Diagnostic Performance of Coronary CT Angiography, Stress Dual-Energy CT Perfusion, and Stress Perfusion Single-Photon Emission Computed Tomography for Coronary Artery Disease: Comparison with Combined Invasive Coronary Angiography and Stress Perfusion Ca

OBJECTIVE: To investigate the diagnostic performance of coronary computed tomography angiography (CCTA), stress dual-energy computed tomography perfusion (DE-CTP), stress perfusion single-photon emission computed tomography (SPECT), and the combinations of CCTA with myocardial perfusion imaging (CCTA + DE-CTP and CCTA + SPECT) for identifying coronary artery stenosis that causes myocardial hypoperfusion. Combined invasive coronary angiography (ICA) and stress perfusion cardiac magnetic resonance (SP-CMR) imaging are used as the reference standard. MATERIALS AND METHODS: We retrospectively reviewed the records of 25 patients with suspected coronary artery disease, who underwent CCTA, DE-CTP, SPECT, SP-CMR, and ICA. The reference standard was defined as ≥ 50% stenosis by ICA, with a corresponding myocardial hypoperfusion on SP-CMR. RESULTS: For per-vascular territory analysis, the sensitivities of CCTA, DE-CTP, SPECT, CCTA + DE-CTP, and CCTA + SPECT were 96, 96, 68, 93, and 68%, respectively, and specificities were 72, 75, 89, 85, and 94%, respectively. The areas under the receiver operating characteristic curve (AUCs) were 0.84 ± 0.05, 0.85 ± 0.05, 0.79 ± 0.06, 0.89 ± 0.04, and 0.81 ± 0.06, respectively. For per-patient analysis, the sensitivities of CCTA, DE-CTP, SPECT, CCTA + DE-CTP, and CCTA + SPECT were 100, 100, 89, 100, and 83%, respectively; the specificities were 14, 43, 57, 43, and 57%, respectively; and the AUCs were 0.57 ± 0.13, 0.71 ± 0.11, 0.73 ± 0.11, 0.71 ± 0.11, and 0.70 ± 0.11, respectively. CONCLUSION: The combination of CCTA and DE-CTP enhances specificity without a loss of sensitivity for detecting hemodynamically significant coronary artery stenosis, as defined by combined ICA and SP-CMR.

Virtual Non-Contrast CT Using Dual-Energy Spectral CT: Feasibility of Coronary Artery Calcium Scoring

OBJECTIVE: To evaluate the feasibility of coronary artery calcium scoring based on three virtual noncontrast-enhanced (VNC) images derived from single-source spectral dual-energy CT (DECT) as compared with true noncontrast-enhanced (TNC) images. MATERIALS AND METHODS: This prospective study was conducted with the approval of our Institutional Review Board. Ninety-seven patients underwent noncontrast CT followed by contrast-enhanced chest CT using single-source spectral DECT. Iodine eliminated VNC images were reconstructed using two kinds of 2-material decomposition algorithms (material density iodine-water pair [MDW], material density iodine-calcium pair [MDC]) and a material suppressed algorithm (material suppressed iodine [MSI]). Two readers independently quantified calcium on VNC and TNC images. The Spearman correlation coefficient test and Bland-Altman method were used for statistical analyses. RESULTS: Coronary artery calcium scores from all three VNC images showed excellent correlation with those from the TNC images (Spearman's correlation coefficient [ρ] = 0.94, 0.88, and 0.89 for MDW, MDC, and MSI, respectively; p < 0.001 for all pairs). Measured coronary calcium volumes from VNC images also correlated well with those from TNC images (ρ = 0.92, 0.87, and 0.91 for MDW, MDC, and MSI, respectively; p < 0.001 for all pairs). Among the three VNC images, coronary calcium from MDW correlated best with that from TNC. The coronary artery calcium scores and volumes were significantly lower from the VNC images than from the TNC images (p < 0.001 for all pairs). CONCLUSION: The use of VNC images from contrast-enhanced CT using dual-energy material decomposition/suppression is feasible for coronary calcium scoring. The absolute value from VNC tends to be smaller than that from TNC.

