US-guided Musculoskeletal Interventions of the Body Wall and Core with MRI and US Correlation.

Chest, abdominal, and groin pain are common patient complaints that can be due to a variety of causes. Once potentially life-threatening visceral causes of pain are excluded, the evaluation should include musculoskeletal sources of pain from the body wall and core muscles. Percutaneous musculoskeletal procedures play a key role in evaluating and managing pain, although most radiologists may be unfamiliar with applications for the body wall and core muscles. US is ideally suited to guide these less commonly performed procedures owing to its low cost, portability, lack of ionizing radiation, and real-time visualization of superficial soft-tissue anatomy. US provides the operator with added confidence that the needle will be placed at the intended location and will not penetrate visceral or vascular structures. The authors review both common and uncommon US-guided procedures targeting various portions of the chest wall, abdominal wall, and core muscles with the hope of familiarizing radiologists with these techniques. Procedures include anesthetic and corticosteroid injection as well as platelet-rich plasma injection to promote tendon healing. Specific anatomic structures discussed include the sternoclavicular joint, costochondral joint, interchondral joint, intercostal nerve, scapulothoracic bursa, anterior abdominal cutaneous nerve, ilioinguinal nerve, iliohypogastric nerve, genitofemoral nerve, pubic symphysis, common aponeurotic plate, and adductor tendon origin. Relevant US anatomy is depicted with MRI correlation, and steps to performing successful safe US-guided injections are discussed. Confidence in performing these procedures will allow radiologists to continue to play an important role in diagnosis and management of many musculoskeletal pathologic conditions. ©RSNA, 2021.

US-guided Musculoskeletal Interventions in the Hip with MRI and US Correlation.

Hip pain is a commonly reported primary symptom with many potential causes. The causal entity can remain elusive, even after clinical history review, physical examination, and diagnostic imaging. Although there are many options for definitive treatment, many of these procedures are invasive, are associated with risk of morbidity, and can be unsuccessful, with lengthy revision surgery required. Percutaneous musculoskeletal intervention is an attractive alternative to more invasive procedures and an indispensable tool for evaluating and managing hip pain. US is an ideal modality for imaging guidance owing to its low cost, portability, lack of ionizing radiation, and capability for real-time visualization of soft-tissue and bone structures during intervention. The authors review both common and advanced US-guided procedures involving the pelvis and hip, including anesthetic and corticosteroid injections, percutaneous viscosupplementation, platelet-rich plasma injection to promote tendon healing, and microwave ablation for neurolysis. In addition, specific anatomic structures implicated in hip pain are discussed and include the hip joint, iliopsoas bursa, ilioinguinal nerve, lateral femoral cutaneous nerve, greater trochanteric bursa, iliotibial band, ischiogluteal bursa, hamstring tendon origin, piriformis muscle, and quadratus femoris muscle. The relevant US-depicted anatomy and principles underlying technically successful interventions also are discussed. Familiarity with these techniques can aid radiologists in assuming an important role in the care of patients with hip pain. ©RSNA, 2019.

Gadolinium-Based Contrast Agents in Kidney Disease: Comprehensive Review and Clinical Practice Guideline Issued by the Canadian Association of Radiologists.

Use of gadolinium-based contrast agents (GBCAs) in renal impairment is controversial, with physician and patient apprehension in acute kidney injury (AKI), chronic kidney disease (CKD), and dialysis because of concerns regarding nephrogenic systemic fibrosis (NSF). The position that GBCAs are absolutely contraindicated in AKI, CKD stage 4 or 5 (estimated glomerular filtration rate [eGFR] <30 mL/min/1.73 m2) and dialysis-dependent patients is outdated, and may limit access to clinically necessary contrast-enhanced MRI examinations. Following a comprehensive review of the literature and reported NSF cases to date, a committee of radiologists and nephrologists developed clinical practice guidelines to assist physicians in making decisions regarding GBCA administrations. In patients with mild-to-moderate CKD (eGFR ≥30 and <60 mL/min/1.73 m2), administration of standard doses of GBCA is safe and no additional precautions are necessary. In patients with AKI, with severe CKD (eGFR <30 mL/min/1.73 m2), or on dialysis, administration of GBCAs should be considered individually and alternative imaging modalities utilized whenever possible. If GBCAs are necessary, newer GBCAs may be administered with patient consent obtained by a physician (or their delegate), citing an exceedingly low risk (much less than 1%) of developing NSF. Standard GBCA dosing should be used; half or quarter dosing is not recommended and repeat injections should be avoided. Dialysis-dependent patients should receive dialysis; however, initiating dialysis or switching from peritoneal to hemodialysis to reduce the risk of NSF is unproven. Use of a macrocyclic ionic instead of macrocyclic nonionic GBCA or macrocyclic instead of newer linear GBCA to further prevent NSF is unproven. Gadopentetate dimeglumine, gadodiamide, and gadoversetamide remain absolutely contraindicated in patients with AKI, with stage 4 or 5 CKD, or on dialysis. The panel agreed that screening for renal disease is important but less critical when using macrocyclic and newer linear GBCAs. Monitoring for and reporting of potential cases of NSF in patients with AKI or CKD who have received GBCAs is recommended.

