18F-FDG PET for detecting myocardial viability: validation of 3D data acquisition.

(18)F-FDG PET is an important diagnostic tool for detecting myocardial viability in patients with coronary artery disease. In combination with perfusion scanning, (18)F-FDG PET allows differentiation between reversibly and irreversibly damaged myocardium and selection of patients likely to benefit from revascularization. Viability PET is usually performed in two-dimensional (2D) mode. Taking into account the rising number of three-dimensional (3D)-only scanners, a validation of 3D acquisition is required. METHODS: Twenty-one patients with coronary artery disease referred for (18)F-FDG PET underwent an imaging protocol of nongated 2D (2D-NG) and gated 2D (2D-G) acquisitions for 15 min each, followed by 3D gated acquisitions for 10 min (3D-10) and 5 min (3D-5), using an ECAT Exact HR+ scanner. Results were analyzed using a 20-segment polar map in terms of activity concentration (Bq/mL), viability (50% uptake threshold), regional activity distribution, visual assessment of viability based on a 3-point rating scale, and left ventricular ejection fraction. RESULTS: Activity concentration measured in each segment with 2D-G, 3D-10, and 3D-5 showed a good linear correlation with 2D-NG. Quantitative viability assessment with 3D-5 gave a sensitivity of 84% and a specificity of 98%, compared with 2D-NG. No differences in regional activity distribution and visual viability assessment were found between the various protocols. Left ventricular ejection fractions obtained with 3D-10 and 3D-5 showed a good linear correlation with those measured with 2D-G. CONCLUSION: An ECG-gated 3D imaging protocol gave results comparable to those of 2D acquisition with regard to absolute and regional myocardial activity distribution, left ventricular function, and visual viability assessment. Sensitivity for viability assessment with a 50% uptake threshold was significantly less with 3D, but specificity was maintained. This protocol delivers a clinical performance nearly equivalent to that of 2D acquisition.     

Benign paroxysmal tonic upgaze of infancy: 2 additional cases]

Benign paroxysmal tonic upgaze is an ill-defined neuro-ophthalmological disorder with onset in infancy. It consists of sudden ocular movements with sustained upward deviation of the eyes. Episodes disappear with time: spontaneous remission occurs within a few months or years without any change in psychomotor development. EEG and neuro-imaging are unrevealing. To date, the pathogenesis of the condition is still unknown. Early recognition of this benign condition minimizes potentially unnecessary investigations and treatments. Herein, we report on 2 additional sporadic cases.     

Cardiac efficiency and oxygen consumption measured with 11C-acetate PET after long-term cardiac resynchronization therapy.

Cardiac resynchronization therapy (CRT) is a treatment option in patients with severe heart failure and left bundle-branch block (LBBB). This study evaluated the effects of 4 and 13 mo of CRT on myocardial oxygen consumption (MVO2) and cardiac efficiency as compared with mild heart failure patients without LBBB. METHODS: Sixteen patients with severe heart failure and LBBB due to idiopathic cardiomyopathy were studied at baseline and after 4 and after 13 mo of therapy. Thirteen patients with mild heart failure without LBBB served as a comparison group. The clearance rate (k2) of 11C-acetate was measured with PET to assess MVO2. Stroke volume was derived from the dynamic PET data according to the Stewart-Hamilton principle and, furthermore, cardiac efficiency using the work metabolic index. RESULTS: After 4 mo of CRT, stroke volume index (SVI) increased by 50% (P = 0.012) and cardiac efficiency increased by 41% (P < 0.001). Global k2 remained unchanged but regional k2 demonstrated a more homogeneous distribution pattern. The parameters showed no significant changes during therapy. Under CRT, cardiac efficiency, SVI, and the distribution pattern of regional k2 did not differ from mild heart failure patients without LBBB. CONCLUSION: CRT improves cardiac efficiency for at least 13 mo, as demonstrated by a higher SVI, whereas MVO2 remains unchanged. Cardiac efficiency, SVI, and the MVO2 distribution pattern reach the level of patients with mild heart failure without LBBB. The unfavorable hemodynamic performance in heart failure with LBBB is effectively restored by long-term CRT to the level of an earlier disease state.     

Depressed antigen presentation function and membrane interleukin-1 activity of peritoneal macrophages after laparotomy

Although major tissue trauma produces profound depression of cell-mediated immunity, it is not known whether surgical trauma (i.e., midline laparotomy) has any adverse effect on the antigen presentation function and membrane interleukin-1 (IL-1) activity of peritoneal macrophages. To study this, C3H/HEJ (endotoxin-tolerant) mice were anesthetized. An approximately 1-inch midline abdominal incision was made, followed by abdominal closure. On days 1, 3, 5, and 7, peritoneal macrophages were harvested by means of peritoneal lavage, and antigen presentation capability was tested by incubating various numbers of peritoneal macrophages with 2 X 10(4) D10.G4.1 cells per well in the presence of conalbumin (400 micrograms/ml). The T helper cell clone (D.10.G4.1) proliferates on recognition of conalbumin in the context of Iak and also proliferates in the presence of membrane-bound IL-1 plus concanavalin A. To measure membrane IL-1 expression in peritoneal macrophages, Concanavalin A (10 micrograms/ml) was substituted for conalbumin. Cultures were incubated for 72 hours, pulsed with tritiated thymidine, and harvested. Peritoneal macrophages from laparotomized mice induced significantly less T helper cell proliferation on days 1 and 3 in the antigen presentation assay (37% and 30%, respectively; p less than 0.05) and in the membrane IL-1 assay (14% and 10%, respectively; p less than 0.05) as compared with the control. This difference was not detectable on day 5. More effective antigen presentation capability (167% of control; p less than 0.05) was seen on day 7. Thus laparotomy by itself produces marked depression of both antigen presentation function and membrane IL-1 activity of peritoneal macrophages, which may enhance susceptibility to intra-abdominal sepsis.     

Intracerebral hemorrhage: natural history and rationale of ultra-early hemostatic therapy

Stroke is a major health problem worldwide, causing high morbidity and mortality. Intracerebral hemorrhage (ICH) accounts for 15% of stroke cases in the US and Europe and up to 30% in Asian populations. It is less treatable than other forms of stroke and causes higher morbidity and disability. Data suggest that early hematomy growth is the principal cause of early neurological deterioration after ICH. Prospective and retrospective studies indicate that early hematoma growth occurs in 18–38% of patients scanned within 3 h of ICH onset, and that hematoma volume is an important predictor of 30-day mortality. As hematoma growth in acute ICH is a dynamic process, intervention with ultra-early hemostatic therapy could lead to minimization and even prevention of early hematomy growth. Recombinant activated factor VII (rFVIIa, ‘NovoSeven’), a powerful initiator of hemostasis, is approved for the treatment of bleeding in patients with hemophilia and inhibitors and may also promote hemostasis in patients with normal coagulation. rFVa acts locally at the bleeding site without activating systemic coagulation and may be a valuable therapy during the hyperacute stage of ICH. A randomized, double-blind, placebo-controlled, dose-ranging trial is currently in progress to investigate the potential of rFVIIa as an ultra-early hemostatic therapy to prevent or minimize hematoma growth in ICH patients without coagulopathy.