[en] To assess the efficacy of three-dimensional CT angiography (3D-CTA) using multi-detector row computed tomography (MDCT) in the evaluation of intracranial aneurysms in patients with non-traumatic acute subarachnoid hemorrhage and to describe those aneurysms which were not found 3D-CTA. 3D-CTA was done in 40 patients with non-traumatic subarachnoid hemorrhage by using a 16-slice MDCT; conventional digital subtraction angiography (DSA) was done in 36 of those patients within 12 hours. The CT and DSA images were reviewed by two radiologists and the site, size and neck of the aneurysms were evaluated. The results from these two modalities were then compared with the operative findings. We calculated the detection rates by 3D-CTA and DSA and evaluated the size differences of aneurysms diagnosed with 3D-DTA and those found at surgery. We also analyzed the locations and sizes of aneurysms missed by 3D-CTA and attempted to explain these false negatives. A total of 55 aneurysms were surgically confirmed in 40 patients. 48 of these were detected pre-operatively by 3D-CTA. Thus, the detection rate by 3D-CTA was 87%. The size difference of aneurysms as calculated by 3-D CTA and found operatively was as follows: less than 1 mm in 17 cases, within 1-2 mm in 15 cases, and more than 2 mm in 16 cases. Seven aneurysms were not detected by 3D-CTA. The major cause of these missed aneurysms was their small size. The undetected aneurysms were less than 2 mm in size, except for 2 instances of PCoA aneurysms. One case was not detected due to difficult image evaluation. A possible explanation of the one remaining missed aneurysms was the filling of the aneurismal sac by thrombosis. Though there were some limitations in the detection of aneurysms, 3D-CTA using 16-channel MDCT may provide sufficient pre-operative information for the management of patients with intracranial aneurysms in cases of emergency operations or DSA-failure

[en] Intracranial chordoma is a rare tumor, originating from embryonic remnants of the primitive notochord. It typically appears as an enhancing extradural midline tumor with bone involvement. We introduce a rare case of a 27-year-old male who had a nonenhancing intradural chordoma showing paramedian location, involving the left cavernous sinus, Meckel's cave, and prepontine cistern. The pathologic diagnosis was confirmed as an intradural chordoma. The imaging findings of this unusual case of a nonenhancing intradural paramedian chordoma will be presented with the differential diagnosis focused on the epidermoid cyst

[en] To assess the significance of fluid-attenuated inversion recovery (FLAIR) magnetic resonance (MR) imaging in the diagnosis of intracranial infarctions and to find out differential points between central lacunar infarctions and perivascular spaces. We consecutively selected 25 cases of territorial infarction in 20 patients, 37 cases of central infarction in 40 patients, and 30 patients with perivascular space. Signal intensity and lesion conspicuity were analyzed and compared between FLAIR and FSE T2-weighted images, and differences in signal intensity between central infarction and perivascular spaces were determined. Lesion conspicuity for FLAIR was better than for T2-weighted images in 12 and 15, worse in 4 and 24, and similar in 9 and 16 of territorial and central infarctions, respectively. In nine cases of territorial and one case of central infarction, there was associated hemorrhage. At FLAIR imaging, perivascular spaces showed a fine round low signal without a peripheral high signal rim in 17 patients but no demonstrable signals in 15. Differential diagnosis of perivascular spaces and central infarction was thus not difficult. FLAIR MRI was useful in the diagnosis of infarctions and in differentiating between central small lacular infarctions and perivascular spaces

[en] The aim of this study was to evaluate the usefulness of combined fluoroscopy- and CT-guided transthoracic needle biopsy (FC-TNB) using a cone beam CT system in comparison to fluoroscopy-guided TNB (F-TNB). We retrospectively evaluated 74 FC-TNB cases (group A) and 97 F-TNB cases (group B) to compare their respective diagnostic accuracies according to the size and depth of the lesion, as well as complications, procedure time, and radiation dose. The sensitivity for malignancy and diagnostic accuracy for small (< 30 mm in size) and deep (≥ 50 mm in depth) lesions were higher in group A (91% and 94%, 92% and 94%) than in group B (73% and 81%, 84% and 88%), however not statistically significant (p > 0.05). Concerning lesions ≥ 30 mm in size and < 50 mm in depth, both groups displayed similar results (group A, 91% and 92%, 80% and 87%: group B, 90% and 92%, 86% and 90%). Pneumothorax occurred 26% of the time in group A and 14% for group B. The mean procedure time and patient skin dose were significantly higher in group A (13.6 ± 4.0 minutes, 157.1 ± 76.5 mGy) than in group B (9.0 ± 3.5 minutes, 21.9 ± 15.2 mGy) (p < 0.05). Combined fluoroscopy- and CT-guided TNB allows the biopsy of small (< 30 mm) and deep lesions (≥ 50 mm) with high diagnostic accuracy and short procedure times, whereas F-TNB is still a useful method for large and superficial lesions with a low radiation dose

