Publications & Research
Challenges and Regulatory Considerations in the Acoustic Measurement of High-Frequency (>20 MHz) UltrasoundOctober 2013
at high ultrasound frequencies (>20 MHz) in the context of regulatory considerations
contained in the US Food and Drug Administration industry guidance
document for diagnostic ultrasound devices. Show Preview
Error sources in the acoustic measurement, including hydrophone calibration and spatial averaging, nonlinear distortion, and mechanical alignment, are evaluated, and the limitations of currently available acoustic measurement instruments are discussed. An uncertainty analysis of acoustic intensity and power measurements is presented, and an example uncertainty calculation is done on a hypothetical 30-MHz high-frequency ultrasound system.
Researchers from Ludwig Maximilians University in Munich found that patients with detectable vascular changes on whole-body MRI faced a 20% chance of a major adverse cardiac and cerebrovascular event (MACCE) in three years. The chance increased to 35% for six years.
In addition, no patients in the study with normal whole-body MRI results experienced such an adverse event (Radiology, September 10, 2013).
“Patients without any pathologic findings on whole-body MR experienced no adverse events over the six-year follow-up period,” lead author Dr. Fabian Bamberg, from the university’s department of radiology, wrote in an email to AuntMinnie.com. “This is specifically interesting as the population had on average 10 years of diabetes.”
Patients with good whole-body MRI results “may be reassured and encouraged that their therapeutic regimen is optimal,” Bamberg added. “Conversely, the event rate among diabetics with pathologic findings was surprisingly high, indicating that more intensified treatment may be required.”
Researchers from the University of California, Los Angeles (UCLA) developed the Dementia Prognosis Index (DPI) software as a way of quantifying information derived from PET scans and improving the modality’s ability to predict whether a patient will develop Alzheimer’s disease.
Study results showed that the PET-derived DPI scores provided more conclusive information for half of the participants in a group whose initial PET scans were indeterminate. Among those whose prognostic status changed, 77% were deemed likely to develop dementia. Conversely, among those whose scans remained indeterminate, only 21% progressed to dementia three years later.
MR images confirmed that women with the condition, known as Mayer-Rokitansky-Kuster-Hauser (MRKH) syndrome, may have large uteri with no conventional structure (defined as rudimentary uteri in this study) that can mimic normal postpubertal uteri. By discovering MRKH syndrome in young women, MRI can prompt the diagnosis of the disorder at an earlier age, avoid an invasive procedure, and lead to appropriate counseling.
“It is a common misconception that women with MRKH syndrome have no uterus, even though the presence of rudimentary uterine structures or buds is well described in [previous] literature,” wrote lead author Dr. Margaret Anne Hall-Craggs and colleagues. “Our study showed rudimentary uteri in nearly 93% of patients, which was very similar to laparoscopic findings [in previous research]” (Radiology, August 13, 2013).
The finding suggests a potential benefit of more accurate diagnosis of Alzheimer’s so that it can be ruled out sooner, said lead author Noam Kirson, PhD, manager at Analysis Group, an economic, financial, and strategy consultancy in Boston.
“We see that a considerable share of these Medicare beneficiaries with Parkinson’s disease and vascular dementia have a history of misdiagnosis of Alzheimer’s disease, and we also see that those who were misdiagnosed with Alzheimer’s disease incur significantly higher medical costs up to and including the period of their correct diagnosis,” Dr. Kirson concluded.