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Biomedical subjects

M Imbriaco

Publications and source records attributed to M Imbriaco.

At least 19 recordsLinked to original sources
PubMed2001

Scintimammography with 99mTc-MIBI versus dynamic MRI for non-invasive characterization of breast masses.

Although mammography remains the technique of choice for the early detection of breast cancer, several imaging techniques, including scintimammography and magnetic resonance imaging (MRI), have recently been proposed as adjuncts for this purpose and included in many diagnostic protocols. This study was undertaken to assess the clinical accuracy of scintimammography with technetium-99m methoxyisobutylisonitrile (MIBI) and contrast-enhanced MRI in the detection of primary breast carcinoma in patients with equivocal mammographic findings. Forty-nine patients with a suspicious breast mass detected either by physical examination or by mammography and ultrasound (US) were studied. All patients underwent scintimammography and dynamic contrast-enhanced MRI 1 week apart. The results of the two techniques were compared and correlated to the final diagnoses. Two independent readers reported the scans using a four-point confidence scale. The areas under the receiver operator characteristic (ROC) curves were obtained. Scintimammography showed an accuracy for tumour detection of 84%, with a sensitivity of 80% and a specificity of 88%. MRI showed an accuracy of 86%, with a sensitivity and specificity of 96% and 75%, respectively. Comparison of the two areas under the ROC curves showed no significant differences between MRI, 0.91+/-0.05 (mean+/-SD), and scintimammography, 0.88+/-0.05 (P=0.9). It is concluded that dynamic MRI and scintimammography possess comparable accuracy in the diagnosis of primary breast carcinoma in patients with equivocal mammographic or US findings.

Biopsy↗
PubMed2000

Whole-Body FDG-PET in Patients with Recurrent Colorectal Carcinoma. A Comparative Study with CT.

Purpose: To assess the clinical accuracy of whole-body 2-[F-18]-fluoro-2-deoxy-D-glucose-positron emission tomography (FDG-PET) in the diagnosis of recurrent colorectal carcinoma in comparison to conventional computed tomography (CT).Materials and methods: Forty patients with suspected recurrent colorectal carcinoma based on either progressive serial carcinoemrbyonic antigen (CEA) serum elevation or positive/equivocal CT findings underwent whole-body FDG-PET. PET results were compared with those of CT and correlated to the final histopathological and clinical findings.Results: A final diagnosis was obtained at 93 sites in 35 patients by histology and in 5 patients by clinical follow up of at least 6 months. Of the 93 sites, 53 were determined to be malignant and 40 benign. FDG-PET evaluated on a 5-point scale (0-4) showed a positive and negative predictive value in the range of 96-98% and 83-93% respectively as the threshold for positivity was moved from 0 through 3. By comparison, CT, also evaluated on a 5-point scale showed a positive and negative predictive value in the range of 75-88% and 67-71% respectively. The area under the fitted receiver operating characteristic curve for PET: A(PET) = 0.96 +/- 0.02 was significantly greater (P < 0.001) than that observed for CT: A(CT) = 0.77 +/- 0.06. The distribution of maximum standardized uptake value (SUVmax) showed that all negative lesions have SUVmax below 5.0 whereas 75% of positive lesions were above 5.0 pointing to the fact that disease positivity is more likely in lesions with high SUV values.Conclusion: The results of this study confirm that whole-body FDG-PET is more accurate than conventional CT in the staging of patients with suspected recurrent colorectal carcinoma.

Journal Article↗
PubMed2000

Magnetic resonance imaging with ferumoxil, a negative superparamagnetic oral contrast agent, in the evaluation of ulcerative colitis.

OBJECTIVE: The introduction of new oral contrast agents that enhance image quality has increased the importance of magnetic resonance imaging (MRI) in the management of ulcerative colitis. The aim of our study was to investigate the usefulness of a new negative superparamagnetic oral contrast (ferumoxil) alone or in association with gadolinium i.v. in the assessment of the disease. METHODS: Twenty-eight patients with clinically active ulcerative colitis and 10 control subjects entered the study. In each patient a clinical, endoscopic, histological, and MRI evaluation was performed. In particular, in 14 patients affected by ulcerative colitis (group A) and in five controls, magnetic resonance images were acquired 1 h after the oral administration of 900 ml of ferumoxil, while the remaining 14 patients (group B) and five controls were submitted to double-contrast MRI (ferumoxil and gadolinium). In both groups, wall thickness, length of affected bowel segments, and, in group B, also percent contrast enhancement were calculated. RESULTS: The comparison of endoscopic and MRI extent of disease was statistically significant. Wall thickness and, in group B, also percent contrast enhancement were significantly correlated with clinical and endoscopic activities. In each group wall thickness was significantly different in the activity phases of the disease. CONCLUSIONS: MRI with negative superparamagnetic oral contrast is comparable to endoscopy in the assessment of ulcerative colitis. The double-contrast imaging does not provide more information than single oral contrast, so we concluded that the latter is preferable in the follow-up of the disease and in patients unable or with a poor compliance to undergo endoscopy.