Retroperitoneal Fasciitis: Spectrum of CT Findings in the Abdomen and Pelvis.

Retroperitoneal fasciitis is a rare but potentially lethal complication of infection. Early diagnosis is crucial and is usually made when there is a high degree of clinical suspicion combined with characteristic imaging findings leading to early surgical intervention. Computed tomography (CT) can play a central role in demonstrating early findings, assessing the extent of disease to help determine the best surgical approach, identifying the primary source of infection, and evaluating the treatment response. The possible presence of retroperitoneal fasciitis should be considered in patients presenting with symptoms of sepsis, including pain that is disproportionate with the clinical abnormality. When retroperitoneal fasciitis is suspected, emergency CT can facilitate early diagnosis and evaluation of the extent of disease. Common findings at CT include fascial thickening and enhancement, muscular edema, fat stranding, fluid collections, and abscess formation. Gas tracking along fascial planes in the retroperitoneum is the hallmark of retroperitoneal fasciitis but is not seen in all cases. Another important clue to the diagnosis is asymmetric involvement of the retroperitoneal fascial planes and deep tissues. Fasciitis in the retroperitoneum may originate from infected retroperitoneal organs or from infection that spreads along indirect and/or direct pathways from a primary source elsewhere in the body. Findings of indirect tracking and transgression of fascial planes may indicate more severe infection associated with the necrotizing form of retroperitoneal fasciitis. Despite aggressive antibiotic treatment, early and repeated surgical débridement may be required to remove nonviable tissue in patients with the necrotizing form of retroperitoneal fasciitis. Awareness of the anatomy of the retroperitoneum, potential routes of spread of infection, and the spectrum of CT findings in retroperitoneal fasciitis is needed to achieve prompt diagnosis and guide treatment.

Gadolinium-Based Contrast Agents in Kidney Disease: A Comprehensive Review and Clinical Practice Guideline Issued by the Canadian Association of Radiologists.

PURPOSE OF REVIEW: Use of gadolinium-based contrast agents (GBCA) in renal impairment is controversial, with physician and patient apprehension in acute kidney injury (AKI), chronic kidney disease (CKD), and dialysis because of concerns regarding nephrogenic systemic fibrosis (NSF). The position that GBCA are absolutely contraindicated in AKI, category G4 and G5 CKD (estimated glomerular filtration rate [eGFR] < 30 mL/min/1.73 m2), and dialysis-dependent patients is outdated and may limit access to clinically necessary contrast-enhanced magnetic resonance imaging (MRI) examinations. This review and clinical practice guideline addresses the discrepancy between existing Canadian guidelines regarding use of GBCA in renal impairment and NSF. SOURCES OF INFORMATION: Published literature (including clinical trials, retrospective cohort series, review articles, and case reports), online registries, and direct manufacturer databases were searched for reported cases of NSF by class and specific GBCA and exposed patient population. METHODS: A comprehensive review was conducted identifying cases of NSF and their association to class of GBCA, specific GBCA used, patient, and dose (when this information was available). Based on the available literature, consensus guidelines were developed by an expert panel of radiologists and nephrologists. KEY FINDINGS: In patients with category G2 or G3 CKD (eGFR ≥ 30 and < 60 mL/min/1.73 m2), administration of standard doses of GBCA is safe and no additional precautions are necessary. In patients with AKI, with category G4 or G5 CKD (eGFR < 30 mL/min/1.73 m2) or on dialysis, administration of GBCA should be considered individually and alternative imaging modalities utilized whenever possible. If GBCA are necessary, newer GBCA may be administered with patient consent obtained by a physician (or their delegate) citing an exceedingly low risk (much less than 1%) of developing NSF. Standard GBCA dosing should be used; half or quarter dosing is not recommended and repeat injections should be avoided. Dialysis-dependent patients should receive dialysis; however, initiating dialysis or switching from peritoneal to hemodialysis to reduce the risk of NSF is unproven. Use of a macrocyclic ionic instead of macrocyclic nonionic GBCA or macrocyclic instead of newer linear GBCA to further prevent NSF is unproven. Gadopentetate dimeglumine, gadodiamide, and gadoversetamide remain absolutely contraindicated in patients with AKI, those with category G4 or G5 CKD, or those on dialysis. The panel agreed that screening for renal disease is important but less critical when using macrocyclic and newer linear GBCA. Monitoring for and reporting of potential cases of NSF in patients with AKI or CKD who have received GBCA is recommended. LIMITATIONS: Limited available literature (number of injections and use in renal impairment) regarding the use of gadoxetate disodium. Limited, but growing and generally high-quality, number of clinical trials evaluating GBCA administration in renal impairment. Limited data regarding the topic of Gadolinium deposition in the brain, particularly as it related to patients with renal impairment. IMPLICATIONS: In patients with AKI and category G4 and G5 CKD (eGFR < 30 mL/min/1.73 m2) and in dialysis-dependent patients who require GBCA-enhanced MRI, GBCA can be administered with exceedingly low risk of causing NSF when using macrocyclic agents and newer linear agents at routine doses.

