Yoko Kaichi

Brain MR Findings in Patients with Systemic Lupus Erythematosus with and without Antiphospholipid Antibody Syndrome

BACKGROUND AND PURPOSE: Antiphospholipid syndrome may affect the incidence and pathogenesis of cerebrovascular diseases in patients with systemic lupus erythematosus. We compared the spectrum of MR findings in patients with systemic lupus erythematosus with and without antiphospholipid syndrome. MATERIALS AND METHODS: We identified 256 patients with systemic lupus erythematosus (45 with, 211 without antiphospholipid syndrome) who underwent MR studies; in 145 (57%), we detected abnormalities. These were categorized as large territorial, lacunar, localized cortical, and borderzone infarctions and as microembolisms, basal ganglia lesions, callosal lesions, hemorrhages, and white matter hyperintensity on T2-weighted and/or FLAIR images, and as stenotic arterial lesions on MR angiograms. Logistic regression analysis was performed to compare the MR findings in patients with systemic lupus erythematosus with and without antiphospholipid syndrome, with patient age and antiphospholipid syndrome as the covariates. RESULTS: Abnormal MR findings were more common in patients with systemic lupus erythematosus with antiphospholipid syndrome (73% versus 53%). Large territorial (P = .01), lacunar (P = .01), localized cortical (P < .01), borderzone infarcts (P < .01), basal ganglia lesions (P = .03), stenotic arterial lesions (P = .04), and the rate of positive findings on MR imaging (P = .01) were significantly associated with antiphospholipid syndrome. Irrespective of age, significantly more patients with antiphospholipid syndrome manifested lacunar infarcts in the deep white matter (P < .01), localized cortical infarcts in the territory of the MCA (P < .01), bilateral borderzone infarcts (P < .01), and anterior basal ganglia lesions (P = .01). CONCLUSIONS: Abnormal MR findings were more common in patients with systemic lupus erythematosus with than in those without antiphospholipid syndrome. Large territorial infarctions, lacunar infarctions in the deep white matter, localized cortical infarctions in the MCA territory, bilateral borderzone infarctions, anterior basal ganglia lesions, and stenotic arterial lesions are common MR findings in patients with systemic lupus erythematosus with antiphospholipid syndrome.

Iterative decomposition of water and fat with echo asymmetry and least-squares estimation (IDEAL) magnetic resonance imaging as a biomarker for symptomatic multiple myeloma.

Introduction To evaluate the effectiveness of iterative decomposition of water and fat with echo asymmetry and least-squares estimation (IDEAL) magnetic resonance imaging (MRI) to discriminate between symptomatic and asymptomatic myeloma in lumbar bone marrow without visible focal lesions. Materials and Methods The lumbar spine was examined with 3-T MRI in 11 patients with asymptomatic myeloma and 24 patients with symptomatic myeloma. The fat-signal fraction was calculated from the ratio of the signal intensity in the fat image divided by the signal intensity of the corresponding ROI in the in-phase IDEAL image. The t test was used to compare the asymptomatic and symptomatic groups. ROC curves were constructed to determine the ability of variables to discriminate between symptomatic and asymptomatic myeloma. Results Univariate analysis showed that β2-microglobulin and bone marrow plasma cell percent (BMPC%) were significantly higher and fat-signal fraction was significantly lower with symptomatic myeloma than with asymptomatic myeloma. Areas under the curve were 0.847 for β2;-microglobulin, 0.834 for fat-signal fraction, and 0.759 for BMPC%. Conclusion The fat-signal fraction as a biomarker for multiple myeloma enables discrimination of symptomatic myeloma from asymptomatic myeloma. The fat-signal fraction offers superior sensitivity and specificity to BMPC% of biopsy specimens.

Coronary Artery Stent Evaluation with Model-based Iterative Reconstruction at Coronary CT Angiography

RATIONALE AND OBJECTIVES This study aims to compare the image quality of coronary artery stent scans on computed tomography images reconstructed with forward projected model-based iterative reconstruction solution (FIRST) and adaptive iterative dose reduction 3D (AIDR 3D). MATERIALS AND METHODS Coronary computed tomography angiography scans of 23 patients with 32 coronary stents were used. The images were reconstructed with AIDR 3D and FIRST. We generated computed tomography attenuation profiles across the stents and measured the width of the edge rise distance and the edge rise slope (ERS). We also calculated the stent lumen attenuation increase ratio (SAIR) and measured visible stent lumen diameters. Two radiologists visually evaluated the image quality of the stents using a 4-point scale (1 = poor, 4 = excellent). RESULTS There was no significant difference in the edge rise distance between the two reconstruction methods (P = 0.36). The ERS on FIRST images was greater than the ERS on AIDR 3D images (325.2 HU/mm vs 224.4 HU/mm; P <0.01). The rate of the visible stent lumen diameter compared to the true diameter on FIRST images was higher than that on AIDR 3D images (51.4% vs 47.3%, P <0.01). The SAIR on FIRST images was lower than the SAIR on AIDR 3D images (0.19 vs 0.30, P <0.01). The mean image quality scores for AIDR 3D and FIRST images were 3.18 and 3.63, respectively; the difference was also significant (P <0.01). CONCLUSION The image quality of coronary artery stent scans is better on FIRST than on AIDR 3D images.