Differentitation between Primary Central Nervous System Lymphoma and Glioblastoma: Added Value of Quantitative Analysis of CT Attenuation and Apparent Diffusion Coefficient

PURPOSE: Purpose of this study was to determine if quantitative measures of CT attenuation and ADC values in combination with conventional imaging features can differentiate primary central nervous system lymphoma (PCNSL) and glioblastoma (GBM). MATERIALS AND METHODS: Twenty-six patients with histologically-proven GBM (14 men and 12 women; median age, 50 years; age range, 22 - 73 years) and 14 patients with PCNSL (11 men and 3 women; median age, 61 years; age range, 41 - 74 years) were enrolled. Maximum CT attenuation, minimum ADC, and lesion to normal parenchyma minimum ADC ratios were measured in solid tumor regions. Conventional imaging features were evaluated for the following: ill-defined margin, homogeneous enhancement pattern, degree of necrosis, extent of tumor involvement and multiplicity. The Mann-Whitney test was used to compare maximum CT attenuation and minimum ADC values for PCNSL and GBM. Fisher's exact test was used to evaluate relationships between pathologic diagnoses and imaging features. RESULTS: The CT attenuations were similar for PCNSL and GBM (37.84 +/- 6.90 HU versus 37.00 +/- 5.54 HU, p = 0.68), but minimum ADC and minimum ADC ratio were significant lower in PCNSL than in GBM (595.01 +/- 228.28 10(-6) mm2/s versus 736.52 +/- 162.05 10(-6) mm2/s; p = 0.028, 0.87 +/- 0.26 versus 1.14 +/- 0.29; p = 0.007). PCNSL showed greater homogeneous enhancement and smaller necrotic areas than GBM (p = 0.003 and p < 0.001, respectively) and was more likely to have multiple tumors than GBM (p = 0.039). When necrotic PCNSL (n = 4) and necrotic GBM (n = 24) were compared, minimum ADC and minimum ADC ratios were also significantly lower in PCNSL, but CT attenuation were not. CONCLUSION: Although CT attenuation does not provide valuable information, minimum ADC and minimum ADC ratio and some imaging features can aid the differentiation of PCNSL and GBM.

Lung Biopsy after Localization of Pulmonary Nodules with Hook Wire / 대한흉부외과학회지

BACKGROUND: A chest computed-tomography has become more prevalent so that it is more common to detect small sized pulmonary nodules that have not been found in previous simple chest x-ray. If those detected nodules are undersized or located in pulmonary parenchyma, it is difficult to accomplish a biopsy since it is vulnerable to explore them either grossly or digitally. Thus, in our hospital, a thoracoscopic pulmonary wedge resection was performed after locating a lesion by means of hook wire with CT-guided. MATERIAL AND METHOD: 31 patients (17 males and 14 female patients) from December in 2006 to June in 2010 became our subjects; their 34 pulmonary nodules were subjected to the thoracoscopic pulmonary wedge resection after locating a lesion by means of hook wire with CT-guided. Also we analyzed a possibility of hook wire dislocation, a frequency of conversion to open thoracotomy, time consumed to operation after location of a lesion, operation time, post operation complication, and histological diagnosis of the lesion. RESULT: 12 of 34 cases were ground glass lesion, whereas 22 cases of them were solitary pulmonary lesion. The median value of the lesion was 8mm in size (range: 3 to 23 mm), while the median value was 12.5 mm in depth (range: 1 to 34 mm). The median value of time consumed from location of the lesion to anesthetic induction was 86.5 minutes (41~473 minutes); furthermore the mean value of operation time was 103 minutes (25~345 minutes). Intrathoracic wire dislocation was found in one case, but a target lesion was successfully excised. Open thoracotomy was performed in four cases due to pleural adhesion. However, there was no case of conversion to open thoracotomy due to failure to detect a target lesion. In histological diagnosis, metastatic cancer were found in 15 cases, which were the most common, primary lung cancer were in 9 cases, non-specific inflammation were in 3 cases, tuberculosis inflammation were in 2 cases, lymph nodes were in 2 cases, active tuberculosis were in 1 case, atypical adenomatous hyperplasia was in 1 case and normal lung parenchymal finding was in 1 case, respectively. CONCLUSION: In our hospital, in order to accomplish a precise histological diagnosis of ground-glass lesion and pulmonary nodules in lung parenchyma, location of pulmonary nodules were exactly located with hook wire under chest computed-tomography, which was followed by lung biopsy. We concluded that this was an accurate, minimally invasive and valuable method to minimize the complications and increase of cost of medical service provided.

