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ABSTRACT: To evaluate the short-term and long-term effects of fluoroscopically guided caudal epidural steroid injection (ESI) for the management of degenerative lumbar spinal stenosis (DLSS) and to analyze outcome predictors.
All patients who underwent caudal ESI in 2006 for DLSS were included in the study. Response was based on chart documentation (aggravated, no change, slightly improved, much improved, no pain). In June 2009 telephone interviews were conducted, using formatted questions including the North American Spine Society (NASS) patient satisfaction scale. For short-term and long-term effects, age difference was evaluated by the Mann-Whitney U test, and gender, duration of symptoms, level of DLSS, spondylolisthesis, and previous operations were evaluated by Fisher's exact test.
Two hundred and sixteen patients (male:female = 75:141; mean age 69.2 years; range 48 approximately 91 years) were included in the study. Improvements (slightly improved, much improved, no pain) were seen in 185 patients (85.6%) after an initial caudal ESI and in 189 patients (87.5%) after a series of caudal ESIs. Half of the patients (89/179, 49.8%) replied positively to the NASS patient satisfaction scale (1 or 2). There were no significant outcome predictors for either the short-term or the long-term responses.
Fluoroscopically guided caudal ESI was effective for the management of DLSS (especially central canal stenosis) with excellent short-term and good long-term results, without significant outcome predictors.
Skeletal Radiology 07/2010; 39(7):691-9. · 1.54 Impact Factor
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ABSTRACT: This study aimed to evaluate the reproducibility of a new grading system for lumbar foraminal stenosis.
Four grades were developed for lumbar foraminal stenosis on the basis of sagittal MRI. Grade 0 refers to the absence of foraminal stenosis; grade 1 refers to mild foraminal stenosis showing perineural fat obliteration in the two opposing directions, vertical or transverse; grade 2 refers to moderate foraminal stenosis showing perineural fat obliteration in the four directions without morphologic change, both vertical and transverse directions; and grade 3 refers to severe foraminal stenosis showing nerve root collapse or morphologic change. A total of 576 foramina in 96 patients were analyzed (from L3-L4 to L5-S1). Two experienced radiologists independently assessed the sagittal MR images. Interobserver agreement between the two radiologists and intraobserver agreement by one reader were analyzed using kappa statistics.
According to reader 1, grade 1 foraminal stenosis was found in 33 foramina, grade 2 in six, and grade 3 in seven. According to reader 2, grade 1 foraminal stenosis was found in 32 foramina, grade 2 in six, and grade 3 in eight. Interobserver agreement in the grading of foraminal stenosis between the two readers was found to be nearly perfect (kappa value: right L3-L4, 1.0; left L3-L4, 0.905; right L4-L5, 0.929; left L4-L5, 0.942; right L5-S1, 0.919; and left L5-S1, 0.909). In intraobserver agreement by reader 1, grade 1 foraminal stenosis was found in 34 foramina, grade 2 in eight, and grade 3 in seven. Intraobserver agreement in the grading of foraminal stenosis was also found to be nearly perfect (kappa value: right L3-L4, 0.883; left L3-L4, 1.00; right L4-L5, 0.957; left L4-L5, 0.885; right L5-S1, 0.800; and left L5-S1, 0.905).
The new grading system for foraminal stenosis of the lumbar spine showed nearly perfect interobserver and intraobserver agreement and would be helpful for clinical study and routine practice.
American Journal of Roentgenology 04/2010; 194(4):1095-8. · 2.78 Impact Factor
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ABSTRACT: The purpose of this study was to evaluate the diagnostic value of a spreading epidural hematoma (SEH) and deep subcutaneous edema (DSE) as indirect signs of posterior ligamentous complex (PLC) injuries on MR imaging of thoracolumbar burst fractures.