Disrupted Brain Activation and Deactivation Pattern during Semantic Verbal Fluency Task in Patients with Major Depression

Background: Patients with major depressive disorder (MDD) exhibit cognitive impairment, and evidence suggests that the semantic version of the verbal fluency task is a reliable cognitive marker of the disorder. Here, using functional magnetic resonance imaging (fMRI), we investigated the dysfunction of neural processing in acute depression and examined the effects of a 6-week pharmacological intervention. Methods: Sixteen patients with MDD participated in 2 fMRI sessions, and 16 healthy control (HC) subjects participated in 1 fMRI session. During each fMRI session, the participants performed a semantic verbal fluency task. Brain activity during the task was compared between groups (MDD 1st fMRI vs. HC) and times (MDD 1st fMRI vs. 2nd fMRI). Results: Significant brain hypoactivation was observed in MDD patients at the prefrontal, lateral parietal, and limbic regions compared to HC, and MDD patients exhibited hyperactivation at the left precuneus compared to HC. Hypoactivity of the left dorsolateral prefrontal cortex (DLPFC) and hyperactivity of the precuneus were normalized with treatment. Conclusions: Hypoactivation of the left DLPFC and hyperactivation of the precuneus should be considered as dysregulation of anticorrelated brain networks during a cognitive demanding task. This failure of network regulation may be an important factor in the pathophysiology of MDD.

Changes over Time in Intracranial Air in Patients with Cerebral Air Embolism: Radiological Study in Two Cases

Cerebral air embolism can be easily identified on computed tomography (CT) scans. However, changes in the distribution and amount of intracranial air are not well known. We report two patients with cerebral air embolism and present imaging findings on the serial changes in the intracranial air. We thought that the embolic source was venous in one patient because CT showed air inflow in cortical veins in the bilateral frontal areas, reflecting air buoyancy. In the other patient, CT showed air inflow into not only the cortical veins but also the bilateral cerebral hemispheres and we thought this to be a paradoxical cerebral air embolism. We found that intracranial air can be promptly absorbed and while cerebral infarcts due to air are clearly visualized on diffusion-weighted images (DWI), the air may rapidly disappear from images. In patients with suspected cerebral air embolism whose CT findings show no intracranial air, DWI should be performed because it may reveal cerebral infarction due to cerebral air embolism.

Measurement of electron density and effective atomic number by dual-energy scan using a 320-detector computed tomography scanner with raw data-based analysis: a phantom study.

Abstract We evaluated the accuracy of the electron densities and effective atomic numbers determined by raw data-based dual-energy analysis on a 320-detector computed tomography scanner. The mean (SD) errors between the measured and true electron densities and between the measured and true effective atomic numbers were 1.3% (1.5%) and 3.1% (3.2%), respectively. Electron densities and effective atomic numbers can be determined with high accuracy, which may help to improve accuracy in radiotherapy treatment planning.

Magnetic Resonance Evaluation of Multiple Myeloma at 3.0 Tesla: How Do Bone Marrow Plasma Cell Percentage and Selection of Protocols Affect Lesion Conspicuity?

Purpose To compare various pulse sequences in terms of percent contrast and contrast-to-noise ratio (CNR) for detection of focal multiple myeloma lesions and to assess the dependence of lesion conspicuity on the bone marrow plasma cell percent (BMPC%). Materials and Methods Sagittal T1-weighted FSE, fat-suppressed T2-weighted FSE (FS- T2 FSE), fast STIR and iterative decomposition of water and fat with echo asymmetry and least-squares estimation (IDEAL) imaging of the lumbar spine were performed (n = 45). Bone marrow (BM)-focal myeloma lesion percent contrast and CNR were calculated. Spearman rank correlation coefficients were obtained between percent contrast, CNR and BMPC%. Percent contrasts and CNRs were compared among the three imaging sequences. Results BM-focal lesion percent contrasts, CNRs and BMPC% showed significant negative correlations in the three fat-suppression techniques. Percent contrast and CNRs were significantly higher for FS- T2 FSE than for STIR (P<0.01, P<0.05, respectively), but no significant differences were found among the three fat-suppression methods in the low tumor load BM group. Conclusion The higher BMPC% was within BM, the less conspicuous the focal lesion was on fat-suppressed MRI. The most effective protocol for detecting focal lesions was FS- T2 FSE. In the high tumor load BM group, no significant differences in lesion conspicuity were identified among the three fat-suppression techniques.

