Kidney Exchange to Overcome Financial Barriers to Kidney Transplantation.

Organ shortage is the major limitation to kidney transplantation in the developed world. Conversely, millions of patients in the developing world with end-stage renal disease die because they cannot afford renal replacement therapy-even when willing living kidney donors exist. This juxtaposition between countries with funds but no available kidneys and those with available kidneys but no funds prompts us to propose an exchange program using each nation's unique assets. Our proposal leverages the cost savings achieved through earlier transplantation over dialysis to fund the cost of kidney exchange between developed-world patient-donor pairs with immunological barriers and developing-world patient-donor pairs with financial barriers. By making developed-world health care available to impoverished patients in the developing world, we replace unethical transplant tourism with global kidney exchange-a modality equally benefitting rich and poor. We report the 1-year experience of an initial Filipino pair, whose recipient was transplanted in the United states with an American donor's kidney at no cost to him. The Filipino donor donated to an American in the United States through a kidney exchange chain. Follow-up care and medications in the Philippines were supported by funds from the United States. We show that the logistical obstacles in this approach, although considerable, are surmountable.

Historical Matching Strategies in Kidney Paired Donation: The 7-Year Evolution of a Web-Based Virtual Matching System.

Failure to convert computer-identified possible kidney paired donation (KPD) exchanges into transplants has prohibited KPD from reaching its full potential. This study analyzes the progress of exchanges in moving from "offers" to completed transplants. Offers were divided into individual segments called 1-way transplants in order to calculate success rates. From 2007 to 2014, the Alliance for Paired Donation performed 243 transplants, 31 in collaboration with other KPD registries and 194 independently. Sixty-one of 194 independent transplants (31.4%) occurred via cycles, while the remaining 133 (68.6%) resulted from nonsimultaneous extended altruistic donor (NEAD) chains. Thirteen of 35 (37.1%) NEAD chains with at least three NEAD segments accounted for 68% of chain transplants (8.6 tx/chain). The "offer" and 1-way success rates were 21.9 and 15.5%, respectively. Three reasons for failure were found that could be prospectively prevented by changes in protocol or software: positive laboratory crossmatch (28%), transplant center declined donor (17%) and pair transplanted outside APD (14%). Performing a root cause analysis on failures in moving from offer to transplant has allowed the APD to improve protocols and software. These changes have improved the success rate and the number of transplants performed per year.

Acute plain anterioposterior radiograph of the pelvis is not useful in detecting fractures of iliac wing and os sacrum: a prospective study of 73 patients using CT as gold standard.

Conflicting opinions exist to what extent interpreters of an acute anterioposterior (AP) radiograph of the pelvis underdiagnose pelvic injury. We have prospectively evaluated the usefulness of a plain AP radiograph of the pelvis in detecting injuries, using CT as the gold standard. Seventy-three haemodynamically stable blunt trauma patients, who had an AP radiograph of the pelvis and an abdominopelvic CT as part of their initial imaging evaluation, were included. There were 14 women and 59 men, with a mean age of 30 (3-61) years. Two senior radiologists, with special interest in CT examinations evaluating trauma, reviewed the radiographs and a month later the CT scans, blinded and independently. Usefulness index of the plain AP radiograph of the pelvis in detecting specific injuries was calculated using CT as the gold standard. A radiograph is regarded as useful if the usefulness index is 0.35 or more. The usefulness index for a plain AP radiograph of the pelvis for detecting a fracture of iliac wing and os sacrum was 0.25 and 0.01, respectively. An acute AP radiograph of the pelvis is not useful in detecting a fracture of iliac wing or os sacrum.

[Magnetic resonance imaging in the evaluation of temperature-controlled radiofrequency volumetric tissue reduction]. / Die Kernspintomographie in der Evaluation radiofrequenzchirurgisch induzierter oropharyngealer Gewebsläsionen. Frühe postoperative Ergebnisse.

