MRI of total hip arthroplasty: technical aspects and imaging findings.

Total hip arthroplasty (THA) is the best surgical approach for treating advanced hip degeneration, providing pain relief, and improved function in most cases. In the past, MR imaging quality has been highly compromised by in-plane distortions, inadequate fat saturation, and other artifacts due to metal components of THA. Technological advancements have made pathologic conditions, which were previously hidden by periprosthetic artifacts, outstanding features due to the optimization of several sequences. To date, several short and long-term complications involving bony and soft-tissue structures may be detected through magnetic resonance imaging (MRI). The use of MRI with adapted sequences and protocols may drastically reduce artifacts thereby providing essential pre-operative elements for planning revision surgery of failed THA. This review has the purpose of conveying new insights to musculoskeletal radiologists about the techniques to suppress metal-related artifacts and the hallmark MRI findings of painful THA. CRITICAL RELEVANCE STATEMENT: Advancements in metal-suppression have given radiologists the opportunity to play an emerging role in THA management. This article provides technical and imaging insights into challenges that can be encountered in cases of THA, which may present complications and characteristic imaging findings. KEY POINTS: Imaging total hip arthroplasty requires adapted MRI protocol and awareness of the common complications. We have reported the available metal-suppression sequences for evaluating total hip arthroplasty. Many structures and conditions should be considered when dealing with painful aseptic or septic arthroplasty.

Dual-energy CT in musculoskeletal imaging: technical considerations and clinical applications.

Dual-energy CT stands out as a robust and innovative imaging modality, which has shown impressive advancements and increasing applications in musculoskeletal imaging. It allows to obtain detailed images with novel insights that were once the exclusive prerogative of magnetic resonance imaging. Attenuation data obtained by using different energy spectra enable to provide unique information about tissue characterization in addition to the well-established strengths of CT in the evaluation of bony structures. To understand clearly the potential of this imaging modality, radiologists must be aware of the technical complexity of this imaging tool, the different ways to acquire images and the several algorithms that can be applied in daily clinical practice and for research. Concerning musculoskeletal imaging, dual-energy CT has gained more and more space for evaluating crystal arthropathy, bone marrow edema, and soft tissue structures, including tendons and ligaments. This article aims to analyze and discuss the role of dual-energy CT in musculoskeletal imaging, exploring technical aspects, applications and clinical implications and possible perspectives of this technique.

Usefulness and Clinical Impact of Whole-Body MRI in Detecting Autoimmune Neuromuscular Disorders.

Autoimmune neuromuscular diseases are a group of heterogenous pathologies secondary to the activation of the immune system that damage the structures of the peripheric nerve, the neuromuscular junction, or the skeleton muscle. The diagnosis of autoimmune neuromuscular disorders comprises a combination of data from clinical, laboratory, electromyography, imaging exam, and biopsy. Particularly, the whole-body MRI examination in the last two decades has been of great use in the assessment of neuromuscular disorders. MRI provides information about the structures involved and the status of activity of the disease. It can also be used as a biomarker, detect the pattern of specific muscle involvement, and is a useful tool for targeting the optimal muscle site for biopsy. In this work, we summarized the most used technical protocol of whole-body MRI and the role of this imaging technique in autoimmune neuromuscular disorders.

Aortic valve and vascular calcium score in pre-TAVI CT: correlation with early post-procedural complications.

PURPOSE: The aim of our study was to evaluate the prevalence of early complications after Transcatheter Aortic Valve Implantation (TAVI) and their correlation with the Calcium Score (CS) of the aortic valve, aorta and ilio-femoral arteries derived from pre-procedural computed tomography (CT). MATERIALS AND METHODS: We retrospectively reviewed 226 patients (100 males, mean age 79.4 ± 6.7 years) undergoing 64-slice CT for pre-TAVI evaluation from January 2018 to April 2021. The population was divided into CS quartiles. RESULTS: Overall, 173 patients underwent TAVI procedure, of whom 61% presented paravalvular leak after the procedure, 28% presented bleeding or vascular complications, 25% presented atrioventricular block, and 8% developed acute kidney injury. The prevalence of paravalvular leak and vascular complications was higher in the upper CS quartiles for aortic valve and ilio-femoral arteries. CONCLUSIONS: Aortic valve and vascular CS could help to predict post-TAVI early complications.