We retrospectively reviewed spinal MR images of 43 patients with thoracolumbar burst fractures: 17 patients with PLC injuries (study group) and 26 without PLC injuries (control group). An SEH was defined as a hemorrhagic infiltration into the anterior or posterior epidural space that spread along more than three vertebrae including the level of the fracture. A DSE was regarded as a fluid-like signal lesion in the deep subcutaneous layer of the back, and its epicenter was at the burst fracture level. The frequency of the SEH/DSE in the two groups was analyzed. In addition, the association between each sign and the degree of vertebral collapse, the severity of central canal compromise, and surgical decisions were analyzed.
Magnetic resonance images showed an SEH in 20 out of 43 patients (46%) and a DSE in 17 (40%). The SEH and DSE were more commonly seen in the study group with PLC injuries (SEH, 15 out of 17 patients, 80%; DSE, 16 out of 17 patients, 94%) than in the control group without PLC injuries (SEH, 5 out of 26, 19%; DSE, 1 out of 26, 4%) (P <0.0001). The SEH and DSE were significantly associated with surgical management decisions (17 out of 20 patients with SEH, 85%, vs 8 out of the 23 without SEH, 35%, P =0.002; 15 out of 17 with DSE, 88%, vs 10 out of 26 without DSE, 38%, P =0.002). The SEH and DSE did not correlate with the degree of vertebral collapse or the severity of central canal compromise.
The SEH and DSE may be useful secondary MR signs of posterior ligamentous complex injury in thoracolumbar burst fractures.
Skeletal Radiology 02/2010; 39(8):767-72. · 1.54 Impact Factor
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ABSTRACT: To investigate the short-term therapeutic effect of percutaneous vertebroplasty (PVP) for intravertebral cleft (IVC) and to analyze possible outcome predictors.
After retrospective review of spot radiographs during PVP, 23 patients were included in this study. Age, sex, symptom duration, functional status, injected cement volume, and type of approach were evaluated using patients' medical and operative records. The following factors were analyzed on radiographs, MRI, dual bone densitometry, spot radiographs during PVP, and CT: anatomical location of the fracture, bone mineral density, morphology of the fracture, IVC morphology, presence of surrounding non-enhanced area and bone marrow edema, degeneration of adjacent discs, co-existing old compression fractures, patterns of cement opacification, pre-procedural kyphosis, and post-procedural kyphosis correction. Effectiveness was defined as a much-improved state or no pain after 1 week, 1 month, and 2 months. Statistical analyses were conducted to evaluate the relationship between those factors and therapeutic outcome using Fisher's exact test, Chi-squared test, and the Mann-Whitney U test.
Percutaneous vertebroplasty of IVC was effective in 16 out of 23 (69.6%) patients after 1 week and 1 month and 15 out of 23 (65.2%) patients after 2 months. Post-procedural kyphosis correction >or=5 and poor functional status (full dependency) were more common in the ineffective group after 1 week and 2 months respectively (P = 0.047, P = 0.02). Kyphotic correction >or=5 was related to pre-procedural kyphosis >or=15 (P = 0.018). Functional status was related to subsequent fracture (P = 0.005). Other factors were not statistically significant (P > 0.05).
Percutaneous vertebroplasty on osteoporotic vertebral compression fractures (VCF) with IVC was effective in only about 69.6% of patients after the first week and month and in 65.2% of patients after 2 months. Post-procedural kyphosis correction >or=5 was associated with poor outcomes after the first week. Two months after PVP, the functional status was more important because of the development of subsequent fractures.
Skeletal Radiology 02/2010; 39(8):757-66. · 1.54 Impact Factor
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IEEE Trans. Med. Imaging. 01/2010; 29:1496-1503.
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ABSTRACT: OBJECTIVE: The objective of this article is to present two cases of percutaneous biopsy and one case of vertebroplasty of the C2 vertebral body using a CT-guided posterolateral approach under local anesthesia. CONCLUSION: The CT-guided posterolateral approach was safe, feasible, and effective for percutaneous intervention of the C2 vertebral body.