BACKGROUND: Due to its minimally invasive character, radiofrequency surgery has become a topic of increasing attention, especially with respect to the surgical treatment of sleep-related breathing disorders. Temperature-controlled radiofrequency volumetric tissue reduction is the most common technique employed in these cases. However, despite the increasingly widespread use of this technique, there is little data available on the induced effects in vivo. The aim of the present study was to investigate whether magnetic resonance imaging could be used in the evaluation of the in vivo effects of radiofrequency surgery at the base of the tongue. PATIENTS AND METHODS: Six patients were treated at the base of tongue with radiofrequency surgery. At 4-6, 8-10 and 24 h after surgery, magnetic resonance imaging was performed using an inversion recovery technique (TIRM) and the lesions created were evaluated. RESULTS: The lesions could be visualised at all postoperative measurement times. They appeared as oval hypointense structures encircled by a hyperintense area. Lesion size diminished slightly over time. DISCUSSION: Lesions induced by radiofrequency surgery can be clearly visualised with magnetic resonance imaging. Lesion size may be assessed in relation to energy application. In the future, the treatment of sleep-related breathing disorders may be further optimised with the help of this technique.

Hemarthrosis after trauma to the pediatric knee joint: what is the value of magnetic resonance imaging in the diagnostic algorithm?

In children, compulsory arthroscopy for hemarthrosis after knee trauma is not justified because ligamentous and meniscal damage is rare. In a prospective study, we analyzed the diagnostic value of radiography, magnetic resonance imaging (MRI), and arthroscopy in 51 patients up to 14 years of age with acute knee trauma. Plain radiography revealed 16 osseous lesions (5 metaphyseal, 3 patellar, 4 physeal fractures, 3 avulsions of the tibial spine, and 1 osseous ligamentous tear). In 29 patients, the cause of hemarthrosis remained unclear. All patients were evaluated by MRI. A diagnosis could be assigned to all 29 patients. MRI demonstrated lesions in 38 patients. In addition, the following lesions were discovered: 8 patellar dislocations, 13 bruises, 1 rupture of the anterior cruciate ligament, 1 osteochondritis dissecans, and 13 joint effusions. In 13 patients, MRI was followed by arthroscopy to confirm the diagnosis. Both, MRI and arthroscopy missed two osteochondral fractures. In addition, three chondral lesions were not picked up by MRI. MRI is a reliable tool for assessing the extent of knee lesions in children.

Fast high-resolution magnetic resonance imaging demonstrates fractality of myocardial perfusion in microscopic dimensions.

The fractal nature of heterogeneity of myocardial blood flow and its implications for the healthy and diseased heart is not yet understood. The main hindrance for investigation of blood flow heterogeneity and its role in physiology and pathophysiology is that conventional methods for determination of myocardial perfusion have severe limitations concerning temporal and spatial resolution and invasiveness. In isolated rat hearts, we developed a nuclear magnetic resonance technique that does not depend on contrast agents and in which the apparent longitudinal relaxation time is made perfusion sensitive by selective preparation of the imaging slice. This perfusion-sensitive relaxation time is determined within 40 seconds as a map with a high spatial in-plane resolution of 140x140 microm(2) and a thickness of 1.5 mm. Perfusion imaging was validated with the established microsphere technique. Additionally, the congruence between perfusion-sensitive T:(1) maps and first-pass perfusion imaging was demonstrated. As an application of high-resolution perfusion imaging, fractal analysis of the spatial distribution of perfusion was performed. We were able to demonstrate that the fractality of this distribution exists even in microscopic dimensions. Vasodilation by nitroglycerin modulated the fractal pattern of perfusion, and the decrease of the fractal dimension indicated a shift toward homogeneity. This implies that parameters of the fractal distribution depend on the microvascular tone rather than on anatomic preformations; ie, fractality is a functional characteristic of perfusion.

[1H-MR spectroscopy in anorexia nervosa: reversible cerebral metabolic changes]. / 1H-MR-Spektroskopie bei Anorexia nervosa: reversible zerebrale Metabolitenänderungen.

PURPOSE: By using localized 1H-MR spectroscopy in the brain of patients with anorexia nervosa we wanted to verify our preliminary results and to look for a reversibility of the metabolic changes under therapy. METHODS: In 22 patients and 17 healthy volunteers (11 follow-up examinations) single voxel 1H-MR spectroscopy (TE = 50 ms, TM = 30 ms, TR = 1500 ms, voxel (2 cm)3, acq.: 256) was used in two different localizations (thalamus and parieto-occipital region). The first examination of the patients was performed before therapy, the follow-up examination at the end of therapy. RESULTS: In both regions of the brain we found a statistically significant elevation of the Cho/Cr-ratio in comparison to normal controls. The follow-up examinations revealed reversibility of the metabolic changes under successful therapy. CONCLUSIONS: 1H-MR spectroscopy reveals metabolic changes in the brain of patients with anorexia nervosa, which are reversible under successful therapy. These metabolic changes can be conclusively explained using a biochemical model.

