How Fast Can We Go: Abbreviated Prostate MR Protocols

PURPOSE OF REVIEW

Multiparametric MRI (mpMRI), composed of T2WI, DWI, and DCE sequences, is effective in identifying prostate cancer (PCa), but length and cost preclude its application as a PCa screening tool. Here we review abbreviated MRI protocols that shorten or omit conventional mpMRI components to reduce scan time and expense without forgoing diagnostic accuracy.

RECENT FINDINGS

The DCE sequence, which plays a limited diagnostic role in PI-RADS, is eliminated in variations of the biparametric MRI (bpMRI). T2WI, the lengthiest sequence, is truncated by only acquiring the axial plane or utilizing 3D acquisition with subsequent 2D reconstruction. DW-EPI_SMS further accelerates DWI acquisition. The fastest protocol described to date consists of just DW-EPI_SMS and axial-only 2D T2WI and runs less than 5 min. Abbreviated protocols can mitigate scan expense and increase scan access, allowing prostate MRI to become an efficient PCa screening tool.

ACR Appropriateness Criteria® Liver Lesion-Initial Characterization

Incidental liver masses are commonly identified on imaging performed for other indications. Since the prevalence of benign focal liver lesions in adults is high, even in patients with primary malignancy, accurate characterization of incidentally detected lesions is of paramount clinical importance. This document reviews utilization of various imaging modalities for characterization of incidentally detected liver lesions, discussed in the context of several clinical scenarios. For each clinical scenario, a summary of current evidence supporting the use of a given diagnostic modality is reported. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Systematic Review of Transgender-Related Research in Radiology Over a Decade: There Is Work to Be Done

PURPOSE

The ACR has established that diversity and inclusion are central to its mission of excellence in the radiologic professions; therefore, radiologists have a responsibility to serve the imaging needs of the transgender community. To understand radiologists' current knowledge of transgender topics, the authors performed a systematic review of publications from radiology journals.

METHODS

A lexicon of 14 transgender-related terms was created and expanded through a PubMed keyword search. From the 129 journals from the radiology, nuclear medicine, and medical imaging category of Journal Citation Reports, 106 journals met the inclusion criteria, including English translation and Scopus data for the study period. Using the Scopus advanced search feature, articles with titles, abstracts, Medical Subject Headings terms, or key words including 1 of 14 transgender terms were identified and analyzed.

RESULTS

Of the more than 200,000 articles published by the 106 journals from January 2008 to July 2019, 29 relevant articles were identified. Only 14 of the 106 journals published any transgender-related topics. The volume of articles has increased over time. The largest proportion of articles was published under the "general radiology" subsection, with the majority of these being editorials (6 of 10). Most of the original research was published under "neuroradiology" (7 of 13). Use of nonpreferred language, such as "transsexual" and "natal sex" was present through 2019.

CONCLUSIONS

Publication on transgender-related topics was uncommon among radiology journals. It is important to encourage further research and publication on transgender topics, as well as use of respectful, accepted language in radiology journals.

ACR Appropriateness Criteria® Jaundice

Jaundice is the end result of myriad causes, which makes the role of imaging in this setting particularly challenging. In the United States, the most common causes of all types of jaundice fall into four categories including hepatitis, alcoholic liver disease, blockage of the common bile duct by a gallstone or tumor, and toxic reaction to a drug or medicinal herb. Clinically, differentiating between the various potential etiologies of jaundice requires a detailed history, targeted physical examination, and pertinent laboratory studies, the results of which allow the physician to categorize the type of jaundice into mechanical or nonmechanical causes. Imaging modalities used to evaluate the jaundiced patient (all etiologies) include abdominal ultrasound (US), CT, MR cholangiopancreatography, endoscopic retrograde cholangiopancreatography and endoscopic US. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Fusion of high B-value diffusion-weighted and T2-weighted MR images increases sensitivity for identification of extraprostatic disease in prostate cancer

PURPOSE

To evaluate whether fusion of high b-value diffusion-weighted imaging (DWI) and T2-weighted imaging (T2WI) increases radiologists' ability to detect pathologic features responsible for upstaging in prostate cancer patients prior to radical prostatectomy (RP).

