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Otosclerosis
Published in Charles Theisler, Adjuvant Medical Care, 2023
Otosclerosis or otospongiosis is an abnormal overgrowth of spongy bone tissue that forms around the innermost bone in the middle ear known as the stapes, or stirrup, and basically locks it in place. This can result in hearing loss, especially of low pitched sounds, or not being able to hear a whisper. Some patients may also experience balance problems or tinnitus. Middle-aged Caucasian women are most at risk.
CT Planning and Guidance for Transcatheter Interventions
Published in Paul Schoenhagen, Frank Dong, Cardiac CT Made Easy, 2023
TAVR planning includes evaluation of the anatomic suitability of aortic annulus size and vascular access anatomy, which facilitates the selection of the correct prosthesis size. MDCT is considered the most reliable modality for identification of anatomic features that are contraindications for TAVR and/or associated with increased risk of complications. MDCT acquisition protocols for planning TAVR should include a cardiac scan including the ascending aorta and a vascular overview of the entire thoracoabdominal aorta including the subclavian vessels and the femoral artery bifurcation. In general ECG-gated spiral scanning with wide pulsing and retrospectively gated reconstruction is recommended for the heart and aortic root/annulus. Measurements at the annulus and root are typically performed in systolic reconstructions (Figures 7.3 and 7.4). The vascular overview is typically acquired with non-gated protocols. Alternatively, a single high-pitch spiral acquisition protocol has been reported to provide good results with reduced contrast and radiation exposure.74
Beta and Alpha Particle Autoradiography
Published in Michael Ljungberg, Handbook of Nuclear Medicine and Molecular Imaging for Physicists, 2022
Anders Örbom, Brian W. Miller, Tom Bäck
Using CCD or CMOS detectors, not for imaging visible photons, but rather for directly registering charge left by ionizing radiation in the pixels of the detector, was employed by a University of Surrey group headed by J. Cabello and detailed in a 2007 paper [60]. This group used room temperature CCD and CMOS detectors to image radiation from 14C and 35S, both from standards and tissue samples as can be seen in Figure 30.8. The detectors have a pixel pitch of 22–25 µm and very low noise levels. The paper also details imaging of 3H but, in that case, the sample was applied to the backside of a CCD that had been back-thinned using acid to reduce the inactive layer where low-energy electrons could be stopped before detection. Although energy information can be read out with these detectors, the CMOS system has such a thin detection layer that it acts mainly as a dE/dx detector, not registering the whole energy of most electrons. In a later paper, Cabello and colleagues also showed 3H imaging using a similarly back-thinned CMOS detector [61].
Determination of the acoustic properties of Turkish ling six sounds used in speech tests
Published in Speech, Language and Hearing, 2022
Çigdem Onen, Guven Mengu, Senay Altinyay, Yusuf Kemal Kemaloglu
The acoustic properties (intensity (in decibels), F0, and formants (f1, f2, and f3)) of the <a>, <u>, and speech sounds were calculated using the Praat software. The analyses were performed automatically by the script, which was then added to the Praat software (Boersma & Weenink, 2017; Kılıç, 2014; Remijsen, 2004). The following standard settings, which Kılıç (2012) suggested, were used: a low F0 of 50 Hz for root mean square (RMS) amplitude, a frequency range of 50–500 Hz for the pitch parameters, a maximum formant frequency of 5500 Hz and a window length of 0.025 for the formant parameters. The formants were measured using the Burg algorithm available in Praat software (Boersma & Weenink, 2017) for five formants, and a mean was selected to measure the mean values of segments.
Coronary CT angiography: a guide to examination, interpretation, and clinical indications
Published in Expert Review of Cardiovascular Therapy, 2021
Filippo Cademartiri, Giancarlo Casolo, Alberto Clemente, Sara Seitun, Cesare Mantini, Eduardo Bossone, Luca Saba, Nicola Sverzellati, Stefano Nistri, Bruna Punzo, Carlo Cavaliere, Ludovico La Grutta, Giovanni Gentile, Erica Maffei
Retrospective ECG gating (low pitch spiral acquisition) is the first method developed at the very beginning of Cardiac applications of CT. It is based on a spiral continuous acquisition with a fixed speed of motion of the table through the gantry (Feed = mm/s). In this case the pitch is very low and there is a very high oversampling of data with multiple spirals around the same geometrical point within the patient. Assuming that pitch = 1 is the standard choice for body imaging (with a wide range depending on body regions and scan purpose of 0.7–1.5), consider that retrospective ECG gating relies on a pitch range of 0.15–0.35. This means a geometric oversampling of 7 times to 3 times. In other words, we scan the same physical point 3–7 times through the cardiac cycle and this is why it is possible to retrospectively reconstruct different phases of cardiac cycle (in principle all of them).
High-intensity focused ultrasound in the treatment of glaucoma: a narrative review
Published in Expert Review of Ophthalmology, 2021
Michele Figus, Francesco Sartini, Giuseppe Covello, Chiara Posarelli
Ultrasound is defined as any sound higher in pitch than that detectable by the human ear, ~25 kHz (thousands of cycles per second). However, medical ultrasonography relies on frequencies in the MHz (millions of cycles per second) range. Like light, ultrasound can be focused, opening the possibilities to therapeutic applications [1]. Initially proposed to treat different central nervous system diseases [2,3], high-intensity focused ultrasound (HIFU) technology was also introduced in oncology to produce prolonged hyperthermia (elevation of tissue temperature to 43°C for 1 h) in the entire cancer volume, obtaining a regression of the disease [4]. Nowadays, many pathologies are treated with HIFU, such as prostatic cancer [5], liver cancer [6], placenta accreta spectrum [7], and benign thyroid nodules [8].