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J Nori

Publications and source records attributed to J Nori.

10 recordsLinked to original sources
PubMed2006

Shape analysis of microcalcifications using Radon transform.

Microcalcifications are one of the early signs of breast cancer, and they are of great importance for an early diagnosis. Moreover, the spatial distribution and the shape of the microcalcifications have a significant impact in medical practice to evaluate the probability of malignancy of the tumor. In this work a method, performing computer-aided classification of the shape of calcifications accordingly to the classification scheme proposed by Le Gal, is presented. In the first stage, in order to remove mammographic background, the image is preprocessed with a matched filter, designed by modeling the microcalcifications as Gaussian spots and the image as a Fractional Brownian Motion. Afterwards, morphology of spots has been evaluated using two different sets of parameters. The first set utilizes the moments of inertia of the second and third order to compute a set of features, which are invariant to rotations and translations of the image. The second set of parameters is derived from the evaluation of the Radon transform, as computed along eight axes. The results of the Radon transform are used to associate to each lesion a set of features, which are invariant to rotation and scaling of the image. In the final stage, a multilayer neural network has been used to assign each microcalcification to the classes introduced by Le Gal. The topology of the neural network is the same for both sets of descriptors, in order to allow comparison of the discriminative power of the two feature sets. Experimental results obtained with the proposed method from a set of digitized mammograms are reported and discussed.

Algorithms↗
PubMed2004

Detection of single and clustered microcalcifications in mammograms using fractals models and neural networks.

Microcalcifications (microCas) are often early signs of breast cancer. However, detecting them is a difficult visual task and recognizing malignant lesions is a complex diagnostic problem. In recent years, several research groups have been working to develop computer-aided diagnosis (CAD) systems for X-ray mammography. In this paper, we propose a method to detect and classify microcalcifications. In order to discover the presence of microCas clusters, particular attention is paid to the analysis of the spatial arrangement of detected lesions. A fractal model has been used to describe the mammographic image, thus, allowing the use of a matched filtering stage to enhance microcalcifications against the background. A region growing algorithm, coupled with a neural classifier, detects existing lesions. Subsequently, a second fractal model is used to analyze their spatial arrangement so that the presence of microcalcification clusters can be detected and classified. Reported results indicate that fractal models provide an adequate framework for medical image processing; consequently high correct classification rates are achieved.

Algorithms↗
PubMed2000

[Breast neoplasms detected only with ultrasonography: incidental finding or clinical evidence?].

INTRODUCTION: Mammography is the only technique of proven efficacy in the early diagnosis of breast cancer, even though its sensitivity is much lower in breasts that are dense or with a high parenchymal-stromal component. In the past malignant breast nodules detected at US in patients with negative mammographic and physical findings were considered incidental findings, but more recent papers report increasing numbers of breast cancers detected only at US. PURPOSE: We investigated the yield of US performed as a diagnostic complement in asymptomatic women with mammographic findings that were either negative or poorly readable because of dense breast. MATERIAL AND METHODS: We examined 13 women 37 to 55 years old (mean 47): 9 of them were asymptomatic and 4 had poorly specific physical findings. The patients underwent physical examination, mammography, US, microhistologic biopsy with 14G needles under US guidance and surgery. RESULTS: Fourteen breast lesions 7.0-15 mm in diameter were detected only by US. Mammography (2 or 3 standard views) was negative in all cases. The lesions detected only by US (10% of all carcinomas) were typified with US-guided needle biopsy and finally confirmed surgically. DISCUSSION AND CONCLUSIONS: Though obtained in a small series, our results seem to suggest that US should be included in the diagnostic work-up, especially of women with dense breast. Also, any hypoechoic lesion detected at breast US in clinically asymptomatic women with negative mammographic findings should be further investigated with US, needle aspiration or core biopsy to make the final diagnosis.

Adult↗
PubMed1998

[Percutaneous biopsy in the definition of breast lesions: fine needle vs. 14-gauge].

