99mTc-MIBI imaging as a predictor of therapy response in osteosarcoma compared with multidrug resistance-associated protein and P-glycoprotein expression.

UNLABELLED: In vitro studies have demonstrated that (99m)Tc-methoxyisobutylisonitrile ((99m)Tc-MIBI) is a transport substrate of multidrug resistance (MDR)-related proteins. The aim of this clinical study was to evaluate whether (99m)Tc-MIBI scintigraphy was a functional imaging tool for in vivo detection of multidrug resistance-associated protein (MRP) expression in osteosarcoma and to investigate the role of MRP and (99m)Tc-MIBI imaging to predict the clinical outcome. We also examined whether the scintigraphic parameters would help to distinguish the functional capacity of P-glycoprotein (Pgp) and MRP. METHODS: Twenty-four patients with a diagnosis of osteosarcoma were studied before neoadjuvant chemotherapy. Tumor-to-background ratios of both early (10 min) and delayed (1 h) images and the percentage washout rate (WR%) of (99m)Tc-MIBI were calculated. Immunohistochemical analysis of MRP and Pgp was performed on biopsy specimens, and the response to preoperative chemotherapy was assessed by histopathologic examination. RESULTS: Fifteen of 24 osteosarcoma samples in our series (62.5%) showed significant expression of MRP. The level of MRP expression was significantly correlated with the WR% of (99m)Tc-MIBI (r = 0.58, P = 0.003), and the WR% of (99m)Tc-MIBI was significantly faster in patients with high MRP expression than in those with a low MRP score (P = 0.007). The clearance rate of (99m)Tc-MIBI was significantly slower in tumor samples with negative or low expression of both Pgp and MRP (16% +/- 6.2%) when compared with osteosarcomas with high expression of both proteins (31.7% +/- 8.7%) (P = 0.001). There was not a significant difference between the WR% of (99m)Tc-MIBI in tumors with coexpression of both proteins and in tumors with high expression of either Pgp or MRP. Both the rate of MRP expression and the WR% of (99m)Tc-MIBI were significantly correlated with response rate. CONCLUSION: Our results suggest that the WR% of (99m)Tc-MIBI is correlated with MRP expression. Both the WR% of (99m)Tc-MIBI and MRP expression are correlated with therapy response. (99m)Tc-MIBI can be used as a general probe for functional imaging of both Pgp and MRP; however, it is not capable of differentiating the functional status of either MDR-related glycoprotein.

Complex regional pain syndrome after thromboendarterectomy: which type is it?

The authors describe a complex regional pain syndrome (CRPS) and discuss its type according to the presence or absence of nerve injury. A patient underwent thromboendarterectomy of the right popliteal artery. Subsequently, right lower limb reflex sympathetic dystrophy developed, which was confirmed by scintigraphy and responded well to calcitonin treatment. Typing according to the new classification of CRPS type I or II with possible nerve injury is discussed, and a short review of the literature is included.

Post-traumatic knee pain leading to the diagnosis of spondyloarthropathy.

The authors report a patient with persistent left knee pain after traumatic injury. The initial bone scan seemed to confirm a valgus stress knee injury. The final diagnosis, however, was focal inflammation of the knee ligaments (enthesopathy) related to ankylosing spondylitis. The diagnostic procedure and the results of other imaging modalities are presented. The bone scan findings are discussed.

[The interest of 18FDG-PET in the management of testicular cancer]. / Apport de l'imagerie au 18FDG dans la prise en charge du cancer du testicule.

The key to prognosis. Initial staging and early recurrence diagnosis are key parameters in the treatment and outcome of testicular cancer. Initial staging. It is difficult using conventional modalities, which can miss node involvement and are non-specific since enlargement does not rhyme with involvement. 18FDG PET improves the accuracy of initial staging. Residual mass and recurrences. Existence of residual mass or enhancement of its Volume in the presence of an otherwise beneficial chemotherapy is difficult to manage. Several studies have demonstrated the value of 18FDG imaging in such cases. As for follow-up whole body 18FDG can prevent multiple diagnostic imaging and can diagnose recurrences with greater diagnostic accuracy than with other imaging modalities.

The impact of PET/CT imaging performed in the early postoperative period on the management of breast cancer patients.

