Radiologic Clinics of North America

Spinal cord pathologic condition often presents as a neurologic emergency where timely and accurate diagnosis is critical to expedite appropriate treatment and minimize severe morbidity and even mortality. MR imaging is the gold standard imaging technique for diagnosing patients with suspected spinal cord pathologic condition. This review will focus on the basic principles of diffusion imaging and how spinal anatomy presents technical challenges to its application. Both the promises and shortcomings of spinal diffusion imaging will then be explored in the context of several clinical spinal cord pathologies for which diffusion has been evaluated...

Localization of lesions in the spinal cord requires knowledge of the functional anatomy of gray and white matter tracts. Using decussation points for white matter tracts can help determine lesion level. Pathologies can affect gray and white matter tracts in distinct ways and pattern recognition can help narrow down the differential diagnosis.

Spine pain is highly prevalent and costly, but evaluation with clinical features and anatomic imaging remain limited. Fat-suppressed MR imaging and molecular imaging (MI) may help identify inflammatory, lesional, and malignant causes. Numerous MI agents are available, each with advantages and disadvantages. Herein, FDG PET, prostate-specific membrane antigen (PSMA), bone radiotracers, and others are highlighted. No specific pain MI agents have been identified, but mechanisms of key agents are shown in video format, and the mechanism of PSMA as a theranostic agent is displayed...

Pain and weakness in the low back, pelvis, and lower extremities are diagnostically challenging, and imaging can be an important step in the workup and management of these patients. Technical advances in magnetic resonance neurography (MRN) have significantly improved its utility for imaging the lumbosacral plexus (LSP). In this article, the authors review LSP anatomy and selected pathology examples. In addition, the authors will discuss technical considerations for MRN with specific points for the branch nerves off the plexus...

Chronic low back pain is a major source of pain and disability globally involving multifactorial causes. Historically, intervertebral disc degeneration and disruption have been associated as primary back pain triggers of the anterior column, termed "discogenic pain." Recently, the vertebral endplates have been identified as another possible pain trigger of the anterior column. This "endplate-driven" model, defined "vertebrogenic pain," is often interconnected with disc degeneration. Diagnosis of vertebrogenic and discogenic pain relies on imaging techniques that isolate pain generators and exclude comorbid conditions...

Epidural steroid injections have demonstrable efficacy and safety in treatment of radicular pain syndromes; transforaminal access has greater evidence of efficacy than interlaminar approaches. The interventionalist must understand epidural and foraminal anatomy and imaging to insure delivery of medication to the target, the ventral epidural space at the site of neural compression. This obligates pre-procedural planning. When performed with appropriate risk mitigation strategies, epidural injections by either access are safe...

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Accurate determination of the local stage of prostate cancer is crucial for treatment planning and prognosis. The primary objective of local staging is to distinguish between organ-confined and locally advanced disease, with the latter carrying a worse clinical prognosis. The presence of locally advanced disease features of prostate cancer, such as extra-prostatic extension, seminal vesicle invasion, and positive surgical margin, can impact the choice of treatment. Over the past decade, multiparametric MRI (mpMRI) has become the preferred imaging modality for the local staging of prostate cancer and has been shown to provide accurate information on the location and extent of disease...

Multiparametric magnetic resonance (MR) imaging has had an expanding role in active surveillance (AS) for prostate cancer. It can improve the accuracy of prostate biopsies, assist in patient selection, and help monitor cancer progression. The PRECISE recommendations standardize reporting of serial MR imaging scans during AS. We summarize the evidence on MR imaging-led AS and provide a clinical primer to help report using the PRECISE criteria. Some limitations to both serial imaging and the PRECISE recommendations must be considered as we move toward a more individualized risk-stratified approach to AS...

Multiparametric MR imaging of the prostate is an essential diagnostic study in the evaluation of prostate cancer. Several entities including normal anatomic structures, benign lesions, and posttreatment changes can mimic prostate cancer. An in depth understanding of the pitfalls is important for accurate interpretation of prostate MR imaging.

The aim of this article is to review the technical and clinical considerations encountered with PI-RADS 3 lesions, which are equivocal for clinically significant Prostate Cancer (csPCa) with detection rates ranging between 10% and 35%. The number of PI-RADS 3 lesions reported vary according to several factors including MRI quality and radiologist training/expertise among the most influential. PI-RADS v.2.1 updated definitions for scores 2 and 3 in the PZ and scores 1 and 2 in the TZ is reviewed. The role of DWI role is highlighted in the assessment of the TZ with the possibility of upgrading score 2 lesions to score 3 based on DWI score...