Administration, Oral↗
PubMed2000

[Relationship between exercise capacity and left ventricular function at rest in patients with heart insufficiency: radionuclide continuous monitoring of left ventricular function].

PURPOSE: To evaluate the relationship of systolic and diastolic function at rest to exercise capacity. MATERIAL AND METHODS: Seventeen patients with ischemic heart failure were included in the study. Ambulatory left ventricular monitoring at rest and during upright exercise with combined analysis of pulmonary gas exchange was performed. Ejection fraction, end-diastolic volume, end-systolic volume, stroke volume, cardiac output, and peak filling rate were measured. RESULTS: Significant positive correlations were found between rest ejection fraction and peak oxygen consumption (r = .60, p < .01), peak cardiac output (r = .77, p < .0001), peak stroke volume (r = .67, p < .005), and peak ejection fraction (r = .69, p < .005). On the other hand, peak filling rate at rest showed a significant inverse correlation with peak end-diastolic (r = -.48, p < .05) and end-systolic (r = -.66, p < .005) volumes. The patients were then subgrouped into two groups according to their rest ejection fraction (lower or higher than 40%). In the group with ejection fraction less than 40% a significant correlation was observed between rest ejection fraction and both peak stroke volume (r = .66, p < .05) and peak ejection fraction (r = .69, p < .05). In the same group of patients an inverse correlation was found between peak filling rate and both end-diastolic (r = -0.65, p < .05) and end-systolic (r = -.82, p < .005) volumes. CONCLUSIONS: The results of the present study suggest that exercise capacity is related to left ventricular function at rest and that rest diastolic function might be a determinant of left ventricular function during exercise in patients with heart failure.

Exercise Tolerance↗
PubMed1999

Prognostic significance of extent of disease in bone in patients with androgen-independent prostate cancer.

PURPOSE: To evaluate the prognostic significance of a bone scan index (BSI) based on the weighted proportion of tumor involvement in individual bones, in relation to other factors and to survival in patients with androgen-independent prostate cancer. PATIENTS AND METHODS: Baseline radionuclide bone scans were reviewed in 191 assessable patients with androgen-independent disease who were enrolled onto an open, randomized trial of liarozole versus prednisone. The extent of skeletal involvement was assessed by scoring each scan using the BSI and independently according to the number of metastatic lesions. The relationship of the scored bone involvement to other known prognostic factors was explored in single- and multiple-variable analyses. RESULTS: In single-variable analyses, the pretreatment factors found to be associated with survival were age (P = .0446), performance status (P = .0005), baseline prostate-specific antigen (P = .0001), hemoglobin (P = .0001), alkaline phosphatase (P = .0002), AST (P = .0021), lactate dehydrogenase (P = .0001), and treatment (P = .0098). The extent of osseous disease was significant using both the BSI (P = .0001) and the number of lesions present (P = .0001). In multiple-variable proportional hazards analyses, only BSI, age, hemoglobin, lactate dehydrogenase, and treatment arm were associated with survival. When the patient population was divided into three equal groups, with BSI values of < 1.4%, 1.4% to 5.1%, and > 5.1%, median survivals of 18.3, 15.5, and 8.1 months, respectively, were observed (P = .0079). CONCLUSION: The BSI quantifies the extent of skeletal involvement by tumor. It allows the identification of patients with distinct prognoses for stratification in clinical trials. Further study is needed to assess the utility of serial BSI determinations in monitoring treatment effects. The BSI may be particularly useful in the evaluation of agents for which prostate-specific antigen changes do not reflect clinical outcomes accurately.

Aged↗
PubMed1998

Interferon-gamma and monoclonal antibody 131I-labeled CC49: outcomes in patients with androgen-independent prostate cancer.