OBJECTIF DE LA REVUE: L'utilisation d'agents de contraste à base de gadolinium (ACBG) est controversée dans les cas d'insuffisance rénale. En effet, en raison de préoccupations concernant la fibrose systémique néphrogénique (FSN), elle suscite l'appréhension des médecins et des patients dans les cas d'insuffisance rénale aiguë (IRA), d'insuffisance rénale chronique (IRC) et chez les patients dépendants de la dialyse. La perception selon laquelle les ACBG seraient formellement contre-indiqués dans les cas d'IRA, d'IRC de stade G4 et G5 (débit de filtration glomérulaire estimé [DFGe] < 30 ml/min/1,73 m2) et de dépendance à la dialyse est obsolète et pourrait limiter l'accès à l'IRM rehaussée par contraste ­ un examen cliniquement nécessaire. La présente revue et les directives cliniques proposées portent sur les incohérences des lignes directrices canadiennes actuelles en regard de l'utilisation des ACBG dans les cas d'insuffisance rénale et de FSN. SOURCES: Nous avons répertorié les cas déclarés de FSN selon l'ACBG utilisé (et sa classe) et selon les populations exposées, dans les articles publiés (essais cliniques, études de cohorte rétrospectives et rapports de cas), les registres en ligne et les bases de données des fabricants. MÉTHODOLOGIE: Nous avons procédé à un examen approfondi des sources pour répertorier les cas de FSN et leur association à une classe d'ACBG, à un ACBG en particulier, à la situation du patient et à la dose administrée (lorsque l'information était disponible). Un comité d'experts (néphrologues et radiologues) a émis de nouvelles lignes directrices consensuelles conformes aux résultats obtenus. PRINCIPAUX RÉSULTATS: Chez les patients atteints d'IRC de stade G2 ou G3 (DFGe ≥ 30 et < 60 ml/min/1,73 m2), l'administration d'ACBG aux doses habituelles est bénigne et aucune précaution n'est nécessaire. Lorsque possible, l'administration d'ACBG devrait faire l'objet d'une évaluation au cas par cas et d'autres modalités d'imagerie devraient être envisagées dans les cas d'IRA, d'IRC de stade G4 ou G5 ou de dépendance à la dialyse. Si le recours aux ACBG est nécessaire, on peut se tourner vers de nouvelles classes d'ACBG à risque excessivement faible (moins de 1 %) d'occasionner une FSN, tant que le médecin (ou son délégué) obtient le consentement du patient. On emploiera les doses d'ACBG habituelles; il n'est pas recommandé d'administrer de doses réduites, et les injections répétées devraient être évitées. Les patients dépendants de la dialyse devraient poursuivre leur traitement. On notera qu'il n'existe aucune preuve que l'initiation d'un traitement de dialyse ou que la transition de la dialyse péritonéale à l'hémodialyse réduise les risques de FSN. Le recours à des ACBG macrocycliques ioniques plutôt que non ioniques, ou à des ACBG macrocycliques plutôt qu'aux plus récents ACBG linéaires, n'a pas été démontré plus efficace pour prévenir la FSN. Par ailleurs, le gadopentétate de diméglumine, le gadodiamide et le gadoversétamide demeurent formellement contre-indiqués dans les cas d'IRA, d'IRC de stade G4 ou G5, et de dépendance à la dialyse. Le comité d'experts a convenu que le dépistage de l'insuffisance rénale, quoiqu'important, s'avère secondaire lors de l'administration des plus récents ACBG linéaires ou d'ACBG macrocycliques. La déclaration et le suivi des possibles cas de FSN liés à l'utilisation des ACBG chez les patients atteints d'IRA ou d'IRC sont recommandés. LIMITES: Plusieurs facteurs limitent la portée de nos résultats : i) la quantité limitée d'articles portant sur l'utilisation du gadoxétate disodique (notamment sur le nombre d'injections et son utilisation dans les cas d'insuffisance rénale); ii) le nombre limité (quoique croissant et généralement de grande qualité) d'essais cliniques évaluant l'administration des ACBG en contexte d'insuffisance rénale et; iii) la quantité limitée de données concernant l'accumulation du gadolinium dans le cerveau, particulièrement chez les patients atteints d'insuffisance rénale. CONCLUSION: Lorsque des examens d'IRM rehaussés par contraste sont nécessaires, les plus récents ACBG linéaires et les ACBG macrocycliques peuvent être administrés aux doses habituelles avec un risque excessivement faible de causer une FSN chez les patients atteints d'IRA, d'IRC de stade G4 et G5 (DFGe < 30 ml/min/1,73 m2), de même que chez les patients dépendants de la dialyse.