Multiparametric MRI and Radiomics in Prostate Cancer: A Review of the Current Literature.

Prostate cancer (PCa) represents the fourth most common cancer and the fifth leading cause of cancer death of men worldwide. Multiparametric MRI (mp-MRI) has high sensitivity and specificity in the detection of PCa, and it is currently the most widely used imaging technique for tumor localization and cancer staging. mp-MRI plays a key role in risk stratification of naïve patients, in active surveillance for low-risk patients, and in monitoring recurrence after definitive therapy. Radiomics is an emerging and promising tool which allows a quantitative tumor evaluation from radiological images via conversion of digital images into mineable high-dimensional data. The purpose of radiomics is to increase the features available to detect PCa, to avoid unnecessary biopsies, to define tumor aggressiveness, and to monitor post-treatment recurrence of PCa. The integration of radiomics data, including different imaging modalities (such as PET-CT) and other clinical and histopathological data, could improve the prediction of tumor aggressiveness as well as guide clinical decisions and patient management. The purpose of this review is to describe the current research applications of radiomics in PCa on MR images.

Focal hepatic intrinsically hyperattenuating lesions at unenhanced CT: Not always calcifications.

Due to the growing use of CT, there has been an increase in the frequency of detecting focal liver lesions. Intrinsically hyperattenuating hepatic lesions or pseudolesions are not uncommon at unenhanced CT. Hyperattenuating hepatic lesions can be divided into non-calcified and calcified. Causes of intrinsic hyperattenuation include hemorrhage, thrombosis, and calcifications. Focal liver lesions can show hyperattenuation on unenhanced CT in case of severe liver steatosis. Recognition of etiologies associated with hyperattenuation on unenhanced CT can help the radiologist in characterizing focal liver lesions and pseudolesions. In this paper, we describe the spectrum of intrinsically hyperattenuating focal liver lesions and pseudolesions at unenhanced CT.

Ischemic hypoxic encephalopathy: The role of MRI of neonatal injury and medico-legal implication.

Hypoxic ischemic encephalopathy is one of the major causes of neonatal death and neurological disability in the child, and represents the most common birth injury claim. Intrapartum asphyxia often leads to several long-term sequalae, such as cerebral palsy and/or developmental delay, epilepsy. Through the neuroimaging it's possible to identify and define the different lesioned pictures and provide useful elements to establish the moment in which the damage occurred; indeed, timing of injury is a key element in the legal arena. Magnetic resonance imaging (MRI) is emerging as one of the most important tools in identifying the etiologic of neonatal encephalopathy as well as in predicting long-term outcomes. The aim of this study is to evaluate all MRI tests performed in a group of infants and young patients with possible neonatal encephalopathy, in order to determine the role of MRI in perinatal hypoxic-ischemic damage and the specific patterns that can point towards a diagnosis of the time of the damage's onset. Another goal is to assess the role of MRI in cases subject to legal-medical ligation. Since the advent of hypothermic neuroprotection, new malpractice allegations have arisen, including the failure to initiate cooling in a timely manner. In all cases, documentation of the status of the baby at birth, including a thorough neurologic exam, can be extremely helpful to the later defence of a malpractice claim, which might occur years later.

Whole-Body Magnetic Resonance Imaging: Current Role in Patients with Lymphoma.

Imaging of lymphoma is based on the use of 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG-PET/CT) and/or contrast-enhanced CT, but concerns have been raised regarding radiation exposure related to imaging scans in patients with cancer, and its association with increased risk of secondary tumors in patients with lymphoma has been established. To date, lymphoproliferative disorders are among the most common indications to perform whole-body magnetic resonance imaging (MRI). Whole-body MRI is superior to contrast-enhanced CT for staging the disease, also being less dependent on histology if compared to 18F-FDG-PET/CT. As well, it does not require exposure to ionizing radiation and could be used for the surveillance of lymphoma. The current role of whole-body MRI in the diagnostic workup in lymphoma is examined in the present review along with the diagnostic performance in staging, response assessment and surveillance of different lymphoma subtypes.

