Myocardial perfusion imaging and cardiac events in a cohort of asymptomatic patients with diabetes living in southern France.

AIMS: To assess the association between abnormal stress myocardial perfusion imaging (MPI) and cardiac events (CE) in asymptomatic patients with diabetes and with > or = 1 additional risk factor. Predictors of abnormal stress MPI were also evaluated. METHODS: Four hundred and forty-seven consecutive patients who underwent stress MPI were prospectively followed for 2.1 [0.5-4.1] years for the subsequent occurrence of hard CE (myocardial infarction and sudden or coronary death) and soft CE (unstable angina and ischaemic heart failure requiring hospitalization). Re-vascularization procedures performed as a result of the screening protocol were not included in the analysis. RESULTS: Follow-up was successful in 419 of 447 patients (94%), of whom 71 had abnormal MPI at baseline. Medical therapy was intensified in all subjects and especially in those with abnormal MPI. Twenty-three patients with abnormal MPI underwent a re-vascularization procedure. CEs occurred in 14 patients, including six of 71 patients (8.5%) with abnormal MPI and eight of 348 patients (2.3%) with normal MPI (P < 0.005). Only two patients developed a hard CE and 12 a soft CE. In multivariate analysis, abnormal MPI was the strongest predictor for CEs [odds ratio (OR) (95% CI) = 5.6 (1.7-18.5)]. Low-density lipoprotein cholesterol > or = 3.35 mmol/l [OR (95% CI) = 7.3; 1.5-34.7] and age > median [OR (95% CI) = 6.0 (1.2-28.6)] were additional independent predictors for CE. The independent predictors for abnormal MPI were male gender, plasma triglycerides > or = 1.70 mmol/l, creatinine clearance < 60 ml/min and HbA1c > 8%, with male gender the strongest [OR (95% CI) = 4.0 (1.8-8.8)]. CONCLUSIONS: Asymptomatic patients with diabetes in this study had a very low hard cardiac event rate over an intermediate period. This could be explained by the effects of intervention or by the low event rate in the background population. Randomized studies of cardiac heart disease screening are required in asymptomatic subjects with diabetes to determine the effectiveness of this intervention.     

Non-invasive temperature imaging of muscles with magnetic resonance imaging using spin-echo sequences

The application of spin-echo magnetic resonance imaging sequences on non-invasive temperature imaging for temperature mapping of human limbs is investigated. In an in vitro expriment performed on a meat sample, the equilibrium magnetisation P and the spin-lattice relaxation time T₁ are calculated from the values for the repetition time TR and the signal intensities obtained by a spin-echo sequence at different tissue temperatures tures as measured by a fibre-optic probe. T₁ is linearly correlated to the tissue temperature, and P is linearly correlated to the reciprocal value of the absolute temperature. Both effects, taken together, lead to a non-linear dependency of the signal intensity on temperature. Therefore a TR leading to maximum temperature dependency of the signal intensity is calculated and used in the futher experiments. In the in vivo experiments, the lower legs of two volunteers are cooled from outside. Images are acquired with a spin-echo sequence (1.5T, TR=1200 ms, TE=10 ms). A rise in signal intensity in the muscle with falling skin temperature is observed, particularly in more peripheral muscle layers. This study shows that spin-echo sequences can be used to monitor temperature changes and temperature differences in living muscle tissue.     

磁共振成像对颅内脑膜瘤水肿分析

目的：探讨脑膜瘤周围脑水肿的程度和肿瘤的生长部位．质地．组织学亚型的相关性．研究其瘤周水肿的形成原因．材料和方法：使用经手术和病理证实的65例脑膜瘤MRI和临床病理资料．观察分析脑膜瘤的瘤周水肿的程度．肿瘤的质地，组织学亚型等．结果：发生于大脑颅盖部或／和有矢状窦受累的脑膜瘤有明显的脑水肿．而发生于其它部位(颅底，丘脑、小脑、脑池等)无或只有轻度脑水肿．结论：轻度脑水肿主要是脑膜瘤对脑组织的直接压迫，而中，重度脑水肿主要是脑膜瘤对大脑表面引流静脉尤其是矢状窦的压迫或阻塞．脑水肿和肿瘤的发生部位有关，面和肿瘤的质地、组织学亚型无关．     

Blood pool ventriculography with a new technetium-labelled complex (99mTc-DEPIC) : a clinical evaluation

