Prostate cancer vs. post‐biopsy hemorrhage: Diagnosis with T2‐ and diffusion‐weighted imaging

Purpose:

To assess the value of quantitative T2 signal intensity (SI) and apparent diffusion coefficient (ADC) to differentiate prostate cancer from post‐biopsy hemorrhage, using prostatectomy as the reference.

Materials and Methods:

Forty‐five men with prostate cancer underwent prostate magnetic resonance imaging (MRI), including axial T1‐weighted imaging (T1WI), T2WI, and single‐shot echo‐planar image (SS EPI) diffusion‐weighted imaging. Two observers measured, in consensus, normalized T2 signal intensity (SI) (nT2, relative to muscle T2 SI), ADC, and normalized ADC (nADC, relative to urine ADC) on peripheral zone (PZ) tumors, benign PZ hemorrhage, and non‐hemorrhagic benign PZ. Tumor maps from prostatectomy were used as the reference. Mixed model analysis of variance was performed to compare parameters among the three tissue classes, and Pearson's correlation coefficient was utilized to assess correlation between parameters and tumor size and Gleason score. Receiver‐operating characteristic (ROC)‐curve analysis was used to determine the performance of nT2, ADC, and nADC for diagnosis of prostate cancer.

Results:

nT2, ADC, and nADC were significantly lower in tumor compared with hemorrhagic and non‐hemorrhagic benign PZ (P < 0.0001). There was a weak but significant correlation between ADC and Gleason score (r = ?0.30, P = 0.0119), and between ADC and tumor size (r = ?0.40, P = 0.0027), whereas there was no correlation between nT2 and Gleason score and tumor size. The areas under the curve to distinguish tumor from benign hemorrhagic and non‐hemorrhagic PZ were 0.97, 0.96, and 0.933 for nT2, ADC, and nADC, respectively.

Conclusion:

Quantitative T2 SI and ADC/nADC values may be used to reliably distinguish prostate cancer from post‐biopsy hemorrhage. J. Magn. Reson. Imaging 2010;31:1387–1394. © 2010 Wiley‐Liss, Inc.

     

Prostate spectroscopy at 3 Tesla using two‐dimensional S‐PRESS

Two‐dimensional (2D) strong‐coupling point‐resolved spectroscopy (S‐PRESS) is introduced as a novel approach to ¹H MR spectroscopy (MRS) in the prostate. The technique provides full spectral information and allows for an accurate characterization of the citrate (Cit) signal. The method is based on acquiring a series of PRESS spectra with constant total echo time (TE). The indirect dimension is encoded by varying the relative lengths of the first and second TEs (TE₁ + TE₂ = TE). In the resulting 2D spectra, only the signal of strongly coupled spin systems is spread into the second dimension, which leads to more clearly arranged spectra. Furthermore, the spectral parameters of Cit (coupling constant J and chemical shift difference δ of the AB spin system) can be determined with high accuracy in vivo. The sequence is analytically optimized for maximal “strong coupling peaks” of Cit at 3T. 2D S‐PRESS spectra are compared with JPRESS spectra in vitro as well as in vivo. Magn Reson Med, 2006. © 2006 Wiley‐Liss, Inc.     

Prostate cancer metabolite quantification relative to water in 1H‐MRSI in vivo at 3 Tesla

¹H magnetic resonance spectroscopic imaging was performed on 16 men with suspected prostate cancer using an 8‐channel external receive coil at 3 T. Choline and citrate (Cit) signals were measured in prostate lesions and normal‐appearing peripheral zone as identified on T₂‐weighted images. Metabolites were quantified relative to unsuppressed water from a separately acquired magnetic resonance spectroscopic imaging dataset using LCModel. Validation experiments were also performed in a phantom containing physiological concentrations of choline, Cit, and creatine. In vitro, fair agreement between measured and true concentrations was observed, with the greatest discrepancy being a 35% underestimation of Cit. In vivo, one dataset was rejected for failure to meet the quality criterion of linewidth <15 Hz, and in 6 of 15 subjects, insufficient normal‐appearing peripheral zone tissue was identified for study. Lesions were found to have higher choline and choline/Cit, and lower Cit, than normal‐appearing peripheral zone. The smaller skew of data obtained using water normalization in comparison with metabolite ratios suggests potential usefulness in longitudinal tumor monitoring and in studies of treatment effects. Magn Reson Med, 2010. © 2010 Wiley‐Liss, Inc.     

Prostate cancer detection with 3 T MRI: Comparison of diffusion‐weighted imaging and dynamic contrast‐enhanced MRI in combination with T2‐weighted imaging

Purpose:

To evaluate the diagnostic ability of diffusion‐weighted imaging (DWI) and dynamic contrast‐enhanced imaging (DCEI) in combination with T2‐weighted imaging (T2WI) for the detection of prostate cancer using 3 T magnetic resonance imaging (MRI) with a phased‐array body coil.

Materials and Methods:

Fifty‐three patients with elevated serum levels of prostate‐specific antigen (PSA) were evaluated by T2WI, DWI, and DCEI prior to needle biopsy. The obtained data from T2WI alone (protocol A), a combination of T2WI and DWI (protocol B), a combination T2WI and DCEI (protocol C), and a combination of T2WI plus DWI and DCEI (protocol D) were subjected to receiver operating characteristic (ROC) curve analysis.

