Magnetic Resonance Sentinel Lymph Node Imaging of the Prostate with Gadofosveset Trisodium-Albumin: Preliminary Results in a Canine Model (original) (raw)
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Acta radiologica (Stockholm, Sweden : 1987), 2015
A variety of magnetic resonance (MR) lymphographic agents have been proposed for mapping the lymph nodes draining the prostate. To investigate the feasibility of using ferumoxytol (an FDA-approved iron oxide agent) for lymph node mapping of the prostate on imaging (MRI) in a non-human primate (NHP) Macaque model. Four NHPs weighing 5-13 kg underwent injection of ferumoxytol after a needle was introduced transrectally under MRI guidance into the prostate using a commercially available intrarectal MRI biopsy guide. Ferumoxytol was administered at dosage in the range of 0.15-0.75 mg Fe/kg in a fixed injection volume of 0.2 mL. T1-weighted MRI was performed at 3 T starting immediately and extending at least 45 min post-injection. Two readers evaluated the images in consensus. The NHPs tolerated the ferumoxytol injections at all doses with no evident side effects. It was determined that the lowest dose of 0.15 mg Fe/kg produced the best outcome in terms of lymph node visualization and dr...
Clinical & Experimental Metastasis, 2012
Sentinel lymph node (SLN) identification with preoperative image guidance may improve pathological staging of prostate cancer by identifying nodes outside the standard template of dissection. Four anesthetized male dogs received an intra-prostatic injection of Ga-68-labeled tilmanocept. Every 20 min the pelvic lymph nodes were imaged using PET/CT fusion imaging. At 90 min postinjection a prostatectomy and extended lymphadenectomy were completed; ex vivo radioactivity was recorded for each node using a handheld gamma detector, and confirmed by calculation of percent-of-injected dose (%ID) via assay of Ga-68 radioactivity. SLNs were defined as containing [10 % of the maximum %ID. Preoperative PET/ CT fusion imaging identified a mean of 4.25 lymph nodes per animal (range 3-7); the mean number of SLN per animal was 4.00 (range 2-6).Of the excised SLNs, 29 % were located in the standard external iliac and obturator distribution. The SLN %ID ranged from 0.07 to 2.40 % (mean 0.744 % ± 0.641 %); SLN ex vivo count rate ranged from 88 to 2,175 cpm (mean 896 ± 715 cpm); and the SLN standardize uptake values (SUVs) ranged from 13 to 237 (mean 79 ± 67).There was a high concordance of PET-CT imaging to SLN activity, with sensitivity of 93 %. In this feasibility study, pelvic SLNs attained SUVs within 60 min. PET/CT effectively identified SLNs with good anatomic specificity, and radioactivity by hand-held detection and scintillation counts demonstrated high concordance with preoperative imaging. Gallium-68-labaled tilmanocept was highly specific for sentinel nodes. Imageguided tumor resection and lymphadenectomy may become a promising future application in urologic oncology and warrants further investigation.
Acta Radiologica, 2011
Post-contrast diffusion-weighted imaging (DWI) is occasionally necessary when the results of the pre-contrast DWI differ from that of the dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI), however, the effects of contrast material on DWI image and apparent diffusion coefficient (ADC) values have not been fully examined. To assess whether the administration of gadolinium-DTPA (Gd-DTPA) significantly affects the DWI of prostate lesions or normal tissue at the 3.0 Tesla magnetic resonance imaging (3.0 T MRI). Fifty-one patients with 52 prostate lesions, including 32 prostate cancer (25 in the peripheral zone [PZ] and seven that could not be confidently located) and 20 benign lesions (11 in PZ and nine in central grand [CG]), underwent echo-planar imaging (EPI)-DWI with b values of 0, 1000 s/mm(2) before and after administration of Gd-DTPA at 3.0 T MRI. Regions of interest (ROI) were drawn in all lesions, 42 normal PZ, 44 CG tissue and air to calculate the signal-to-noise ratio (SNR) and ADC values of lesions and normal tissue, and contrast-to-noise ratio (CNR) of lesions for pre- and post-contrast images. Statistical differences between pre- and post-contrast data were assessed by use of a paired t test. No significant differences between pre- and post-contrast images were found in the CNR of lesions and SNR of all the tissue except CG, which showed a statistically significant decline (9.6%, p < 0.0001) in SNR after contrast relative to the pre-contrast images. The post-contrast ADC values were statistically significantly lower than pre-contrast for prostate cancer (0.80 ± 0.11 mm(2)/s Vs 0.89 ± 0.12 mm(2)/s, p < 0.0001) and benign lesions (1.14 ± 0.30 mm(2)/s vs. 1.2 ± 0.29 mm(2)/s, p < 0.0001). No significant differences were detected for normal tissue. The administration of Gd-DTPA can slightly affect the DWI image quality of the prostate and reduce the ADC value of lesions at 3.0T MRI. Applications of post-contrast DWI require caution in interpretation.