To assess the tumor targeting, safety, and efficacy of monoclonal antibody 131I-labeled CC49 in patients with androgen-independent prostate cancer, 16 patients received 75 mCi/m2 of the radiolabeled antibody after 7 days of IFN-gamma pretreatment. Sequential tumor biopsies in three patients showed a median 5-fold (range, 2-6-fold) increase in the proportion of cells staining positively for the TAG-72 antigen, whereas one showed a decrease in staining. Fourteen patients received 131I-labeled CC49, whereas 2 showed a disease-related decrease in performance status, precluding antibody treatment. The antibody localized to sites of metastatic androgen-independent prostate cancer in 86% (12 of 14; 95% confidence interval, 57-95%) of cases. Both osseous and extraosseous sites were visualized, and in six (42%) patients, more areas were visible when the radioimmunoconjugate was used than were apparent when conventional scanning techniques were used. The localization of the conjugate in the marrow cavity was usually a site not visualized by the radionuclide bone scan, in which the isotope localizes primarily to the tumor-bone interface. The dose-limiting toxicity was thrombocytopenia because five (36%) patients showed grade IV and seven (50%) showed grade III effects. In addition, six (42%) patients, four of whom were hospitalized, showed a flare in baseline pain, and four showed a decrease in pain. No patient showed a >50% decline in prostate-specific antigen, although radionuclide bone scans remained stable in four cases for a median of 4 months. The results are consistent with dosimetry estimates showing that the delivered dose to tumor was subtherapeutic and suggest that approaches that exclusively target the bone tumor interface or the marrow stroma may be unable to completely eradicate disease in the marrow cavity. For CC49, improving outcomes would require repetitive dosing, which was precluded by the rapid development of a human antimouse antibody response.

Aged↗
PubMed1998

A new parameter for measuring metastatic bone involvement by prostate cancer: the Bone Scan Index.

In this report, we describe a method for quantitative bone scan interpretation (the Bone Scan Index or BSI) in advanced prostate cancer. The BSI estimates the fraction of the skeleton that is involved by tumor, as well as the regional distribution of the metastases in the bones. The purpose of this report is to describe the development and validation of this method in terms of reproducibility and the application of BSI for determining extent of disease and monitoring disease progression. We analyzed 263 bone scans from 90 patients being studied under four protocols at Memorial Sloan-Kettering Cancer Center for progressive, androgen-independent prostate cancer (AIPC), who had bone scans as a part of their work-up. We determined: (a) the intraobserver and interobserver variability of the BSI; (b) the comparison between a change in BSI and prostate-specific antigen (PSA); (c) the regional distribution of bony metastases in early stage D prostate cancer (<3% skeletal involvement); and (d) the rate of growth of bony metastases from prostate cancer. A cube root transformation of the percentage of involvement of the entire skeleton was used to stabilize the variance over the entire span of values (0-60% tumor involvement). The range of interobserver variability between readers was 0.2-0.5 times the cube root of the BSI (69 scans, 18 patients). Intraobserver variability was minimal when the same reader read the same scans after a 2-year interval, showing a correlation coefficient of 0.97 (reader 1) and 0.99 (reader 2), P < 0.001. There was a parallel rise in the BSI and the PSA in 24 patients (105 scans) treated for AIPC with hydrocortisone followed by suramin at PSA relapse (Pearson's moment correlation, 0.71). In a group of 27 patients with limited bone involvement by AIPC (i.e., <3% BSI), the distribution of early metastases was not random within the skeleton but was distributed in the central skeleton in a manner that matched the distribution of the normal adult bone marrow. Also, in a group of 21 patients (62 scans), the change in BSI as a function of time after diagnosis was explored graphically. The progression of bone scan changes in AIPC, from early involvement (<3%) to late involvement, was fitted to a Gompertzian equation. It showed a rapid exponential growth phase, with an estimated tumor doubling time of 43 days when the BSI was 3.3%. The change in BSI rapidly approached a more gradual slope as the percentage of skeletal involvement increased. The BSI provides a reproducible new parameter for quantitative assessment of bone involvement by AIPC. These results suggest that the BSI will be useful for stratifying patients entering treatment protocols for extent of tumor involvement of bone. Although further study is necessary, serial bone scan BSI appears capable of quantifying both the progression of bony involvement by tumor as well as the response to treatment.

Aged↗
PubMed1997

Segmentation of lung lesion volume by adaptive positron emission tomography image thresholding.

