tailieunhanh - Pediatric PET Imaging - part 7

ADHD cộng với đối lập, thực hiện, học tập, hoặc rối loạn tâm trạng, và điều khiển trong một nhiệm vụ thực hiện trên máy vi tính liên tục bằng cách sử dụng technetium 99m ethylcysteinate dimer (99mTc-ECD) SPECT. Mặc dù có sự khác biệt giữa các đối tượng, tất cả các đối tượng với một chẩn đoán bổ sung đã giảm tưới máu ở một hoặc cả ha | 338 Chapter 19 Neurodevelopmental and Neuropsychiatric Disorders perfusion may be related to the presence of coexisting conditions. Lorberboym and colleagues 23 studied young adolescent boys with pure ADHD ADHD plus oppositional conduct learning or mood disorders and controls during a computerized continuous performance task using technetium-99m ethylcysteinate dimer 99mTc-ECD SPECT. Although there were differences among subjects all subjects with an additional diagnosis had decreased perfusion in one or both temporal lobes. Several studies have also been done using ligands related to specific neurotransmitters rather than glucose utilization or perfusion. Ernst and colleagues 25 26 used 18F-fluorodopa 18F-FD to assess the integrity of DA uptake processes in the midbrain striatum and prefrontal cortex of adults and children with ADHD compared with controls. Adults showed more than a 50 decrease in uptake in medial and lateral prefrontal cortex 25 whereas children showed an almost 50 increase in the right midbrain 26 . The most common neurotransmitter component studied in ADHD is DAT. Methylphenidate the most commonly prescribed medication for treating ADHD blocks dopamine reuptake at the transporter 27 . Many types of studies implicate the DA system in ADHD symptoms 28 29 and genetic studies implicate DAT polymorphisms in ADHD 30 . Several studies 31-33 though not all 34 have found elevated levels of DAT binding in adults with ADHD one study in children 35 showed that medication-naive children with ADHD have 14 to 70 increases in DAT binding in the striatum compared with controls. In summary decreased perfusion in the frontal lobes and basal ganglia are typically found in subjects with ADHD compared with controls. Subjects tend to activate more widespread neural networks in response to attention-demanding tasks. Findings between studies differ with respect to laterality 5 21-24 . Findings in children and adults show both similarities and differences but .