[Impact of breast MRI and PET-CT in breast cancer staging]. / Apport de l'IRM mammaire et du PET-CT dans le bilan initial du cancer du sein.

The preoperative staging of breast carcinoma determines the type of surgery. Mammography and echography are considered standard. Even though, breast MRI shows better performance for evaluation of the size of the tumor and for detection of additional foci of the tumor. Breast MRI appears to lead to more extensive surgery or increased numbers of mastectomy. But it remains unclear whether breast MRI contributes to reduce positive surgical margins, local recurrences and whether it increases survival. Because of the low predictive positive value, every MRI finding should be confirmed by core needle biopsy. PET-CT has the best sensibility for the detection of distant metastasis but should only be used in very high risk patients.

Influence of variability of interpretation of contrast venography for screening of postoperative deep venous thrombosis on the results of a thromboprophylactic study.

To assess interobserver variability of venography for screening for postoperative deep venous thrombosis (DVT), we used 185 bilateral ascending contrast venograms (366 lower limbs) which were performed using the long-leg film technique, in the frame of a trial of the efficacy of two low-molecular-weight-heparin fractions (initial evaluation). These venograms were submitted in a multicenter setting to three further readers who performed a serial scoring as DVT, no DVT or non-evaluable. DVTs were diagnosed in 78, 55 and 59/366 limbs (initial evaluation: 58). The proximal locations of DVTs were 16, 9 and 16 (initial evaluation: 15) and the non evaluable limbs 3, 5 and 18 (initial evaluation: 0). Apparent pairwise agreement between the three readers ranged from 87 to 90% (true coefficient of agreement Kappa 0.63-0.70). It ranged from 89 to 93% (Kappa 0.63-0.74) for the comparison between the readers and the initial evaluation. This considerable degree of disagreement among experienced readers should be taken into account in calculating sample sizes in prospective thromboprophylactic studies. Indeed, one of the two prophylactic regimens proved to be significantly (p = 0.012, p = 0.031, p = 0.049) or non-significantly (p = 0.073) superior to the other one depending upon the reading of venograms.

Satellite PET and lung cancer: a prospective study in surgical patients.

Positron emission tomography (PET) appears to be an innovative method for imaging the proliferative activity of malignant tissue, in particular by means of 18F-labelled fluorodeoxyglucose (FDG). The potential role of PET scanning was investigated in a satellite centre as an adjunct to conventional methods for estimating the likelihood of pulmonary malignancy. Therefore the sensitivity of detection of lung cancer in candidates was determined prior to exploratory or therapeutic thoracotomy by FDG PET imaging. The study involved 36 patients with abnormal chest roentgenogram and suspected lung cancer who were due for thoracotomy. The PET scans were evaluated qualitatively and semiquantitatively. Pulmonary malignancy was found in 31/36 patients and 29 had a focal increase in FDG pulmonary uptake. Benign pulmonary lesions were found in 5/36 patients, three of whom had a negative PET scan. The sensitivity of detection of lung cancer by FDG PET was therefore 93.5%. Bayesian study shows that FDG PET could be the most useful method in a population with a low prevalence of lung cancer. As illustrated by our study, a simple FDG PET scanning protocol in a satellite PET centre could provide adequate clinical information and help in deciding subsequent patient management.

Quantitative metabolic PET imaging of a plasma cell granuloma.

We report a patient who underwent surgical resection of two lung nodules that proved to be recurrent plasma cell granuloma, also known as inflammatory pseudotumor. Prior to surgery, positron emission tomography (PET) was performed with 18F-labeled fluoro-2-deoxy-D-glucose (18FDG) and rubidium-82 (82Rb). The 18FDG PET scan revealed that the nodules corresponded to two areas of intense uptake. PET imaging with 82Rb, the marker of flow, also showed intense uptake. Thus, PET demonstrated both a high degree of metabolic activity and increased perfusion. These features suggest a lesion with high cellular activity rather than a simple reparative process. The true nature of this lesion remains unknown.