[en] To clarify the value of mass screening for thyroid cancer by ultrasonography. We evaluated the incidence of thyroid nodules and the detection rate of malignant nodules in 2856 patients who underwent screening thyroid ultrasonography while undergoing breast ultrasonography. We also analyzed the ultrasonographic characteristics of nodules in the screening (34 patients) and clinical (48 patients) groups which were diagnosed with thyroid cancer. The incidence of thyroid nodules detected by ultrasonography was 39% and the detection rate of thyroid cancer was 1.19% in the screening group and 17% in the clinical group. The mean size of nodules in clinical group was larger than that in the screening group (p<0.05) and the prevalence of nodules with ill-defined margin in the screening group was higher than that in the clinical group (p<0.05). There was no significant difference in internal echogenicity, shape, presence of internal calcifications, lymph node metastasis and extrathyroidal extension between the two groups. Although the incidence of thyroid cancer was low, sonographic screening for thyroid cancer while undergoing breast ultrasonography could be valuable

[en] To describe the associated conditions and clinical significance of lenticulostriate uasculopathy (LSV) as demonstrated by cranial sonography. We retrospectively studied 77 LSV cases who between January 1994 and January 1996 had undergone cranial sonography for neonatal asphyxia, seizure, or bulging of anterior fontanel. Cranial sonography was performed with 7MHz real-time linear and sector transducers using an Acuson computed sonography unit;examinations were performed in sagittal and coronal planes. Twenty-six LSV patients underwent color Doppler studies, and in 24 of these, color signal and arterial pulse spectral wave were detected. LSV was grouped as one of three types, according to echogenicity:type I (less echogenic than sylvian fissure), type II (similar to sylvian fissure), and type III (more echogenic than sylvian fissures). We retrospectively evaluated associated sonographic abnormalities of the brain, and reviewed medical records for associated conditions and neurologic sequelae. Follow-up sonographic examinations were performed in 23 patients. There were 56 type I cases (73%), 17 of type II (22%) and 4 of type III (5%). Cranial sonographic results were normal in 36 cases (47%) and abnormal in 41(53%). Forty-eight cases of nonspecific causes and 29 cases of perinatal and acquired causes accounted for associated conditions. The echogenicity of LSV had not changed in 21 of 23 follow-up cases. Neurologic examinations were performed in 18 cases and in 14 of these (78%) there was no neurologic sequela. LSV in basal ganglia may be associated with nonspecific neonatal conditions, in addition to well known perinatal causes

[en] We performed this study to evaluate the most common site of the nasolacrimal systemic obstruction and causes of the nasolacrimal stent insertion failure and reobstruction following the insertrion of the stent. Nasolacrimal stent insertion was attempted in 26 cases(24 patients) of 30 cases (25 patients) with complete obstruction of the nasolacrimal system at the dacryocystography. We retrospectively assessed the obstruction site of nasolacrimal system, and evaluated the rate and causes of stent insertion failure and reobstruction following insertion of the stent of follow-up. The obstructive sites of the nasolacrimal system were junction level of the lacrimal sac and nasolacrimal duct(80%), common canaliculi(10%), and nasolacrimal duct(10%). In seven cases, we failed to insert the nasolacrimal stent four of the seven cases had a history of previous operation on paranasal sinus or nasolacrimal system. At 4 weeks follow up, epiphora redeveloped in four of 10 cases(reobstruction rate, 40%). Inflammatory process around the nasolacrimal duct stent was conndered to be the cause of reobstruction in two of the four reobstructed cases. Success rate of nasolacrimal duct stent insertion was 73%, and failure rate was 27%. The causes of the stent insertion failure included fibrosis and granulation tissue due to the previous operation around nasolacrimal duct system and paranasal sinus area. Inflammatory process around the stent caused recurrent obstruction

