Efecto de Diferentes Técnicas de Acabado y Pulido Sobre la Rugosidad de un Composite de Nanoparticulas / Effect of Different Finishing and Polishing Techniques on the Roughness of a Nanoparticle Composite

El objetivo fue comparar la rugosidad de un composite nanoparticulado con diferentes técnicas de acabado y pulido. Se obtuvieron 20 discos en conformadores ad-hoc en los que se insertó un composite nanoparticulado en capas de 2mm. Se activó cada incremento durante 30s con una intensidad de 1450 mw/cm2. Todas las probetas se pulieron con la secuencia completa de discos Sof-lex a velocidad media y luego se asignaron a uno de 4 grupos (n=5) tratados de la siguiente manera: G1: sin tratamiento extra; G2: con cepillos Astrobrush y JC-SICRA-G; G3: con pasta de diamantes Diamond Gloss aplicada con fieltro; y pasta de óxido de aluminio Poligloss y fieltro; G4: igual que G3 + cepillos (igual que G2). Las superficies se evaluaron con un perfilómetro óptico tridimensional. Se registró la rugosidad promedio (Ra) en tres puntos de cada espécimen, se consideró la Ra a la media de los tres registros obtenidos. Los datos se analizaron mediante ANOVA de una vía y prueba de Tukey para comparaciones múltiples. Los resultados obtenidos fueron: G1: 132,20nm (26,16); G2: 77,20 nm (20,64); G3: 78,74 nm (10,04); G4: 66,47nm (31,08). Se encontró diferencia estadísticamente significativa entre los grupos (P=0.0017); de las comparaciones múltiples surge que G1 presentó una rugosidad media significativamente mayor que los restantes. G1>G2 (P<0.01), G1>G3 (P<0,05), G1>G4 (P<0,01). En conclusión, el uso de sistemas anexos de pulido permite lograr mayor lisura superficial. El uso de más de un sistema complementario no mejora el resultado (AU)

Ductal carcinoma in situ diagnosed with stereotactic core needle biopsy: can invasion be predicted?

PURPOSE: To determine whether mammographic or histologic features can be used to predict which cases diagnosed as ductal carcinoma in situ (DCIS) without invasion by means of stereotactic core needle biopsy (SCNB) will have invasive disease at surgery. MATERIALS AND METHODS: From July 1992 to March 1999, DCIS without invasion was diagnosed by means of SCNB in 59 patients. Seventeen (29%) were found to have invasive disease after surgery. The underestimation rate for SCNB was compared with that obtained by means of open surgical biopsy. Mammographic and histologic features of cases with and those without invasion were compared. RESULTS: All patients had calcifications on mammograms. There was no significant difference (P: =.26) between the underestimation rate for SCNB with the 11-gauge vacuum-assisted device and that for open surgical biopsy. No statistically significant differences between cases with and those without invasion were seen in patient age, mean number of core specimens, level of suspicion, size of lesion, distribution and morphology of the calcifications, presence of an associated mass or density, subtype of DCIS, nuclear grade, or presence of necrosis or desmoplasia. CONCLUSION: Mammographic and histologic features cannot be used reliably to predict cases that are underestimated with SCNB. However, SCNB with the 11-gauge vacuum-assisted device was as reliable as open surgical biopsy for diagnosing DCIS without invasion.

Underestimation of breast cancer with II-gauge vacuum suction biopsy.