The Diagnostic Accuracy of the 64-slice Multi-detector CT Coronary Angiography for the Assessment of Coronary Artery Stenosis in Symptomatic Patients

PURPOSE: We evaluated the diagnostic accuracy of a 64-slice multi-detector CT (MDCT) coronary angiography against a conventional coronary angiography (CCA) for the detection of significant stenosis (> or =50% lumen diameter narrowing). MATERIALS AND METHODS: Sixty-four patients underwent a MDCT and a subsequent CCA to evaluate the presence of atypical chest pain or suspected coronary artery disease (CAD). A MDCT angiography was performed using a 64-slice MDCT-scanner (Sensation 64, slice collimation 32x0.6 mm). The coronary artery segments were classified according to a 15-segment model. The sensitivity, specificity, and diagnostic accuracy of the 64-slice MDCT for the detection or exclusion of significant CAD were calculated on a per-segment and per-patient basis. RESULTS: Fifty-nine of the 64 (92%) coronary CT angiograms were of diagnostic image quality with 93.5% (809 of 865) of the coronary segments assessable by CT angiography. One-hundred two (12.6%) segments showed significant stenosis by CCA. Stenosis of 50% or greater was detected by sensitivity, specificity, accuracy, positive predictive valve, and negative predictive value on a per segment basis (89%, 99%, 97%, 90%, and 98%, respectively) and a per-patient basis (96%, 69%, 90%, 92%, and 82%, respectively). CONCLUSION: The 64-slice MDCT coronary angiography demonstrated a high diagnostic accuracy for both the per-segment and per-patient analyses for this symptomatic patient group.

Focal Sparing of the Fatty Liver Caused by a Nontumorous Arterioportal Shunt

We present two cases of focal fatty sparing caused by a nontumorous arterioportal shunt. Two patients underwent ultrasonography (US) as a part of routine medical screening, which revealed a hypoechoic lesion in the diffuse fatty liver. Each lesion appeared to be an arterioportal shunt on triphasic mutidetector computed tomography (CT) and was seen as being slightly hyperdense on noncontrast CT. No tumors were delineated around or within the arterioportal shunt. Both lesions remained unchanged on six-month follow-up US.

What's New 2007 in Thoracic Radiology? / 결핵및호흡기질환

No abstract available.

Fine Needle Aspiration of Focal Lung Lesion under CT Fluoroscopic Guidance

PURPOSE: We wanted to assess the efficacy of using CT fluoroscopy during Fine Needle Aspiration (FNA) for focal lung lesion. MATERIALS AND METHODS: We retrospectively reviewed 22 patients who had undergone FNA under CT fluoroscopic guidance. The final diagnosis of focal lung lesion was based on surgery, the results of biopsy taken from another site or the clinical diagnosis with imaging follow-up. We reviewed the imaging and recorded the location of the lesion, the lesion size and the depth from the puncture site. RESULTS: In 24 cases of 22 patients, 16 lesions were benign and 8 were malignant. The sensitivity and specificity for malignant lesions were 100%, and 75%, respectively. The mean size of the malignant lesions was 3.75+/-1.68 cm, and that of the benign lesion was 3.05+/-2.98 cm. The mean depth of the lesion divided by the size was 1.85+/-1.09 for 20 lesions of the correct result group and 3.13+/-1.73 for 4 lesions of the incorrect result group; the difference between the two groups was statistically different (p=0.030). The complications after FNA were pneumothoraces in three cases and parenchymal hemorrhage in one case, but no significant complication was noted after the procedures. CONCLUSION: We could perform the FNA accurately and safely under CT fluoroscopy guidance, so this technique can be used for FNA of focal lung lesion for obtaining a correct result with fewer complications.