BACKGROUND: It is common protocol in radionuclide therapies to administer a tracer dose of a radiopharmaceutical, determine its lesion uptake and biodistribution by gamma imaging, and then use this information to determine the most effective therapeutic dose. This treatment planning approach can be used to quantitate accurately the activity and volume of lesions and organs with positron emission tomography (PET). In this article, the authors focus on the specification of appropriate volumes of interest (VoI) using PET in association with computed tomography (CT). METHODS: The authors have developed an automatic image segmentation schema to determine the VoI of metastases to the lung from PET images, under conditions of variable background activity. An elliptical Jaszczak phantom containing a set of spheres with volumes ranging from 0.4 to 5.5 mL was filled with F-18 activity (2-3 microCi/mL) corresponding to activities clinically observed in lung lesions. Images were acquired with a cold background and then with variable source-to-background (S/B) ratios of: 7.4, 5.5, 3.1, and 2.8. Lesion VoI analysis was performed on 10 patients with 17 primary or metastatic lung lesions, applying the optimum threshold values derived from the phantom experiments. Initial volume estimates for lung lesions were determined from CT images. Approximate S/B ratios were obtained for the corresponding lesions on F-18-fluoro-2-deoxy-D-glucose (18FDG)-PET images. From the CT estimate of the lesion size and the PET estimate of the S/B ratio, the appropriate optimum threshold could be chosen. The threshold was applied to the PET images to obtain lesion activity and a final estimate of the lesion volume. RESULTS: Phantom data analysis showed that image segmentation converged to a fixed threshold value (from 36% to 44%) for sphere volumes larger than 4 mL, with the exact value depending on the S/B ratios. For patients, the use of optimum threshold schema demonstrated a good correlation (r = 0.999) between the initial volume from CT and the final volume derived from the 18FDG-PET scan (P < 0.02). The mean difference for those volumes was 8.4%. CONCLUSIONS: The adaptive thresholding method applied to PET scans enables the definition of tumor VoI, which hopefully leads to accurate tumor dosimetry. This method can also be applied to small lesions (<4 mL). It should enable physicians to track objectively changes in disease status that could otherwise be obscured by the uncertainties in the region-of-interest drawing, even when the scans are delineated by the same physician.

Aged↗
PubMed1997

Thallium-201 scintigraphy for the evaluation of tumor response to preoperative chemotherapy in patients with osteosarcoma.

BACKGROUND: The degree of tumor necrosis after preoperative intravenous chemotherapy is likely to be an indicator of prognosis for patients with primary osteosarcoma. This study was undertaken to evaluate the efficacy of thallium-201 (Tl-201) scintigraphy in assessing response to chemotherapy in patients with osteosarcoma and to correlate the findings with the degree of tumor necrosis assessed histologically. METHODS: Twenty-four patients with biopsy-proven osteosarcoma underwent Tl-201 imaging before and immediately after preoperative intravenous chemotherapy. The maximum pixel counts taken over the tumor divided by those taken of a background region yielded a tumor-to-background ratio. The percentage of change in the tumor-to-background ratio before and after chemotherapy, defined as the alteration ratio, was correlated with the percentage of tumor necrosis. The percentages of tumor necrosis were classified into 4 grades: Grade 1, <50%; Grade 2, 50-89%; Grade 3, 90- 99%; Grade 4, 100%. RESULTS: Three patients with Grade 1 histologic response had an alteration ratio of 31% +/- 4 (mean +/- standard deviation). Three patients with Grade 2 response had an alteration ratio of 76% +/- 9. Nine patients with Grade 3 response had an alteration ratio of 84% +/- 11. Nine patients with Grade 4 response had an alteration ratio of 96% +/- 5. These ratios correlated well with the histologic grades (P < 0.001). CONCLUSIONS: The results of this study suggest that Tl-201 scintigraphy is a powerful tool in the evaluation of tumor response to chemotherapy in patients with osteosarcoma.

Adolescent↗
PubMed1997

Ambulatory monitoring of left ventricular function: walk and bicycle exercise in congestive heart failure.

