Assessment of Prostate Cancer Aggressiveness Using Dynamic Contrast-enhanced Magnetic Resonance Imaging at 3 T

Background

A challenge in the diagnosis of prostate cancer (PCa) is the accurate assessment of aggressiveness.

Objective

To validate the performance of dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI) of the prostate at 3 tesla (T) for the assessment of PCa aggressiveness, with prostatectomy specimens as the reference standard.

Design, settings, and participants

A total of 45 patients with PCa scheduled for prostatectomy were included. This study was approved by the institutional review board; the need for informed consent was waived.

Outcome measurements and statistical analysis

Subjects underwent a clinical MRI protocol including DCE-MRI. Blinded to DCE-images, PCa was indicated on T2-weighted images based on histopathology results from prostatectomy specimens with the use of anatomical landmarks for the precise localization of the tumor. PCa was classified as low-, intermediate-, or high-grade, according to Gleason score. DCE-images were used as an overlay on T2-weighted images; mean and quartile values from semi-quantitative and pharmacokinetic model parameters were extracted per tumor region. Statistical analysis included Spearman's ρ, the Kruskal-Wallis test, and a receiver operating characteristics (ROC) analysis.

Results and limitations

Significant differences were seen for the mean and 75th percentile (p75) values of wash-in (p = 0.024 and p = 0.017, respectively), mean wash-out (p = 0.044), and p75 of transfer constant (K^trans) (p = 0.035), all between low-grade and high-grade PCa in the peripheral zone. ROC analysis revealed the best discriminating performance between low-grade versus intermediate-grade plus high-grade PCa in the peripheral zone for p75 of wash-in, K^trans, and rate constant (K_ep) (area under the curve: 0.72). Due to a limited number of tumors in the transition zone, a definitive conclusion for this region of the prostate could not be drawn.

Conclusions

Quantitative parameters (K^trans and K_ep) and semi-quantitative parameters (wash-in and wash-out) derived from DCE-MRI at 3 T have the potential to assess the aggressiveness of PCa in the peripheral zone. P75 of wash-in, K^trans, and K_ep offer the best possibility to discriminate low-grade from intermediate-grade plus high-grade PCa.     

Magnetic Resonance Imaging in Hemospermia

Purpose

We evaluated the prostate and seminal tract with magnetic resonance imaging (MRI) in patients with hemospermia.

Materials and Methods

To evaluate the prostate and seminal tract in 17 patients 20 to 59 years old (mean age 44) with hemospermia we performed transrectal ultrasound and MRI using an endorectal surface coil with a 1.5 tesla unit. Mean duration of hemospermia was 32 months (1 week to 16 years).

Results

Abnormalities were noted on transrectal ultrasound in 15 of the 17 patients (88%) and on MRI in all. Of the 12 cases of hemorrhage 10 involved the seminal vesicle and 2 involved the ejaculatory duct. There were 12 cystic lesions, including 7 in the mullerian and 5 in the ejaculatory ducts. Of 19 cases calculi were detected in the prostate in 5, seminal vesicle in 8, and ejaculatory and mullerian duct cysts in 4 and 2, respectively. There was 1 case of prostatic atrophy and 1 wolffian duct anomaly associated with an ejaculatory duct cyst, ectopic ureterocele and absence of the left kidney.

Conclusions

MRI with an endorectal surface coil is a powerful modality for evaluating the seminal tracts of patients with hemospermia. It can be performed clinically when transrectal ultrasonography is not satisfactory.     

股骨头坏死的系列MRI表现

目的观察系列MRI上股骨头坏死的坏死信号和坏死面积比例变化。方法自1997年至2005年5月,根据股骨头坏死的诊断标准,对10例(20髋)具有两次及以上MRI成像的股骨头坏死进行研究,两次MRI成像平均相差18.1个月,观察其坏死信号和坏死面积比例变化。结果两次MRI检查时,均有180个层面,共有38个层面出现信号改变。在无外科干预及软骨下骨折出现的11髋102个层面中,5个层面发生信号改变;在行髓芯减压治疗的6髋和出现软骨下骨折的3髋78个层面中,33个层面发生信号改变,P=0.000,具有显著统计学差异。第一次MRI检查时的平均坏死面积比例为(52.62±17.90)%;第二次MRI检查时的平均坏死面积比例为(52.24±19.39)%,P=0.687,两者无显著性差异。结论股骨头坏死的坏死面积比例不随病程的延长及临床分期的进展而改变。如无外科干预或软骨下骨折出现,股骨头坏死的信号强度也无明显变化。     

Magnetic Resonance Imaging of Shoulder Arthroplasty

Background

Magnetic resonance (MR) imaging evaluation of the painful failed shoulder arthroplasty is a useful imaging modality due to advancements in metal artifact reduction techniques, which allow assessment of the integrity of the supporting soft-tissue envelope and the implant.

Questions/Purposes

The focus of this pictorial review is to illustrate the benefits of MR imaging, whether used alone or as an adjunct to other imaging modalities, in aiding the clinician in the complex decision making process.

Methods

A PubMed (MEDLINE) search focusing on the complications and imaging assessment of shoulder arthroplasty was performed. Articles were selected for review based on their pertinence to the aforementioned topics.

