Comparison between 99mTc-sestamibi scintimammography and X-ray mammography in the characterization of clusters of microcalcifications: a prospective long-term study

BACKGROUND

The early diagnosis of non-palpable breast cancer is the object of recent developments in the imaging procedures employed for screening purposes. In some patients, the presence of microcalcifications (MC) is the only indication of tumor. Although X-ray mammography (MRx) has high sensitivity in detecting MC, its specificity is however too low for diagnostic purposes. The aim of this study was to compare (99m)Tc-sestamibi scintimammography (SMM) and MRx in the differential diagnosis between benign and malignant clusters of MC and to assess the possible incremental value of SMM on specificity.

PATIENTS AND METHODS

A total of 283 consecutive women (mean age 53+/-8 years) with MC identified on X-ray mammograms underwent SMM. Scintigraphic images were acquired 10 minutes after the i.v. injection of (99m)Tc-sestamibi (740 MBq). Planar images of both breasts were simultaneously obtained in the lateral prone position and in the anterior and oblique projections using a dual head camera. Sixty-nine women underwent surgery, whereas the remaining 214 patients had completely negative follow-up for 5 years (a 5-year follow-up period is considered the "gold standard" for diagnosing benign lesions).

RESULTS

Histology demonstrated 32/69 primary breast carcinomas (prevalence of disease: 11% of all the 283 patients) and 37/69 benign lesions. The receiver operating characteristic (ROC) statistical technique was employed to compare the diagnostic value of Mrx alone to that of combined MRx and SMM. The detected difference between the areas under the MRx ROC curve (area=0.72, standard error 0.052) and the MRX and SMM ROC curve (area=0.86, standard error 0.039) was statistically significant (p<0.01). Moreover, the combination of MRx and SMM provided a significant improvement of the negative predictive value (NPV=98%) for MC with low-suspicion of malignancy at MRx.

CONCLUSION

SMM can be considered as a complementary tool in the pre-operative work-up of patients with breast lesions. Furthermore, the high negative predictive value of this technique, makes it especially valuable in the perspective of reducing the number of negative breast biopsies or unnecessary surgical interventions.

Oxidative and genotoxic damage after radio‐iodine therapy of Graves' hyperthyroidism

PURPOSE

To evaluate genetic damage and oxidative stress following a single therapeutic dose of 131I in Graves' disease patients monitored up to 180 days after treatment.

MATERIALS AND METHODS

Genetic damage induction was estimated as the increase in micronuclei in peripheral lymphocytes of patients. As indicators of radiogenic oxidative stress, vitamin E and lipoperoxide levels were assessed in the plasma of patients, as well as the release of plasmic clastogenic factors measured by the induction of micronuclei in vitro in peripheral lymphocytes of a healthy donor.

RESULTS

Vitamin E depletion lasted at least 3 days and the basal level was restored within 7 days. No statistically significant variations were observed in lipoperoxide plasma levels. A sharp increase of micronuclei in the peripheral lymphocytes of patients was correlated (p < 0.001) with the release of clastogenic factor in the plasma. The highest micronucleus value was negatively correlated (p < 0.03) with the lowest vitamin E level observed in each patient.

CONCLUSIONS

Micronuclei induction was the direct consequence not only of the energy deposition of 131I on the genetic material, but also of oxidative stress, likely via the release of clastogenic factor.