Prostate cancer (PCa) is the most common non-cutaneous cancer diagnosed in males. Multiparametric Magnetic Resonance Imaging (mpMRI) with targeted biopsy can detect PCa and is currently the recommended initial test in men at risk for PCa. Micro-Ultrasound (MicroUS) is a novel high-resolution 29-MHz ultrasound with ∼three times greater resolution of conventional transrectal ultrasound (TRUS) resolution. Preliminary data suggest improved accuracy of ultrasound for targeted prostate biopsy. A growing body of evidence has become available supporting MicroUS as a potentially time and cost saving modality for PCa detection, with early results suggesting comparable accuracy to mpMRI...

The discovery and clinical development of radiolabeled small-molecule ligands targeting prostate-specific membrane antigen (PSMA) has had a profound influence on the field of nuclear medicine. Such agents have been successfully deployed for both imaging and therapeutic applications. In particular, PSMA radioligand therapy (PRLT) has been shown to be a life-prolonging therapy for men with metastatic, castration-resistant prostate cancer and has also brought nuclear medicine physicians and nuclear radiologists into the forefront of direct patient care...

Prostate magnetic resonance imaging (MRI) is increasingly being used to diagnose and stage prostate cancer. The Prostate Imaging and Data Reporting System (PI-RADS) version 2.1 is a consensus-based reporting system that provides a standardized and reproducible method for interpreting prostate MRI. This primer provides an overview of the PI-RADS system, focusing on its current role in clinical interpretation. It discusses the appropriate use of PI-RADS and how it should be applied by radiologists in clinical practice to assign and report PI-RADS assessments...

Prostate-specific membrane antigen PET (PSMA-PET) has emerged as a powerful imaging tool for prostate cancer primary staging, biochemical recurrence, and advanced disease assessment. This article offers a concise overview of the benefits and challenges associated with PSMA-PET for prostate cancer evaluation. The article highlights the advantages of PSMA-PET over conventional imaging, such as its higher sensitivity and specificity for detecting metastases, and the potential for guiding personalized treatment decisions...

Detection of prostate cancer recurrence after whole-gland treatment with curative intent is critical to identify patients who may benefit from local salvage therapy. Among the different imaging modalities used in clinical practice, MR imaging is the most accurate in identifying local prostate cancer recurrence; indeed, it is an excellent technique for local recurrence detection superior to PET/CT, even at low PSA, but provides no information about extra-pelvic lymph nodes or bone metastasis. In 2021, a group of experts developed the Prostate Imaging for local Recurrence Reporting scoring system to standardize acquisition, interpretation, and reporting of prostate cancer recurrence...

Prostate cancer is the most common malignancy diagnosed in men. MR imaging-guided therapies for prostate cancer have become an increasingly common treatment alternative to traditional whole-gland therapies, such as radical prostatectomy or radiation therapy. This is especially true in men with localized, low- to intermediate-risk prostate cancer. Although long-term oncologic data remain limited, the authors describe several MR imaging-guided therapeutic options for the treatment of prostate cancer, including cryoablation, laser ablation, transrectal high-intensity focused ultrasound, and transurethral ultrasound ablation...

The emergence of multiparametric MR imaging has enabled a more reliable targeted approach to diagnosis of prostate cancer. Targeted biopsies are central to the MR imaging-dependent pathway to prostate cancer diagnosis and potentially improve the detection of clinically significant prostate cancers. In a targeted biopsy, tissue samples are obtained from suspicious regions identified on a prebiopsy diagnostic MR imaging. This article describes and compares principles, advantages, and disadvantages of the different strategies available for targeting an MR imaging-visible suspicious lesion...

Prostate MR imaging quality has improved dramatically over recent times, driven by advances in hardware, software, and improved functional imaging techniques. MRI now plays a key role in prostate cancer diagnostic work-up, but outcomes of the MRI-directed pathway are heavily dependent on image quality and optimization. MR sequences can be affected by patient-related degradations relating to motion and susceptibility artifacts which may enable only partial mitigation. In this Review, we explore issues relating to prostate MRI acquisition and interpretation, mitigation strategies at a patient and scanner level, PI-QUAL reporting, and future directions in image quality, including artificial intelligence solutions...

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