Assessment for Carotid Atherosclerotic Plaque Using Vessel Wall Magnetic Resonance Imaging: A Multireader ROC Study to Determine Optimal Sequence for Detecting Vessel Wall Calcification.

INTRODUCTION: We aimed to compare conventional vessel wall MR imaging techniques and quantitative susceptibility mapping (QSM) to determine the optimal sequence for detecting carotid artery calcification. METHODS: Twenty-two patients who underwent carotid vessel wall MR imaging and neck CT were enrolled. Four slices of 6-mm sections from the bilateral internal carotid bifurcation were subdivided into 4 segments according to clock position (0-3, 3-6, 6-9, and 9-12) and assessed for calcification. Two blinded radiologists independently reviewed a total of 704 segments and scored the likelihood of calcification using a 5-point scale on spin-echo imaging, FLASH, and QSM. The observer performance for detecting calcification was evaluated by a multireader, multiple-case receiver operating characteristic study. Weighted κ statistics were calculated to assess interobserver agreement. RESULTS: QSM had a mean area under the receiver operating characteristic curve of 0.85, which was significantly higher than that of any other sequence (p < 0.01) and showed substantial interreader agreement (κ = 0.68). A segment with a score of 3-5 was defined as positive, and a segment with a score of 1-2 was defined as negative; the sensitivity and specificity of QSM were 0.75 and 0.87, respectively. CONCLUSION: QSM was the most reliable MR sequence for the detection of plaque calcification.

Analysis of bone erosions in rheumatoid arthritis using HR-pQCT: Development of a measurement algorithm and assessment of longitudinal changes.

PURPOSE: The purpose of this study was to establish an algorithm for measuring bone erosions at metacarpophalangeal (MCP) joints using high-resolution peripheral quantitative computed tomography (HR-pQCT), to investigate the precision of measurements, and to assess longitudinal changes in bone erosions among patients with rheumatoid arthritis (RA). METHODS: The 2nd and 3rd MCP joints were scanned at a voxel size of 60.7 µm using second-generation HR-pQCT. Bone erosions on MCP joints were identified using a semi-automated algorithm we developed, and each erosion parameter was measured. Measurement reproducibility was evaluated in 19 healthy subjects using intraclass correlation coefficients (ICCs) and root mean square percent coefficient of variance (RMS%CV). Finally, longitudinal changes in bone erosions over a period of 12 months were assessed in 26 patients with RA based on the calculated least significant change (LSC). RESULTS: Reproducibilities for measurement parameters regarding bone erosions with our algorithm were good (all ICCs ≥ 0.98; all RMS%CVs < 5%). No erosion parameters showed significant changes after 12 months of treatment in terms of median values in all erosions, while both progression and repair of erosions were observed individually (e.g., erosion volume: progression, 26% (+0.62 mm3); repair, 34% (-0.85 mm3); no change, 40%). CONCLUSIONS: The measurement algorithm developed for bone erosions at MCP joints showed good reproducibility. Both progression and repair of bone erosions were observed in patients with RA even after 12 months of appropriate treatment. Our algorithm may be useful to investigate the etiology of RA and assess drug efficacy.

The Ulnar Nerve at Elbow Extension and Flexion: Assessment of Position and Signal Intensity on MR Images.

Purpose To assess the position and signal intensity of the ulnar nerve at elbow extension and flexion by using magnetic resonance imaging. Materials and Methods Institutional review board approval and written informed consent were obtained. Transverse T2-weighted images were obtained perpendicular to the upper arm in 100 healthy elbows of 50 volunteers (23 men, 27 women; age range, 21-57 years) and nine elbows with ulnar neuropathy (five men, four women; age range, 24-59 years) with extension and 130° of flexion. Ulnar nerve position was classified into three types: no dislocation, subluxation, or dislocation. One-way analysis of variance, paired t tests, Student t tests, and multiple regression analysis were used to analyze correlations between ulnar nerve movement angle during flexion and age, sex, presence of the anconeus epitrochlearis muscle, and ulnar neuropathy and to compare the contrast-to-noise ratio of nerve to muscle between extension and flexion. Results Nerve positions in healthy elbows were as follows: All had no dislocation at extension, and at flexion, 51 of 100 elbows (51.0%) had no dislocation, 30 of 100 elbows (30.0%) had subluxation, and 19 of 100 elbows (19.0%) had dislocation. Nerve movement angle was smaller in elbows with the anconeus epitrochlearis muscle than in those without the muscle (P = .045, .015). Presence of the muscle was the only significant factor associated with nerve movement angle (P = .047, .013). Only dominant elbows with nerve movement angle of less than 15° and nondominant elbows with nerve movement angle of less than 10° showed contrast-to-noise ratio increase at flexion (P = .021-.030). Conclusion Ulnar nerve movement during flexion was apparent in approximately half of healthy elbows and was similar between healthy elbows and elbows with ulnar neuropathy. Nerve signal intensity increased during flexion only in elbows without apparent nerve movement. (©) RSNA, 2016 Online supplemental material is available for this article.