[1H-MR spectroscopy in anorexia nervosa: the characteristic differences between patients and healthy subjects]. / 1H-MR-Spektroskopie bei Anorexia nervosa: charakteristische Unterschiede zwischen Patienten und gesunden Probanden.

PURPOSE: The neurophysiological and neuromorphological changes in patients with anorexia nervosa (AN) are well-known but the reason of both is still unknown. We have evaluated the usefulness of hydrogen (H1) magnetic resonance spectroscopy in anorexia nervosa. METHOD: We investigated 15 patients with clinically diagnosed AN (ICD F50.0) and 17 controls without eating disorders. The body mass index (BMI) was 15.8 and 21, respectively. The spectroscopy was recorded on two voxels in the parieto-occipital white matter or in the thalamus with a water-suppressed STEAM-sequence. The metabolites were recorded with respect to phosphocreatine (PCr). RESULTS: The ratio of NAA/PCr in both voxels were not significantly different when comparing patients vs. controls. Patients showed significantly higher ratios of choline-containing components (Cho) or, respectively Cho/PCr and NAA/PCr in the white matter. Distinct, but not significant differences were detected both for m-Ino and m-Ino/PCr in the parieto-occipital region and for the Cho- and m-Ino contained ratios in the thalamus. CONCLUSION: AN is not associated with neuronal damage. The ratio of Cho/PCr and NAA/Cho may reflect the disturbance of membrane-turnover. It is possible that the increase of membrane catabolism leads to a hyperosmolar state. The change of m-Ino/PCr ratio may reflect the regulation of osmolarity.

Proton magnetic resonance spectroscopy in acute, juvenile anorexia nervosa.

Anorexia nervosa is usually associated with a shrinkage of the brain that is at least partially reversible with weight gain. The pathogenesis of this brain abnormality is unclear. The purpose of this study was to investigate potential alterations in localized proton magnetic resonance (1H MR) spectra of anorectic patients immediately after an interval of excessive weight loss. Twelve patients and seventeen control subjects were examined. Water suppressed 1H MR spectra were recorded from two voxels placed in the thalamus and in the parieto-occipital white matter. The spectra of ten patients could be evaluated. Comparing patients and control subjects, significantly higher signal intensity ratios of choline containing compounds (Cho) relative to total creatine (Cr) as well as significantly lower ratios of N-acetyl-aspartate (NAA) relative to Cho were found in the white matter region. We hypothesize that these results indicate an abnormal starvation, associated membrane turnover, which predominantly takes place in the white matter. No evidence for neuronal degeneration was found in the thalamus or in the white matter region.

Cerebrovascular reserve capacity in patients with occlusive cerebrovascular disease: assessment with dynamic susceptibility contrast-enhanced MR imaging and the acetazolamide stimulation test.

PURPOSE: To quantitatively assess cerebrovascular reserve capacity in patients with occlusive cerebrovascular disease. MATERIALS AND METHODS: In 21 symptomatic patients with occlusive cerebrovascular disease, magnetic resonance (MR) imaging was performed with a 1.5-T system. Before, during, and after a brief bolus injection of gadopentetate dimeglumine into the antecubital vain, a series of 32 rapid T2*-weighted gradient-echo images of two different sections were acquired simultaneously to measure the concentration-time-curves in the brain tissue and in the brain-feeding arteries. Principles of indicator dilution analysis were applied to compute regional cerebral blood flow (rCBF) and volume. Each patient underwent two examinations, the first before and the second after acetazolamide stimulation. RESULTS: In the asymptomatic hemisphere, a mean increase in rCBF value of 47.1% was observed after acetazolamide stimulation. In the affected areas of the symptomatic hemisphere, a statistically significantly reduced response to acetazolamide stimulation was found, indicating a severely compromised cerebrovascular reserve capacity. CONCLUSION: MR imaging with the described techniques provides quantitative information about the cerebrovascular reserve capacity in patients with occlusive cerebrovascular disease.

[Simultaneous corpus fractures of the os triquetrum and os hamatum diagnosed by magnetic resonance tomography. A case report]. / Die simultanen Korpusfrakturen des Os triquetrum und des Os hamatum diagnostiziert durch Kernspintomographie. Eine Fallbeschreibung.