[en] We performed this study to describe the findings of MR Myelography (MRM) of herniated disc disease, spinal stenosis and spinal tumor and to evaluate this usefulness of the MRM in comparison to MRI. MRI and MRM were performed in 31 patients with herniated disc disease (12 patients), spinal stenosis (11 patients) and spinal tumor (8 patients). MRI and MRM were done with 1.5-T Signa MR, using fat suppressed heavily T2-weighted fast spin echo technique. We retrospectively analyzed MRM images about the thecal sac indentation, compression or displacement of the nerve root, extent and degree of narrowing of spinal canal, relationship between spinal tumor and spinal cord. MRM findings were compared with MRI in all cases. In 18 herniated disc cases of 12 patients, focal filling defect with cutoff or displacement of the nerve root in eight of paracentral herniated disc was seen. Cutoff and displacement of the nerve root were more clearly delineated on MRM than MRI. In the patients of spinal stenosis (11 cases), hourglass deformity of the thecal sac or complete spinal block of the subarachnoid space was clearly demonstrated. The extent and severity of spinal stenosis were more accurately evaluated on MRM than MRI. MRM finding of intramedullary tumor (3 cases) was enlargement of spinal cord. Five cases of intradural extramedullary tumor showed intradural filling defect, which caused contralateral displacement of the spinal cord with meniscus sign on inferior margin of the mass. MRM shows characteristic findings of herniated disc disease, spinal stenosis and spinal tumor. MRM yields excellent definition of the thecal sac, nerve roots and nerve root sleeves in relation to herniated disc and may be more accurate in evaluation of the degree and extent of spinal stenosis than MRI

[en] The purpose of this experiment is to investigate the image quality of CT coronary angiography using a 16-slice multi-detector row CT and to determine the optimal image reconstruction window. CT coronary angiography was obtained in 36 nonsymptomatic volunteers using a 16-slice multi-detector row CT (SOMATOM Sensation, Siemens Medical System). The mean heart rates were 70 beats per minute (bpm) or less in 18 persons and more than 70 bpm in 18 persons. Eleven data sets were obtained for each patient (reconstructed at 30%-80% of the cardiac cycle with an increment of 5%). Image quality of the eight coronary segments [left main coronary artery (LM), proximal and middle segments of left anterior descending artery (p-LAD, m-LAN) and left circumflex coronary artery (p-LCx, m-LCx) and proximal, middle and distal segments of right coronary artery (p-RCA, m-RCA, d-RCA)] was assessed. The optimal reconstruction windows in the cardiac cycle for the best image quality were 60-70% for the segments of the LM, LAD, and LC arteries in two groups (bpm < 70, bpm > 70) and 55-65% (bpm < 70) or 30-40% and 65-70% (bpm > 70) for the segments of the RCA. On the best dataset for each coronary segment, the following diagnostic image quality was achieved in the two groups: LM: 100%, 83%; p-LAD: 100%, 88% m-LAD: 100%, 72%; p-LCx: 100%, 72%; m-LCx: 100%, 72%; p-RCA: 94%, 72%; m-RCA: 61%, 50%; d-RCA: 100%, 80%. The 16 slice multi-detector row CT scan provided visualization of the coronary arteries with high resolution. Especially in the group with a mean heart rate of 70 bpm or less, all the coronary segments except the RCA showed diagnostic image quality. Optimal image quality was achieved with a 60-70% trigger delay for all coronary arterial segments, but the best images of RCA were achieved in the earlier cardiac phase in the patients with a mean heart rate of more than 70 bpm

[en] The purpose of this study was to evaluate the usefulness of three experimental blood pool contrast agents for equilibrium phase magnetic resonance angiography. MR angiography was performed in 21 rabbits before and 1 , 5, 10, 20 and 30 minutes and 24 hours after the injection of gadolinium-based blood pool contrast agents (Gadomer-17, Gadofluorine M), and superparamagnetic iron oxide blood pool agent (Ferucarbotran). 3D TOF SPGR images of the thoracic and abdominal aorta (and involving the renal arteries) were obtained. The signal difference-to noise ratios (SDNRs) were measured over time in the aorta. These images were then compared to that of images with Gd-DTPA. MR angiography with the three blood pool agents yielded excellent visualization results of the rabbit abdominal aorta. At the same dose, the three agents provided a significant increase of the aorta-to-tissue SDNR in comparison with that achieved with the Gd-DTPA (a 250% increase for Gadomer-17, a 124% increase for Gadofluorine and a 88% increase for Ferucarbotran). The SDNRs using Ferucarbotran especially showed continuously increasing values to 30 minutes after the injection of contrast agent. The three blood pool agents were found to be very useful contrast agents for equilibrium phase MR angiography