Clinical application of effective atomic number for classifying non-calcified coronary plaques by dual-energy computed tomography.

BACKGROUND AND AIMS: Coronary computed tomography (CT) angiography allows non-invasive classification of non-calcified coronary plaques (NCCPs) based on Hounsfield unit (HU) values. This methodology, however, is somewhat limited for reliable classification of NCCPs. Therefore, we evaluated the effective atomic number (EAN) for classifying NCCPs by single-source dual-energy CT with fast tube voltage switching (SSDECT). METHODS: We prospectively enrolled 18 patients undergoing both SSDECT and intravascular ultrasonography (IVUS). Monochromatic images at 70 keV and EAN images were reconstructed from SSDECT data sets. Regions of interest (ROIs) within NCCPs were placed on IVUS-matched SSDECT images, and mean HU values and EANs for soft and fibrous plaques, classified using IVUS, were compared with an unpaired t-test. RESULTS: We placed 96 ROIs in 29 soft plaques and 37 ROIs in 15 fibrous plaques in 12 coronary arteries of 11 patients. The mean HU value in soft plaques (58.2 ± 32.8 HU) was significantly lower than that in fibrous plaques (103.9 ± 48.3 HU) (p < 0.001). The mean EAN in soft plaques (8.7 ± 0.5) was also significantly lower than that in fibrous plaques (9.6 ± 0.5) (p < 0.0001). Area under the curve for EAN (0.91) was significantly higher than that for HU value (0.79) in receiver operating characteristic curve analysis (p = 0.046). With a cutoff EAN of 9.3, sensitivity was 90% and specificity, 87%; whereas with a cutoff HU value of 55.0 HU, sensitivity was 62% and specificity, 93%. CONCLUSIONS: EAN measurement by SSDECT can be clinically useful for accurately classifying soft and fibrous coronary plaques.

Vasodilatation of multiple cerebral arteries in early stage of stroke-like episode with MELAS.

We describe a patient with mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes (MELAS), with multiple cerebral vasodilatations in a stroke-like episode visualised by using magnetic resonance angiography (MRA) and CT angiography (CTA). In the acute stroke-like episode stage, T2-weighted and fluid-attenuated inversion recovery MRI showed high-intensity areas in the left occipital area. In addition, MRA and CTA revealed prominent dilatation of the left posterior cerebral artery and temporal branches of the middle cerebral artery with focal hyperperfusions using CT perfusion (CTP) that corresponded to the MRI. After 10 days, with the development of aphasia, MRI indicated the lesions had spread to the temporal and parietal regions, and this distribution was not confined to major vascular territories. The patient's symptoms gradually improved, accompanied by the attenuation of MRI, CTA, and CTP findings. These characteristic features along with the MRI changes that spread beyond vascular boundaries and the multiple cerebral vasodilatations prior to the development of clinical symptoms are not fully explained by the mitochondrial angiopathy or cytopathy theories. These findings provide further evidence supporting neuronal hyperexcitability in stroke-like episodes of MELAS.

Analysis of coronary arterial calcification components with coronary CT angiography using single-source dual-energy CT with fast tube voltage switching.

Clinical cardiac applications of single-source dual-energy computed tomography (DECT) have recently been introduced. This study aimed to analyze the components of coronary arterial calcification (CAC) in vivo by material decomposition achieved with DECT. We reconstructed computed tomography (CT) angiography images for 51 consecutive patients with CACs who had undergone electrocardiography-gated coronary CT angiography by single-source DECT with fast tube voltage switching. We placed regions of interest (ROIs) within the CAC with margins of at least 0.5 mm to minimize partial volume averaging. We compared histograms for the effective atomic number (EAN) and the median, mean, and maximum EANs for each CAC with the theoretical EANs for possible CAC components, including hydroxyapatite (HA), calcium oxalate monohydrate (COM), and dicalcium phosphate dehydrate. We also investigated the in vivo EAN for COM and in vitro EAN for HA by our phantom experiment. Analysis of the CAC components was feasible in 177 ROIs from 28 patients. The median EAN was 13.8 ± 0.8 (95% confidence interval 13.7-13.9), which is similar to the theoretical EAN for COM (13.8). The EAN for HA in vitro was 16.5 ± 0.1, which was slightly higher than the theoretical EAN value for HA (16.1). Notably, the median EAN in 144 ROIs (81.4%) was between 11.2 and 14.4, which is the reported range of the in vivo EAN for COM. Our results suggest that COM might be a more frequent CAC component than previously reported.