Pigmented Villonodular Synovitis of the Spine: A Case Report

Pigmented villonodular synovitis(PVNS) is a synovial lesion of joints or tendon sheaths, characterized by villous and nodular overgrowth of the synovial membrane. It commonly occurs in synovial joints of the appendicular skeleton, particularly those of the knee and hip, but rarely affecting those of the spine. We report a case of PVNS of the lumbar spine mimicking epidural mass.

Imaging Findings of Arteriovenous Malformations Involving Lung and Liver in Hereditary Hemorrhagic Telangiectasia (Osler-Weber- Rendu Disease): Two Cases Report

Hereditary hemorrhagic telangiectasia (HHT) or Osler-Weber-Rendu disease is an autosomal dominant disorder characterized by repeated episodes of bleeding. Multiple telangiectases consisting of thin-walled, dilated vascular channels with arteriovenous communication may involve, for example, mucocutaneous tissue, the gastrointestinal tract, and the liver, lung, and brain. We report the imaging findings of two cases of HHT involving arteriovenous malformation of both the lungs and liver, a rare condition. Chest radiography revealed a round mass, while helical CT showed a feeding artery and draining vein with arteriovenous malformation in the lung. Color Doppler sonography revealed an enlarged and tortuous hepatic artery with high systolic velocity. CT demonstrated an enlarged hepatic artery, arteriovenous shunt, and early draining hepatic vein in the liver. Celiac angiography showed arteriovenous malformation.

CT Angiography in Patients with Spontaneous Intracerebral Hematoma

PURPOSE: The purpose of this study was to assess the usefulness of CT angiography(CTA) in patients withintracerebral hematoma. MATERIALS AND METHODS: Eighteen patients with spontaneous intracerebral hematoma underwentCTA ; 20-30 seconds after the onset of an injection of contrast media(100mL, with the use of a power injector, ata rate of 3 mL/sec), Scanning(30-second continuous exposure and 60-90mm length) was performed with a table speedof 2-3 mm/sec and section thickness of 2mm. The starting point selected was the floor of the sella turcica. Theresulting data were reformatted by maximum intensity projection(MIP) after reconstruction at 1-mm intervals, andCTA findings were compared with those of conventional angiography(n=17), surgery(n=6), and postcontrast CT(n=10). RESULTS: The diagnostic findings of CTA included five arteriovenous malformations, two aneurysms, one venousangioma, and one venous sinus occlusion, while the remaining nine patients had no vascular lesion. In all cases,CTA findings correlated well with those of conventional angiography and surgery ; in four cases, they weresuperior to those of postcontrast CT. In one cases of arteriovenous malformation, however, the feeding artery anddraining vein were not definite on CTA, and in one case of sinus occlusion, the full length of the superiorsagittal sinus could not be delineated. CONCLUSION: In patients with spontaneous intracerebral hematoma, CTA is avaluable screening method.

Collateral Vessels in Moyamoya Disease: Comparison of MR and MRA with Conventional Angiography