BASIC PROCEDURES

This was a retrospective study including 103 patients who underwent RP and a prostate MRI performed at 3T. High b-value DWI and T2WI were fused and interpreted by three radiologists with different degrees of experience. Prior to and after fusion, readers answered questionnaires about cancer presence, extraprostatic extension (EPE), seminal vesicle (SV) invasion, lymph node (LN) involvement, and reader confidence. Pathology reports served as the reference standard.

MAIN FINDINGS

High b-value DWI-T2WI fusion increased sensitivity for detection of EPE from 65.6% to 77.4% (p < 0.05), SV invasion from 40.5% to 48.8% (p < 0.05), and LN metastasis by 23.8% to 44.4% (p < 0.05). Readers' confidence significantly improved with the use of fusion imaging. Across all readers, confidence of cancer detection increased by 12.5% (p < 0.05), EPE by 14.7% (p < 0.05), SV invasion by 8.1% (p < 0.05), and LN metastasis by 2.5% (p < 0.05) using Wilcoxon signed rank test.

PRINCIPAL CONCLUSIONS

Fusion overlay of high b-value DWI and T2WI increases sensitivity for detection of extraprostatic disease resulting in upstaging at the time of RP.

ACR Appropriateness Criteria® Pancreatic Cyst

Incidental pancreatic cysts are increasingly detected on imaging studies performed for unrelated indications and may be incompletely characterized on these studies. Adequate morphological characterization is critical due to the small risk of malignant degeneration associated with neoplastic pancreatic cysts, as well as the risk of associated pancreatic adenocarcinoma. For all pancreatic cysts, both size and morphology determine management. Specifically, imaging detection of features, such as pancreatic ductal communication and presence or absence of worrisome features or high-risk stigmata, have important management implications. The recommendations in this publication determine the appropriate initial imaging study to further evaluate a pancreatic cyst that was incidentally detected on a nondedicated imaging study. The recommendations are designed to maximize the yield of diagnostic information in order to better risk-stratify pancreatic cysts and assist in guiding future management. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

ACR Appropriateness Criteria® Chronic Liver Disease

The liver fibrosis stage is the most important clinical determinate of morbidity and mortality in patients with chronic liver diseases. With newer therapies, liver fibrosis can be stabilized and possibly reversed, thus accurate diagnosis and staging of liver fibrosis are clinically important. Ultrasound, CT, and conventional MRI can be used to establish the diagnosis of advanced fibrosis/cirrhosis but have limited utility for assessing earlier stages of fibrosis. Elastography-based ultrasound and MRI techniques are more useful for assessment of precirrhotic hepatic fibrosis. In patients with advanced fibrosis at risk for hepatocellular carcinoma (HCC), ultrasound is the surveillance modality recommended by international guidelines in nearly all circumstances. However, in patients in whom ultrasound does not assess the liver well, including those with severe steatosis or obesity, multiphase CT or MRI may have a role in surveillance for HCC. Both multiphase CT and MRI can be used for continued surveillance in patients with a history of HCC, and contrast-enhanced ultrasound may have an emerging role in this setting. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Acute pancreatitis: an update on the revised Atlanta classification

Acute pancreatitis (AP) is the most common gastrointestinal disease resulting in hospitalization in the United States with reports of over 270,000 hospitalizations and costs up to 2.6 billion dollars per year. AP is highly variable in disease course and outcome. Established in 1992, the original Atlanta classification system aimed to categorize the wide spectrum of AP by creating consensus-based terminology for AP types, severity, and complications. Though the original system standardized terminology, certain terms and definitions (i.e. pancreatic abscess) were unclear and often misused. The 2012 revised Atlanta classification (RAC) system updated terms, clarified definitions, and incorporated the medical community's improved understanding of the physiology of AP. The resulting RAC effectively defined the morphologic types of pancreatitis, provided a more standardized system for disease severity grading, further classified the local retroperitoneal complications, and established objective measures to describe this highly variable but common disease. This review provides an update on the recent literature evaluating the RAC, discusses both the strengths and shortcomings of the RAC system (including problematic interobserver agreement), and considers improvements for future classification systems.

