Biomedical subjects

Catherine W Piccoli

Publications and source records attributed to Catherine W Piccoli.

7 recordsLinked to original sources

PubMed2003

Classification of breast masses in ultrasonic B scans using Nakagami and K distributions.

Classification of breast masses in greyscale ultrasound images is undertaken using a multiparameter approach. Five parameters reflecting the non-Rayleigh nature of the backscattered echo were used. These parameters, based mostly on the Nakagami and K distributions, were extracted from the envelope of the echoes at the site, boundary, spiculated region and shadow of the mass. They were combined to create a linear discriminant. The performance of this discriminant for the classification of breast masses was studied using a data set consisting of 70 benign and 29 malignant cases. The Az value for the discriminant was 0.96 +/- 0.02, showing great promise in the classification of masses into benign and malignant ones. The discriminant was combined with the level of suspicion values of the radiologist leading to an Az value of 0.97 +/- 0.014. The parameters used here can be calculated with minimal clinical intervention, so the method proposed here may therefore be easily implemented in an automated fashion. These results also support the recent reports suggesting that ultrasound may help as an adjunct to mammography in breast cancer diagnostics to enhance the classification of breast masses.

Adult↗

PubMed2003

ROC analysis of ultrasound tissue characterization classifiers for breast cancer diagnosis.

Breast cancer diagnosis through ultrasound tissue characterization was studied using receiver operating characteristic (ROC) analysis of combinations of acoustic features, patient age, and radiological findings. A feature fusion method was devised that operates even if only partial diagnostic data are available. The ROC methodology uses ordinal dominance theory and bootstrap resampling to evaluate A(z) and confidence intervals in simple as well as paired data analyses. The combined diagnostic feature had an A(z) of 0.96 with a confidence interval of at a significance level of 0.05. The combined features show statistically significant improvement over prebiopsy radiological findings. These results indicate that ultrasound tissue characterization, in combination with patient record and clinical findings, may greatly reduce the need to perform biopsies of benign breast lesions.

Age Factors↗

PubMed2003

Malignant and benign breast tissue classification performance using a scatterer structure preclassifier.

Benign and malignant breast tissue classification is examined for generalized-spectrum parameters computed from RF ultrasound data when a preclassification of subregions based on general scattering properties is performed. Results using a clinical database of 84 patients show statistically significant improvements (over 10% in receiver operation characteristic (ROC) areas) when only coherent scatterer subregions are used as compared to using all subregions within the region of interest.

Algorithms↗

PubMed2003

Computer-aided classification of breast masses in ultrasonic B-scans using a multiparameter approach.

Classification of breast masses in ultrasonic B-scan images is undertaken using a multiparameter approach. The parameters are generated on the basis of a non-Rayleigh statistic model of the backscattered envelope from the breast tissue. They can be computed automatically with minimal clinical intervention once the location of the mass is known. A new discriminant is developed that combines these parameters linearly. It is seen that this new discriminant performs classification of masses into benign or malignant better than the classification by any one of the individual parameters. The data set studied consisted of 99 cases (70 patients with benign masses and 29 patients with malignant masses). The areas under the receiver operating characteristic (ROC) curves (Az) and statistical attributes of the areas were studied to establish the enhancement in performance. The Az value after combining all the parameters was found to be 0.8701. Upon combining this parameter with the level of suspicion (LOS) scores of a radiologist, the performance is further enhanced with an area under the (empirical) ROC of 0.94 having an operating point at a sensitivity of 0.965 and specificity of 0.87. It is suggested that this automated approach may hold promise as a means of classifying breast masses.

Algorithms↗

PubMed2003

Evaluation of neck and body metastases to nodes with ferumoxtran 10-enhanced MR imaging: phase III safety and efficacy study.

