Cardiopulmonary Baroreflex Control of Renal Sympathetic Nerve Activity Is Impaired in Dogs With Left Ventricular Dysfunction

BackgroundActivation of neurohormonal systems contributes to the progression of heart failure (HF). The mechanism(s) whereby these systems become activated is(are) not fully explained. We determined whether vagal cardiopulmonary baroreflex control of renal sympathetic nerve activity is abnormal in dogs with left ventricular (LV) dysfunction in the absence of clinical HF, and the relationship of abnormalities in baroreflexes to the development of the neurohumoral excitatory state.MethodsLV end-systolic and end-diastolic dimensions (echocardiography), arterial baroreflex sensitivity (slope of ΔRR/Δsystolic BP during phenylephrine or nitroglycerin bolus), and neurohumoral profiles (plasma norepinephrine, renin activity, and arginine vasopressin) were measured serially in conscious dogs (n=24) with progressive LV dysfunction due to rapid ventricular pacing. LV dimensions were used to define groups with mild, moderate, and marked LV dilatation (LVD; increase in LV end-diastolic volume <15%, 15–30%, and >30% of control, respectively). Changes in renal nerve activity (RNA) were recorded in response to increases in pulmonary capillary wedge pressure (PCWP) induced by volume infusion in anesthetized, sinoaortic-denervated dogs.ResultsCardiopulmonary baroreflex sensitivity (slope of %ΔRNA/ΔPCWP) for mild LVD (?17.8%/mmHg) was the same as controls (?17.7%/mmHg). However, the slopes of moderate (?5.8%/mmHg) and severe LVD (?1.9%/mmHg) were decreased significantly compared with controls (P < .05). Arterial baroreflex sensitivity was preserved at all stages of LVD. Plasma norepinephrine, renin activity, and arginine vasopressin remained unchanged after 4, 7, and 11 days of pacing.ConclusionsVagal cardiopulmonary baroreflex control of renal sympathetic nerve activity is blunted early in the development of LVD. These abnormalities precede neurohumoral excitation and abnormal arterial baroreflexes and become apparent when LV end-diastolic volume starts to increase.     

Ablation protocols and ancillary procedures in tumor ablation therapy: consensus from Japanese experts

Purpose

A panel of Japanese experts on tumor ablation therapy gathered to reach a general consensus on topics surrounding ablation therapy.

Materials and methods

Questionnaires relating to ablation protocols for radiofrequency ablation (RFA) and cryoablation, as well as ancillary procedures required for safe and secure ablation therapy, were sent to seven institutions. Experts from these institutions discussed each topic based on the evidence and the questionnaire data, and a consensus was reached at an annual meeting of the Japan Image-guided Ablation Group in Maebashi, Japan, in October 2015.

Results

A consensus was reached on each of six topics, including “management of antiplatelet and anticoagulation drug therapy”; “pain control in the perioperative period”; “arterial embolization combined with ablation therapy”; “protection of non-target organs”; “RFA and cryoablation protocols”; and “ablative margins.”

Conclusions

The consensus achieved here will serve as the framework for tumor ablation therapies in Japan.

     

Pre-surgical identification of epileptogenic areas in temporal lobe epilepsy by 123I-iomazenil SPECT: a comparison with IMP SPECT and FDG PET

OBJECTIVES: The aim of this study was to evaluate the usefulness of (123)I-iomazenil (IMZ) single photon emission computed tomography (SPECT) for the pre-surgical identification of epileptogenic areas in patients with temporal lobe epilepsy and to compare the results with those of (123)I-IMP SPECT and (18)Fluorodeoxyglucose positron emission tomography (FDG PET). METHODS: We examined seven patients with medically refractory temporal lobe epilepsy (five men and two women; mean age, 28 years) with no remarkable findings on magnetic resonance imaging. Before surgery, IMZ SPECT, IMP SPECT and FDG PET were all performed in the interictal state. Then, visual assessment and region-of-interest (ROI) analysis were performed on each image. Final definitions of the epileptogenic areas were made by electrocorticography and histopathology. RESULTS: By IMZ SPECT, a decreased IMZ uptake in the ipsilateral temporal lobe was found in all patients, while a similar decrease in the contralateral temporal lobe was also found in one patient. In comparison to IMP SPECT, the extent of the abnormal area on IMZ SPECT was equal to that on IMP SPECT in one patient while it was more restricted to the epileptogenic area in five patients. In comparison to FDG PET, the extent of the abnormal area on IMZ SPECT was equal to that on FDG PET in three patients while it was more restricted in the epileptogenic area in four patients. In ROI analysis, decreases of IMZ, IMP and FDG uptake were observed in the epileptogenic area, although they were not statistically significant. CONCLUSIONS: IMZ SPECT was considered to be useful for pre-surgical determination of the epileptogenic areas in temporal lobe epilepsy with no remarkable MRI findings, and it was also found to be superior to IMP SPECT and FDG PET for this purpose.     

