90% (reading task) of patients. Language domi-nancedetermined by activated signals in the frontal lobe was consistent in 87.5%, 75%, and 80% of patients in eachstimulation task (verb generation, noun generation, and reading), respectively. The consistency rate of ac-tivatedsignals in the temporoparietal lobe was 87.5%, 87.5% and 80% of patients in each task. The mean val-ue of thelateralization index, calculated on the basis of activated signals in the temporoparietal lobe was higher thanthat in the hemisphere or frontal lobe. The verb generation task showed a higher lateralization index than thenoun generation or reading task. CONCLUSION: The lateralization index was higher in the verb generation task andin the region of the tem-poroparietal lobe than in other stimulation tasks or regions. fMRI is a potentiallyuseful non-invasive method for the determination of language dominance.

Interventional Radiologic Placement of Tunneled Central Venous Catheters: Results and Complications in 557Cases

PURPOSE: To evaluate prospectively the results of interventional radiologic placement of tunneled centralve-nous catheters, and subsequent complications. MATERIALS AND METHODS: Between April 1997 and April 1998, a totalof 557 tunneled central venous catheters were percutaneously placed in 517 consecutive patients in aninterventional radiology suite. The indications were chemotherapy in 533 cases, total parenteral nutrition in 23and transfusion in one. Complications were e-valuated prospectively by means of a chart review, chest radiography,central vein angiography and blood/catheter culture. RESULTS: The technical success rate for tunneled centralvenous catheter placement was 100% (557/557 cases). The duration of catheter placement ranged from 4 to 356 (mean,112 +/-4.6) days; Hickman catheters were re-moved in 252 cases during follow-up. Early complications included 3cases of pneumothorax(0.5%), 4 cases of local bleeding/hematoma(0.7%), 2 cases of primary malposition(0.4%), and 1case of catheter leakage(0.2%). Late complications included 42 cases of catheter-related infection(7.5%), 40 casesof venous thrombosis (7.2%), 18 cases of migration (3.2%), 5 cases of catheter / pericatheter of occlusion(0.8%),and 1 case of pseudoa-neurysm(0.2%) . The infection rate and thrombosis rate per 1000 days were 1.57 and 1.50,respectively. CONCLUSIONS: The technical success rate of interventional radiologic placement of tunneled centralvenous catheters was high. In comparison to conventional surgical placement , it is a more reliable method andleads to fewer complications.

Bronchiectasis: Diagnostic Accuracy of Chest Computed Radiography

PURPOSE: The aim of this study was to assess the diagnostic accuracy of chest comput-ed radiography for thedetection of bronchiectasis diagnosed by high-resolution CT. MATERIALS AND METHODS: Our study included 100consecutive patients with bronchiec-tasis and 20 normal subjects, all seen on high-resolution CT. Two independentobservers analyzed chest computed radiographs and recorded the presence and type of bronchiectasis, and the invo lved lobe. RESULTS: On high-resolution CT, bronchiectasis was seen in one lobe in 29 patients, two lobes in 29,three lobes in 16, four lobes in 14, five lobes in 10, and six lobes in t wo. The bronchiectasis was tubular in 55patients, mixed tubular and cystic in 29, and cystic in 16. For observer 1, the sensitivity, specificity, andaccuracy of chest com-puted radiography was 95%, 85%, and 93%, respective l y, while for observer 2, thecorresponding figures were 93%, 85%, and 92%. Sensitivity and specificity for observ-er 1 were 33% and 96% for theright upper lobe (46% and 95% for observer 2), 68% and 86% for the right middle lobe (76% and 86%), 70% and 78%for the right lower lobe (48% and 83%), 50% and 100% for the left upper lobe (50% and 97%), 63% and 90% for thelingular segment (49% and 93%), and 87% and 75% for the left lower lobe (75% and 90%), respective l y. Tubularbronchiectasis involving a single lobe was the most common source of false negative readings based on the findingsof chest com-puted radiography. CONCLUSION: Because chest computed radiography is not inferior to high-resolutionCT for the detection of bronchiectasis, the routine use of chest computed radiography in screening forbronchiectasis is feasible. Howeve r, due to its low sensitivity in detect-ing bronchiectasis in a specific lobe,preoperative high-resolution CT examination may be needed.

Value of MR Imaging after CT in Patients with Focal Hepatic Lesion

PURPOSE: To determine the usefulness of magnetic resonance imaging (MRI) after computed tomography (CT) inpatients with focal hepatic lesion. MATERIALS AND METHODS: We evaluated 100 patients with 103 focal hepaticlesions. The diagnosis of each lesion was made pathologically (n=19), or radiologically and clinically (n=84), andthe findings were as follows: he-mangioma (n=53), hepatocellular carcinoma (n=17), metastasis (n=10), cyst (n=5),regenerative nodule (n=3), and adenomatous hyperplasia (n=3). The patients underwent conventional CT (n=25),two-phase spi-ral CT (n=17) or three-phase spiral CT (n=61). MRI was performed using conventional T1- andT2-weighted imaging and dynamic contrast enhancement. The value of MRI after CT was assigned to one of fourgrades, according to the consensus of three radiologists: grade I (decisive), grade II (helpful), grade III (notadditional), or grade IV (confused). RESULTS: The outcome of MRI of 103 lesions was grade I in 14 cases(14%), IIin 34 (33%), III in 49 (48%), and IV in 6 (6%). MRI was not helpful (grade III or IV) in 40% (10/25), 47% (8/17),and 61%(31/61) of lesions after conventional, two-phase spiral, and three-phase spiral CT, respectively. Grade IIIor IV lesions were present in 45% of hemangiomas (24/53), 59% of hepatocellular carcinomas (10/17), and 80% ofcases in which metastasis had occurred(8/10). CONCLUSION: MRI after CT in patients with focal hepatic lesion washelpful in less than half of all cases. It was particularly valuable for patients who did not undergo three-phasespiral CT and in whom hemangioma was suspected.

Diagnostic Accuracy of Three-dimensional CT Angiography in Intracranial Aneurysms

PURPOSE: To determine the accuracy of three-dimensional CT angiography(CTA) in the diagnosis of intracranialaneurysms. MATERIALS AND METHODS: 3D-CTA was performed in 46 consecutive patients with subarachnoid hemorrhage orsuspected intracranial aneurysm. Images were obtained using a helical CT scanner and the SSD techinque. 3D CTAfindings were reviewed retrospectively and independently in blind fashion by two neuroradiologists. Digitalsubtraction angiography(DSA) was used as the reference standard. RESULTS: DSA revealed, in 36 patients, 40aneurysms ranging from 2mm to 12mm in maximal diameter, and negative findings in 10 patients. For observer 1, theaccuracy of 3D-CTA for all aneurysms and all patients was 85.2% and 82.7%, respectively. For observer 2, therespective figures were 94.6% and 91.9%. The agreement rates between the two observers were 86% for all aneurysmsand 87% for all patients (Kappa value 0.58, 0.59). CONCLUSION: Three-dimensional CTA is a useful imagingtechnique for the diagnosis of intracranial aneurysms, with an accuracy of over 85%