Validation of MSKCC pre-prostatectomy nomogram in men who undergo MRI-targeted prostate biopsy prior to radical prostatectomy

14

Background: The Memorial Sloan Kettering Cancer Center (MSKCC) Pre-Prostatectomy nomogram is a widely used resource using clinical factors to predict the likelihood of adverse pathology at radical prostatectomy. The increasing adoption of magnetic resonance imaging (MRI) and MRI-targeted biopsy (TB) permits optimized detection of clinically-significant cancer over systematic biopsy sampling alone. We aim to validate the prognostic utility of the MSKCC Pre-Prostatectomy nomogram with TB pathology results. Methods: Men who underwent systematic extended-sextant prostate biopsy (SB) followed by MRI TB who later underwent radical prostatectomy at our institution were included. Patient information was entered into the MSKCC Pre-Prostatectomy nomogram using five biopsy reporting schemes (SB alone, TB alone reported each of two ways (individual core (IC) technique or aggregate cores (AG) technique combining cores from a single MRI targeted lesion), and SB with TB combined with TB reported by both IC and AG methods. The likelihood of extracapsular extension (EPE), lymph node involvement (LNI), and seminal vesicle invasion (SVI) as predicted by the nomogram for each biopsy reporting schema were compared to radical prostatectomy pathology. Results: We identified 63 men from January 2014 to November 2017. On ROC analysis, IC-TB, AG-TB, SB plus IC-TB, and SB plus AG-TB exhibited similar, if not improved, AUC compared to SB alone in predicting EPE (0.671, 0.674, 0.658, and 0.6613 versus 0.6085). For LNI, superior AUC was observed for AG-TB (0.647) compared to IC-TB (0.571) and SB alone (0.524) Equivocal SVI prediction was observed for SB plus IC-TB compared to SB alone (0.727 versus 0.733). Conclusions: Using TB pathology results either alone or combined with SB pathology results for the MSKCC Pre-Prostatectomy nomogram appears comparable, if not improved, in prognosticating adverse pathologic features on radical prostatectomy compared to using SB core data alone from which the nomogram was developed.

Imaging as a Personalized Biomarker for Prostate Cancer Risk Stratification

Biomarkers provide objective data to guide clinicians in disease management. Prostate-specific antigen serves as a biomarker for screening of prostate cancer but has come under scrutiny for detection of clinically indolent disease. Multiple imaging techniques demonstrate promising results for diagnosing, staging, and determining definitive management of prostate cancer. One such modality, multiparametric magnetic resonance imaging (mpMRI), detects more clinically significant disease while missing lower volume and clinically insignificant disease. It also provides valuable information regarding tumor characteristics such as location and extraprostatic extension to guide surgical planning. Information from mpMRI may also help patients avoid unnecessary biopsies in the future. It can also be incorporated into targeted biopsies as well as following patients on active surveillance. Other novel techniques have also been developed to detect metastatic disease with advantages over traditional computer tomography and magnetic resonance imaging, which primarily rely on defined size criteria. These new techniques take advantage of underlying biological changes in prostate cancer tissue to identify metastatic disease. The purpose of this review is to present literature on imaging as a personalized biomarker for prostate cancer risk stratification.