OBJECTIVE: The purpose of this study was to determine the mammographic and histologic features of cancerous lesions underestimated using 11-gauge vacuum suction biopsy. MATERIALS AND METHODS: Retrospective review of 11-gauge vacuum suction biopsy was performed to identify lesions diagnosed as atypical ductal hyperplasia or carcinoma. The histology of the core and surgical specimens was compared. Of 158 cases of cancer, underestimation occurred in 15 (9.5%). The mammographic and histologic features were assessed. RESULTS: Of 15 underestimated cases, six were atypical ductal hyperplasia that proved to be cancer (5 ductal carcinoma in situ and 1 invasive) and nine were ductal carcinoma in situ that proved to have invasion. The underestimation rate for calcifications was 16.3% (14/86) and for masses was 1.6% (1/64) (p = 0.007). Most (5/6) underestimated atypical ductal hyperplasia cases were reported as "markedly atypical," and four of nine underestimated ductal carcinoma in situ cases were reported as "possible invasion." No significant difference was seen in the number of core specimens obtained or the sizes of the lesions for underestimated cases versus accurately diagnosed cases. The percentage of calcifications retrieved was significantly different (p = 0.017). No underestimations were found among cases in which the entire mammographic lesion was removed at vacuum suction biopsy. CONCLUSION: The cancer underestimation rate with vacuum suction biopsy was 9.5%. The underestimation rate for calcifications (16.3%) was significantly higher than that for masses (1.6%) (p = 0.007). The percentage of the lesion removed was an important factor in reducing underestimation, as reflected by the percentage of calcifications retrieved and the instances of complete resolution of the lesion seen on mammography.

Follow-up of breast lesions diagnosed as benign with stereotactic core-needle biopsy: frequency of mammographic change and false-negative rate.

PURPOSE: To determine how often lesions diagnosed as benign with stereotactic core-needle biopsy (SCNB) change at follow-up mammography and to determine the optimal follow-up strategy and the delayed false-negative rate. MATERIALS AND METHODS: From July 1992 through December 1995, 355 of 540 cases (66%) in which SCNB yielded benign results were managed with follow-up mammography. Mammographic follow-up was available for 298 of these cases (84%). Follow-up mammography reports were reviewed. When a change was reported, pre- and postbiopsy mammograms, pathology reports, and results of subsequent mammographic follow-up were reviewed. RESULTS: Mammographic change occurred in 21 of 298 cases (7%) at intervals of 6-55 months (mean, 20 months). Change occurred after initial mammographic stability in 10 of 21 cases. Repeat biopsy was performed in 18 of 21 cases. Malignancy was diagnosed in two cases: one mass that changed at 6 months and one case of microcalcifications that changed at 24 months. This represented a delayed false-negative rate of 2% (two of 105 malignancies among 540 biopsies). CONCLUSION: A small percentage of cases diagnosed as benign with SCNB will change on follow-up mammograms, which may necessitate repeat biopsy. These results suggest that 6-month follow-up for cases that yield nonspecific benign results at SCNB and yearly screening mammography for cases with specific benign results is a reasonable management strategy.

Total-body echo-planar MR imaging in the staging of breast cancer: comparison with conventional methods--early experience.

PURPOSE: To test breast cancer staging with total-body echo-planar magnetic resonance (MR) imaging. MATERIALS AND METHODS: Nineteen patients with newly diagnosed breast cancer were imaged by using a 1.5-T echo-planar MR system. By using a table sweep method, 180 contiguous axial images were obtained from the cranial vertex through the feet with T2-weighted spin-echo and inversion-recovery sequences. Results were compared with those of conventional imaging. Therapeutic decisions based on echo-planar MR imaging and conventional imaging results were compared. Diagnostic truth was determined by means of tissue diagnosis, further imaging findings, and follow-up findings (median, 18 months). RESULTS: Staging with total-body echo-planar MR imaging was correct in 18 patients (95%)--eight with metastases and 10 without--while staging with conventional imaging was correct in 15 patients (79%). In one patient, both echo-planar MR imaging and conventional imaging findings incorrectly indicated probable metastases. In one patient thought to have bone metastases at conventional imaging, echo-planar MR imaging findings were normal, which was correct. Two patients with stage IV disease were not suspected to have disease at conventional imaging: One had liver involvement and the other had skeletal metastases. The therapeutic decisions in these two patients were altered by the echo-planar MR imaging results. CONCLUSION: Total-body echo-planar MR imaging was at least as accurate as conventional imaging for staging newly diagnosed breast cancer and was faster, simpler, and completely noninvasive.

