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  • ultrasound  (3)
  • GRADE  (2)
  • LEAKAGE CORRECTION  (2)
Keywords
  • 1
    Keywords: CANCER ; TIME ; MRI ; EXPERIENCE ; ultrasound ; GUIDANCE ; GUIDED BIOPSY
    Abstract: Abstract Purpose: To determine the targeting error of a novel stereotactic prostate biopsy system that integrates preinterventional MRI with peri-interventional ultrasonography (US) for perineal navigated prostate biopsies. Materials and Methods: We performed stereotactic biopsies on five prostate phantoms (one CIRS 053-MM and four CIRS 066). Phantom 053-MM incorporates three MRI- and transrectal ultrasonography (TRUS)-visible lesions, while lesions within phantom 066 are only detectable on MRI. In both phantoms, the 0.5 cc volume lesions are placed randomly. The phantoms were examined by 3T-MRI preinterventionally. Then three stereotactic biopsies from one lesion in phantom 053-MM and from all US-invisible lesions in the 066 phantoms were taken under live-fusion imaging guidance. During intervention, a mix of blue ink and gadobutrol was injected into each biopsy channel. Afterward, another 3T-MRI was obtained. These MRI images were then fused again with the intraoperative TRUS data. Thus, the targeting error (TE) between the planned and performed biopsy cores could be measured. In addition, the procedural targeting error (PTE) between the virtually planned biopsy trajectory and the manually registered three-dimensional needle position of every single biopsy core taken was calculated. Results: The overall TE of the 39 biopsy cores taken was 0.83 mm (standard deviation [SD]: 0.48 mm) with the highest TE in the sagittal plane (1.09+/-0.54 mm), followed by the coronal (0.72+/-0.43 mm) and axial (0.69+/-0.34 mm) planes. The procedural TE, which is provided intraoperatively, was 0.26 mm on average (SD: 0.46 mm). Comparing PTE and TE, there was no statistically significant difference (P=0.39). Conclusion: The TE of stereotactic biopsies using our novel perineal prostate biopsy system is below 1 mm and can be estimated in vivo by the automatically calculated procedural TE. Thus, stereotactic prostate biopsies guided by the combination of MRI and US allow effective and precise examination of MRI lesions.
    Type of Publication: Journal article published
    PubMed ID: 22283184
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  • 2
    Keywords: MULTIFORME ; BRAIN-TUMORS ; GLIOMA ; COEFFICIENTS ; LEAKAGE CORRECTION ; PRIMARY CEREBRAL LYMPHOMA ; PRIMARY CNS LYMPHOMAS ; BLOOD-VOLUME
    Abstract: Purpose To compare multiparametric diagnostic performance with diffusion-weighted, dynamic susceptibility-weighted contrast material-enhanced perfusion-weighted, and susceptibility-weighted magnetic resonance (MR) imaging for differentiating primary central nervous system lymphoma (PCNSL) and atypical glioblastoma. Materials and Methods This retrospective study was institutional review board-approved and informed consent was waived. Pretreatment MR imaging was performed in 314 patients with glioblastoma, and a subset of 28 patients with glioblastoma of atypical appearance (solid enhancement with no visible necrosis) was selected. Parameters of diffusion-weighted (apparent diffusion coefficient [ADC]), susceptibility-weighted (intratumoral susceptibility signals [ITSS]), and dynamic susceptibility-weighted contrast-enhanced perfusion-weighted (relative cerebral blood volume [rCBV]) imaging were evaluated in these 28 patients with glioblastoma and 19 immunocompetent patients with PCNSL. A two-sample t test and chi(2) test were used to compare parameters.The diagnostic performance for differentiating PCNSL from glioblastoma was evaluated by using logistic regression analyses with leave-one-out cross validation. Results Minimum, maximum, and mean ADCs and maximum and mean rCBVs were significantly lower in patients with PCNSL than in those with glioblastoma (P 〈 .01, respectively), whereas mean ADCs and mean rCBVs allowed the best diagnostic performance. Presence of ITSS was significantly lower in patients with PCNSL (32% [six of 19]) than in those with glioblastoma (82% [23 of 28]) (P 〈 .01). Multiparametric assessment of mean ADC, mean rCBV, and presence of ITSS significantly increased the probability for differentiating PCNSL and atypical glioblastoma compared with the evaluation of one or two imaging parameters (P 〈 .01), thereby correctly predicting histologic results in 95% (18 of 19) of patients with PCNSL and 96% (27 of 28) of patients with atypical glioblastoma. Conclusion Combined evaluation of mean ADC, mean rCBV, and presence of ITSS allowed reliable differentiation of PCNSL and atypical glioblastoma in most patients, and these results support an integration of advanced MR imaging techniques for the routine diagnostic workup of patients with these tumors. (c) RSNA, 2014.