PURPOSE: To determine the value of magnetic resonance imaging(MR) and magnetic resonance angiography(MRA) inassessing collateral vessels of moyamoya disease. MATERIALS AND METHODS: Twenty-four patients with moyamoyadisease who underwent MR, 3D TOF MRA, and conventional angiography participated in this study. Two radiologistsworking independently and with no knowledge of the angiographic findings, interpreted the MR and MRA images. Todetermine the presence of parenchymal and leptomeningeal collaterals(48 hemispheres) and transdural collaterals(38hemispheres in 19 patients were depicted by angiography of the external carotid), the findings were compared withthose of angiography. RESULTS: Parenchymal, leptomeningeal, and transdural collaterals were depicted byconventional angiography in 34(71%), 32(67%), and 11(29%) hemispheres respectively. The sensitivity andspecificity of MR/MRA for collateral vessels were 79.1/ 88.1% for parenchymal collaterals, 72.1/ 88.1% forleptomeningeal collaterals, and 0.1/18.1% for transdural collaterals, respectively. Respective sensitivity andspecificity of MR/MRA were 88.94/94.1% for leptomeningeal collaterals, and 18.93/55.1% for transdural collaterals,when the prominent posterior cerebral and external carotid artery were regarded as secondary signs ofleptomeningeal and transdural collateral vessels. CONCLUSION: In moyamoya disease, MR and MRA are useful imagingmodalities for the assessment of collateral vessels. The prominent posterior cerebral artery and external carotidartery can be useful secondary signs of leptomeningeal and transdural collateral vessels.

Radiologic Findings of Pulmonary Endometriosis

PURPOSE: To evaluate the effectiveness of percutaneous transluminal angioplasty (PTA) and pulsed-spraypharmacomechanical thrombolysis (PSPMT) using urokinase for the management of insufficient hemodialysis access. MATERIALS AND METHODS: Between September 1996 and May 1998, 21 insufficient hemodialysis accesses were treated in 16 patients (3 artificial arteriovenous fistulae, AVF ; and 13 arteriovenous graft, AVG). PTA and PSPMT were performed in 6 and 15 and 15 cases, respectively, and success and long-term patency rates were evaluated. RESULTS: The overall success rate of PTA and PSPMT for insufficient hemodialysis access was 76.2%(16/21). The success rates of PTA and PSPMT were 83.3%(5/6) and 73.3%(11/15), respectively. the primary patency rates of PSPMT were 69+/-12.8% at 6 months and 38+/-18.6% at 12 months. One of the two initially successful PTAs had been patent for 7months, and the second PTA was performed at that time due to venous stenosis. The other was patent for 15 months throughout the follow-up period. CONCLUSION: PTA and PSPMT are effective primary methods for the treatment of insufficient hemodialysis access ; success and patency rates were high, and the procedures can be performed repeatedly.

Anterior Cruciate Ligament Tear: Comparison of MR Features between Complete and Partial Tear

PURPOSE: To determine the MRI features which distinguish complete and partial tear of the anterior cruciate ligament (ACL) and to thus improve MRI interpretation. MATERIALS AND METHODS: In 80 patients, we analyzed MR findings of direct and indirect signs of ACL tear (complete tear, 61 cases, partial tear, 19 cases) confirmed by arthroscopy or surgery, and compared the relative incidence of each sign in cases of complete and partial tear. RESULTS: Direct and indirect signs were found in 61 (100%) and 60 cases (98.4%), respectively, in complete tears, but in 16 (84.2%) and 15 cases (78.9%), respectively, in partial tears. Poor visualization, discontinuity and hyperintensity were seen in all complete tears but in only nine case (47.4%) of partial tear. A wavy or abnormal contour was seen in 53 cases (86.9%) of complete tear and 14 (73.7%) of partial tear. A wavy contour without other direct signs was seen in only five cases (26.3%) of partial tear. Three cases (15.8%) of partial tear showed normal MR finding. Indirect signs, i. e. abnormal ACL angle, abnormal ACL-Blumensaat line angle, abnormal posterior cruciate ligament (PCL) line, abnormal PCL angle, PCL buckling, anterior displacement of tibia, posterior displacement of lateral meniscus, bone bruise, Segond fracture, tear of collateral ligaments, PCL, and tear of meniscus were commoner in complete than in partial tears. Two cases of O'Donoghue's triad and two of popliteus injury were seen only in complete tears. CONCLUSION: Direct and indirect signs of ACL tear were more commonly noted in complete than in partial tears. The latter showed MR features varying from normal to almost complete tear. We suggest that a wavy contour other direct signs is indicative of a partial tear, and that O'Donoghue's triad and popliteus muscle injury are indirect signs of a complete tear.