Imaging the COVID-19: a practical guide.

The Coronavirus Disease 2019 (COVID-19) represents the first medical catastrophe of the new millennium. Although imaging is not a screening test for COVID-19, it plays a crucial role in evaluation and follow-up of COVID-19 patients. In this paper, we will review typical and atypical imaging findings of COVID-19.

Focused Ultrasound in Neuroscience. State of the Art and Future Perspectives.

Transcranial MR-guided Focused ultrasound (tcMRgFUS) is a surgical procedure that adopts focused ultrasounds beam towards a specific therapeutic target through the intact skull. The convergence of focused ultrasound beams onto the target produces tissue effects through released energy. Regarding neurosurgical applications, tcMRgFUS has been successfully adopted as a non-invasive procedure for ablative purposes such as thalamotomy, pallidotomy, and subthalamotomy for movement disorders. Several studies confirmed the effectiveness of tcMRgFUS in the treatment of several neurological conditions, ranging from motor disorders to psychiatric disorders. Moreover, using low-frequencies tcMRgFUS systems temporarily disrupts the blood-brain barrier, making this procedure suitable in neuro-oncology and neurodegenerative disease for controlled drug delivery. Nowadays, tcMRgFUS represents one of the most promising and fascinating technologies in neuroscience. Since it is an emerging technology, tcMRgFUS is still the subject of countless disparate studies, even if its effectiveness has been already proven in many experimental and therapeutic fields. Therefore, although many studies have been carried out, many others are still needed to increase the degree of knowledge of the innumerable potentials of tcMRgFUS and thus expand the future fields of application of this technology.

Broad neurodevelopmental features and cortical anomalies associated with a novel de novo KMT2A variant in Wiedemann-Steiner syndrome.

Wiedemann-Steiner syndrome (WDSTS) is a rare genetic disorder including developmental delay/intellectual disability (DD/ID), hypertrichosis cubiti, short stature, and distinctive facial features, caused by mutation in KMT2A gene, which encodes a histone methyltransferase (H3K4) that regulates chromatin-mediated transcription. Different neurodevelopmental phenotypes have been described within the WDSTS spectrum, including a peculiar Autism Spectrum Disorder (ASDs) subtype in some affected individuals. Here, we report a 9-year-old Caucasian male found by next-generation panel sequencing to carry a novel heterozygous de novo KMT2A frameshift variant (NM_001197104.2:c.4433delG; p. Arg1478LeufsTer108). This boy presented a WDSTS phenotype associated with broad neurodevelopmental features, including an unusual speech difficulty (i.e., palilalia), and brain imaging studies revealed an array of cortical anomalies (e.g., frontal simplified gyration, focal frontal cortical dysplasia). These clinical and radiological observations expand the known WDSTS-related neurodevelopmental phenotypes and further strengthen the important role of KMT2A in brain function and cortical development.

Role of computed tomography and magnetic resonance imaging in local complications of acute pancreatitis.

Acute pancreatitis (AP) represents a pancreas inflammation of sudden onset that can present different degrees of severity. AP is a frequent cause of acute abdomen and its complications are still a cause of death. Biliary calculosis and alcohol abuse are the most frequent cause of AP. Computed tomography (CT) and magnetic resonance imaging (MRI) are not necessary for the diagnosis of AP but they are fundamental tools for the identification of the cause, degree severity and AP complications. AP severity assessment is in fact one of the most important issue in disease management. Contrast-enhanced CT is preferred in the emergency setting and is considered the gold standard in patients with AP. MRI is comparable to CT for the diagnosis of AP but requires much more time so it is not usually chosen in the emergency scenario. Complications of AP can be distinguished in localized and generalized. Among the localized complications, we can identify: acute peripancreatic fluid collections (APFC), pseudocysts, acute necrotic collections (ANC), walled off pancreatic necrosis (WOPN), venous thrombosis, pseudoaneurysms and haemorrhage. Multiple organ failure syndrome (MOFS) and sepsis are possible generalized complications of AP. In this review, we focus on CT and MRI findings in local complications of AP and when and how to perform CT and MRI. We paid also attention to recent developments in diagnostic classification of AP complications.