Quantification of lung perfusion blood volume with dual-energy CT: assessment of the severity of acute pulmonary thromboembolism.

OBJECTIVE: The purpose of this study was to evaluate the usefulness of quantification of lung perfused blood volume (PBV) with dual-energy CT (DECT) for assessment of the severity of acute pulmonary thromboembolism (PTE). MATERIALS AND METHODS: We retrospectively analyzed the records of 72 patients with PTE and 168 without PTE who underwent DECT. The PTE patients were divided into high-, intermediate-, and low-risk groups based on clinical symptoms and right ventricular dysfunction. Correlations between quantification of whole-lung PBV and clinical severity were evaluated. Also evaluated was the relation between quantification of whole-lung PBV and right-to-left ventricular diameter ratio on CT images, which was used as an indicator of right ventricular dysfunction. RESULTS: In the PTE and control groups, the whole-lung PBVs were 27.6 ± 7.9 and 29.9 ± 6.8 HU with a significant difference between them (p < 0.0281). In the high-, intermediate-, and low-risk PTE groups, the whole-lung PBVs were 16.0 ± 2.9, 21.0 ± 4.2, and 31.4 ± 5.8 HU with a significant difference between them (p < 0.05). There was no significant difference in whole-lung PBV between the control group and the low-risk PTE group, but there was a significant difference between the control group and the other two PTE groups. In PTE patients, whole-lung PBV had negative correlation with right-to-left ventricular diameter ratio (R = -0.567, p < 0.001). CONCLUSION: Quantification of lung PBV with DECT is useful for assessment of the clinical severity of PTE and can be used as an indicator of right ventricular dysfunction.

Comparison of outcome in aortic dissection with single false lumen versus multiple false lumens: CT assessment.

PURPOSE: To investigate the clinical features and outcomes of type B multibarreled (multiple false lumens) aortic dissection (AD) compared with those of double-barreled (single false lumen) AD by using computed tomography (CT). MATERIALS AND METHODS: The ethics committee approved this study. Informed consent was waived. A total of 221 consecutive patients (127 men; median age, 62 years) with acute type B AD were evaluated by using CT. The clinical outcome, including AD-related events, AD-related deaths, and long-term survival, was retrospectively reviewed and compared with that of patients with double-barreled AD during the follow-up period (median, 60 months). Survival analysis was performed by using Kaplan-Meier analysis with the log-rank test within 10 years after onset. The Cox proportional hazards model was used to estimate the risk for AD-related events and death. RESULTS: In 201 of 221 patients (91.0%), double-barreled AD was identified at initial CT. In 20 of 221 patients (9%), multibarreled AD was identified at initial CT (n = 16) and follow-up CT (n = 4). In 15 of 20 patients (75%) with multibarreled AD, AD-related events occurred, and nine patients (45%) died of AD-related complications. Patients with multibarreled AD showed significantly poorer survival rates than patients with double-barreled AD (P = .0002). The presence of a multibarreled false lumen was the most powerful risk factor for AD-related deaths according to multivariate analysis (hazard ratio, 5.61; 95% confidence interval: 2.44, 12.90; P < .0001). CONCLUSION: Multibarreled AD occurs in 9% of acute type B dissections. The presence of multibarreled AD is a powerful predictor of AD-related deaths.

[Image assessment of the cartilage and subchondral bone in patients with osteoarthritis].

The most recommendable MRI sequence for the morphologic assessment of the cartilage damage due to osteoarthritis (OA) is gradient echo fat suppression T1 weighted image (SPGR: Spoiled gradient recalled acquisition in the steady state, FLASH: Fast low-angle shot). For the detection of the cartilage degeneration before the morphological change, T2 mapping, dGEMRIC (delayed Gd-DTPA2-Enhanced MRI of Cartilage), and T1ρ mapping are suggested. Subchondral bone structural changes such as bone sclerosis and cyst are deeply related to the etiology of OA, and quantitative evaluation for them using MDCT (Multi-Detector row CT) and 3TMRI are suggested.

Patient allocation based on preoperative assessment of pancreatic fibrosis to secure pancreatic anastomosis performed by trainee surgeons: a prospective study.