Multidetector Computed Tomography-Based Microstructural Analysis Reveals Reduced Bone Mineral Content and Trabecular Bone Changes in the Lumbar Spine after Transarterial Chemoembolization Therapy for Hepatocellular Carcinoma

Purpose It is well recognized that therapeutic irradiation can result in bone damage. However, long-term bone toxicity associated with computed tomography (CT) performed during interventional angiography has received little attention. The purpose of this study was to determine the prevalence of osteoporosis and trabecular microstructural changes in patients after transarterial chemoembolization (TACE) for hepatocellular carcinoma therapy using an interventional-CT system. Materials and Methods Spinal microarchitecture was examined by 64-detector CT in 81 patients who underwent TACE, 35 patients with chronic hepatitis, and 79 controls. For each patient, the volumetric CT dose index (CTDIv) during TACE (CTDIv (TACE)), the dose-length product (DLP) during TACE (DLP (TACE)), and CTDIv and DLP of routine dynamic CT scans (CTDIv (CT) and DLP (CT), respectively), were calculated as the sum since 2008. Using a three dimensional (3D) image analysis system, the tissue bone mineral density (tBMD) and trabecular parameters of the 12th thoracic vertebra were calculated. Using tBMD at a reported cutoff value of 68 mg/cm3, the prevalence of osteoporosis was assessed. Results The prevalence of osteoporosis was significantly greater in the TACE vs. the control group (39.6% vs. 18.2% for males, P<0.05 and 60.6% vs. 34.8% for females, P<0.01). Multivariate regression analysis demonstrated that sex, age, and CTDIv (CT) significantly affected the risk of osteoporosis. Of these indices, CTDIv (CT) had the highest area under the curve (AUC) (0.735). Correlation analyses of tBMD with cumulative radiation dose revealed weak correlations between tBMD and CTDIv (CT) (r 2 = 0.194, P<0.001). Conclusion The prevalence of osteoporosis was significantly higher in post TACE patients than in control subjects. The cumulative radiation dose related to routine dynamic CT studies was a significant contributor to the prevalence of osteoporosis.

Systemic Lupus Erythematosus: Prediction by MRI of the Subsequent Development of Brain Lesions

RATIONALE AND OBJECTIVES Many patients with systemic lupus erythematosus (SLE) manifest the recurrence of new brain lesions on follow-up magnetic resonance imaging (MRI) scans. We assessed whether the initial MRI findings help to predict the subsequent development of brain lesions in patients with SLE. MATERIALS AND METHODS We enrolled 64 patients with SLE who had undergone initial and follow-up MRI studies. Two radiologists reviewed and categorized the initial MRI findings and divided the patients into those with no lesions on the initial and follow-up MRI scans (group A, n = 18), those with lesions on the initial scans only (group B, n = 32), and those with lesions on the first and new lesions on the follow-up MRI scans (group C, n = 14). We then looked for independent predictors of the subsequent development of brain lesions, such as antiphospholipid syndrome (APS) and findings on the initial MRI studies. RESULTS The incidence of lacunar and localized cortical infarcts was significantly greater in group C than group B (50% vs. 0%, P < .001 and 50% vs. 9%, P < .05, respectively). Multivariate logistic regression analysis indicated that lacunar or localized cortical infarcts on the initial MRI scans were independent predictors of the subsequent development of brain lesions (odds ratio [OR]: 5.412, 95% confidence interval [CI]: 1.18-24.85, P = .03), whereas the presence of APS was not (OR: 0.621, 95% CI: 0.18-2.19). CONCLUSIONS The presence of lacunar and/or localized cortical infarcts on initial MRI scans may predict the development of new brain lesions in patients with SLE.

Imaging features of papillary renal cell carcinoma with cystic change-dominant appearance in the era of the 2016 WHO classification

PurposePapillary renal cell carcinoma (P-RCC) typically exhibits a homogeneous, solid hypovascular mass; P-RCC with a cystic appearance is atypical. Tubulocystic RCC (TC-RCC), a newly proposed entity for renal tumors in the 2016 WHO classification, and cystic papillary RCC, may yield similar imaging findings. Therefore, we investigated the incidence of papillary RCC with cystic changes and compared its CT and pathologic features to differentiate between two entities.MethodsWe retrospectively evaluated 26 consecutive patients diagnosed with P-RCC. Two radiologists consensually identified dominant masses indicative of cystic changes on CT scans and recorded their Bosniak classification. In addition, two pathologists inspected the whole area of tumors macroscopically, labeled them as solid- or cystic change-dominant tumors, determined the pathogenesis of the cystic components (necrosis or hemorrhage), and recorded their inherent cystic characteristics (with/without TC-RCC components). We defined masses with cystic changes involving more than 50% of the entire tumor as cystic change-dominant tumors.ResultsOf the 26 tumors, 7 (27%) were diagnosed cystic change-dominant based on imaging and pathologic findings, of these, 2 were classified as Bosniak type III and 5 as Bosniak type IV. The pathologists confirmed that two type IV tumors demonstrated extensive necrosis and one type IV tumor revealed extensive hemorrhage. Four P-RCCs (type III and IV, 2 each) were of a mixed type harboring both solid and cystic components. Only one tumor exhibited a multilocular cystic appearance. All 7 cystic change-dominant P-RCCs were pathologically diagnosed as a pure P-RCC without TC-RCC components.ConclusionWhile P-RCCs may contain cystic features, the multilocular type of cystic P-RCC is rare.