18F-Florbetaben PET/CT to Assess Alzheimer's Disease: A new Analysis Method for Regional Amyloid Quantification.

BACKGROUND AND PURPOSE: While AD can be definitively confirmed by postmortem histopathologic examination, in vivo imaging may improve the clinician's ability to identify AD at the earliest stage. The aim of the study was to test the performance of amyloid PET using new processing imaging algorithm for more precise diagnosis of AD. METHODS: Amyloid PET results using a new processing imaging algorithm (MRI-Less and AAL Atlas) were correlated with clinical, cognitive status, CSF analysis, and other imaging. The regional SUVR using the white matter of cerebellum as reference region and scores from clinical and cognitive tests were used to create ROC curves. Leave-one-out cross-validation was carried out to validate the results. RESULTS: Forty-four consecutive patients with clinical evidence of dementia, were retrospectively evaluated. Amyloid PET scan was positive in 26/44 patients with dementia. After integration with 18F-FDG PET, clinical data and CSF protein levels, 22 of them were classified as AD, the remaining 4 as vascular or frontotemporal dementia. Amyloid and FDG PET, CDR 1, CSF Tau, and p-tau levels showed the best true positive and true negative rates (amyloid PET: AUC = .85, sensitivity .91, specificity .79). A SUVR value of 1.006 in the inferior frontal cortex and of 1.03 in the precuneus region was the best cutoff SUVR value and showed a good correlation with the diagnosis of AD. Thirteen of 44 amyloid PET positive patients have been enrolled in clinical trials using antiamyloid approaches. CONCLUSIONS: Amyloid PET using SPM-normalized SUVR analysis showed high predictive power for the differential diagnosis of AD.

Role of Imaging in the Assessment of Age Estimation.

Age assessment by skeletal age estimation of unknown individuals is of paramount importance in forensic science, both for assessing imputability (if the author of a crime is old enough to be tried and judged), both in case of unaccompanied minors, or whether refugees and asylum seekers are adults or juveniles, which implies different legal issues and procedures. The aim of this article is to review the age estimation methods used in forensic practice.

Imaging features of adrenal masses.

The widespread use of imaging examinations has increased the detection of incidental adrenal lesions, which are mostly benign and non-functioning adenomas. The differentiation of a benign from a malignant adrenal mass can be crucial especially in oncology patients since it would greatly affect treatment and prognosis. In this setting, imaging plays a key role in the detection and characterization of adrenal lesions, with several imaging tools which can be employed by radiologists. A thorough knowledge of the imaging features of adrenal masses is essential to better characterize these lesions, avoiding a misinterpretation of imaging findings, which frequently overlap between benign and malignant conditions, thus helping clinicians and surgeons in the management of patients. The purpose of this paper is to provide an overview of the main imaging features of adrenal masses and tumor-like conditions recalling the strengths and weaknesses of imaging modalities commonly used in adrenal imaging.

Glypican-3 and Hep Par-1 are Useful Biomarkers in the Cytologic Assessment of Ascites.

Till date, the utility of cytologic assessment of ascites for the identification of hepatocellular carcinoma (HCC) cells is still debated and the usefulness of immunocytochemistry for glypican-3 (GPC3) and Hep Par-1 in this setting has not been reported. Liquid-based cytology of ascitic fluid of 28 cirrhotic patients was performed and the spots obtained were stained with hematoxylin and eosin, papanicolau, and with GPC3 and Hep Par-1 antibodies. GPC3 and Hep Par-1 antibodies stained positively the atypical cells in the ascites of 2 patients with HCC showing an exophytic growth pattern. The specimens of the patients with nonexophytic HCC, other non-HCC cancers, or cirrhosis stained negatively. We hypothesize a relationship with the exophytic growth of the tumor. Thus, GPC3 and Hep Par-1 are useful in the cytologic assessment of peritoneal effusions to distinguish mesothelial cells and neoplastic non-HCC cells from HCC cells, presence of which, however, represent a very rare event. This is the first study in which GPC3 and Hep Par-1 immunostaining has been used in the cytologic assessment of HCC ascites.