American Journal of Roentgenology 12/2009; 193(6):1703-5. · 2.78 Impact Factor
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ABSTRACT: The purpose of our study was to determine the MRI findings of rheumatoid arthritis (RA) and tuberculous arthritis, with emphasis on differential diagnostic features.
MR images of 63 joints in 62 patients with clinically or pathologically proven RA (36 joints in 35 patients) or tuberculous arthritis (27 joints in 27 patients) were evaluated retrospectively with regard to pattern and degree of synovial thickening, size of bone erosions, rim enhancement at bone erosions, degree of bone marrow and periarticular soft-tissue edema, and presence and number of extraarticular cystic masses. MRI findings were compared between RA and tuberculous arthritis by statistical analysis using kappa statistics, the Mann-Whitney U test, linear-by-linear association, and the chi-square test.
Nonuniform and greater degree of synovial thickening was more frequent in RA (p < 0.01); the thicker the synovial membrane, the greater the likelihood of RA (p < 0.01). Bone erosions of tuberculous arthritis were larger (p < 0.01), and the likelihood of tuberculous arthritis increased proportionally to the increment of size of the bone erosions (p < 0.01). Rim enhancement at bone erosion was more frequent in tuberculous arthritis (p < 0.01). Extraarticular cystic masses were more frequently seen and more numerous in tuberculous arthritis (p < 0.01).
Uniform synovial thickening, large size of bone erosion, rim enhancement at site of bone erosion, and extraarticular cystic masses were more frequent and more numerous in tuberculous arthritis. MRI may be helpful in the differentiation between RA and tuberculous arthritis.
American Journal of Roentgenology 11/2009; 193(5):1347-53. · 2.78 Impact Factor
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ABSTRACT: To investigate the type of MR imaging diagnosis that corresponded to spinal lesions detected on a bone scan according to the number of lesions in breast cancer patients.
We retrospectively reviewed spinal MR images of 134 patients with breast cancer whose bone scans showed one or more spinal hot uptakes. The patients were grouped according to the number of spinal lesions detected on the bone scan: one or two lesions versus multiple (more than two) lesions. By using MR imaging, we determined the etiology of the spinal lesions in terms of being either benign or malignant. If the lesions were benign, we further categorized them into several specific pathologies.
Sixty-four (48%) of 134 patients had one or two spinal lesions as seen on a bone scan. On MR imaging, 45 (70%) of the 64 lesions had benign pathologies, whereas 19 lesions (30%) were malignant. The benign pathologies in the 45 patients included facet arthrosis in 20 patients (44%), discovertebral degeneration in 12 patients (27%), compression fractures in eight patients (18%), and Schmorl's nodes in five patients (11%). Seventy (52%) of 134 patients had multiple spinal lesions as seen on the bone scan, and MR imaging revealed multiple bone metastases in 67 patients (96%) and facet arthrosis in three patients (4%).
One or two spinal lesions seen on a bone scan in breast cancer patients are more likely to be benign pathologies such as facet arthrosis, discovertebral degeneration, compression fracture or Schmorl's node on MR imaging.
