Biomedical subjects

Daniela Origgi

Publications and source records attributed to Daniela Origgi.

7 recordsLinked to original sources

PubMed2006

Magnetic resonance mammography in the evaluation of recurrence at the prior lumpectomy site after conservative surgery and radiotherapy.

INTRODUCTION: The aim was to assess the value of magnetic resonance mammography (MRM) in the detection of recurrent breast cancer on the prior lumpectomy site in patients with previous conservative surgery and radiotherapy. METHODS: Between April 1999 and July 2003, 93 consecutive patients with breast cancer treated with conservative surgery and radiotherapy underwent MRM, when a malignant lesion on the site of lumpectomy was suspected by ultrasound and/or mammography. MRM scans were evaluated by morphological and dynamic characteristics. MRM diagnosis was compared with histology or with a 36-month imaging follow-up. Enhancing areas independent of the prior lumpectomy site, incidentally detected during the MRM, were also evaluated. RESULTS: MRM findings were compared with histology in 29 patients and with a 36-month follow-up in 64 patients. MRM showed 90% sensitivity, 91.6% specificity, 56.3% positive predictive value and 98.7% negative predictive value for detection of recurrence on the surgical scar. MRM detected 13 lesions remote from the scar. The overall sensitivity, specificity, positive predictive value and negative predictive value of MRM for detection of breast malignancy were 93.8%, 90%, 62.5% and 98.8%, respectively. CONCLUSION: MRM is a sensitive method to differentiate recurrence from post-treatment changes at the prior lumpectomy site after conservative surgery and radiation therapy. The high negative predictive value of this technique can avoid unnecessary biopsies or surgical treatments.

Adult↗

PubMed2005

Survey of computed tomography techniques and absorbed dose in Italian hospitals: a comparison between two methods to estimate the dose-length product and the effective dose and to verify fulfilment of the diagnostic reference levels.

The aim of this study was the production of the first Italian survey of radiation dose in computed tomography (CT) prior to the widespread adoption of multislice CT, in order to have a reference point to facilitate later investigation of dose exposure changes brought by this new CT modality. The collected dose data were compared with diagnostic reference levels (DRLs). The agreement between experimental dose evaluation and Monte Carlo (MC) simulations was investigated. The survey was carried out in 29 Italian hospitals, covered 48 CT scanners and 232 examinations. The dose-length product (DLP) and effective dose (E) values were estimated based on MC simulations for seven clinical protocols using the CT-Dose program. Statistical analysis showed a significant difference (p<0.01) in the DLP between the two methods, with MC values being greater than the experimental ones. For E, the MC values were greater in routine head (8.2%), cervical spine (2.7%) and lumbar spine (2.9%) studies. The weighted CT dose index, the DLP and E were always below the DRLs set by the European Community. This dose survey gives a good but incomplete picture of the Italian CT dose situation and may be useful as a reference baseline for defining clinical multislice protocols in the near future.

Data Collection↗

PubMed2004

MR and CT image fusion for postimplant analysis in permanent prostate seed implants.

PURPOSE: To compare the outcome of two different image-based postimplant dosimetry methods in permanent seed implantation. METHODS AND MATERIALS: Between October 1999 and October 2002, 150 patients with low-risk prostate carcinoma were treated with (125)I and (103)Pd in our institution. A CT-MRI image fusion protocol was used in 21 consecutive patients treated with exclusive brachytherapy. The accuracy and reproducibility of the method was calculated, and then the CT-based dosimetry was compared with the CT-MRI-based dosimetry using the dose-volume histogram (DVH) related parameters recommended by the American Brachytherapy Society and the American Association of Physicists in Medicine. RESULTS: Our method for CT-MRI image fusion was accurate and reproducible (median shift <1 mm). Differences in prostate volume were found, depending on the image modality used. Quality assurance DVH-related parameters strongly depended on the image modality (CT vs. CT-MRI): V(100) = 82% vs. 88%, p < 0.05. D(90) = 96% vs. 115%, p < 0.05. Those results depend on the institutional implant technique and reflect the importance of lowering inter- and intraobserver discrepancies when outlining prostate and organs at risk for postimplant dosimetry. CONCLUSIONS: Computed tomography-MRI fused images allow accurate determination of prostate size, significantly improving the dosimetric evaluation based on DVH analysis. This provides a consistent method to judge a prostate seed implant's quality.

Aged↗

PubMed2003

Brain changes with aging: MR spectroscopy at supraventricular plane shows differences between women and men.

PURPOSE: To assess the effect of aging on the proportions of choline (Cho), creatine, and N-acetylaspartate (NAA) in the brains of elderly women and men. MATERIALS AND METHODS: A transverse plane above the ventricle of the brain was mapped with magnetic resonance spectroscopy. Examinations were performed in 1995-1996 with 271 healthy subjects (age range, 60-90 years; mean age, 73 years) and were repeated 4 years later (1999-2000). Student t tests were used for statistical analysis. RESULTS: Difference analysis of the changes in 4 years (paired data) reproduced the decrease in Cho in women only (2.9% per year, P <.001) that had been indicated with intersubject correlation analyses. Decreases in NAA, though significant in both men and women according to age correlation analyses (P <.01 for both), did not reach significance. The resulting sex difference in the Cho/NAA ratio at a mean age of 77 years, while not yet significant at a mean age of 73 years, was especially manifest in the posterior half of the plane analyzed. CONCLUSION: Increasing sex differences in Cho/NAA ratios in a supraventricular plane indicate that brain metabolite levels differ between women and men at advanced age.

