Background Auditory and non‐auditory safety concerns associated with the appreciable sound levels inherent to magnetic resonance imaging (MRI) procedures exist for neonates. However, current gaps in knowledge preclude making an adequate risk assessment. Purpose To measure acoustic exposure (duration, intensity, and frequency) during neonatal brain MRI and compare these values to existing hearing safety limits and data. Study Type Phantom. Phantom Cylindrical doped water phantom. Field Strength/Sequence Neonatal brain protocols acquired at 1–3 T. Scans in the model protocol included a diffusion tensor imaging scan, a gradient echo, a three‐dimensional (3D) fast spin echo, 3D fast spin‐echo single‐shots, a spin echo, a turbo spin echo, a 3D arterial spin labeling scan, and a susceptibility‐weighted fast spin‐echo scan. Assessment The sound pressure levels (SPLs), frequency profile, and durations of five neonatal brain protocols on five MR scanners (scanner A [3 T, whole‐body], scanner B [1.5 T, whole‐body], scanner C [1 T, dedicated neonatal], scanner D [1.5 T, whole‐body], and scanner E [3 T, whole‐body]) located at three different sites were recorded. The SPLs were then compared to the International Electrotechnical Commission (IEC) hearing safety limit and existing data of infant non‐auditory responses to loud sounds to assess risk. Statistical Tests Mann‐Whitney U test to assess whether the dedicated neonatal scanner was quieter than the other machines. Results The average level A‐weighted equivalent value (LAEQ) across all five MR scanners and scans was 92.88 dBA and the range of LAEQs across all five MR scanners and scans was 80.8–105.31 dBA. The duration of the recorded neonatal protocols maintained by neonatal scanning facilities (from scanners A, B, and C) ranged from 27:33 to 37:06 minutes. Data Conclusion Neonatal protocol sound levels straddled existing notions of risk, exceeding sound levels known to cause non‐auditory responses in neonates but not exceeding the IEC MRI SPL safety limit. Level of Evidence 5 Technical Efficacy Stage 5

Corsi-Rosenthal (CR) boxes efficiently and cost-effectively clean the air in an environment; however, the constant broadband noise they produce is a concern. Measuring sound power levels of CR boxes would provide a metric for noise comparisons, but traditional sound power level measurements are not readily adaptable for the average consumer. Measuring the sound power level in a free field over a reflecting plane is an accurate method but is complicated and expensive involving multiple microphones in an anechoic chamber (ANSI S12.54-1999). The Comparison Method is a simpler procedure that can be performed directly in the environment of interest but requires an expensive calibrated source (ANSI S12.57-2011). To allow for simple and inexpensive sound power measurements of CR boxes, we used ANSI S12.54-1999 to measure the sound power of a $30 hand vacuum (Black+Decker HNVC115JB06) to explore its potential as a DIY calibrated source for the Comparison Method. The reproducibility and uncertainty of this DIY method will be discussed. The DIY method has the potential to enable noise comparison of air cleaners or other devices for the average consumer.

No abstract

The magnetic resonance (MR) scan is a standard means to image the human body that produces significant sound pressure levels. Steps have been taken to explore and mitigate this threat for the adult patient, but now, it is becoming standard practice to use MR scanners on neonates, who are believed to be more sensitive than adults to loud sounds. We present (1) a survey of the neonatal MR practices of hospitals in the DC area, (2) details of the sound levels produced during neonatal scan protocols, and (3) an appraisal of the threat level to the neonatal patient based on our findings and the current literature surrounding neonatal hearing.