Cumulative patient effective dose in cardiology

Medical radiation from X-rays and nuclear medicine is the largest non-natural (man-made) source of radiation exposure in Western countries. The aim of this study was to assess the individual cumulative effective dose in patients admitted to our cardiology ward. We collected a cumulative radiological history from a structured questionnaire and access to hospital records in 50 consecutive adult patients (36 males; age, 66.7+/-10.8 years) admitted to the Institute of Clinical Physiology in Pisa. The cumulative effective dose was assessed as an indicator of stochastic risk of cancer. We derived the effective dose for each individual examination from the Medical Imaging Guidelines of the European Commission (2001). On average, each patient underwent a median of 36 examinations (interquartile range, 23-46). The median cumulative effective dose was 60.6 mSv. Three types of procedures were responsible for approximately 86% of the total collective effective dose: (i) arteriography and interventional cardiology (12% of examinations, 48% of average dose per patient); (ii) nuclear medicine (5% of examinations, 21% of average dose per patient); and (iii) CT (4% of examinations, 17% of average dose per patient). The median estimated extra risk of cancer was approximately 1 in 200 exposed subjects. In conclusion, the average contemporary cardiological patient is exposed to a significant cumulative effective dose from diagnostic and therapeutic interventions. It is important to log cumulative dose for each patient at the time of each examination. Every effort should be made to justify the indications and to optimize the doses.

Possible association between thyroid autoimmunity and Menière's disease

Various aetiopathological mechanisms have been postulated to be at the root of Menière's disease (MD), and some data suggest that there may be also an underlying autoimmune factor. In fact, Menière patients manifest certain characteristics that are typical of autoimmune involvement association of particular human leucocyte antigen haplotypes, the presence of antibodies against internal ear antigens. In this study, we evaluated the association between thyroid autoimmunity and MD in a non-selected group of patients. We recruited 50 consecutive MD patients and two groups as controls: group A, 82 healthy volunteers; and group B, 50 subjects suffering from acute unilateral peripheral vestibulopathy. All subjects were submitted to instrumental assessment of cochlear-vestibular function and analysis of thyroid-stimulating hormone (TSH), free triiodothyronine, free thyroxine, anti-TSH receptor antibody (TR-Ab), anti-thyroperoxidase antibody (TPO-Ab) and anti-thyroglobulin antibody (Tg-Ab) in the blood. The prevalence of autoimmune thyroiditis in group B [6/50 (12%); 66.7% TPO-Ab and 33.3% Tg-Ab] was superimposable with the healthy controls [6/82 (7%); 66.7% TPO-Ab and 33.3% Tg-Ab]. In contrast, 38% of the MD patients (P = 0.0001 versus group A and group B) had significant autoantibody levels (68.4% TPO-Ab; 15.8% TPO-Ab + TR-Ab; 10.5% Tg-Ab; 5.2% TPO-Ab + Tg-Ab). Furthermore, 14% of the MD patients were hyperthyroid under l-thyroxine therapy, while no dysfunction was seen in the control groups. Overall, our data demonstrate a significant association between MD and thyroid autoimmunity, which suggests that an autoimmune factor is involved in the aetiopathogenesis of this disease. These findings suggest that it should be useful to submit MD patients to multi-disciplinary clinical investigation.

Anticlastogenic effect of Ginkgo biloba extract in Graves' disease patients receiving radioiodine therapy

BACKGROUND

Chromosomal damage, as assessed by clastogenic factors (CFs) and micronuclei (MN) appearance, after radioiodine therapy of Graves' disease has been reported.

OBJECTIVE AND METHODS

Our objective was to evaluate the effect of Ginkgo biloba extract (EGb 761) supplementation on the time course (up to 120 d) of CFs and MN appearance in lymphocytes from patients with Graves' disease after iodine-131 ((131)I) therapy. Patients were randomly assigned to EGb 761 or placebo, in a blinded manner.

RESULTS

In the placebo group, MN increased early (P < 0.001) after (131)I, peaking at the 21st day (P = 0.0003) and declining thereafter. In EGb 761-treated patients, MN increased early (P < 0.05), while returning toward baseline value thereafter. Therefore, mean MN increment was significantly higher in the placebo group as compared with EGb 761-treated patients (P < 0.01). Moreover, an early (P < 0.0001) and sustained (up to 35 d; P < 0.001) MN increase induced by CFs was observed in the placebo group. Conversely, in EGb 761-treated patients, MN increase induced by CFs never reached the statistical significance; therefore, the mean of the MN increments was significantly lower than in placebo (P < 0.05). A significant positive correlation between MN maximum increment and the bone marrow dose was observed in the placebo group only (P = 0.03). No significant difference was observed in clinical outcome between the two groups.