Superior Mesenteric Artery Syndrome: Clinical, Endoscopic, and Radiological Findings.

BACKGROUND: The superior mesenteric artery (SMA) syndrome is a rare entity presenting with upper gastrointestinal tract obstruction and weight loss. Studies to determine the optimal methods of diagnosis and treatment are required. AIMS AND METHODS: This study aims at analyzing the clinical presentation, diagnosis, and management of SMA syndrome. Ten cases of SMA syndrome out of 2074 esophagogastroduodenoscopies were suspected. A contrast-enhanced computed tomography (CECT) scan was performed to confirm the diagnosis. After, a gastroenterologist and a nutritionist personalized the therapy. Furthermore, we compared the demographical, clinical, endoscopic, and radiological parameters of these cases with a control group consisting of 10 cases out of 2380 EGDS of initially suspected (but not radiologically confirmed) SMA over a follow-up 2-year period (2015-2016). RESULTS: The prevalence of SMA syndrome was 0.005%. Median age and body mass index were 23.5 years and 21.5 kg/m2, respectively. Symptoms developed between 6 and 24 months. Median aortomesenteric angle and aorta-SMA distance were 22 and 6 mm, respectively. All patients improved on conservative treatment. In our series, a marked (>5 kg) weight loss (p = 0.006) and a long-standing presentation (more than six months in 80% of patients) (p = 0.002) are significantly related to a diagnosis of confirmed SMA syndrome at CECT after an endoscopic suspicion. A "resembling postprandial distress syndrome dyspepsia" presentation may be helpful to the endoscopist in suspecting a latent SMA syndrome (p = 0.02). The narrowing of both the aortomesenteric angle (p = 0.001) and the aortomesenteric distance (p < 0.001) was significantly associated with the diagnosis of SMA after an endoscopic suspicion; however, the narrowing of the aortomesenteric distance seemed to be more accurate, rather than the narrowing of the aortomesenteric angle. CONCLUSION: SMA syndrome represents a diagnostic and therapeutic challenge. Our results show the following findings: the importance of the endoscopic suspicion of SMA syndrome; the preponderance of a long-standing and chronic onset; a female preponderance; the importance of the nutritional counseling for the treatment; no need of surgical intervention; and better diagnostic accuracy of the narrowing of the aorta-SMA distance. Larger prospective studies are needed to clarify the best diagnosis and management of the SMA syndrome.

Clinical and prognostic value of 18F-FDG-PET/CT in restaging of pancreatic cancer.