Additional reduction in serum phosphorus levels by pulverized lanthanum carbonate chewable in hemodialysis patients.

Lanthanum carbonate (LC) is one of the relatively new phosphate binders. The general LC dosage form is a chewable pharmaceutical preparation. This investigation was targeted to subjects who do not chew LC chewable preparations adequately, for the purpose of studying the clinical efficacy of changing to pulverized prescriptions, such as changes in serum phosphorus levels (P levels). The study took place at Minamisenju Hospital in October 2011, with 41 subjects on maintenance hemodialysis. We pulverized all of the LC chewable medicines of the LC insufficient mastication group (non-chewing: NC group, n = 18) using a crusher, and changed them to pulverized prescriptions. The testing period was set at 10 weeks. In the NC group, there was a significant lowering of P levels from 5.86 ± 1.31 mg/dL before pulverization of the LC chewable preparation (week 0) to 5.38 ± 1.26 mg/dL after 2 weeks of administration of the pulverized medication (P = 0.0310), 5.20 ± 1.25 mg/dL after 4 weeks (P = 0.0077), and 5.12 ± 1.34 mg/dL after 6 weeks (P = 0.0167). P levels in other patients than NC group showed no significant change. In this study, the P levels in the NC group was lowered significantly by changing the LC chewable to the pulverized prescription, and the residual LC images on the abdominal X-rays disappeared to the point where they could barely be confirmed.

Administration of angiotensin receptor II blockade improves vascular function, urinary albumin excretion, and left ventricular hypertrophy in low-risk essential hypertensive patients receiving antihypertensive treatment with calcium channel blockers.

We examined calcium channel blockers (CCBs) and angiotensin receptor II blockers in low-risk hypertensives to evaluate renal, vascular function and left ventricular mass (LVM) from the viewpoint of salt intake (SI). Low-risk hypertensives who had not met blood pressure (BP) goals with CCB were administered telmisaltan. Office and home BP, urinary albumin excretion (uAE), brachial ankle pulse wave velocity (baPWV) and LVM were significantly reduced. uAE and baPWV correlated with SI. It is therefore necessary to evaluate the organ-protecting effects from the viewpoint of SI. In low-risk hypertensives, telmisartan with CCB improves renal, vascular function and LVM.

Switching to tacrolimus extended-release improved the effectiveness of immunosuppressive therapy in a heart transplant patient: A case report.

We report on a 25-year-old female heart transplant patient who presented with recurrent episodes of cellular rejection due to decreased adherence to immunosuppressive therapy. She received a heart transplantation in 1994 when she was 10 years old. In order to improve her adherence to immunosuppressive therapy, switching to the once-daily extended-release formulation of tacrolimus was performed in a step-wise fashion. First, the twice-daily formulation of cyclosporin A was replaced with the twice-daily preparation of tacrolimus. When the trough blood levels of tacrolimus reached a plateau in the range of 5.0 ng/mL, it was changed to the once-daily extended-release formulation of tacrolimus after confirming the absence of new rejection episodes. There were no significant changes in renal function before and after the switch. After being discharged from the hospital, the patient made significant advancements in adherence to immunosuppressive therapy. Her subsequent clinical course was uneventful, with no adverse events observed. Most patients who undergo solid organ transplantation must receive lifelong immunosuppressive therapy. This case demonstrates that conversion to the extended-release formulation of tacrolimus from other calcineurin inhibitor preparations is a reasonable choice to consider in the management of compromised immunosuppressive therapy adherence in heart transplant patients during the late posttransplant period.