Ex Vivo Assessment of Various Histological Differentiation in Human Carotid Plaque with Near-infrared Spectroscopy Using Multiple Wavelengths.

We previously reported that near-infrared hyperspectral imaging enabled the localization of atherosclerotic plaques from outside the vessels, but not the optical characteristics of each histological component. Therefore, the near-infrared spectrum of each component was collected from the sliced section of the human carotid plaque obtained with endarterectomy and the optical characteristics were confirmed in several wavelengths. Based on this information, we assessed the diagnostic accuracy for ex vivo chemogram in each plaque component created with near-infrared spectroscopy (NIRS), using multiple wavelengths. The chemogram projected on the actual image of plaque was created based on light intensity and transmittance change at three wavelengths. The wavelengths that were mainly were 1440, 1620, 1730, and 1930 nm. We evaluated the accuracy of histological diagnosis in chemogram compared with pathological findings, analyzing interobserver agreement with κ-statistics. The chemograms that we created depicted the components of fibrous tissue, smooth muscle, lipid tissue, intraplaque hemorrhage, and calcification. Diagnostic odds ratio in each component was as follows: 259.6 in fibrous tissue, 144 in smooth muscle, 1123.5 in lipid tissue, 29.3 in intraplaque hemorrhage, and 136.3 in calcification. The κ-statistics revealed that four components, excluding intraplaque hemorrhage, had substantial or almost perfect agreement. Thus, this study demonstrated the feasibility of using chemogram focused on specific component during the histological assessment of atherosclerotic plaques, highlighting its potential diagnostic ability. Chemograms of various target components can be created by combining multiple wavelengths. This technology may prove to be useful in improving the histological assessment of plaque using NIRS.

Quantitative assessment of gadolinium deposition in dentate nucleus using quantitative susceptibility mapping.

PURPOSE: Gadolinium deposition in dentate nucleus (DN) has been reported after serial administration of gadolinium-based contrast agents (GBCAs). Gadolinium complexes have paramagnetic properties; therefore, we evaluated susceptibility changes of gadolinium deposition in DN using quantitative susceptibility mapping (QSM) for patients after serial administration of GBCAs. MATERIALS AND METHODS: In all, 48 patients with brain tumors, who had had serial GBCA administrations (GBCA group), and 48 healthy volunteers without any history of GBCA administrations (non-GBCA group) were enrolled in this study. Susceptibility values in DN on QSM and DN-to-cerebellum signal intensity ratios on unenhanced T1 -weighted images (T1 ratios) on 3T were analyzed. The relationship between the number of times of GBCA administrations and susceptibility values or T1 ratios were evaluated in the GBCA group. RESULTS: Susceptibility values at DN in the GBCA group were 0.107 ± 0.029 ppm, and significantly higher than those of the non-GBCA group (0.079 ± 0.025 ppm) (P < 0.0001). T1 ratios in DN of the GBCA group were 1.059 ± 0.070, and also significantly higher than that of the non-GBCA group (0.993 ± 0.016) (P < 0.0001). Spearman rank correlation coefficients between susceptibility values and the number of times of linear GBCA administration showed a modest significant correlation (ρ = 0.45, P = 0.0015). There was good correlation between T1 ratios and the number of times of linear GBCA administration, as reported previously (ρ = 0.76, P < 0.0001). CONCLUSION: Susceptibility values on QSM in DN of the GBCA group, after serial administration of GBCAs, were significantly higher than those of the non-GBCA group. Evidence Level: 3 J. MAGN. RESON. IMAGING 2017;45:1352-1358.

Healthcare resource utilization and clinical outcomes associated with acute care and inpatient rehabilitation of stroke patients in Japan.