Canceled stereotactic core-needle biopsy of the breast: analysis of 89 cases.

PURPOSE: To determine reasons for cancellation of stereotactic core-needle breast biopsy and outcome in canceled cases. MATERIALS AND METHODS: Among 572 scheduled stereotactic core-needle biopsies, 89 cases (16%) in 88 patients were canceled. In canceled cases, mammogram origin, mammographic abnormality, reason for cancellation, and outcome were determined. RESULTS: In canceled cases, 50 (57%) of 88 patients were referred from another facility. Mammographic abnormality in most cases (72 [81%] of 89 canceled biopsies) was a mass(es); calcifications occurred in 14 cases (16%). Reasons for cancellation included (a) lesion was not recognized (26 cases [29%]), (b) lesion was reassessed as benign (17 cases [19%]), (c) cysts were diagnosed with ultrasound (US) (12 cases [13%]) or aspiration (11 cases [12%]), (d) lesion location was suboptimal (12 cases [13%]), (e) patient was intolerant of procedure (seven cases [8%]), and (f) other (four cases [4%]). Numbers of canceled biopsies from another facility and those from the authors' institution differed in cases in which lesions were reassessed as benign (12 and five cases, respectively) or cysts were diagnosed with US (10 and two cases, respectively). Lesions that could not be targeted included many pseudolesions and three cancers. CONCLUSION: Complete work-up, including US examination, of breast lesions is necessary before stereotactic core-needle biopsy is scheduled. Inability to recognize a suspected lesion on stereotactic images should not preclude biopsy with another method.

Clinical importance of unilaterally enlarging lymph nodes on otherwise normal mammograms.

PURPOSE: To determine the clinical importance of unilateral enlargement of axillary or intramammary lymph nodes on otherwise normal mammograms. MATERIALS AND METHODS: Twenty-four patients (aged 33-76 years) with unilaterally enlarging lymph nodes on otherwise normal mammograms were identified in a review of mammographic reports from 1991 to 1995. Mammograms, medical history, follow-up findings, and biopsy results were reviewed. RESULTS: The initial nodal size was 3-17 mm. The size increased by 20%-312%. Seven patients had a history of malignancy. Six patients had a clinical history suggestive of a benign cause of nodal enlargement. Seven patients underwent biopsy. Two patients had results positive for malignancy (one, melanoma; one, lymphoma). Both patients had a known history of malignancy and a size increase of greater than 100%. In 17 patients, mammographic follow-up findings at 6-58 months (mean, 26 months) showed decreased nodal size in 13 and no change in four patients. CONCLUSION: Enlarging lymph nodes on otherwise normal mammograms are usually benign. Clinical history can reveal possible causes of nodal enlargement. If the patient has no history of malignancy, the amount of nodal size increase is small, and the node maintains a benign appearance, mammographic follow-up is a reasonable alternative to biopsy.

Optical breast lesion localization fiber: preclinical testing of a new device.

Preclinical testing was performed of an optical breast lesion localization fiber to guide surgical excision. The prototype device comprised dual 0.010- inch (0.254-mm)-diameter hooks attached to the tip of a 1,000-microns (0.03937-inch)-diameter optical fiber, which allowed retention in soft tissue after passage through a 17-gauge extra-thin-wall needle. The proximal end of the optical fiber was attached to a 15-mW, 635-nm diode laser, with a thumbscrew connector. The tip of the optical fiber was visible through several centimeters of breast tissue in two human mastectomy specimens, which facilitated determination of the location of the hooks. The optical localization fiber may allow lesions to be approached at surgery by many different paths. Clinical tests are indicated to further evaluate this device.

Wilms tumor occurring as a botryoid renal pelvicalyceal mass.

Wilms tumor usually occurs as an abdominal mass arising from the renal parenchyma. A case was encountered in which the neoplasm filled the pelvicalyceal system of an 8-year-old boy as a botryoid mass, with minimal parenchymal involvement. The radiologic manifestations, pathologic features, and surgical implications are discussed.