INTRODUCTION: Any breast lesion/abnormality detected at mammography must be characterized as (non)-neoplastic before surgery. Fine needle aspiration cytology (FNAC) permits a precise diagnosis in over 70% of cases but exhibits many inadequate, false negatives or questionable findings. This makes surgical biopsy mandatory in many cases. An alternative is offered by fine needle biopsy (FNB: 16-18 G needles) or by large core biopsy (LCB: 14 G needles), which procedures can reduce the number of questionable diagnoses with no major discomfort or side-effects for the patient. MATERIAL AND METHODS: January, 1996, to October, 1997, we performed 422 microhistologic biopsies on breast lesions at the Unità Integrata di Senologia, Azienda Ospedaliera Careggi, Florence, Italy. 383 of these lesions were nonpalpable. FNB was performed in 221 cases and LCB in 201. Most biopsies (65%) were carried out under US guidance and some others (25%) under stereotactic guidance. RESULTS: Microhistologic biopsy allowed accurate lesion characterization in most cases, even though LCB obviously performed much better. Samples were inadequate in 5.88% of cases with FNB and only in 2.98% of cases with LCB. The false negative rate was 1.92% for FNB and 0.99% for LCB. Surgical biopsy was needed for an unquestionable diagnosis only in 9.5% of FNB and 3.9% of LCB cases. CONCLUSIONS: Our results confirm the literature data on how LCB can be considered a valid alternative to surgical biopsy (and, to some extent, to FNAC); in particular, its advantages are: moderate invasiveness, little patient discomfort and high diagnostic accuracy. Moreover, the procedure is short (5-10 minutes) and costs much less than surgical biopsies (1/2 to 1/4).

Adult↗
PubMed1991

[Role of magnetic resonance in the staging of endometrial carcinoma].

Biopsy is the technique of choice for the definitive diagnosis of endometrial carcinoma. Since lymphatic tumor spread has been demonstrated to depend on the degree of myometrial involvement, the definition of the latter with imaging techniques may significantly affect both prognosis and therapy. We investigated, by means of MR imaging at 0.5 T, 14 patients with endometrial carcinoma, to assess both tumor stage and myometrial involvement. FIGO staging system was employed, and M parameter evaluated (M0 = no myometrial involvement; M1 = involvement confined to the inner third; M2 = involvement confined to the middle third; M3 = involvement of the whole myometrium). Another parameter was the characteristic high signal of the tumor on PD and T2W images. The patients were then operated and MR information was correlated with surgical findings. Overall diagnostic accuracy of MR imaging was 85.7% in tumor staging, and 92.2% in defining M parameter. Tumor spread into adnexa and into cervical canal was poorly demonstrated by MR imaging.

Aged↗
PubMedDate not supplied

[Histologic microbiopsy with 14 G needle in the diagnosis of breast lesions. Experience with 1000 cases].

PURPOSE: We report our experience with large core biopsy (LCB: 14-Gauge needles) of questionable or suspicious breast lesions detected at mammography and/or US. All biopsies were performed under instrumental guidance. We also report on technique, costs, time, advantages and disadvantages of the method and, finally, give precise indications on when and why large core biopsy is needed. MATERIAL AND METHODS: From january 1996 to may 2000 we performed 1000 microhistologic biopsies on breast lesions at the Unità Integrata di Senologia, Azienda Ospedaliera Careggi, Florence; 650 (65%) were non palpable lesions. Large core needles were used (14-Gauge caliber). In the majority of cases (70%) we used US guidance, in the others a stereotactic guidance was employed. RESULTS: Microhistologic biopsy allowed accurate characterization in most cases. Inadequate samples were obtained in 15 cases. The false negative rate was 6%. Surgery was needed to characterize the lesion unquestionably in 13 cases only. CONCLUSION: In agreement with literature reports, our results confirm large core biopsy as an adequate alternative to surgical biopsy and, to some extent, to FNAC, thanks to its moderate invasiveness, low costs, short execution time, little patient discomfort and high sensitivity (93.98%) and specificity (99.7%).

Biopsy, Needle↗
PubMedDate not supplied

[Role of computerized tomography in the pre-second look re-staging of neoplasms of the ovary].

Twenty-five patients with ovarian carcinoma who had been operated and treated with chemotherapy underwent clinical examination and CT before reintervention (second-look laparotomy) to detect the presence of eventual recurrences. The prediction of recurrence based on CT and clinical findings was compared with the surgical findings at reintervention. CT proved to be more accurate than clinical examination in detecting recurrences; this was especially true for masses in the abdominal cavum, with the exception of small peritoneal nodules. The authors suggest the use of CT for staging the patients candidate to reintervention. This might help to avoid reintervention in patients with persistent disease and to plan treatment.

Adult↗