Search PubMed⌕ Search

Biomedical subjects

M Mazzoli

Publications and source records attributed to M Mazzoli.

44 records · Page 3Linked to original sources
PubMedDate not supplied

Clinical applicability of transient evoked otoacoustic emissions: identification and classification of hearing loss.

The study aimed at the development of a clinically applicable methodology that could: (1) discriminate transient evoked otoacoustic emission (TEOAE) recordings from normal hearing or hearing impaired individuals; (2) classify the nature of the hearing loss as conductive or as cochlear, and (3) define clear-cut TEOAE clinical criteria. A classification algorithm based on a multivariate discriminant analysis of fast Fourier transform data from recordings evoked by click stimuli of 50 +/- 2, 62 +/- 2, 68 +/- 2 and 80 +/- 2 dB SPL was used to discriminate 302 normal subjects from 383 subjects suffering from mild to moderate hearing losses. The best discriminant model (QDF80) produced a sensitivity of 93.8% and a specificity of 79.4%. When extra correlation criteria were serially applied to the classification outcome, the specificity was increased to 85.3%, but the sensitivity was marginally decreased to 91.7%. The classification of the correctly identified hearing-impaired cases yielded 93.8% identification of conductive and 75.1% identification of cochlear cases. A sensitivity analysis of the misclassified hearing-impaired cases suggested that the TEOAE spectra are well correlated with the 2-kHz but poorly correlated with the 4-kHz octave frequency.

Acoustic Stimulation↗
PubMedDate not supplied

Identification of hearing loss using TEOAE descriptors: theoretical foundations and preliminary results.

It was hypothesized that the relationship between transiently evoked otoacoustic emission (TEOAE) signals and the functional status of the outer hair cells provides an opportunity to design a clinical procedure that can evaluate the normality of cochlear function. To discriminate normal subjects from subjects suffering from mild to moderate hearing loss (HL), it was assumed that every subject population has unique and discrete TEOAE signal descriptors. The main classification algorithm was based on a discriminant analysis of raw fast Fourier transform data. When it was applied to a sample set of TEOAE recordings (from 56 normal and 68 HL subjects) elicited from 68-dB SPL click stimuli, it correctly identified 90.2% of the normal and 87.5% of the HL subjects. The same algorithm yielded an 85.5% discrimination between TEOAE recordings from conductive and cochlear HL cases.

Acoustic Stimulation↗
PubMedDate not supplied

Audiometric patterns of genetic non-syndromal sensorineural hearing loss.

Sixty-five families with non-syndromal sensorineural hearing loss (NS-SNHL) of genetic aetiology were subtyped according to Gorlin et al. Individual audiogram shapes were also classified in order to detect inter- and intra-familial variations. In 48 families with an Autosomal Dominant (AD) inherited form, 26 exhibited the features of (high-frequency) progressive NS-SNHL, 12 those of mid-frequency NS-SNHL, 5 were affected by congenital low-frequency NS-SNHL; 1 kindred showed a progressive low-frequency pattern and another 1 a unilateral NS-SNHL; only 3 kindreds were affected by severe congenital NS-SNHL. Autosomal Recessive (AR) inherited forms were composed of 9 kindreds with severe congenital NS-SNHL, and 7 with moderate congenital NS-SNHL. One X-linked form was identified. AD- and AR-inherited NS-SNHL differed significantly both in severity of hearing impairment and in audiogram shapes. With few exceptions, in each family classified according to Gorlin, most of the affected subjects shared the same audiogram profile. Intrinsic progression of the disease versus ageing was studied in the larger subtype of individuals with the high-frequency loss. Gorlin's classification still remains the best system to classify NS-SNHL, and can provide a broad base to separate a very heterogeneous group of disorders. Results obtained in gene mapping in single large human families or in homologous gene search could be tested in our families. For some of them, namely those with high frequency progressive and low-frequency NS-SNHL, testing should already be feasible.

Adult↗
PubMedDate not supplied

Hearing in the elderly: a population study.

An epidemiological study comparing speech audiometry with self-assessed hearing disability and an analysis of other factors influencing the quality of life was conducted. In the Veneto region (Italy), a representative sample of 2700 independently living individuals of 65 years of age and older was selected for the study. All participants were administered a comprehensive questionnaire and a brief examination at their home, including a general physical examination, speech audiometry, Sanders' Speech Disability test, part I and III, Mini Mental State Examination, CES-D scale for depression, visual acuity, self-reported diseases and physical function. Auditory function was worst in the older individuals: auditory performance was within acceptable limits up to the 75-79 age group, while it rapidly deteriorates in the older groups. This trend is consistent with self-reported auditory disability (Sanders' test). A detailed analysis of the type of errors made in the speech audiometry was conducted for each subject. Speech audiometry is a good indicator of real hearing difficulties faced by the elderly, and it might be preferred to pure-tone audiometry, since hearing deficits with age are not always limited to an increased detection threshold, but include other aspects of hearing such as distortion of sounds, comprehension of speech and noise discrimination.

Age Distribution↗
PubMedDate not supplied

Multidetector CT-urography in the study of urological complications in renal transplant.