OBJECTIVES: The aim of the study was to evaluate the role of F-fluorodeoxyglucose ((18)F-FDG) PET/computed tomography (CT) in the early postoperative staging of breast cancer and to document (18)F-FDG PET/CT-based stage alterations and any subsequent impact on management. MATERIALS AND METHODS: Between January 2009 and June 2012, PET/CT images of patients with histopathologically proven breast cancer who underwent surgery with no previous chemotherapy or radiotherapy were retrospectively reviewed. Any stage alteration due to a change in nodal or metastatic status on PET/CT was noted. RESULTS: A total of 77 women (median age: 52 years; range: 26-87 years) were included. PET/CT revealed distant metastases that were previously undetected in 12 of the 77 women (15.6%). Of these women, one (8.3%) was diagnosed with stage I, four (33.3%) with stage II, and seven (58.4%) with stage III disease before the PET study. In two patients, lung lesions were diagnosed as metastases by conventional imaging methods, and in one patient the lesions were revealed to have a low probability for malignancy on PET/CT, and they were confirmed as benign on follow-up CT. Thus, changes in disease stage occurred in 15 of 77 (19.5%) patients following PET/CT. The disease was upstaged in 14 patients (18.2%) and downstaged in one (1.3%). CONCLUSION: The impact of (18)F-FDG PET/CT is highest in newly diagnosed stage III breast cancer because of the identification of previously undetected extra-axillary lymph nodes and distant metastases. Early postoperative (18)F-FDG PET/CT imaging may alter the staging and potentially contribute to the management of these patients.

Hand involvement in Behçet's disease.

AIMS: To study the clinical hand findings in Behçet's disease (BD) and to observe scintigraphic changes of these areas. METHODS: Fifty-seven randomly selected BD patients and the patients in the control group (N=40) were evaluated by two blind rheumatologists. The hands were examined for the presence of pain, tenderness, swelling, effusion, erythema, warmth, range of motion and limitation of motion, deformities and muscle atrophy. Then scintigraphic examination of the hands was performed. Control hand scintigrams were obtained from 40 age- and sex-matched patients and were examined by the same two observers. RESULTS: Thirty-two of the 57 patients (56.1%) showed Behçet's clinical hand findings. Terminal phalangeal pulp atrophy was observed in 17 (29.81%), rheumatoid-like hand findings were observed in 16 (28.1%), dorsal interosseos atrophy was observed in 12 (20.05%) and erythema over the digits was observed in 12 (20.05%). Twenty-four patients (42.1%) had scintigraphic involvement. The disease duration was observed to be an important factor for hand findings (P=0.040) and scintigraphic involvement (P=0.011). CONCLUSION: High prevalence of hand involvement in BD and its relationship with disease duration is demonstrated. Hand involvement tends to be overlooked and careful examination is required in the evaluation of BD. The scintigraphic involvement detected in hands requires special consideration, too.

In vitro and in vivo study of 99mTc-MIBI encapsulated in PEG-liposomes: a promising radiotracer for tumour imaging.

Encapsulation of technetium-99m sestamibi ((99m)Tc-MIBI) in polyethyleneglycol-liposomes ((99m)Tc-MIBI-PEG-liposomes) could extend the duration of its circulation in blood and alter its biodistribution, enabling its concentration in tumours to be increased. An original method to encapsulate (99m)Tc-MIBI in PEG-liposomes is described. The (99m)Tc-MIBI-PEG-liposomes were compared with free (99m)Tc-MIBI with respect to (a) tumour availability (b) ability to distinguish between chemotherapy-sensitive and -resistant cells and (c) uptake ratio in tumour imaging. PEG-liposomal systems composed of distearoylphosphatidylcholine/cholesterol/PEG(2000)-distearoyl phosphatidylethanolamine and lissamine-rhodamine B-labelled liposomes were used. The encapsulation of (99m)Tc-MIBI in liposomes was achieved using the K(+) diffusion potential method. We compared the uptake of free versus encapsulated (99m)Tc-MIBI by sensitive and resistant erythroleukaemia (K562) and breast tumour (MCF-7ras) cells. To assess the internalisation of these liposomes into cells, rhodamine B-labelled PEG-liposomes were used and visualised by fluorescence microscopy. Biodistribution and imaging characteristics of encapsulated and free radiotracer were determined in rats and tumour-bearing nude mice. The efficiency of (99m)Tc-MIBI encapsulation in PEG-liposomes was 50+/-5%. Use of (99m)Tc-MIBI-PEG-liposomes did not impair the ability of this tracer to distinguish between chemotherapy-sensitive and -resistant tumour cells; the percentage of radioactivity accumulated in the sensitive K562 cells was 1.24+/-0.04%, as compared with 0.41+/-0.04% in the resistant K562 cells. One hour post injection in rats, PEG-liposomes showed a ten times higher activity in blood than free (99m)Tc-MIBI, whereas activity of free (99m)Tc-MIBI in kidneys and bladder was markedly higher than that of encapsulated (99m)Tc-MIBI, indicating faster clearance of the free radiotracer. In the (MCF7-ras)-bearing nude mice, PEG-liposome uptake in tumour was two times that of free (99m)Tc-MIBI. Summarising, the (99m)Tc-MIBI-PEG-liposomes demonstrated a longer blood circulation time, enabled distinction between chemotherapy-sensitive and -resistant cells and improved tumour to background contrast in in vivo imaging. (99m)Tc-MIBI-PEG-liposomes therefore show promising potential for tumour imaging.