Nuclear Medicine Communications 10/2009; 30(9):736-41. · 1.40 Impact Factor
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ABSTRACT: Compression ratio (CR) has been the de facto standard index of compression level for medical images. The aim of the study is to evaluate the CR, peak signal-to-noise ratio (PSNR), and a perceptual quality metric (high-dynamic range visual difference predictor HDR-VDP) as objective indices of image fidelity for Joint Photographic Experts Group (JPEG) 2000 compressed body computed tomography (CT) images, from the viewpoint of visually lossless compression approach. A total of 250 body CT images obtained with five different scan protocols (5-mm-thick abdomen, 0.67-mm-thick abdomen, 5-mm-thick lung, 0.67-mm-thick lung, and 5-mm-thick low-dose lung) were compressed to one of five CRs (reversible, 6:1, 8:1, 10:1, and 15:1). The PSNR and HDR-VDP values were calculated for the 250 pairs of the original and compressed images. By alternately displaying an original and its compressed image on the same monitor, five radiologists independently determined if the pair was distinguishable or indistinguishable. The kappa statistic for the interobserver agreement among the five radiologists' responses was 0.70. According to the radiologists' responses, the number of distinguishable image pairs tended to significantly differ among the five scan protocols at 6:1-10:1 compressions (Fisher-Freeman-Halton exact tests). Spearman's correlation coefficients between each of the CR, PSNR, and HDR-VDP and the number of radiologists who responded as distinguishable were 0.72, -0.77, and 0.85, respectively. Using the radiologists' pooled responses as the reference standards, the areas under the receiver-operating-characteristic curves for the CR, PSNR, and HDR-VDP were 0.87, 0.93, and 0.97, respectively, showing significant differences between the CR and PSNR (p = 0.04), or HDR-VDP (p < 0.001), and between the PSNR and HDR-VDP (p < 0.001). In conclusion, the CR is less suitable than the PSNR or HDR-VDP as an objective index of image fidelity for JPEG2000 compressed body CT images. The HDR-VDP is more promising than the PSNR as such an index.
Medical Physics 08/2009; 36(7):3218-26. · 2.83 Impact Factor
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ABSTRACT: OBJECTIVE: The purpose of our study was to describe the MRI findings of angioleiomyoma in the soft tissue of the extremities. CONCLUSION: Angioleiomyoma should be considered a possible diagnosis when a well-demarcated subcutaneous mass of isointense signal on T1-weighted images, heterogeneous high signal intensity on T2-weighted images with homogeneous strong enhancement, and an adjacent tortuous vascular structure is seen in the extremities.
American Journal of Roentgenology 07/2009; 192(6):W291-4. · 2.78 Impact Factor
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ABSTRACT: To describe a posterior labral cleft at direct computed tomographic (CT) arthrography of the shoulder by using multidetector CT and to compare this finding with a true posterior labral tear.
Institutional ethics review board approval was obtained, and informed consent was waived. One hundred twenty-seven shoulders in 126 patients were examined with direct CT arthrography by using 16- or 64-section multidetector CT and arthroscopy. Two musculoskeletal radiologists retrospectively reviewed CT arthrographic images for the presence, location, and size of a posterior labral tear, defined as a detectable contrast material-filled focal discontinuity of the labrum on an axial image, proved by using arthroscopy. A posterior labral cleft was defined as a false-positive lesion at CT arthrography that was proved to be a normal finding arthroscopically. Sensitivity, specificity, accuracy, positive and negative predictive values of tears and clefts were determined; incidence according to the patient's age and sex and the laterality (right or left shoulder), location, and size of the lesion were compared.
In 127 shoulders, radiologists 1 and 2 found 12 and 11 posterior labral tears, respectively, seen exclusively in male patients with posterior instability. Radiologist 1 observed 24 (18.9%) clefts, and radiologist 2 observed 20 (15.7%) clefts, seen more commonly in female patients (P = .037 for radiologist 1, P = .026 for radiologist 2) and in the inferior quadrant of the posterior labrum (along 7- to 8-o'clock positions, P < .05 for both radiologists); these clefts were shallower than labral tears (P = .005 for radiologist 1, P = .025 for radiologist 2).
At direct CT arthrography, a labral cleft may be a normal variation of the posterior labrum.
Radiology 07/2009; 253(3):765-70. · 5.73 Impact Factor
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ABSTRACT: To prospectively evaluate the incidence of, characteristics of, and risk factors for pulmonary cement embolism after percutaneous vertebroplasty (PVP) in osteoporotic vertebral compression fractures (VCFs).