Alveolar Septal Pulmonary Amyloidosis: A Case Report

Primary pulmonary amyloidosis is a rare disease, and is classified as either tracheobronchial or parenchymal ; the latter is also divided into nodular and diffuse alveolar septal forms. The alveolar form is extremely rare and usually produces reticular and nodular opacities. We describe a case of alveolar septal pulmonary amyloidosis manifested as multiple small nodules on chest radiograph and disseminated micronodules mainly in centrilobular and subpleural location without reticular opacities, on HRCT.

Comparison between Mammography and Ultrasonography for Palpable Breast Mass: Focusing Fibroadenoma and Breast Cancer

PURPOSE: The purpose of our study was to compare the diagnostic accuracy of mammography and breast ultrasonography between fibroadenoma and palpable breast cancer and to evaluate the feasibility of ultrasonography as a primary diagnostic modality to differentiate between these two tumor types. MATERIALS AND METHODS: In 36 cases of fibroadenoma and 35 of breast cancer, all palpable and pathologically-proven, the diagnostic accuracy of mammography and ultrasonography was retrospectively analysed. RESULTS: In fibroadenoma cases, the diagnostic accuracy of mammography and ultrasonography was 53% and 80%, respectively, and the difference was statistically significant (p=0.0162). In cases of breast cancer, the corresponding figures were 74% and 82%, respectively ; the difference was not statistically significant (p=0.55). Overall, the diagnostic accuracy of mammography and ultrasonography was 63% and 82%, respectively, and this difference was statistically significant (p=0.0164). The total diagnostic accuracy of both studies was 90%, and this was significantly different (p=0.044) from that of ultrasonography (82%). CONCLUSION: In patients who have clinically palpable breast masses, ultrasonography can be recommended as the primary diagnostic modality, though for other breast lesions, mammography is the recommended primary modality.

HRCT Findings of Bleomycin-Related Lung Toxicity: A Report of 2 Case

Many drugs can result in a variety of pathologic reactions in the lung, especially the cytotoxic drugs. Amongcytotoxic drugs bleomycin is a prototype. Bleomycin-related pulmonary toxicity is usually known as dose-dependent and can be enhanced with concurrent oxygen therapy, irradiation, or other chemotherapeutic agents. The incidence of bleomycin-induced pulmonary toxicity has been reported as varying from 2 to 46%, and 1% of fatal lung disease. We describe the radiographic and HRCT findings of bleomycin-related pulmonary toxicity developed in two patients: one in ovarian teratocarcinoma, the other malignant lymphoma patient. Chest radiographs and HRCT of these patients showed ground-glass opacities, consolidation, linear and reticular opacities, and interlobular septal thickening. These abnormalities were bilateral, and symmetrical and were found predominantly in the area of mid-and lower-lung zone.

Comparison of Magnetic Resonance Angiography and CT Angiography in the Evaluation of Intracranial Aneurysm

PURPOSE: The purpose of this study was to assess the relative diagnostic capability of magnetic resonance angiography(MRA) and CT angiography(CTA) in the evaluation of intracranial aneurysm. MATERIALS AND METHODS: MRA and CTA were performed in 14 intracranial aneurysms (Including four which were ruptured) confirmed in the II patients involved by conventional angiography(CA). The size(in largest dimension) of the aneurysms ranged between 3 mm and 20 mm and the mean was 10.5 mm. For MRA, the 3D TOF method, with magnetization transfer suppression, wasused at 1.5T. For CTA, twenty seconds after beginning the injection of contrast media(100mL with use of a power injector at the rate of 3 mL/sec), CT scanning(30-second exposure and 60-mm length) was performed with a table speed of 2 mm/sec and a section thickness of 2mm. The resulting data were reformatted by MIP. MRA and CTA were compared with regard to the detection of aneurysms and their neck, size, shape, direction, intensity and relationship to adjacent bony structures or vessels. RESULTS: All aneurysms were clearly visualized with CTA. Inone case with a 3-mm aneurysm, however, this was not defined on MRA. Of the 13 aneurysms demonstrated by both MRA and CTA, eight were seen equally well with both modalities. CTA was considered to be superior to MRA in fivecases, either because calcification in the aneurysm wall was seen only on CTA(n = 3) or because the relationship with adjacent bony structures were seen better with CTA(n = 2). With CTA, the intensities of the aneurysm were homogeneous in all cases ; with MRA, however, the intensities of three large aneurysms were different. CONCLUSION: MRA and CTA may be useful in the evaluation of intracranial aneurysm, CTA has specific advantages over MRA inthe evaluation of large aneurysms, calcification of aneurysm wall and relationship with adjacent bony structure.