PURPOSE: To determine the safety and efficacy of ferumoxtran 10-enhanced magnetic resonance (MR) imaging for diagnosis of metastases to lymph nodes and the clinical usefulness of ferumoxtran 10 in nodal staging. MATERIALS AND METHODS: One hundred fifty-two patients were injected with ferumoxtran 10. Readers independently evaluated precontrast MR images by using node size criteria and subjective assessment of other imaging features. Ferumoxtran 10-enhanced MR images were evaluated alone and paired with precontrast images for comparison. The diagnostic performances of precontrast MR size criteria and postcontrast MR imaging were evaluated with receiver operating characteristic (ROC) analysis. Lymph node signal intensity was correlated with histopathologic findings. MR imaging and histopathologic nodal stages were compared. RESULTS: Node-level sensitivity, specificity, and accuracy of precontrast MR imaging were 54%, 82%, and 68%, respectively, with node size criterion alone; 91%, 51%, and 71%, respectively, with subjective reader assessment; 85%, 85%, and 85%, respectively, with postcontrast MR imaging alone; and 83%, 77%, and 80%, respectively, with paired pre- and postcontrast MR imaging. Compared with size criteria, subjective reader assessment had higher sensitivity but substantially lower specificity. Areas under the ROC curve for pre- and postcontrast MR imaging were 0.76 and 0.83, respectively. Nonmetastatic nodes had significantly lower signal intensity than metastatic nodes on postcontrast T2-weighted MR images (P <.001). Postcontrast nodal staging was significantly more accurate than precontrast nodal staging (P <.01). Headache, back pain, vasodilatation, and urticaria each occurred in 6% of patients. CONCLUSION: Ferumoxtran 10-enhanced MR imaging was safe and effective and facilitated improved diagnostic performance. Use of iron oxide-enhanced MR imaging increased the positive predictive value by 20% and the accuracy by 14% compared with reader assessment. Differentiating patients with no nodal metastatic involvement was more reliable with ferumoxtran 10-enhanced MR imaging than with precontrast MR imaging.

Adolescent↗

PubMed2002

Correlation of single-lumen silicone implant integrity with chemical shift artifact on T2-weighted magnetic resonance images.

PURPOSE: To correlate the integrity of single-lumen silicone gel implants with chemical shift artifact (CSA) associated with infolding of the elastomer shell. MATERIALS AND METHODS: The T2-weighted images of presurgical MRI examinations of 54 implants were retrospectively reviewed by two breast radiologists blinded to the operative and pathologic findings. CSA associated with intraluminal membranes was quantified by determining the fraction of membranes with it and categorized as minimal (0-1/3 of membranes involved), moderate (>1/3- <2/3), and marked (2/3 to all). CSA was qualified by noting whether CSA intensity of the membranes was less than or similar to that of blood vessels. The CSA was correlated with the surgical or pathology findings to judge integrity of the implant. RESULTS: Nineteen implants were intact, 35 were dysfunctional (gel leakage or rupture). Twenty-eight of 29 (97%) with a minimal fraction of membranes with CSA were dysfunctional; 17/21 (81%) with CSA associated with a marked fraction of membranes were intact (P < 0.001). All 28 implants with CSA intensity less than vessels were dysfunctional, 19/26 (73%) with CSA equal to vessels were intact (P < 0.001). All 25 implants with minimal CSA and intensity less than vessels were dysfunctional. Seventeen of 19 (89%) implants with CSA associated with a marked fraction of membranes and intensity equal to vessels were intact (P = 0.02). The magnetic resonance imaging (MRI) signs were combined with strong CSA as a predictor of integrity, and 22 of 26 (85%) implants were correctly diagnosed, 4 dysfunctional and 18 intact (P < 0.0001). CONCLUSION: CSA correlates with integrity of silicone gel implants on T2-weighted images and can be used with other MRI signs to improve diagnosis.

Artifacts↗

PubMed2002

Hepatic tumor detection: MR imaging and conventional US versus pulse-inversion harmonic US of NC100100 during its reticuloendothelial system-specific phase.

PURPOSE: To compare conventional ultrasonography (US) and magnetic resonance (MR) imaging with contrast agent-enhanced US for detection of VX-2 liver tumors in rabbits. MATERIALS AND METHODS: Conventional gray-scale liver US was performed in 65 rabbits, 38 of which had VX-2 hepatic tumor implants. Twenty minutes after contrast agent injection, gray-scale pulse-inversion harmonic US images of the liver-specific phase were obtained. Following sacrifice of the animals, T1- and T2-weighted MR imaging was performed at 4-mm intervals. Pathologic analysis was performed as the reference standard. The capability of each imaging modality to correctly depict tumor presence or absence and the number of tumors was compared. RESULTS: Conventional US correctly depicted the presence or absence of tumors in 54 rabbits, for an accuracy of 83%, sensitivity of 71%, and specificity of 100%. With contrast-enhanced US, accuracy increased to 92% (60 correct cases); sensitivity, to 87%; and specificity, to 100%. MR imaging facilitated 56 correct diagnoses, for an accuracy of 86%, sensitivity of 82%, and specificity of 93%. There was a marginally significant difference between US with and US without contrast agent (P =.07) but not between MR imaging and contrast-enhanced US (P > or = .34). When the numbers of correctly detected tumors were compared, contrast-enhanced US performed significantly better than MR imaging (P =.02) and conventional US (P =.04). CONCLUSION: There was no significant difference between contrast-enhanced US and MR imaging in the detection of hepatic tumors, whereas contrast-enhanced US had the highest accuracy (92%) of the three modalities studied.

Animals↗