BACKGROUND: A fragile or non-fibrotic pancreas increases the risk of postoperative pancreatic fistula (POPF) after pancreatic head resection, whereas pancreatic fibrosis decreases the risk. The degree of pancreatic fibrosis can be estimated using the time-signal intensity curve (TIC) of the pancreas, obtained with dynamic magnetic resonance imaging (MRI). We have investigated whether trainee surgeons can perform pancreatic anastomosis safely, without the occurrence of POPF, when patients are selected carefully based on a preoperative assessment of pancreatic fibrosis. METHODS: Seventy-two consecutive patients who underwent pancreatic head resection were enrolled in this prospective trial. Dynamic contrast-enhanced MRI of the pancreas was performed preoperatively in all patients who, based on their pancreatic TIC profile, were then allocated to one of two groups: Group A comprised patients with type I pancreatic TIC, signifying a normal pancreas without fibrosis (n = 46); Group B comprised patients with type II or III pancreatic TIC, signifying a fibrotic pancreas (n = 26). An end-to-side duct-to-mucosa pancreaticojejunostomy was performed in all patients, with all patients in Group A operated on by two experienced surgeons, and all patients in Group B operated on by one of eight trainee surgeons at various stages of training. RESULTS: There was no operative mortality. POPF developed in 19 patients: 12 patients with grade A POPF and seven with grade B. All except one of the POPF occurred in Group A patients. The POPF in the one patient from Group B was grade A (p < 0.001). CONCLUSIONS: A trainee surgeon can perform a secure pancreatic anastomosis without the occurrence of POPF in patients with a pancreas displaying a fibrotic pancreatic TIC on dynamic MRI scans.

Analysis of hip geometry by clinical CT for the assessment of hip fracture risk in elderly Japanese women.

Two case-control studies were designed to investigate the contribution of the geometry and bone mineral density (BMD) of the proximal femur to bone strength in Japanese elderly women. We also investigated whether clinical CT is useful to assess the risk of hip fracture. Subjects in the neck fracture study included 20 Japanese women with neck fracture (age: mean+/-SD; 80.1+/-4.5 years old) and 20 age-matched control women (79.2+/-2.6 years old). Subjects in the trochanteric fracture study included 16 Japanese women with trochanteric fracture (82.6+/-5.0 years old) and 16 age-matched control women (80.8+/-3.8 years old). CT examination of the proximal femur was performed between the date of admission and the date of surgery. The CT scanners used were an Aquillion 16 (Toshiba) and Somatom 64 (Siemens); the scanning conditions including spatial resolution and scanning energy were adjusted, and the same type of reference phantom containing hydroxyapatite was used. QCT PRO software (Mindways) was used to analyze data for BMD, geometry, and biomechanical parameters. Both the neck and trochanteric fracture cases had significantly lower total and cortical BMD, a significantly smaller cortical cross-sectional area (CSA), and a larger trabecular CSA. Both had significantly thinner cortex and smaller distance to center of bone mass, and women with trochanteric fracture had a significantly smaller cortical perimeter in the cross-sectional femoral neck. Women with neck fracture had a longer hip axis length (HAL) and women with trochanteric fracture had a significantly larger neck-shaft angle (NSA). Both groups had significantly lower cross-sectional moment of inertia (CSMI), and only women with neck fracture had a significantly higher buckling ratio (BR) compared to their respective controls. According to the multiple logistic regression analysis, women with neck fracture had a significantly longer HAL, lower CSMI, and higher BR, and women with trochanteric fracture had a significantly smaller cortical CSA of the femoral neck. We conclude that clinical CT may be useful for the assessment of the risk of neck and trochanteric fracture.

Role of magnetic resonance imaging in the assessment of disease activity in thyroid-associated ophthalmopathy.

Two different phases in disease activity are observed during the clinical course of thyroid-associated ophthalmopathy (TAO). The assessment of disease activity is important for predicting the outcome of medical management because medical treatment can be effective in the active stage. The aim of this study was to investigate whether magnetic resonance imaging (MRI) could assess the disease activity in TAO. To investigate the relation between MRI-T2 signal intensity (SI) and extraocular muscle (EOM) size, 11 patients with TAO were evaluated. EOM sizes (enlargement, volume) were measured by MRI-T1 image. T2-SI of EOM was expressed as a percentage of temporal muscle. The reduction in T2-SI was significantly positively correlated with that of EOM enlargement after treatment. Additionally, T2-SI in pretreatment showed a significant correlation with reduction in EOM volume for therapeutic effect, which indicates T2-SI in pretreatment can be one of the reliable parameters for predicting the therapeutic outcome of treatment. To investigate whether MRI-T2 pattern could predict the reversibility of diplopia, 28 patients with Graves' disease with or without ophthalmopathy were evaluated. Patients with TAO with reversible diplopia showed an uniform T2 pattern in enlarged EOM. However, in patients with irreversible diplopia caused by the mechanical limitation of EOM, MRI-T2 image showed no uniformity with a partial appearance of low T2-SI. The partial low T2-SI may indicate the progress of inactive (fibrotic) change in EOM after active (inflammatory) change. In conclusion, MRI is a useful tool for detection not only of EOM enlargement, but also disease activity in TAO. MRI-T2 SI and pattern can predict the outcome of medical management in TAO.