PURPOSE: To evaluate the value of CT-urography in the diagnosis and follow-up of the urological complications of renal transplantation. MATERIALS AND METHODS: We performed 19 CT-urography examinations (3 of which were follow-up) on 15 patients by using a spiral multislice CT scanner and multiplanar reconstructions. The examinations were carried out directly after administration of 100 ml of iodinated contrast medium by slow iv infusion, with acquisitions starting 5 minutes after the end of the infusion. Surgery was regarded as the gold standard for the diagnosis of urological complications in the operated patients, whereas in patients who had undergone medical therapy or stent placement the gold standard was 1 month ultrasound and clinical follow-up with evaluation of diuresis and renal function. RESULTS: Between January 1999 and December 2001 a total of 210 kidney transplantations were performed at our hospital. There were 34 urological complications in 28 patients with a 16.1% prevalence, consistent with the major international studies. The complications detected were 14 urine leaks and 19 ureteral obstructions secondary to stones, oedema, blood clots and stricture. We observed one case of reflux in the allograft ureter. Fourteen out of 16 CT-urography examinations yielded important clues for the diagnosis of urological complications in kidney allografts, completely replacing standard urography. In particular, CT-urography correctly detected 5 urinary fistulas by demonstrating iodinated contrast material leaks along the ureteral tract, and 8 cases of obstructive uropathy due to different causes (1 submucosal tunnel edema, 1 blood clot, 1 stone and 5 cases of ureteral stricture). One case of urinary fistula and one of obstructive uropathy were not detected. DISCUSSION AND CONCLUSIONS: CT-urography proved to be an important diagnostic tool in the evaluation of urological complications of kidney allografts, showing a diagnostic accuracy over 90%; it is useful for confirming the type and site of urological lesions, and therefore to provide guidance for a targeted surgical approach. Compared with excretory urography, which is no longer used in this diagnostic field, CT-urography is more complete and precise as it provides information not only about the urinary tract, but also about the kidney parenchyma and pararenal fluid collections. The only disadvantage, which limits its use to selected cases, is the risk associated with the use of iodinated contrast agents in patients with impaired renal function.

Contrast Media↗
PubMedDate not supplied

Spiral CT evaluation of pulmonary emphysema using a low-dose technique.

PURPOSE: To evaluate the diagnostic accuracy and clinical acceptability of low-dose spiral CT for determining pulmonary volumes and emphysema extension in patients with pulmonary emphysema, in comparison with studies based on spiral CT at conventional dose. MATERIALS AND METHODS: We prospectively evaluated eighteen patients, current or former smokers, with a clinical diagnosis of chronic obstructive pulmonary disease. All the patients underwent: HRCT with three scans at predetermined levels; quantitative spiral CT, with two inspiratory scans, one conventional scan at 240 mA, and the second one a low-dose scan at 80 mA. We used the following parameters: 120 kV, rotation time 0.8", scan time less than 20" (single inspiratory breath-hold), layer thickness 7.5 mm, pitch 6 (high speed), interpolation algorithm at 180 degrees. A 3D reconstruction was performed, with segmentation of the lungs and automatic quantification of pulmonary volumes. We compared the volumes of absolute and percent emphysema and the ratings of the dose delivered to the patient (CTDIw and DLP) obtained with the two spiral CT scans with each other and with the respiratory function tests. RESULTS: The average total lung capacity (TLC) obtained by conventional-dose spiral CT (CTs1) was 6889.4 cc (SD +/-1813.2), and the capacity with low-dose spiral CT (CTs2) was 6929.4 cc (SD +/-1811.6). The percentage of emphysema was 39.7% (range: 2.2-63.5%; SD: +/-19.9) for the CTs1 and 41.1% (range: 2.1-66.4%; SD: +/-20). The CTDIw corresponding to CTs1 was 12.2 mGy (range: 11.9-16.4; SD: +/-1), the one corresponding to CTs2, 3.6 mGy (range: 3.6-4.9; SD: +/-0.3). The DLP corresponding to CTs1 was 391.7 mGy x cm (range: 333.3-518.9; SD: +/-46.7), the one corresponding to CTs2 was 117.8 mGy x cm (range: 100.3-156; SD: +/-14). As for the respiratory function tests, the total lung capacity (TLC) obtained by body plethysmography was 7061 cc (SD: +/-2029.7); the percent TLC was 115.9 (range: 66-165; SD: +/-27.6), the forced expiratory volume at one second (FEV1%, percentage of predicted value) was 46.7% (range: 17-123; SD: +/-27.3), residual volume (RV%) as a percentage of predicted value was 186.3 (range: 84-359; SD: +/-80.7), the Tiffeneau index (TI) was 46% (range: 25-71; SD: +/-15.7). We observed a very significant correlation between radiological and functional TLC for both CT methods. The percentage scores for emphysema obtained with the two methods correlated significantly with the functional indexes. The pixel index of CTs1 correlated with TLC% (r=0.87; p<0.0001), FEV1% (r=-0.53; p<0.02), RV% (r=0.76; p=0.004), TI (r=-0.79; p=0.0001). The pixel index of CTs2 correlated with TLC% (r=0.87; p<0.0001), FEV1% (r=-0.56; p=0.01), RV% (r=0.78; p=0.003), TI (r=-0.8; p=0.0001). The adoption of the method with low tube current entailed a highly significant reduction in the estimated dose delivered to patients (CTDIw and DLP) with r=0.9 and p < 0.0001. DISCUSSION AND CONCLUSIONS: Quantitative low-dose spiral CT is a very good method to quantify pulmonary volumes and calculate the extension of the anatomic emphysema. The reduction of mA from 240 to 80 lowers the estimated dose by 30%, without compromising the accuracy of the results. Our study achieved a highly significant correlation between the results obtained with the two spiral CT techniques and between these results and the respiratory function tests. In clinical practice, the easiest way to reduce the dose in spiral CT of the lung is to reduce the tube current. The low-dose method allows a significant reduction in radiation exposure. Further studies are required to establish to what extent the dose can be reduced without increasing in quantum noise and thereby compromising the quality of the study.

Adult↗