Results

We discuss the ability of MR imaging to identify why a patient’s arthroplasty may have failed. Specific causes including component loosening and implant failure, rotator cuff and deltoid integrity, infection, subtle fractures, and nerve pathology are reviewed, with illustrative sample images.

Conclusion

MRI is a valuable tool in the assessment for pathology in the shoulder following arthroplasty.

Electronic supplementary material

The online version of this article (doi:10.1007/s11420-014-9399-3) contains supplementary material, which is available to authorized users.     

Achilles Impingement Tendinopathy on Magnetic Resonance Imaging

Haglund's syndrome is impingement of the retrocalcaneal bursa and Achilles tendon caused by a prominence of the posterosuperior calcaneus. Radiographic measurements are not sensitive or specific for diagnosing Haglund's deformity. Localization of a bone deformity and tendinopathy in the same sagittal section of a magnetic resonance imaging scan can assist with the diagnosis in equivocal cases. The aim of the present cross-sectional study was to determine the prevalence of Haglund's syndrome in patients presenting with Achilles tendinopathy and note any associated findings to determine the criteria for a diagnosis of Haglund's syndrome. We reviewed 40 magnetic resonance imaging scans with Achilles tendinopathy and 19 magnetic resonance imaging scans with Achilles high-grade tears and/or ruptures. Achilles tendinopathy was often in close proximity to the superior aspect of the calcaneal tuberosity, consistent with impingement (67.5%). Patients with Achilles impingement tendinopathy were more often female (p < .04) and were significantly heavier than patients presenting with noninsertional Achilles tendinopathy (p = .014) or Achilles tendon rupture (p = .010). Impingement tendinopathy occurred medially (8 of 20) and centrally (10 of 20) more often than laterally (2 of 20) and was associated with a posterior prominence or hyperconvexity with a loss of calcaneal recess more often than a superior projection (22 of 27 versus 8 of 27; p < .001). Haglund's deformity should be reserved for defining a posterior prominence or hyperconvexity with loss of calcaneal recess because this corresponds with impingement. Achilles impingement tendinopathy might be more appropriate terminology for Haglund's syndrome, because the bone deformity is often subtle. Of the 27 images with Achilles impingement tendinopathy, 10 (37.0%) extended to a location prone to Achilles tendon rupture. Given these findings, insertional and noninsertional Achilles tendinopathy are not mutually exclusive and impingement might be a subtle, unrecognized cause of Achilles tendinopathy and subsequent rupture.     

Magnetic Resonance Imaging of the Postoperative Meniscus

Imaging of the postoperative meniscus is a challenge. Nevertheless, magnetic resonance imaging (MRI) of the symptomatic knee after meniscal surgery is a valuable diagnostic study of both the menisci and the entire joint. At present, symptomatic patients who have had partial meniscectomy of less than 25% may be evaluated by MRI. For those with partial meniscectomy of greater than 25% or after meniscal repair, direct or indirect magnetic resonance arthrography (MRA) should be considered. Currently, the decision of whether to perform direct (intra-articular) versus indirect (intravenous) MRA must be reviewed on a case-by-case basis considering both the patient's ability to tolerate intra-articular injection and whether a significant effusion already exists, which will imbue the tear with synovial fluid (making intra-articular injection of less importance). In such cases of significant effusion, indirect MRA would be preferred. If MRI or MRA is contraindicated, computed tomography arthrography seems a promising alternative. For a patient who has undergone meniscal allograft transplantation, MRI seems adequate for detecting meniscocapsular healing, allograft extrusion, and allograft tear. Future improvements in MRI sequencing may obviate the need for invasive modalities.     

胆囊的MRI评价

胆囊作为贮存和浓缩胆汁的器官，其内的胆汁易于析出，凝集而形成结石。胆囊最常见的疾病多与结石相关，如胆石症、急慢性胆囊炎、胆囊癌等；其他影响胆囊的病理状态还包括胆道动力障碍、术后改变等。超声对胆囊结石及胆囊炎的诊断有较高的敏感性及特异性。还可通过摄取高脂食物前后对比评价胆囊功能，     

Functional Magnetic Resonance Imaging in Prostate Cancer

Context

Magnetic resonance imaging (MRI) combined with magnetic resonance spectroscopy imaging (MRSI), dynamic contrast-enhanced MRI, and diffusion-weighted MRI emerged as promising tests in the diagnosis of prostate cancer, and they show encouraging results.

Objective

This review emphasizes different functional MRI techniques in the diagnosis of prostate cancer and includes information about their clinical value and usefulness.

Evidence acquisition

The authors searched the Medline, Embase, and Cochrane Library databases. There were no language restrictions. The last search was performed in October 2008.

Evidence synthesis

The combination of conventional MRI with functional MRI techniques is more reliable for differentiating benign and malignant prostate tissues than any other diagnostic procedure. At present, no guideline is available that outlines which technique is best in a specific clinical situation. It also remains uncertain whether improved spatial resolution and signal-to-noise ratio of 3-T MRI will improve diagnostic performance.

Conclusions

A limited number of small studies suggest that functional MRI may improve the diagnosis and staging of prostate cancer. This finding needs further confirmation in larger studies, and cost-effectiveness needs to be established.