Institutional review board approval and written informed consent were obtained. From June 2006 to September 2007, 75 patients (57 women, 18 men; mean age, 74.78 years; range, 48-93 years) who underwent 78 PVP sessions at 119 levels for osteoporotic VCFs were prospectively enrolled in this study. Computed tomographic (CT) scans of the chest and treated vertebrae were obtained after PVP. The presence, location, involved pulmonary arteries, number, and size of each pulmonary cement embolus were analyzed at CT. Possible risk factors were analyzed as follows: Age, injected cement volumes, and numbers of treated vertebrae were analyzed by using the Mann-Whitney U test; operators (radiologist or nonradiologist), level of treated vertebrae, guidance equipment, approach (uni- or bipedicular), presence of intravertebral vacuum clefts, and presence of paravertebral venous leakage were analyzed by using Pearson chi(2) and Fisher exact tests.
Pulmonary cement emboli developed in 18 (23%) of 78 PVP sessions and were detected in the distal to third-order pulmonary arteries. Only cement leakage into the inferior vena cava showed a statistically significant relationship to pulmonary cement embolism (P = .03). A higher frequency of pulmonary cement embolism was noted for the absence of intravertebral vacuum clefts, for the bipedicular approach, and for a nonradiologist operator with C-arm fluoroscopy (P > .05).
In osteoporotic VCFs, pulmonary cement embolism was detected in 23% of PVP sessions, developed in the distal to third-order pulmonary arteries, and was related to leakage into the inferior vena cava.
Radiology 05/2009; 251(1):250-9. · 5.73 Impact Factor
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ABSTRACT: The aim of this study was to investigate whether samples obtained using two kinds of small trephines, 2.4 and 1.8 mm in inner diameter, are sufficient for the quantitative evaluation of metabolic bone disease using micro-computed tomographic (CT) three-dimensional parameter data sets.
A total of 19 porcine lumbar vertebrae prior to biopsy and biopsy samples from the use of 2.4- and 1.8-mm trephines were examined using micro-CT imaging. For quantitative analysis, seven three-dimensional structural parameters, including trabecular bone volume, trabecular number, trabecular thickness, trabecular separation, the structure model index, the degree of anisotropy, and the trabecular bone pattern factor, were measured using CtAn software. The difference and agreement between the biopsy samples and the baseline vertebrae specimens before biopsy were assessed using paired t tests and Bland-Altman analysis, respectively.
There were no significant differences between the 2.4-mm samples and the baseline vertebrae specimens for trabecular bone volume, trabecular thickness, and trabecular number, with mean differences of -0.9%, 2.3%, and -3.1%, respectively; there was no significant difference between the 1.8-mm samples and the baseline vertebrae specimens only for trabecular thickness, with a mean difference of 1.9%.
Samples taken from the use of the 2.4-mm trephine were better for quantitative analysis than those from the use of the 1.8-mm trephine and were acceptable for the quantitative evaluation of trabecular bone volume, trabecular thickness, and trabecular number.
