Radiation dose reduction for chest radiography of infants in intensive care units using a high peak kilovoltage-technique.

BACKGROUND: Chest radiography is an important tool in the care of infants in intensive care units. Image optimization must be monitored to minimize radiation exposure in this susceptible population. OBJECTIVE: To examine the use of a high tube peak kilovoltage technique to achieve radiation dose reduction while maintaining adequate image quality. MATERIALS AND METHODS: A retrospective study was conducted. Radiation doses of chest radiographs performed in the pediatric intensive care units in our institution were calculated. The radiographs were divided into two groups based on the value of the peak kilovoltage used: above and below 60 kilovolts (kV). Image quality was blindly assessed by two fellowship-trained pediatric radiologists. Air kerma, effective dose and quality score for the high versus the low peak kilovoltage group were compared and analyzed. RESULTS: The study included 376 radiographs. One hundred and seven radiographs were performed using peak kilovoltage values equal to or above 60 kV and 269 radiographs were performed using values under 60 kV. The average air kerma for the lower peak kilovoltage group was 56.6 microgray (µGy) (30.7-81.9) vs. 22.9 µGy (11.8-34.4) for the higher peak kilovoltage group (P<0.0001). The mean difference in effective dose between the groups was 11.68 (P<0.0001). The mean difference for the quality score was 0.06 (±0.03, P=0.10), not statistically significant. CONCLUSION: A high peak kilovoltage technique may enable a statistically significant radiation dose reduction without compromising the diagnostic value of the image.

Hematopoietic stem cell transplantation for mitochondrial neurogastrointestinal encephalopathy: A single-center experience underscoring the multiple factors involved in the prognosis.

BACKGROUND: Mitochondrial neurogastrointestinal encephalomyopathy (MNGIE) is a progressive autosomal recessive disorder characterized by cachexia, gastrointestinal (GI) dysmotility, ptosis, peripheral neuropathy, and brain magnetic resonance imaging (MRI) white matter changes. Bi-allelic TYMP mutations lead to deficient thymidine phosphorylase (TP) activity, toxic accumulation of plasma nucleosides (thymidine and deoxyuridine), nucleotide pool imbalances, and mitochondrial DNA (mtDNA) instability. Death is mainly due to GI complications: intestinal perforation, peritonitis, and/or liver failure. Based on our previous observations in three patients with MNGIE that platelet infusions resulted in a transient 40% reduction of plasma nucleoside levels, in 2005 we performed the first hematopoietic stem cell transplantation (HSCT) worldwide as a life-long source of TP in a patient with MNGIE. PROCEDURE: HSCT was performed in a total of six patients with MNGIE. The multiple factors involved in the prognosis of this cohort were analyzed and compared to the literature experience. RESULTS: Cell source was bone marrow in five patients and peripheral stem cells in one, all from fully human leukocyte antigen (HLA)-matched related donors, including four who were TYMP mutation carriers. Four of six (66%) survived compared to the 37% survival rate in the literature. Reduced intensity conditioning regimen contributed to secondary graft failure in two patients. Fifteen years post HSCT, the first transplanted patient is seemingly cured. Severe GI symptoms before transplantation were mostly irreversible and were poor prognostic factors. CONCLUSIONS: Allogenic HSCT could constitute a curative therapeutic option for carefully selected, young, presymptomatic, or mildly affected patients. Timing, donor selection, and optimal conditioning protocol are major determinants of outcome. HSCT is inadvisable in patients with advanced MNGIE disease.