Results:

The sensitivity, specificity, accuracy, and area under the ROC curve (Az) for region‐based analysis were: 61%, 91%, 84%, and 0.8415, respectively, in protocol A; 76%, 94%, 90%, and 0.8931, respectively, in protocol B; 77%, 93%, 89%, and 0.8655, respectively, in protocol C; and 81%, 96%, 92%, and 0.8968, respectively in protocol D. ROC analysis revealed significant differences between protocols A and B (P = 0.0008) and between protocols A and D (P = 0.0004).

Conclusion:

In patients with elevated PSA levels the combination of T2WI, DWI, DCEI using 3 T MRI may be a reasonable approach for the detection of prostate cancer. J. Magn. Reson. Imaging 2010;31:625–631. © 2010 Wiley‐Liss, Inc.     

ACR Appropriateness Criteria Posttreatment Follow-up of Prostate Cancer

Although prostate cancer can be effectively treated, recurrent or residual disease after therapy is not uncommon and is usually detected by a rise in prostate-specific antigen. Patients with biochemical prostate-specific antigen relapse should undergo a prompt search for the presence of local recurrence or distant metastatic disease, each requiring different forms of therapy. Various imaging modalities and image-guided procedures may be used in the evaluation of these patients. Literature on the indications and usefulness of these radiologic studies and procedures in specific clinical settings is reviewed. The ACR Appropriateness Criteria(?) are evidence-based guidelines for specific clinical conditions that are reviewed every 2 years by a multidisciplinary expert panel. The guideline development and review include an extensive analysis of current medical literature from peer-reviewed journals and the application of a well-established consensus methodology (modified Delphi) to rate the appropriateness of imaging and treatment procedures by the panel. In those instances in which evidence is lacking or not definitive, expert opinion may be used to recommend imaging or treatment.     

前列腺癌内分泌治疗后复发的MRI研究

目的探讨前列腺癌内分泌治疗后复发的MR I征象。方法10例经临床诊断证实的前列腺癌内分泌治疗后复发的病人,在内分泌治疗过程中肿瘤复发前后都进行了MR I检查。对2次MR I图像中前列腺T2信号、体积变化、对周围组织侵犯、扫描范围内的骨转移和淋巴结转移等情况进行对比分析。结果与复发前对比,前列腺体积增大的有7例,体积未见明显变化的有3例。复发后新出现的周围组织侵犯包括精囊腺(3例)、膀胱(2例)、直肠(1例)、盆底肌(1例)。复发后扫描范围内(骨盆至髂血管分叉水平)原有骨转移病灶进展的有3例,新出现转移灶的有4例。新出现髂血管旁肿大淋巴结的有4例,腹股沟肿大淋巴结的有2例。结论MR I检查能提供有助于诊断内分泌治疗后肿瘤复发的多方面影像信息。     

Radiologists’ Contribution to Variation in Detecting Clinically Significant Prostate Cancer in Men With Prostate MRI

ObjectiveAssess radiologists’ contribution to variation in clinically significant prostate cancer (csPCa) detection in patients with elevated prostate-specific antigen (PSA) and multiparametric MRI (mpMRI).MethodsThis institutional review board–approved, retrospective cohort study was performed at a tertiary, academic, National Cancer Institute–designated Comprehensive Cancer Center with a multidisciplinary prostate cancer program. Men undergoing mpMRI examinations from January 1, 2015, to December 31, 2019, with elevated PSA (≥4 ng/mL) and biopsy within 6 months pre- or post-MRI or prostatectomy within 6 months post-mpMRI were included. Univariate and multivariable hierarchical logistic regression assessed impact of patient, provider, mpMRI examination, mpMRI report, and pathology factors on the diagnosis of Grade Group ≥ 2 csPCa.ResultsStudy cohort included 960 MRIs in 928 men, mean age 64.0 years (SD ± 7.4), and 59.8% (555 of 928) had csPCa. Interpreting radiologist was not significant individually (P > .999) or combined with mpMRI ordering physician and physician performing biopsy or prostatectomy (P = .41). Prostate Imaging Reporting and Data System (PI-RADS) category 2 (odds ratio [OR] 0.18, P = .04), PI-RADS category 4 (OR 2.52, P < .001), and PI-RADS category 5 (OR 4.99, P < .001) assessment compared with no focal lesion; PSA density of 0.1 to 0.15 ng/mL/cc (OR 2.46, P < .001), 0.15 to 0.2 ng/mL/cc (OR 2.77, P < .001), or ≥0.2 ng/mL/cc (OR 4.52, P < .001); private insurance (reference = Medicare, OR 0.52, P = .001), and unambiguous extraprostatic extension on mpMRI (OR 2.94, P = .01) were independently associated with csPCa. PI-RADS 3 assessment (OR 1.18, P = .56), age (OR 0.99, P = .39), and African American race (OR 0.90, P = .75) were not.DiscussionAlthough there is known in-practice variation in radiologists’ interpretation of mpMRI, in our multidisciplinary prostate cancer program we found no significant radiologist-attributable variation in csPCa detection.