MRI/US fusion-guided prostate biopsy allows for equivalent cancer detection with significantly fewer needle cores in biopsy-naive men

PURPOSE

We aimed to investigate the efficiency and cancer detection of magnetic resonance imaging (MRI) / ultrasonography (US) fusion-guided prostate biopsy in a cohort of biopsy-naive men compared with standard-of-care systematic extended sextant transrectal ultrasonography (TRUS)-guided biopsy.

METHODS

From 2014 to 2016, 72 biopsy-naive men referred for initial prostate cancer evaluation who underwent MRI of the prostate were prospectively evaluated. Retrospective review was performed on 69 patients with lesions suspicious for malignancy who underwent MRI/US fusion-guided biopsy in addition to systematic extended sextant biopsy. Biometric, imaging, and pathology data from both the MRI-targeted biopsies and systematic biopsies were analyzed and compared.

RESULTS

There were no significant differences in overall prostate cancer detection when comparing MRI-targeted biopsies to standard systematic biopsies (P = 0.39). Furthermore, there were no significant differences in the distribution of severity of cancers based on grade groups in cases with cancer detection (P = 0.68). However, significantly fewer needle cores were taken during the MRI/US fusion-guided biopsy compared with systematic biopsy (63% less cores sampled, P < 0.001) CONCLUSION: In biopsy-naive men, MRI/US fusion-guided prostate biopsy offers equal prostate cancer detection compared with systematic TRUS-guided biopsy with significantly fewer tissue cores using the targeted technique. This approach can potentially reduce morbidity in the future if used instead of systematic biopsy without sacrificing the ability to detect prostate cancer, particularly in cases with higher grade disease.

MRI findings guiding selection of active surveillance for prostate cancer: a review of emerging evidence

Active surveillance (AS) for prostate cancer (PCa) is generally considered to be a safe strategy for men with low-risk, localized disease. However, as many as 1 in 4 patients may be incorrectly classified as AS-eligible using traditional inclusion criteria. The use of multiparametric magnetic resonance imaging (mpMRI) may offer improved risk stratification in both the initial diagnostic and disease monitoring setting. We performed a review of recently published studies to evaluate the utility of this imaging modality for this clinical setting. An English literature search was conducted on PubMed for original investigations on localized PCa, AS, and magnetic resonance imaging. Our Boolean criteria included the following terms: PCa, AS, imaging, MRI, mpMRI, prospective, retrospective, and comparative. Our search excluded publication types such as comments, editorials, guidelines, reviews, or interviews. Our literature review identified 71 original investigations. Among these, 52 met our inclusion criteria. Evidence suggests mpMRI improves characterization of clinically significant prostate cancer (csPCa) foci, and the enhanced detection and risk-stratification afforded by this modality may keep men from being inappropriately placed on AS. Use of serial mpMRI may also permit longer intervals between confirmatory biopsies. Multiple studies demonstrate the benefit of MRI-targeted biopsies. The use of mpMRI of the prostate offers improved confidence in risk-stratification for men with clinically low-risk PCa considering AS. While on AS, serial mpMRI and MRI-targeted biopsy aid in the detection of aggressive disease transformation or foci of clinically-significant cancer undetected on prior biopsy sessions.

Detection of extraprostatic disease and seminal vesicle invasion in patients undergoing magnetic resonance imaging-targeted prostate biopsies

Background

Finding incidental extraprostatic extension (EPE) or seminal vesicle invasion (SVI) by prostate cancer (PCa) is rare on standard prostate biopsy. We evaluated the clinical-pathologic features associated with EPE and SVI on multiparametric magnetic resonance imaging (MRI)/ultrasound (US) fusion-guided targeted biopsy (TB).

Methods

A retrospective review was performed from 2014-2017, selecting patients who had undergone TB. Clinical, pathologic, and radiologic features were evaluated.