AIM: The aim of this retrospective multicentre study was to evaluate the clinical and prognostic effect of fluorine-18-fluorodeoxyglucose (F-FDG)-PET/computed tomography (CT) in the restaging process of pancreatic cancer (PC). MATERIALS AND METHODS: Data from patients treated for primary PC, who underwent F-FDG-PET/CT for suspicious of disease progression, were collected. Accuracy was assessed employing conventional diagnostic procedures, multidisciplinary team case notes, further F-FDG-PET/CT scans and/or follow-up. Receiver operating characteristic curve and likelihood ratio (LR+/-) analyses were used for completion of accuracy definition. Progression-free survival (PFS) and overall survival were assessed by using Kaplan-Meier method. The Cox proportional hazards model was used to identify predictors of outcome. RESULTS: Fifty-two patients (33 males and 19 females, with mean age of 59 years and range: 42-78 years) with PC were finally included in our study. Sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of F-FDG-PET were 85, 84, 90, 76, and 84%, respectively. Area under the curve was 0.84 (95% confidence intervals: 0.72-0.96; P<0.05). LR+ and LR- were 5.3 and 0.17, respectively. F-FDG-PET/CT revealed new metastatic foci in 5/52 patients (10%) and excluded suspicious lesions in 11/52 (21%). Analysis of PFS revealed F-FDG-PET/CT positivity to be associated with a worse cumulative survival rate over a 6 and 12-month period in comparison with F-FDG-PET/CT negativity (6-month PFS 95 vs. 67%, P<0.05; 12-month PFS 81 vs. 29%, P<0.05). A negative F-FDG-PET/CT result was associated with a significantly longer overall survival than a positive one (70 vs. 26% after 2 years, P<0.05). In addition, a positive F-FDG-PET/CT scan result and an maximum standardized uptake value (SUVmax) value more than 6 were significantly associated with an increased risk of disease progression (PET positivity hazard ratio=3.9, P=0.01; SUVmax>6 h=4.2, P=0.02) and death (PET positivity hazard ratio=3.5, P=0.02; SUVmax>6 h=3.7, P=0.01). CONCLUSION: F-FDG-PET/CT showed high diagnostic accuracy for restaging process of PC, proving also its potential value in predicting clinical outcome after primary treatment.

MRI patient selection for endovascular thrombectomy in acute ischemic stroke: correlation between pretreatment diffusion weighted imaging and outcome scores.

INTRODUCTION: Eligibility for endovascular treatment (EVT) in patients with acute ischemic stroke (AIS) depends, amongst other factors, on CT- or MR-based scores. The aim of this study was to investigate the role of Alberta Stroke Program Early CT score based on diffusion weighted imaging (MR-ASPECT) in the assessment of brain damage pre-EVT, patient selection for EVT and outcome. MATERIALS AND METHODS: We included in this study patients with National Institute of Health stroke score (NIHSS) at admission ≥ 8, MR-ASPECT ≥ 5 and anterior AIS, who were treated with EVT in our hospital. All patients were clinically evaluated at admission, post-EVT, discharge and at 3-month follow-up. We used MR-ASPECT to establish infarct core extension at admission. We evaluated ASPECT score at admission (CT-ASPECT-IN), 24 h after EVT and at discharge, NIHSS, modified Ranking Scale (mRS), Thrombolysis in Cerebral Infarction scale (TICI), onset-to-intervention-delay (OTID) and Collateral Circulation Score (CCS). RESULTS: 68 patients (mean age 78 ± 11.9 years) were included in this study. 54.4 and 64.7% of patients had strong clinical improvement after 24 h from EVT and at discharge, respectively. NIHSS evaluated 24 h after EVT correlated with CCS, TICI and OTID. We observed a favourable outcome (mRS 0-2) in 52.9% of patients at 3-month follow-up. MR-ASPECT score correlated with post-EVT outcome better than CT-ASPECT-IN scores. CONCLUSION: MR-ASPECT score based on diffusion weighted imaging is useful for the selection of patients with AIS that can have a favourable outcome from EVT. A prompt EVT has huge impact on patient outcome.

Rotator cuff calcific tendinopathy: from diagnosis to treatment.

Rotator cuff calcific tendinopathy (RCCT) is a very common condition caused by the presence of calcific deposits in the rotator cuff (RC) or in the subacromial-subdeltoid (SASD) bursa when calcification spreads around the tendons. The pathogenetic mechanism of RCCT is still unclear. It seems to be related to cell-mediated disease in which metaplastic transformation of tenocytes into chondrocytes induces calcification inside the tendon of the RC. RCCT is a frequent finding in the RC that may cause significant shoulder pain and disability. It can be easily diagnosed with imaging studies as conventional radiography (CR) or ultrasound (US). Conservative management of RCCT usually involves rest, physical therapy, and oral NSAIDs administration. Imaging-guided treatments are currently considered minimally-invasive, yet effective methods to treat RCCT with about 80% success rate. Surgery remains the most invasive treatment option in chronic cases that fail to improve with other less invasive approaches.