CONCLUSIONS

EGb 761 supplementation neutralized genotoxic damage induced by radioiodine treatment, without affecting the clinical outcome. Although (131)I therapy is generally safe, our data suggest that Gingko biloba extracts may prevent genetic effects of radioiodine therapy for hyperthyroid Graves' disease.

Contrast-enhanced MR imaging in patients with BI-RADS 3-5 microcalcifications

PURPOSE

The aim of this study was to evaluate the role of magnetic resonance imaging (MRI) in patients with microcalcifications classed as Breast Imaging Reporting and Data Systems (BI-RADS) 3-5.

MATERIALS AND METHODS

Fifty-five patients with mammographic microcalcifications classified as BI-RADS categories 3, 4 or 5 underwent MRI and biopsy with stereotactic vacuum-assisted biopsy (VAB). Our gold standard was microhistology in all cases and histology with histological grading in patients who underwent surgery. Patients with a microhistological diagnosis of benign lesions underwent mammographic follow-up for at least 12 months. MRI was performed with a 1.5-Tesla (T) unit, and T1 coronal three-dimensional (3D) fast low-angle shot sequences were acquired before and after injection of paramagnetic contrast agent (0.1 mmol/kg). MRI findings, according to the Fisher score, were classified into BI-RADS classes. In patients with cancer who underwent surgery, we retrospectively compared the extension of the mammographic and MRI findings with histological extension.

RESULTS

Histology revealed 26 ductal in situ cancers (DCIS) and ductal microinvasive cancers (DCmic), three atypical ductal hyperplasias (ADH) and 26 benign conditions. Histological grading of the 26 patients with cancer revealed four cases of G1, 11 cases of G2 and 11 cases of G3. If we consider mammographic BI-RADS category 3 as benign and BI-RADS 4 and 5 as malignant, mammography had 77% sensitivity, 59% specificity, 63% positive predictive value (PPV), 74% negative predictive value (NPV) and 67.2% diagnostic accuracy. If we consider MRI BI-RADS categories 1, 2 and 3 as benign and 4 and 5 as malignant, MRI had 73% sensitivity, 76% specificity, 73% PPV, 76% NPV and 74.5% diagnostic accuracy. As regards disease extension, mammography had 45% sensitivity and MRI had 84.6% sensitivity.

CONCLUSION

Mammography and stereotactic biopsy still remain the only techniques for characterising microcalcifications. MRI cannot be considered a diagnostic tool for evaluating microcalcifications. It is, however, useful for identifying DCIS with more aggressive histological grades. An important application of MRI in patients with DCIS associated with suspicious microcalcifications could be to evaluate disease extension after a microhistological diagnosis of malignancy, as it allows a more accurate presurgical planning.

Use of surgical gamma probe for the detection of lymph node metastases in differentiated thyroid cancer

BACKGROUND

Patients with differentiated thyroid cancer (DTC) after total or near-total thyroidectomy require 131I therapy. After surgery the persistence of lymph node metastases in our series of patients was frequent (30%). Such patients are preferentially treated with radioiodine and shifted to surgical reintervention when the nodal lesions persist after two 131I treatments.

AIM

Use of an intraoperative radioactive probe (C-TraK) to allow a more radical surgical approach in thyroid cancer patients submitted to surgery for lymph node metastases.

METHODS AND RESULTS

After adequate withdrawal of L-thyroxine suppressive therapy six patients were given high 131I doses followed by post-therapy WBS which demonstrated cervical activity in 5 patients and peri-jugular activity in 1. Surgery with the help of a gamma probe allowed to detect and remove all metastatic nodes. After excision all surgical specimens showed higher radioactive counts with respect to the background. The post-surgical scan showed the disappearance of all areas of 131I uptake. Histology confirmed the presence of metastatic lesions from papillary thyroid cancer.

CONCLUSIONS

We conclude that the use of a gamma probe can be successful in patients with metastatic neck lesions resistant to 131I treatment, particularly in patients with nonpalpable lesions.