Academic radiology 04/2009; 16(3):332-40. · 2.09 Impact Factor
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ABSTRACT: To assess the advantages of the Joint Photographic Experts Group (JPEG)2000 3D (part 2) over JPEG2000 in compressing thin-section abdomen CT data sets, 60 thin-section (0.67 mm) scans from 35 males and 25 females, ranging from 23 to 95 years of age (mean, 58 years), were compressed reversibly (as a negative control) and irreversibly to 4:1, 6:1, 8:1, 10:1, and 12:1 using JPEG2000 3D and JPEG2000 algorithms. Encoding and decoding times and peak signal-to-noise ratios (PSNRs) were measured. For 60 (one image per scan) representative sections containing abnormalities, three radiologists independently compared original and compressed images and graded compression artifacts as 0 (none, indistinguishable), 1 (barely perceptible), 2 (subtle), or 3 (significant). According to pooled radiologists' responses, the range of visually lossless threshold (VLT, the highest compression ratio at which a compressed image is indistinguishable from its original) was determined as one of <4:1, 4:1-6:1, 6:1-8:1, 8:1-10:1, 10:1-12:1, and >12:1. Wilcoxon signed rank tests and exact tests for paired proportions were used for the comparisons between the two compressions. At each irreversible compression ratio, compared to JPEG2000, JPEG2000 3D required two- or threefold greater computing times (p < 0.001) and introduced less artifacts in terms of PSNR (p <0.001) and the grade (p < 0.02 at 6:1 or higher) and the presence of perceived artifacts (p <0.008, at 6:1 for all readers and at 8:1 for two readers). According to PSNR and readers' responses, 6:1 and 8:1 JPEG2000 3D compressions showed more artifacts than 4:1 and 6:1 JPEG2000 compressions, respectively, and 10:1 and 12:1 JPEG2000 3D compressions showed similar artifacts to those of 8:1 and 10:1 JPEG2000 compressions, respectively. The determined VLT range was higher for JPEG2000 3D than for JPEG2000 (p < 0.001): the 3D compression showed the VLT ranges of 4:1-6:1, 6:1-8:1, and 8:1-10:1 for 24 (40%), 30 (50%), and 6 (10%) of the 60 original images, respectively, while the 2D compression showed the VLT ranges of <4:1, 4:1-6:1, and 6:1-8:1 for 1 (1.7%), 40 (66.7%), and 19 (31.6%) images, respectively. Compared to JPEG2000, JPEG2000 3D increased the VLT range in 23 of the 60 original images by one (n=22) or two ranges (n=1), while the remaining 37 images had the same VLT range between the two compressions. In conclusion, compared to JPEG2000 compression, JPEG2000 3D compression yields less artifacts in compressing thin-section abdomen CT images but requires significantly greater computing times. For the tested data set compressed to the range from 4:1 to 12:1, JPEG2000 3D could increase compression level reasonably (by 2 or less in terms of compression ratio) compared to JPEG2000 for the same amount of artifacts.
Medical Physics 03/2009; 36(3):835-44. · 2.83 Impact Factor
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ABSTRACT: The purpose of this study was to evaluate the usefulness of MRI performed with a microscopy coil in the preoperative evaluation of small soft-tissue masses of the hand and foot.
Sixteen patients with clinically suspected soft-tissue masses of the hand or foot underwent MRI with both a conventional surface coil and a microscopy coil and were included in this study. All MR images were obtained with a 1.5-T system and a 47-mm microscopy coil. MR images were qualitatively analyzed for size, number, location, morphologic details, extent and margin quality, and growth pattern of the mass and the relation between the mass and adjacent anatomic structures. For quantitative analysis, we measured the signal-to-noise ratio of each mass on MR images obtained with both coils. MRI findings with the two coils were compared, and the findings were correlated with the surgical and histopathologic findings on all 16 patients who underwent surgery.
Relation between adjacent anatomic structures and the mass (n = 15), internal morphologic features (n = 14), and extent or margin quality (n = 11) of masses were clearly delineated on MRI performed with a microscopy coil (p = 0.0001). These findings correlated well with the surgical and pathologic findings. In addition, small soft-tissue masses not detected with a conventional surface coil were readily detected with a microscopy coil (n = 3). The signal-to-noise ratios of masses detected with a microscopy coil were significantly higher than those of masses detected with a conventional surface coil (p = 0.006).
MRI with a microscopy coil was useful in the preoperative assessment of small soft-tissue masses of the hand and foot.
American Journal of Roentgenology 01/2009; 191(6):W256-63. · 2.78 Impact Factor
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ABSTRACT: This study was designed to investigate whether the use of MR diskography would result in improved reader confidence over the use of CT diskography alone for evaluating foraminal impingement causing lumbar radiculopathy.