Feasibility of diffusion‐weighted MRI for defining placental invasion

The purpose of this clinical note is to describe the feasibility of using diffusion‐weighted imaging for diagnosing placental invasion with a case of placenta increta and six cases without it. Diffusion‐weighted imaging (DWI) at a b‐value of 1000 sec/mm² can clearly define the border between the placenta and myometrium because only the placenta shows very high signal intensity. The corresponding image at a b‐value of 0 sec/mm² shows the myometrium with high signal intensity compared with the surrounding fat. Therefore, fusion of the two images can be used additionally to visualize thickness of the myometrium. As a result, DWI can be used to visualize the focal thinning of the myometrium caused by placenta increta, which has been difficult to diagnose on conventional magnetic resonance imaging sequences without contrast enhancement. However, the use of DWI for placental invasion should be determined following careful consideration of its risks and benefits, as fetus safety has not been established. J. Magn. Reson. Imaging 2009;30:666–671. © 2009 Wiley‐Liss, Inc.     

Diagnostic performance of Tc-99m HMPAO SPECT for early and late onset Alzheimer’s disease: a clinical evaluation of linearization correction

Objective  This study examined the influence of linearization correction (LC) on brain perfusion single-photon emission computed tomography (SPECT) for the diagnosis of Alzheimer’s disease (AD). Methods  The early onset group (<65 years old) consisted of 10 patients with AD, and the late onset group (≥65 years old) of 13 patients with AD. Age-matched controls included seven younger and seven older normal volunteers. Tc-99m hexamethyl propyleneamine oxine (HMPAO) SPECT images were reconstructed with or without LC [LC (+) or LC (−)] and a statistical analysis was performed using a three-dimensional stereotactic surface projection (3D-SSP). In addition, a fully automatic diagnostic system was developed, which calculated the proportion of the number of abnormal pixels in the superior and inferior parietal lobule, as well as in the precuneus and posterior cingulate gyrus. Results  The areas under the receiver-operating characteristic curve (AUCs) of the early onset group for conventional axial SPECT images, SPECT + 3D-SSP images and the fully automatic diagnostic system were 0.71, 0.88, and 0.92 in LC (−) and 0.67, 0.85, and 0.91 in LC (+), respectively. The AUCs of the late onset group were 0.50, 0.61, and 0.79 in LC (−) and 0.49, 0.67, and 0.85 in LC (+), respectively. Conclusion  LC on Tc-99m HMPAO SPECT did not significantly influence the diagnostic performance for differentiating between AD and normal controls in either early or late onset AD. Further examination with individuals suffering from very mild dementia is, therefore, expected to elucidate the effect of LC on minimally hypoperfused areas.     

Serum S-100B is superior to neuron-specific enolase as an early prognostic biomarker for neurological outcome following cardiopulmonary resuscitation

IntroductionMost patients with cardiac arrest (CA) admitted to hospitals after successful cardiopulmonary resuscitation (CPR) are discharged with various degree of neurological deficits. To determine predictor of neurological outcome early and accurately, and to determine cutoff values, serum levels of protein S-100B and neuron-specific enolase (NSE) within 24 h after CA were assessed.Methods and resultsA multicenter prospective observational study was conducted between May 2007 and April 2008 at three medical institutions in Japan on 107 consecutive non-traumatic CA patients with return of spontaneous circulation after CPR. Based on “best-ever achieved” Glasgow-Pittsburgh cerebral performance categories (CPC) score within 6 months after CA, patients were classified into a “poor neurological outcome” group (CPC3 to CPC5) (n = 67) and “favorable neurological outcome” group (CPC1 and CPC2) (n = 13). Blood was sampled on admission, at 6 and 24 h after CA. Serum S-100B and NSE in “poor outcome” group were higher than those in “favorable outcome” group (P < 0.01). On ROC analysis, area under the curve of S-100B was 0.85, 0.94 and 1.0, respectively. These were greater than those of NSE at all sampling points. The “100%-specific” cutoff values of S-100B predictive of poor neurological outcome were 1.41, 0.21, and 0.05 ng/mL, respectively. These values corresponded to sensitivities of 20.9%, 62.8%, and 100%, respectively, each of which was higher than those of NSE.ConclusionsS-100B is more reliable as an early predictor of poor neurological outcome within 24 h after CA than NSE and can be applied clinically.