    Type of Publication: Journal article published
    PubMed ID: 24814181
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  • 3
    Keywords: CANCER ; RISK ; TIME ; ANTIGEN ; SPECTROSCOPY ; MEN ; prostate cancer ; FEASIBILITY ; ultrasound ; COIL ; detection rate ; 1.5 T ; ROUTINE ; PSA ; TRUS ; MRI-guided biopsy ; Significant carcinoma
    Abstract: PURPOSE: To investigate the positive biopsy rate of MRI-guided biopsy (MR-GB) in a routine clinical setting, identify factors predictive for positive biopsy findings and to report about the clinical significance of the diagnosed tumors. METHODS: Patients with at least one negative trans-rectal-ultrasound-guided biopsy (TRUS-GB), persistently elevated or rising serum prostate specific antigen (PSA) and at least one lesion suspicious for PCa on diagnostic 1.5 Tesla endorectal coil MRI (eMR) were included. Biopsies were carried out using a 1.5 Tesla MRI and an 18 G biopsy gun. Clinical information and biopsy results were collected; logistic regression analysis was carried out. Definite pathology reports of patients with diagnosis of PCa and subsequent radical prostatectomy (RP) were analyzed for criteria of clinical significance. RESULTS: One hundred patients were included, mean number of previous biopsies was 2 (range 1-9), mean PSA at time of biopsy was 11.7 ng/ml (1.0-65.0), and mean prostate volume was 46.7 ccm (range 13-183). In 52/100 (52.0%) patients, PCa was detected. Out of 52 patients, 27 patients with a positive biopsy underwent RP, 20 patients radiation therapy, and 5 patients active surveillance. In total, 80.8% of the patients revealed a clinically significant PCa. In univariate regression analysis, only serum PSA levels were predictive for a positive biopsy result. Number of preceding negative biopsies was not associated with the likelihood of a positive biopsy result. CONCLUSIONS: MR-GB shows a high detection rate of clinically significant PCa in patients with previous negative TRUS-GB and persisting suspicion for PCa.
    Type of Publication: Journal article published
    PubMed ID: 21512807
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  • 4
    Keywords: CANCER ; DIFFERENTIATION ; TISSUE ; LOCALIZATION ; PARAMETERS ; CONTRAST-ENHANCED MRI ; GRADE ; TUMOR-DETECTION ; IMAGE QUALITY ; WATER DIFFUSION
    Abstract: PURPOSE: To flesh out the ESUR guidelines for the standardized interpretation of multiparametric magnetic resonance imaging (mMRI) for the detection of prostate cancer and to present a graphic reporting scheme for improved communication of findings to urologists. MATERIALS AND METHODS: The ESUR has recently published a structured reporting system for mMRI of the prostate (PI-RADS). This system involves the use of 5-point Likert scales for grading the findings obtained with different MRI techniques. The mMRI includes T2-weighted MRI, diffusion-weighted imaging, dynamic contrast-enhanced MRI, and MR spectroscopy. In a first step, the fundamentals of technical implementation were determined by consensus, taking into account in particular the German-speaking community. Then, representative images were selected by consensus on the basis of examinations of the three institutions. In addition, scoring intervals for an aggregated PI-RADS score were determined in consensus. RESULTS: The multiparametric methods were discussed critically with regard to implementation and the current status. Criteria used for grading mMRI findings with the PI-RADS classification were concretized by succinct examples. Using the consensus table for aggregated scoring in a clinical setting, a diagnosis of suspected prostate cancer should be made if the PI-RADS score is 4 or higher (〉/= 10 points if 3 techniques are used or 〉/= 13 points if 4 techniques are used). Finally, a graphic scheme was developed for communicating mMRI prostate findings. CONCLUSION: Structured reporting according to the ESUR guidelines contributes to quality assurance by standardizing prostate mMRI, and it facilities the communication of findings to urologists.
