Optimisation of exposure parameters using a phantom for thoracic spine radiographs in antero-posterior and lateral views.

INTRODUCTION: To investigate the exposure parameters for thoracic spine/(TS) radiography that allows the image acquisition at the lowest dose possible, while maintaining an adequate image quality/(IQ) to identify all relevant anatomical criteria. METHODS: An experimental phantom study was conducted, and 48 different radiographs of TS (24 AP/24 lateral) were acquired. The Automatic Exposure Control/(AEC) with the central sensor was used to select the beam intensity, while Source-to-Detector-Distance/(SDD) (AP:115/125 cm; Lateral:115/150 cm), tube potential (AP:70/81/90 kVp; Lateral: 81/90/102 kVp), use of grid/no grid and focal spot (fine/broad) were manipulated. IQ was assessed by observers with ViewDEX. Effective Dose (ED) was estimated using PCXMC2.0 software. Descriptive statistics paired with intraclass correlation coefficient (ICC) were applied to analyse data. RESULTS: The ED increased with a greater SDD for lateral-view, presenting a significant difference (p = 0.038), however IQ was not affected. For both AP and lateral, the use of grid had a significant effect on ED (p < 0.001). Despite the images acquired without grid had lower IQ scores, the observers considered the IQ adequate for clinical use. A 20% reduction in ED (0.042mSv-0.033 mSv) was observed when increasing the beam energy from 70 to 90 kVp for AP grid in. The observers ICC ranged from moderate to good (0.5-0.75) in lateral and good to excellent (0.75-0.9) for AP views. CONCLUSIONS: The optimised parameters in this context were 115 cm SDD, 90 kVp with grid for the best IQ and lowest ED. Further studies in clinical setting are necessary to enlarge the context and cover different body habitus and equipment. IMPLICATIONS FOR PRACTICE: The SDD impacts on dose for TS; Higher kVp and grid are necessary to better image quality.

Hypersomnia in association with dysthymia in comparison with idiopathic hypersomnia and normal controls.

Polysomnographic studies in hypersomniac patients with mood disorders are rare. Previous studies investigated patients with a severe mood disorder, but our study was done in patients with dysthymia, who complained of sleepiness. Mean sleep latency test (MSLT) and continuous polysomnographic recording (CPR) were done in 12 dysthymic patients, in comparison with 12 idiopathic hypersomnia patients, and 12 normal controls. In dysthymic patients mean sleep latency on the MSLT (13 +/- 1) was normal, and when CPR was done during 24 hours, no hypersomnia was found (553 +/- 24). Dysthymic patients showed an abnormal macrostructure of sleep (characterised by an excess of sleep stage I and a decrease of stages 3 and 4), which could be related to their complaint of hypersomnia.

Hypersomnia associated with mood disorders: a new perspective.

Thirty-six subjects affected with hypersomnia associated with mood disorders, 31 with a diagnosis of dysthymia, 4 with a diagnosis of bipolar disorder and one with a diagnosis of major recurrent depression underwent standardized polysomnographic procedures including night 1, MSLT and night 2 (uninterrupted). 36.1% of these subjects had a reduced or intermediate mean sleep latency on the MSLT and 13.8% slept over 9 hr at night. In addition 17 of these subjects underwent prolonged polysomnography during day 2. In comparison with eight subjects affected with idiopathic hypersomnia, mean sleep latency on the MSLT was significantly longer and total sleep time during night 2 and during night 2 plus day 2 was significantly lower in subjects affected with hypersomnia associated with mood disorders. It is concluded that a positive diagnosis of hypersomnia associated with a mood disorder requires both behavioral observation and polysomnography. Among these subjects there may be subjects with well-documented hypersomnia and subjects with anergia facilitating or mimicking sleep.