Magnetic resonance evaluation of regional left ventricular function. Effect of through-plane motion.

RATIONALE AND OBJECTIVES. Measurements of segmental contraction of the left ventricle by standard magnetic resonance imaging (MRI) and two-dimensional echocardiography involve the comparison of diastolic and systolic time frames acquired from the same imaging plane in space. As the cone-shaped left ventricle shortens along its long axis during systole, the observed contraction may differ from the true myocardial contraction. METHODS. Spin-echo MRI examinations in 21 healthy subjects were performed to evaluate the error caused by failing to compensate for through-plane motion. RESULTS. The authors found that at the base and the mid-ventricle the observed contraction systematically underestimates true contraction by an average of 16% and 21%, respectively (P less than .001). At the apex, the segmental contraction may be overestimated or underestimated. CONCLUSIONS. Because of this error, standard MRI and echocardiography are less suited for basic research on cardiac contraction patterns. However, standard imaging techniques are valuable in clinical studies comparing groups of patients, because all measurements will suffer from the same systematic error.     

Treatment of single brain metastasis: Radiotherapy alone or combined with neurosurgery

Most patients treated for single or multiple brain metastases die from progression of extracranial tumor activity. This makes it uncertain whether the combination of neurosurgery and radiontherapy for treatment of single brain metastasis will lead to better results than less invasive treatment with radiotherapy alone. The effect of neurosurgical excision plus radiotherapy was compared with radiotherapy alone in a prospectively randomized trial with 63 evaluable patients with systemic cancer and a radiological diagnosis of single brain metastasis. Radiotherapy was given to the whole brain by a novel scheme of 2 faractions per day of each 2 Gy for a total of 40 Gy. Before randomization, patients were stratified by site (lung cancer vs nonlung cancer) and status of extracranial disease (progressive vs. stable). Survival as such and functionally independent survival (FIS; defined as world Health Organization performance status ≤ 1 and neurological funcition ≤ 1) were compared between both treatment arms. The combined treatment compared with radiotherapy alone led to a longer survival (p =0.04) and a longer FIS (p=0.06). This was most pronounced in patients with stable extracranial disease (median survival, 12vs 7 mo; median FIS 9 vs 4 Mo). Patients with progressive extracranial cancer had a median overall survival of 5 months and a FIS of 2.5 months irrespective of given treatment. Improvement in functional status occurred more rapidly and for longer periods of time after neurosurgial excision and radiotherapy than after radiotherpy alone. Patients older than 60 years had a hazard ratio of dying of 2.74(p=0.001) compared with younger patients, but in both age groups the combined treatment did better then radiotherapy alone. We coclude that patients with single brain metastasis and stable extracranial tumor activity should be treated with surgical excision and radiotherapy. For patients with progressive extracranial disease during the previous 3 months, radiotherapy alone appears to be sufficient. After treatment of single brain metastasis, parients remain functionally independent until a few months before death.     

Effect of warm ischemia time and HLA (A and B) matching on renal cadaveric graft survival and rejection episodes

In a retrospective single-center study the influence of warm ischemia time and simultaneous influence of HLA (A and B) matching on one-year renal graft survival was analyzed in 170 adult recipients of primary cadaveric renal grafts. One-year survival of grafts with warm ischemia times longer than 50 min was only 40% (n = 10). When warm ischemia time was shorter than 50 min, a 1-min increase of warm ischemia time correlated with 1% decrease in one-year graft survival as a result of rejection. This detrimental effect of warm ischemia time on graft survival was not yet significant one month after transplantation, but became more evident as follow-up time was lengthened. Warm ischemia time also correlated with the number of reversible rejection episodes in patients with a graft functioning for longer than one year (P less than 0.04). The beneficial influence of HLA (A and B) matching on one-year graft survival was significant (P less than 0.05 log linear test). This influence was even more evident with longer warm ischemia times. It is concluded that warm ischemia has a detrimental influence on graft survival that is mediated by rejection, and it is suggested that this might be due in part to altered presentation or expression of HLA-antigens of ischemically damaged kidney tissues.     

Translumbar catheter redirection using a tip-deflector technique

A new technique is described for reversing the direction of the catheter tip during translumbar aortography, without the need for partial withdrawal of the catheter from the aortic lumen. The method ensures optimal delivery of contrast medium at the desired level, while avoiding the risk of retroperitoneal bleeding or dislodgement during catheter manipulation.