    Type of Publication: Journal article published
    PubMed ID: 23404430
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  • 5
    Keywords: MODEL ; SYSTEM ; IMPACT ; MRI ; MEN ; FUSION ; ultrasound ; GUIDANCE ; ACTIVE SURVEILLANCE ; CANCER DETECTION
    Abstract: Objective: To optimize image-guided prostate biopsy by minimizing the target error with trocar-sharpened needle tips instead of beveled needles, which constantly deviate away from the bevel. Materials and Methods:We performed stereotactic biopsies on two prostate phantoms, which incorporate three randomly placed TRUS-visible lesions. Four stereotactic biopsies per lesion were taken under live-ultrasound guidance through a template: two biopsies with conventional beveled needles and two biopsies with novel trocar-sharpened needles. The procedural targeting error (PTE) between the virtually planned biopsy trajectory and the manually registered 3D needle position of every single biopsy core taken was calculated. Results: The absolute overall targeting error using the novel needle-tip design was 0.13 mm (SD: +/- 0.15 mm) with the highest PTE in the sagittal plane (0.18 +/- 0.16 mm), followed by the coronal (0.13 +/- 0.17 mm) and axial (0.09 +/- 0.05 mm) planes. Comparing the PTE of the novel trocar-shaped needles with conventional beveled needles, there was a statistically significant difference in the axial plane [p (overall) = 0.47, p(axial) = 0.03]. Conclusion: The targeting error of stereotactic biopsies using trocar-sharpened needles is significantly lower than the targeting error of classical beveled needles. Thus, trocar-tip configurations improve the accuracy of computer-assisted biopsies and allow precise assessment of suspicious lesions in the prostate and in other organs accessible to image-guided biopsy.
    Type of Publication: Journal article published
    PubMed ID: 23838372
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  • 6
    Keywords: TUMORS ; CENTRAL-NERVOUS-SYSTEM ; physiology ; GLIOMAS ; GRADE ; CEREBRAL BLOOD-VOLUME ; T-2-ASTERISK-DOMINANT EXTRAVASATION CORRECTION ; VASCULAR INPUT FUNCTION ; LEAKAGE CORRECTION ; CEDIRANIB
    Abstract: BACKGROUND AND PURPOSE: Dynamic contrast-enhanced MR imaging can provide in vivo assessment of the microvasculature in intracranial tumors. The aim of the present study was to evaluate the diagnostic performance of dynamic contrast-enhanced MR imaging derived vascular permeability parameters, including the volume transfer constant, the volume of extravascular extracellular space, and the flux rate constant between the extravascular extracellular space and plasma, for the differentiation of primary CNS lymphoma and glioblastoma. MATERIALS AND METHODS: Sixty glioblastomas and 11 primary central nervous system lymphomas were included. Pretreatment T1-weighted dynamic contrast-enhanced MR imaging with a 3D T1-weighted spoiled gradient-echo sequence was performed on a 3T MR imaging scanner. Perfusion parameters (volume transfer constant, the volume of extravascular extracellular space, and the flux rate constant) were measured on the basis of the Tofts-Kernmode model. The Mann-Whitney U test and receiver operating characteristic analysis were used to compare those parameters between primary central nervous system lymphoma and glioblastoma. Histopathologic correlation of dynamic contrast-enhanced MR imaging findings was performed by using reticulin staining and CD31 immunohistochemistry. RESULTS: Median volume transfer constant and flux rate constant values were significantly higher in primary central nervous system lymphoma (0.145 +/- 0.057 and 0.396 +/- 0.088) than in glioblastoma (0.064 +/- 0.021 and 0.230 +/- 0.058) (P 〈 .001, respectively). Median volume of extravascular extracellular space values did not differ significantly between primary central nervous system lymphoma (0.434 +/- 0.165) and glioblastoma (0.319 +/- 0.107). On receiver operating characteristic analysis, volume transfer constant had the best discriminative value for differentiating primary central nervous system lymphoma and glioblastoma (threshold, 0.093; sensitivity, 90.9%; specificity, 95.0%). Histopathologic evaluation revealed intact vascular integrity in glioblastoma despite endothelial proliferation, whereas primary central nervous system lymphoma demonstrated destroyed vessel architecture, thereby promoting vascular disintegrity. CONCLUSIONS: Primary central nervous system lymphoma demonstrated significantly higher volume transfer constant and flux rate constant values compared with glioblastoma, implying a higher vascular permeability in primary central nervous system lymphoma. These findings confirm initial observations from perfusion CT and dynamic contrast-enhanced MR imaging studies, correlating with underlying histopathologic features, and may be useful in distinguishing primary central nervous system lymphoma from glioblastoma.
    Type of Publication: Journal article published
    PubMed ID: 24722313
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