UNLABELLED: The aim of this study was to assess changes in left ventricular (LV) function during 6-min walk test and cardiopulmonary exercise by continuous radionuclide monitoring in patients with congestive heart failure (CHF). METHODS: Seventeen patients with CHF and 10 normal subjects underwent monitoring of LV function (Vest) during 6-min walk test and during bicycle exercise with combined analysis of pulmonary gas exchange. During cardiopulmonary exercise, all parameters of LV function were measured at rest, at the anaerobic threshold (AT) and at peak oxygen uptake (peak VO2). RESULTS: In the normal subjects, during the walk test, heart rate (HR), ejection fraction (EF), end-diastolic volume (EDV), cardiac output (CO) and stroke volume (SV) significantly increased from rest to peak (all p < 0.001), while end-systolic volume (ESV) significantly decreased from rest to peak (p < 0.001). In patients with CHF, during the walk test, HR, EDV, ESV and CO significantly increased from rest to peak (p < 0.001), EF significantly decreased from rest to peak (p < 0.001) and SV did not show significant change. During cardiopulmonary exercise, normal subjects showed a significant increase in HR and CO, from rest to AT and from AT to the peak VO2 (p < 0.001). EF, EDV and SV significantly increased from rest to AT (p < 0.001), with no significant change from AT to peak VO2. ESV decreased from rest to AT (p < 0.001), showing no significant change from AT to peak VO2. In patients with CHF, HR, CO, ESV and EDV increased significantly from rest to AT (p < 0.001) and from AT to peak VO2 (p < 0.001). EF and SV did not show significant changes from rest to AT, showing a significant decrease from AT to peak VO2 (p < 0.001). CONCLUSION: Vest can be used to evaluate cardiac responses during 6-min walk test and cardiopulmonary exercise in patients with CHF. In such patients, significant impairment of LV function is already present during submaximal physical exercise becoming more evident during the anaerobic phases of bicycle exercise.

Case-Control Studies↗
PubMed1997

Technetium-99m-MIBI versus fluorine-18-FDG in diffuse multiple myeloma.

Experience of scintigraphic detection of bone lesion and active bone marrow involvement of multiple myeloma, especially with sestamibi and FDG-PET scans is in evolution. We report a case of intense sestamibi uptake in bone marrow correlating with the extent of the disease, while FDG-PET scans showed activity only in areas of active disease progression associated with pain. Technetium-99m-sestamibi appears to indicate the extent of the disease, while [18F]FDG-PET scans show sites of active tumor proliferation and may be useful in directing local therapy such as radiation.

Aged↗
PubMed1997

Quantitative bone metastases analysis based on image segmentation.

UNLABELLED: Preliminary evidence indicates that the fraction of bone containing metastatic lesions is a strong prognostic indicator of survival longevity for prostate and breast cancer. Our current approach to quantify metastatic bone lesions, called the Bone Scan Index, is based on an inspection of the bone scan, estimating visually the fraction of each bone involved and then summing across all bones to determine the percentage of total skeletal involvement. This approach, however, is time consuming, subjective and dependent on individual interpretation. METHODS: To overcome these problems, a semiautomated image segmentation program was developed for the quantitation of metastases from planar whole-body bone scans. The user is required to insert a seed point into each metastatic region on the image. The algorithm then connects pixels to the seed pixel in all directions until a contrast-dependent threshold is reached. The optimal threshold for cessation of the region growing is determined from phantom studies. On the images, lesion delineation and size measurements were performed by the algorithm. Each delineated lesion is associated with a bone site using pull-down menus. The program then computes the fraction of lesion involvement in each bone based on look-up-tables containing the relationship of bone mass with race, sex, height and age. These look-up-tables were obtained by multiple regression of the skeletal mass measurements in humans. The total fraction of skeletal involvement is then obtained from the individual fractional masses. For individual fractional mass, values given in International Commission on Radiation Protection Publication No. 23 were used. RESULTS: The bone metastases analysis system has been used on 11 scans from 6 patients. The correlation was high (r = 0.83) between conventional (manually drawn region-of-interest) and this analysis system. Bone metastases analysis results in consistently lower estimates of fractional involvement in bone compared with the conventional region-of-interest drawing or visual estimation method. This is due to the apparent broadening of objects at and below the limits of resolution of the gamma camera. CONCLUSION: Image segmentation reduces the delineation and quantitation time of lesions by at least two compared with manual region-of-interest drawing. The objectivity of this technique allows the detection of small variations in follow-up patient scans for which the manual region-of-interest method may fail, due to performance variability of the user. This method preserves the diagnostic skills of the nuclear medicine physician to select which bony structures contain lesions, yet combines it with an objective delineation of the lesion.

Adolescent↗