Results

Five out of 333 (1.5%) patients who had PCa detected on TB had EPE and/or SVI. The average age and prostate-specific antigen (PSA) was 71 years and 17 ng/mL, respectively. The average number of cores taken on TB was 4.2. Two patients had a prior negative SB and two patients had a prior positive SB, one of which underwent radiation therapy. All patients had a PIRADSv2 suspicion score of 4 or 5. Four out of five (80%) patients underwent both SB and concurrent TB, of which 3/4 (75%) had EPE identified only on TB. One out of four (25%) patients also had both EPE and SVI, identified only on TB. One patient underwent only TB for MRI suspicion of SVI, which was pathologically confirmed on TB. On TB, one patient had Grade Group 3, two patients had Grade Group 4, and two patients had Grade Group 5 PCa. Perineural invasion (PNI) was present in 4/5 (80%) patients on TB.

Conclusions

Based on our small series, we hypothesize that MRI/US fusion TB outperforms SB in the identification of EPE and SVI. However, given the small sample size and the overall rarity of these pathologic findings on prostate biopsy, further validation is needed.

Validation of contrast-enhanced time-resolved magnetic resonance angiography in pre-ablation planning in patients with atrial fibrillation: comparison with traditional technique

Bolus timing is critical to optimal magnetic resonance angiography (MRA) acquisitions but can be challenging in some patients. Our purpose was to evaluate whether contrast-enhanced time-resolved magnetic resonance angiography (TR-MRA), a dynamic multiphase sequence that does not rely on bolus timing, is a viable alternative method to conventional 3D fast-long angle shot contrast-enhanced magnetic resonance angiography (CE-MRA). Coronal subtracted conventional CE-MRA images in 50 consecutive patients presenting for pre-atrial fibrillation ablation pulmonary venous (PV) mapping were compared with 50 TR-MRA images performed in 50 subsequent patients. The TR-MRA protocol was modified to optimize spatial resolution with slightly reduced temporal resolution (6.1 s scan time). Three experienced readers evaluated each scan's image quality and relative left atrial (LA) opacification based on a 4-point scale and diagnostic PV visualization in a binary fashion. Additionally, LA signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), and PV dimensions were measured for both techniques. TR-MRA had significantly higher overall image quality (3.10 ± 0.69 vs. 2.42 ± 0.69, p < 0.0001), and LA opacification scores (3.33 ± 0.70 vs. 2.15 ± 1.13, p < 0.0001) compared to CE-MRA. The proportion of diagnostically visualized pulmonary veins was 137/150 (91%) in the CE-MRA group vs. 147/150 (98%) with TR-MRA (p = 0.010). Both SNR and CNR were higher with TR-MRA vs. CE-MRA (277.9 ± 48.9 vs. 106.8 ± 41, p = 0.002 and 100.3 ± 41.7 vs. 70.7 ± 48.0, p = 0.002, respectively). Inter-reader variance of individual PV measurements for each of the MR techniques ranged between 0.62 and 1.47 mm and the ICC for vein measurements was higher with TR-MRA (range: 0.62-0.81) compared to CE-MRA (range: 0.47-0.64). TR-MRA, modified to maximize spatial resolution, offers an alternative method for performing high quality MRA examinations in patients with AF. TR-MRA offers greater overall image quality, PV visualization, and similarly reproducible PV measurements compared to traditional CE-MRA, without the challenges of proper bolus timing.

Contrast-enhanced ultrasound of benign liver lesions

Liver lesions are often incidentally detected on ultrasound examination and may be incompletely characterized, requiring further imaging. Contrast-enhanced ultrasound (CEUS) was recently approved by the Food and Drug Administration in the United States for liver lesion characterization. CEUS has the ability to characterize focal liver lesions and has been shown to be superior to color Doppler and power Doppler ultrasound in the detection of tumor vascularity. Differentiating benign from malignant liver lesions is essential to characterizing liver lesions. The CEUS imaging characteristics of benign liver lesions are reviewed, including hepatic cysts, hemangiomas, focal fat, focal nodular hyperplasia, hepatocellular adenomas, abscesses, and traumatic lesions.