We are reporting the case of a patient with a rare fracture of the corpus of the triquetrum after falling on the ulnar abducted and extended hand. The magnetic resonance imaging (MRI) of the wrist surprisingly showed an additional fracture of the hamate.

[Noninvasive quantification of cerebral blood volume and blood flow with dynamic MR tomography. Studies of probands and patients with cerebrovascular insufficiency]. / Nichtinvasive Quantifizierung des zerebralen Blutvolumens und Blutflusses mit der dynamischen MR-Tomographie. Untersuchungen an Probanden und Patienten mit zerebrovaskulärer Insuffizienz.

PURPOSE: A non-invasive MR-method for the quantification of regional cerebral blood flow (rCBF) and blood volume (rCBV) is used to examine healthy volunteers and patients with cerebrovascular disorders. MATERIALS AND METHODS: 20 healthy volunteers and 10 patients with severe cerebrovascular disorders were examined. MR imaging was performed on a 1.5 T imaging system. Before, during and following brief antecubital vein bolus injection of Gd-DTPA, a series of 32 rapid T2*-weighted gradient echo images of two different slices ere simultaneously acquired in order to measure th concentration-time-curves in the brain tissue and the arterial input function in the brain feeding arteries. From these series of images the concentration-time-curves were computed. Principles of indicator dilution analysis were applied to compute rCBF and rCBV. The volunteers underwent one examination each. All patients underwent two examinations, one before and the second after azetazolamide stimulation. RESULTS: In volunteers the measured rCBF and rCBV values are in good agreement with data from positron emission tomography studies. In patients with cerebrovascular disorders in the asymptomatic hemisphere a mean increase of rCBF of 43,45 +/- 18.04% was observed after azetazolamide stimulation. In the affected areas of the symptomatic hemisphere in 8 from 10 patients the acetazolamide test reveals a significantly reduced response to azetazolamide stimulation, indicating an exhausted cerebrovascular reserve capacity. CONCLUSION: Dynamic MR-Imaging can provide quantitative information about rCBF and rCBV. In patients with cerebrovascular disorders, this method can be applied to estimate the cerebrovascular reserve capacity.

[Nuclear magnetic resonance tomography as a functional diagnostic method. New approaches to non-invasive quantification of cerebral blood volume and blood flow]. / Kernspintomographie als funktionsdiagnostische Methode. Neue Ansätze zur nichtinvasiven Quantifizierung von zerebralem Blutvolumen und Blutfluss.

This paper presents a brief introduction to the current status of cerebral blood volume and blood flow imaging with magnetic resonance imaging (MRI) techniques. A new method for the quantitative assessment of regional cerebral blood volume (rCBV) and regional cerebral blood flow (rCBF) on the basis of the indicator dilution theory is described and preliminary quantitative results from healthy volunteers are presented. The mean values for the rCBV are 8.27 +/- 1.85 ml/100 g for grey matter and 3.78 +/- 1.34 ml/100 g for white matter. The mean values for the rCBF are 44.8 +/- 11.29 ml/min/100 g for the grey matter and 20.88 +/- 8.42 ml/min/100 g for the white matter. These results are in good agreement with PET results from the literature.

Postural disequilibrium quantification in children with chronic lead exposure: a pilot study.

Previous studies reported that some children who survive acute lead encephalopathy suffer from ataxia and have difficulties maintaining postural equilibrium. More recent studies have failed to quantify postural imbalance in association with lower levels of lead exposures, perhaps due to the insensitivity of the clinical measure. In our study, we noninvasively measured postural disequilibrium with a microprocessor-based force platform. The test provides a real time quantification of the body's center of gravity movement pattern. Measurements were made in a cohort of 33 inner city children (mean age: six years +/- 0.4 SD) with well documented blood lead histories. The average maximum blood lead of these children during their first six years of life was 23.5 micrograms/dl (range = 8.5 to 49.4). The children performed four postural tests [i.e., standing eyes open (EO) and closed (EC), on firm surface and standing on a compliant foam surface with eyes open (FO) and closed (FC)]. The results indicated that the maximum blood lead incurred during the second year of life was significantly positively related to postural sway, and the body balance was most affected in the EC test where visual cues were eliminated and proprioceptive feedback was not modified. Fetal Pb exposure levels as well as Pb exposures during the first year of life were not correlated with postural sway of six year olds. However, the maximum blood lead concentration beyond two years of life was significantly associated with the postural sway at six years of age.