A new, single bolus method of in vivo blood pool imaging using a technetium Tc99m phosphine isocyanide complex (DEPIC) which binds to pre-albumin was evaluated in volunteers (n=4) and patients (n=20). DEPIC was assessed for its safety and possible drug interactions. Its duration of action and quality of ventriculography were compared with imaging using standard in vivo red cell labelling (PYP) during two 3-h scanning periods 1 week apart. DEPIC had a mean plasma halflife of 3.3 h. The count rate over the left ventricle was initially 42% higher with DEPIC than with PYP. However, removal of DEPIC by the liver resulted in equivalent count rates by 1 h, and by 3 h PYP count rates were 22% higher than DEPIC. Immediately post injection mean (SD) difference in the left ventricular ejection fraction between the two methods was 2.4% (7.7%). Satisfactory DEPIC scans were obtained up to 2 h post injection, but by 3 h there was a mean difference of 13% (11.3%). DEPIC was found to be a safe alternative to red all labelling for blood pool angiography, suitable for routine work. The single bolus methodology and high initial count rates offer improved efficiency and a capability for truly emergency scanning.     

Gliomatosis cerebri with good prognosis

A 52-year-old man was admitted to our clinic with severe headache and bilateral papilledema. Magnetic resonance (MR) images on admission demonstrated diffuse swelling of the cerebral cortex without formation of a tumor mass. Biopsy revealed diffuse infiltration with neoplastic glial cells. After radiation and chemotherapy, the MR images returned to normal. The morphological and neurological features of the present case met the criteria for gliomatosis cerebri. However, this patient showed an unusually good response to radiation and chemotherapy.     

核素显像对小儿消化道出血的病因诊断

目的探讨核素显像对小儿消化道出血，特别是对Ｍｅｃｋｅｌ憩室、肠重复畸形的病因诊断的价值。方法对２６例腹痛、便血为主要症状的患儿行９９ｍ锝酸盐（９９ｍＴｃＯ－４）显像，其中１２例显像阴性者于检查后２４小时有活动性出血者，再行９９ｍ锝标记红细胞显像。所有病例的诊断均经手术、病理及内窥镜等检查所证实。结果９９ｍＴｃＯ－４显像诊断Ｍｅｃｋｅｌ憩室和肠重复畸形的敏感性、特异性、准确性分别为８５．７％（１２／１４）、９１．７％（１１／１２）及８８．５％（２３／２６）。结论核素显像具有无创、方法简单易行等特点，特别是对异位胃粘膜诊断具有较好的灵敏性和特异性。核素显像可作为下消化道出血病因诊断的有效方法。     

Evidence of an abnormal intramuscular component of fatigue in multiple sclerosis

The goals of this study were to investigate muscle fatigue in patients with multiple sclerosis (MS), and to determine the relationships between muscle fatigue, clinical status, and perceived fatigue. The fatigability of the anterior tibial muscle was quantitated in patients and controls during 9 min of intermittent stimulation (used to eliminate central sources of muscle fatigue). During exercise, the decline in tetanic force, phosphocreatine, and intracellular pH was greater in patients than in controls. The compound muscle action potential amplitude did not decrease during exercise, indicating that there was no failure of neuromuscular transmission during fatigue. Thus, the excessive fatigue in MS developed from sources beyond the muscle membrane. Following exercise, the recovery of tetanic force was delayed in patients (a pattern that suggests abnormal excitation–contraction coupling), whereas the recovery of metabolites was complete in both groups. Muscular fatigue was correlated with clinical disability but not with perceived fatigue. These results suggests that fatigue in MS has both central (perception, upper motor neuron dysfunction) and peripheral (impaired metabolism and excitation–contraction coupling) components.© 1995 John Wiley &Sons, Inc.     

Image technique optimization in MR imaging of a titanium alloy joint prosthesis

The purpose of this study was to explore systematically the effect of the imaging parameters changeable by the user in spin-echo (SE) imaging sequences to minimize image distortion when imaging joint prostheses. A titanium alloy hip joint prosthesis was studied at 1.0 T. The SE imaging parameters were bandwidth/pixel (BW/p), TE, strength of encoding gradients (matrix size), echo train length (ETL), and direction of phase and frequency encoding. The effect of ETL in rapid acquisition relaxation enhanced (RARE) sequences was also evaluated with a turbo-SE sequence using a different ETL with the same TR and an effective TE. It is concluded that an optimized image quality can be achieved in SE imaging by using a high bandwidth/pixel value (at least 130 Hz/pixel), a high resolution matrix (256–512), sequences with multiple refocusing, and a frequency-encoding axis parallel to the long axis of the prosthesis. The degree of distortion is reduced with this optimized technique.