Distal Ureteral Calculi: The Usefulness of Transrectal Ultrasound and Comparision with Intravenous Urography

PURPOSE: To determine the usefulness of transrectal ultrasound (TRUS) and to compare TRUS with intravenousurography (IVU) in the evaluation of distal ureteral calculi. MATERIALS AND METHODS: TRUS and IVU were perfomed in 24 patients with distal ureteral calculi. Using TRUS, we evaluated the presence and size of calculus, type of ureteral jet at the affected site and diameter of ureter proximal to calculus, and using IVU evaluated the presence and size of calculus, degree of ureteral obstruction, and degree of hydroureter. TRUS and IVU findings, were compared. RESULTS: In each patient, TRUS detected calculus of the distal ureter ; in only 18cases (75%),were the calculi demonstrated with IVU. In 18 cases where calculi were detected by both modalities, average calculus size was 4.5 X 3.0mm (longest and shortest dimensions) by IVU, and 6.1 X 3.7 mm by TRUS. Betwee TRUS and IVU(p0.05). CONCLUSION: TRUS appears to be a useful adjunctive method for the evaluation of distal ureteral calculus.

Orbital Blowout Fracture: MR Findings

PURPOSE: To access the usefulness of magnetic resonance(MR) in the evaluation of orbital blowout fracture. MATERIALS AND METHODS: Fourteen patients with orbital blow out fractures diagnosed by plain radiography(n = 8) or computed tomography(CT)(n = 6) were examined with MR. Twenty blowout fractures including six patients with two lesions were presented and the fracture site of the orbit was the medial wall in 11 cases and the orbital floor innine cases. MR images in nine cases of six patients could be compared with CT scans. On MR images, were trospectively evaluated the presence of fracture, herniation of orbital fat, abnormality of extraocular muscle, intraorbital hematoma and intrasinus hemorrhage. In nine cases we also compared these findings with CT scans. RESULTS: Eighteen orbital blowout fractures with fat herniation could be diagnosed on MR images. In only nine of these 18 cases, the fracture itself could be seen on MR images as a disruption of the orbital wall, which produce a signal void. But two blow out fractures without orbital fat herniation, seen on CT, were not detected on MRimages. Twenty abnormalities of extraocular muscle in 18 cases were depicted on MR images. There were nosignificant differences between MR and CT in the evaluation of orbital fat herniation and extraocular muscle abnormality ; however, in one case oblique sagittal MR images provided more useful information about the status ofthe inferior rectus muscle. Intraorbital hematoma was detected by MR in three patients. We were able to establish the presence of intraorbital hematoma by using the different signal intensities from fat or muscle on T1- and/or T2-weighted images. MR was found to be superior to CT in one case of intraorbital hematoma because of the iso-density of hematoma compared to muscle. MR also detected intrasinus hemorrhage which on T1-weighted images revealed high signal intensity in ten cases. MR was more valuable in demonstrating intrasinus hemorrhage in onecase where a CT scan showed only hypodense fluid. CONCLUSION: MR is a useful diagnostic modality in the evaluation of orbital blowout fracture with orbital fat herniation. Compared with CT, it also provides more valuable information about associated extraocular muscle abnormality, subacute hemorrhage in the orbit and paranasal sinus.