Urology, 2003
To explore the use of magnetic resonance imaging (MRI) with gadolinium enhancement as a noninvasive method to image the extent of ablation after minimally invasive treatment. Minimally invasive methods for ablating prostatic tissue have emerged as a viable option in the treatment of prostate disease. As these devices enter the mainstream of patient care, imaging methods that verify the exact location, extent, and pattern of the ablation are needed. Nineteen patients with prostate cancer were evaluated. All received some type of minimally invasive treatment, post-treatment gadolinium-enhanced MRI sequences, and radical retropubic prostatectomy for histopathologic evaluation. Visual comparisons of gadolinium defects and areas of coagulation necrosis as seen on histopathologic evaluation were made by us. Volumetric and two-dimensional area measurements of the ablation lesions were also compared for correlation between the MRI and histopathologic results. Gadolinium-enhanced MRI could be matched to histopathologic findings by visual comparison in 17 of the 19 cases. Surgically distorted histopathologic specimens and a small periurethral lesion caused 2 patients to have MRI and histopathologic results that could not be matched. Complete volumetric measurements were available for 16 of the 19 patients and correlated strongly (r = 0.924). The two-dimensional area data for all patients also showed significant correlation (r = 0.886). Correlation with histopathologic findings showed gadolinium-enhanced MRI to be useful for determining the location, pattern, and extent of necrosis caused within the prostate by minimally invasive techniques. Gadolinium-enhanced MRI gives the urologist a useful tool to evaluate the effectiveness of new minimally invasive therapies.
Pilot study of gadoxetate disodium-enhanced mri for localized and metastatic prostate cancers
Scientific Reports, 2021
OATP1B3 is expressed de novo in primary prostate cancer tissue and to a greater degree in prostate cancer metastases. Gadoxetate disodium is a substrate of OATP1B3, and its uptake has been shown to correlate with OATP1B3 expression in other cancers. We aimed to evaluate use of gadoxetate disodium to image prostate cancer and to track its utility as a biomarker. A single center open-label non-randomized pilot study recruited men with (1) localized, and (2) metastatic castration resistant prostate cancer (mCRPC). Gadoxetate disodium-enhanced MRI was performed at four timepoints post-injection. The Wilcoxon signed rank test was used to compare MRI contrast enhancement ratio (CER) pre-injection and post-injection. OATP1B3 expression was evaluated via immunohistochemistry (IHC) and a pharmacogenomic analysis of OATP1B3, NCTP and OATP1B1 was conducted. The mCRPC subgroup (n = 9) demonstrated significant enhancement compared to pre-contrast images at 20-, 40- and 60-min timepoints (p < ...
Magnetic resonance imaging of the prostate: an overview for radiologists
Radiologia Brasileira, 2009
Prostate adenocarcinoma is the second tumor in incidence and mortality among malignant neoplasms in men. The differentiation between tumors confined to the organ and those with extraprostatic extension is critical for an appropriate therapeutic planning. Different studies have demonstrated that magnetic resonance imaging of the prostate with endorectal coil is useful in the local staging of these tumors. The present article presents information on the prostate gland anatomy, the tumor aspect at magnetic resonance imaging, specific signs of extracapsular extension and seminal vesicles invasion, protocol suggestions, general principles and relevance of proton spectroscopy, perfusion and diffusion imaging, role of magnetic resonance imaging in the postoperative and post-radiotherapy detection of local tumor recurrence, and also in the detection of lesions in patients with clinical/laboratory suspicion of prostate adenocarcinoma. Additionally, the present article describes differential diagnoses and limitations of the method.