Sixteen disk levels in 14 consecutive patients with suspected foraminal impingement causing lumbar radiculopathy were prospectively included in the study. A mixture of diluted gadodiamide and iodinated contrast material was injected at each disk level. After diskography, a CT scan (CT diskography) and T1-weighted fat-suppressed MR image (MR diskography) were obtained. Two spine radiologists and an orthopedic spine surgeon independently scored CT diskography and MR diskography for foraminal evaluation on a 3-point scale: 1, low confidence; 2, moderate confidence; and 3, high confidence. Each reader also assessed whether MR diskography showed an additional benefit over CT diskography with regard to the depiction of foraminal abnormalities only. Another radiologist reviewed conventional MR images focused on disk height and morphology.
The reviewers' confidence scores for MR diskography were superior to those for CT diskography (reader 1, p = 0.00008; reader 2, p = 0.0008; reader 3, p = 0.0015) (p < 0.05). MR diskography was considered beneficial in 13 of 16 disk levels (reader 1), 14 of 16 (reader 2), and 14 of 16 (reader 3). MR diskography increased the confidence scores for the detection of foraminal impingement, especially in cases of severe disk degeneration, but did not show additional benefits in cases of an extensive vacuum in the disk or large disk extrusion.
Simultaneous MR diskography and CT diskography with a mixture of gadodiamide and iodinated contrast material may be beneficial for evaluating foraminal impingement causing lumbar radiculopathy.
American Journal of Roentgenology 10/2008; 191(3):710-5. · 2.78 Impact Factor
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ABSTRACT: The objective of our study was to investigate the difference of perceptible artifacts between the lungs and the chest wall and mediastinum in Joint Photographic Experts Group (JPEG) 2000-compressed low-dose chest CT images and to show that a perceptual image quality metric-the High-Dynamic Range Visual Difference Predictor (HDR-VDP)-can reproduce this regional difference.
Twenty images were compressed reversibly and irreversibly to 6:1-30:1. To analyze the two regions separately (lungs; and chest wall and mediastinum), the compressed pixels outside each tested region were replaced with the original pixels. By comparing the compressed and original images, three radiologists independently rated the compression artifacts as grade 0, none, indistinguishable; 1, barely perceptible; 2, subtle; or 3, significant. At each compression level, the two regions were compared for the readers' responses, peak signal-to-noise ratio (PSNR), and HDR-VDP results. Wilcoxon's signed rank tests and exact tests for paired proportions were used with a p value threshold of 0.05.
Artifacts were rated as lower grades in the lungs than in the chest wall and mediastinum, showing statistical significances at 10:1-20:1 for reader 1, 8:1-15:1 for reader 2, and 8:1-20:1 for reader 3. Grade 0 was more frequent in the lungs, showing statistical significances at 10:1 for reader 1 and at 8:1-10:1 for readers 2 and 3. The results of PSNR indicated greater artifacts in the lungs (p < 0.001), whereas HDR-VDP results indicated fewer artifacts in the lungs (p < 0.001).
Although compression artifacts are mathematically greater in the lungs than in the chest wall and mediastinum, radiologists' artifact perceptions are the opposite, which can be successfully reproduced by HDR-VDP.
American Journal of Roentgenology 08/2008; 191(2):W30-7. · 2.78 Impact Factor
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ABSTRACT: The purpose of our study was to show the difference of Joint Photographic Experts Group (JPEG) 2000 compression artifacts in the lung between thin- and thick-section CT images.
Thirty-five thin-section (1 mm) and 35 corresponding thick-section (5 mm) images were compressed to reversible and irreversible 4:1, 6:1, 8:1, 10:1, and 15:1. In each compressed image, pixels outside the lung were replaced with those from the original image. By comparing the compressed and original images, three radiologists independently rated the compression artifacts using grades of 0 (none, the two images were indistinguishable), 1 (image differences were barely perceptible), 2 (image differences were subtle), or 3 (image differences were significant). At each compression level, thin and thick sections were compared for peak signal-to-noise ratio (PSNR) using paired t tests and for the readers' responses using Wilcoxon's signed rank tests and exact tests for paired proportions.