Aged↗

PubMed2003

Analogic versus digital mammographic examination a radiological study of mammary microcalcifications on 52 surgical samples.

PURPOSE: Digital mammography is known to have lower spatial resolution compared to conventional analogic mammography. The aim of this study was to evaluate whether this physical feature could compromise the perception of microcalcifications in radiological findings. MATERIALS AND METHODS: Fifty-two surgical samples of non-palpable breast lesions with microcalcifications were imaged using both techniques. The images were examined by four different radiologists. Data processing was limited to comparing the number of microcalcifications found on the conventional and digital images, in both standard and magnified modality. The cases were classified into 3 groups according to the number of calcifications demonstrated in the surgical sample: less than 10, 10 to 30, and more than 30. The differences in the count of microcalcifications with the two acquisition modalities were evaluated with the Kappa test. In order to compare the differences we synthesised by percentage those cases exhibiting a larger or lesser number of calcifications. RESULTS: The Kappa test was 0.546 in standard analogic vs standard digital, 0.582 in magnified analogic vs magnified digital, 0.828 in standard analogic vs magnified analogic and 0.492 in standard digital vs magnified digital. The most significant results were observed on comparing the magnifications produced with the two modalities: in 25% of cases, digital magnification detected more calcifications than did traditional magnification. The number of cases where standard digital images allowed the detection of more calcifications than standard analogic images was significant, although less important (17.8%). CONCLUSIONS: The study was able to provide data that confirm the overall equivalence of the two techniques, as far as subtle mammographic findings (such as microcalcifications) are concerned. In particular, as applied to the series we examined, there is a cautious advantage in favour of the digital technique. More clinical studies, on larger series, will be necessary for a further and more thorough comparison of the two techniques, so that the results might be consistently useful in clinical practice.

Breast Diseases↗

PubMed2002

A wavelet packets decomposition algorithm for quantification of in vivo (1)H-MRS parameters.

In this paper a novel method for the extraction of magnetic resonance spectroscopy (MRS) parameters is presented. The method applies the traditional time-domain linear prediction singular value decomposition (LPSVD) on the set of orthonormal sub-signals obtained by wavelet packets (WP) decomposition of the original free induction decay (FID) signal. Using the properties of WP the desired, optimal, sub-band FID decomposition is obtained and used to progressively separate the different metabolic components in distinct sub-bands. A pseudo-optimal WP tree is obtained using the minimum description length (MDL) criteria. The proposed algorithm preserves all the advantages of the traditional LPSVD method, but the WP decomposition considerably improves the LPSVD performances in the presence of noise. The paper addresses this aspect in details by comparing the innovative sub-band and the traditional full-band approaches. Algorithms are tested on simulated signals that mimic real MRS data.

Algorithms↗

PubMedDate not supplied

Digital mammography: quality and dose control.

PURPOSE: For almost 3 years, Radiologists and Physicists from Padova and Ferrara Universities have collaborated together, with the aim of collecting and comparing experimental data useful to define the most significant parameters for quality controls in digital mammography. Successively, radiologists and physicists working in other sites where a digital mammography unit was installed joined the work-group. MATERIALS AND METHODS: In this study we report the results obtained from measurements of linearity, uniformity, short- and long-term reproducibility, AEC stability performed on 5 digital equipment by using a simple test object. X-ray beam quality and tube yield were preliminarily checked in such a way that possible uncertainties of digital system responses could be separated from those due to differences among X-ray tubes. RESULTS: Results showed that the equipment considered, comparable in terms of both beam quality (HVL) and tube yield, always displayed linear response and reproducibility errors lower than 5%. Uniformity was very good and the grey level compensation as a function of exposure parameters remained within 5%. Differences in choice of parameters by exposure control system (AOP) were emphasised, especially for crossing between track/filter combinations (from Mo/Mo to Mo/Rh and from Mo/Rh to Rh/Rh); those differences were attributed to the +/-2 mm tolerance of breast thickness measurement (mechanically obtained) greater than the AOP tolerance (+/-1 mm). DISCUSSION AND CONCLUSIONS: Obtained results can be useful, as comparison and reference values, for users employing a digital mammography unit of the same kind reported in this paper. Moreover, the same results could be used as "orientation" also by other users having different digital mammography technologies, whose operation should be nevertheless specifically studied and understood in order to find the most useful parameters for quality controls. The acquired experience clearly showed us that years of investigations will be necessary in order to be able to write reliable protocols. This should induce people to contemplate the necessity of not improvising "theoretical" protocols, that are unreliable and dangerous for their negative clinical implications.

Humans↗