OBJECTIVE: To investigate healthcare resource utilization and changes in functional status in stroke patients during hospitalization in an acute hospital and a rehabilitation hospital. DESIGN: Retrospective cohort study. SETTING: One acute and one rehabilitation hospital in Japan. PARTICIPANTS: Patients who were admitted to the acute hospital due to stroke onset and then transferred to the rehabilitation hospital (n = 263, 56% male, age 70 ± 12 years). MAIN OUTCOME MEASURES: Hospitalization costs and functional independence measure (FIM) were evaluated according to stroke subtype and severity of disability at discharge from the acute hospital. RESULTS: Median (IQR) costs at the acute hospital were dependent on the length of stay (LOS) and implementation of neurosurgery, which resulted in higher costs in subarachnoid hemorrhage [$52 413 ($49 166-$72 606) vs $14 129 ($11 169-$19 459) in cerebral infarction; and vs $15 035 ($10 920-$21 864) in intracerebral hemorrhage]. The costs at the rehabilitation hospital were dependent on LOS, and higher in patients with moderate disability than in those with mild disability [$30 026 ($18 419-$39 911) vs $18 052 ($10 631-$24 384)], while those with severe disability spent $25 476 ($13 340-$43 032). Patients with moderate disability gained the most benefits during hospitalization in the rehabilitation hospital, with a median (IQR) total FIM gain of 16 (5-24) points, compared with a modest improvement in patients with mild (6, 2-14) or severe disability (0, 0-5). CONCLUSIONS: The costs for in-hospital stroke care were substantial and the improvement in functional status varied by severity of disability. Our findings would be valuable to organize efficient post-acute stroke care.

Carotid artery plaque assessment using quantitative expansive remodeling evaluation and MRI plaque signal intensity.

OBJECTIVE: Plaque characteristics and morphology are important indicators of plaque vulnerability. MRI-detected intraplaque hemorrhage has a great effect on plaque vulnerability. Expansive remodeling, which has been considered compensatory enlargement of the arterial wall in the progression of atherosclerosis, is one of the criteria of vulnerable plaque in the coronary circulation. The purpose of this study was risk stratification of carotid artery plaque through the evaluation of quantitative expansive remodeling and MRI plaque signal intensity. METHODS: Both preoperative carotid artery T1-weighted axial and long-axis MR images of 70 patients who underwent carotid endarterectomy (CEA) or carotid artery stenting (CAS) were studied. The expansive remodeling ratio (ERR) was calculated from the ratio of the linear diameter of the artery at the thickest segment of the plaque to the diameter of the artery on the long-axis image. Relative plaque signal intensity (rSI) was also calculated from the axial image, and the patients were grouped as follows: Group A = rSI ≥ 1.40 and ERR ≥ 1.66; Group B = rSI< 1.40 and ERR ≥ 1.66; Group C = rSI ≥ 1.40 and ERR < 1.66; and Group D = rSI < 1.40 and ERR < 1.66. Ischemic events within 6 months were retrospectively evaluated in each group. RESULTS: Of the 70 patients, 17 (74%) in Group A, 6 (43%) in Group B, 7 (44%) in Group C, and 6 (35%) in Group D had ischemic events. Ischemic events were significantly more common in Group A than in Group D (p = 0.01). CONCLUSIONS: In the present series of patients with carotid artery stenosis scheduled for CEA or CAS, patients with plaque with a high degree of expansion of the vessel and T1 high signal intensity were at higher risk of ischemic events. The combined assessment of plaque characterization with MRI and morphological evaluation using ERR might be useful in risk stratification for carotid lesions, which should be validated by a prospective, randomized study of asymptomatic patients.

Contrast-enhanced carotid color-coded duplex sonography for carotid stenting follow-up assessment.

Proper assessment of endovascular patency after carotid stent (CS) placement with carotid color-coded duplex sonography (CCCD) can be difficult. We investigated the usefulness of contrast-enhanced (CE) CCCD for post-CS follow-up. CCCD images could not depict the entire bloodstream in overlapped stents and in highly positioned stents. CE-CCCD images, however, did provide anatomic information almost equivalent to that of intra-arterial angiography. CE-CCCD is useful in screening for post-CS restenosis.