Thin sections had smaller PSNR (p < 0.0001). Thin sections had higher grades of artifacts than thick sections, showing significant differences at compression levels of 10:1 (mean score, 0.8 vs 0.4, 0.9 vs 0.1, 0.3 vs 0.0; p < 0.009 for the three readers) and 15:1 (1.9 vs 1.0, 1.9 vs 1.1, 1.5 vs 0.6; p < 0.0001). The percentages of distinguishable pairs (grades 1-3) were greater for thin sections than for thick sections, showing a statistically significant difference at 10:1 for two readers (31% vs 3% and 74% vs 37%; p < 0.006).
The lung shows more compression artifacts on thin sections than on thick sections. Section thickness should be taken into consideration when adjusting the compression level for lung CT images.
American Journal of Roentgenology 08/2008; 191(2):W38-43. · 2.78 Impact Factor
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ABSTRACT: Our study was based on our hypotheses that in idiopathic acute transverse myelitis (ATM), fractional anisotropy (FA) values would be abnormal not only in the T2-hyperintense lesion but also in the surrounding normal-appearing spinal cord and that the abnormal FA values in the spinal cord could be related to clinical outcome.
Sagittal diffusion tensor imaging (DTI) was performed in 10 patients with idiopathic ATM (four men, six women; mean age, 45 years; age range, 20-66 years) and 10 sex- and age-matched normal volunteers. FA measurements were made in the spinal cord at three levels: lesion, proximal normal-appearing spinal cord, and distal normal-appearing spinal cord. The grade of FA decrease (mild, less than 10% decrease [(FA normal - FA pt) x 100 / FA normal]; moderate, 10-20%; severe, more than 20%) was related to the clinical outcome, which was determined by a neurologist using Paine's scale of normal, good, fair, or poor.
Mean FA values in patients were significantly lower than those in normal volunteers in lesions (0.5328 vs 0.7125, p = 0.002) and distal normal-appearing spinal cord (0.6676 vs 0.7720, p = 0.0137). All three patients with a mild FA decrease or increase in distal normal-appearing spinal cord showed a normal or good outcome, but all three patients with a severe FA decrease in distal normal-appearing spinal cord showed a fair outcome, among the eight patients to whom steroid treatment was given.
FA values in lesions and in distal normal-appearing spinal cord significantly decreased in patients with idiopathic ATM, and FA decrease in distal normal-appearing spinal cord might be related to clinical outcome.
American Journal of Roentgenology 08/2008; 191(2):W52-7. · 2.78 Impact Factor
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ABSTRACT: OBJECTIVE: The purpose of this study was to evaluate the MRI features of the "MR corner sign" and to determine its diagnostic usefulness in ankylosing spondylitis. We reviewed the spinal MR images of 52 patients with ankylosing spondylitis and compared these images with those of 52 age- and sex-matched control subjects. CONCLUSION: The MR corner sign was defined as a triangular and sharply marginated corner abnormality in a vertebral body unassociated with osteophytes or Schmorl's node. MR corner lesions were significantly more common in the ankylosing spondylitis group than in the control group (Fisher's exact test, p < 0.001). The sensitivity, specificity, and positive and negative predictive values of the MR corner sign were 44%, 96%, 92%, and 63%, respectively. The most frequent feature of signal intensity was a Modic type II change (77%). In patients with ankylosing spondylitis, the MR corner sign was fre quently seen at the thoracolumbar junction, whereas degenerative corner lesions were commonly seen in the lower lumbar spine. When the MR corner sign is detected on spinal MR images in daily practice, it should not be overlooked because it suggests the possibility of ankylosing spondylitis, which should then be further evaluated.
American Journal of Roentgenology 07/2008; 191(1):124-8. · 2.78 Impact Factor
