Cardiac MRI of Hereditary Cardiomyopathy.

Hereditary cardiomyopathy comprises a heterogeneous group of diseases of the cardiac muscle that are characterized by the presence of genetic mutations. Cardiac MRI is central to evaluation of patients with cardiomyopathy owing to its ability to allow evaluation of many different tissue properties in a single examination. For example, cine MRI is the standard of care for assessment of myocardial structure and function. It clearly shows regions of asymmetric wall thickening that are typical of hypertrophic cardiomyopathy and allows it to be differentiated from other hereditary disorders such as Fabry disease or transthyretin cardiac amyloidosis that produce concentric hypertrophy. Late gadolinium enhancement provides a different tissue property and allows these latter two causes of concentric hypertrophy to be distinguished on the basis of their enhancement appearances (Fabry disease shows midwall basal inferolateral enhancement, and amyloidosis shows global subendocardial enhancement). Native T1 mapping may similarly allow differentiation between Fabry disease and amyloidosis without the use of contrast material. T2*-weighted MRI is important in the detection and quantification of iron overload cardiomyopathy. Other hereditary entities for which comprehensive MRI has proven essential include Danon disease, familial dilated cardiomyopathy, hereditary muscular dystrophy, arrhythmogenic right ventricular cardiomyopathy, and ventricular noncompaction. As a result of the diagnostic power of cardiac MRI, cardiac MRI examinations are being requested with increasing frequency, not only in academic centers but also in community practices. The genetic background, pathophysiologic characteristics, and clinical presentation of patients with hereditary cardiomyopathy are described; the characteristic cardiac MRI features of hereditary cardiomyopathy are discussed; and the role of MRI in risk stratification, treatment, and prognostication in patients with cardiomyopathy is reviewed. ©RSNA, 2022 Online supplemental material is available for this article.

Imaging features of fungal pneumonia in haematopoietic stem cell transplant patients.

Patients who have received haematopoietic stem cell transplantation (HSCT) have a high rate of pulmonary complications, and in this immunosuppressed population, fungal pneumonia is of great concern. Fungal pneumonia can have a similar appearance to non-infectious pulmonary processes in HSCT patients, and radiologists should be familiar with the subtle features that may help to differentiate these disease entities. The focus of this article is on the diagnosis of fungal pneumonia in HSCT patients with an emphasis on radiologists' roles in establishing the diagnosis of fungal pneumonia and the guidance of clinical management.

Comprehensive review of pericardial diseases using different imaging modalities.

Pericardial abnormalities are common cardiovascular disease entity, which are encountered in various clinical settings. Imaging plays an integral role in evaluation of pericardial abnormalities. The appropriate use of multiple imaging modalities is crucial to initiate the diagnosis and guide the referring providers to establish a management plan. Echocardiography (echo) is the initial imaging modality of choice. Computed tomography (CT) and magnetic resonance imaging (MRI) are complementary imaging tools with better tissue characterization. Pericardial abnormalities include pericardial effusion, pericarditis, pericardial constriction, tamponade, pneumopericardium, pericardial rupture, fistulas, congenital abnormalities, and pericardial tumors. Pericardial effusion is a common clinical entity, where there is accumulation of fluid in the pericardial sac. Pericarditis can be acute, incessant, chronic, or recurrent. Pericardial thickening or enhancement are the main CT findings in acute pericarditis. Pericardial constriction results into diastolic heart failure. Differentiating constrictive pericarditis from restrictive cardiomyopathy is important, since these conditions can present with similar clinical and hemodynamic findings and both have different management. Right atrial or right ventricular compression by the pericardial sac contents should raise the suspicion for tamponade. Immediate pericardiocentesis to release the elevated intra-pericardial pressure can be lifesaving. Pericardial rupture is a serious condition that can occur after trauma and can lead to cardiac herniation. The main purpose of this article is to do a comprehensive review of the imaging appearance of pericardial diseases on different imaging modalities and establish a structured diagnostic approach for pericardial diseases to appropriately guide management.

Apical variant hypertrophic cardiomyopathy "multimodality imaging evaluation".

Apical variant hypertrophic cardiomyopathy (AHCM) is characterized by asymmetric hypertrophy of the left ventricular (LV) apex. T wave inversions of variable degree, particularly in the left precordial leads, and left ventricular hypertrophy (LVH) are common EKG findings in AHCM. Echocardiography is typically the initial imaging modality used in the diagnosis and evaluation of AHCM. The diagnosis is made when the LV apex has apical wall thickness of ≥ 15 mm or a ratio of apical to basal LV wall thickness of ≥ 1.3 at end-diastole. The use of microbubble contrast agents with echocardiography is helpful for visualization of the apex. Cardiac magnetic resonance (CMR) has the advantage of a large field of view and the ability to perform tissue characterization. Late gadolinium enhancement (LGE) sequences are essential in the assessment of potential areas of myocardial scarring. Cardiac computed tomography (CCT) has the advantage of being able to evaluate coronary arteries in addition to assessing cardiac anatomy and function. A "Solar Polar" map pattern is the characteristic feature of AHCM on myocardial perfusion imaging (MPI) in cases not associated with apical aneurysm (APA). Recognition of typical perfusion patterns in AHCM patients is not only important in the diagnostic evaluation of this disease process, but also for avoiding unnecessary and costly tests. The purpose of this article is to review the imaging features of AHCM from different imaging modalities and assess the value added of each modality in the diagnosis of AHCM.

Imaging of Merkel Cell Carcinoma: What Imaging Experts Should Know.

Merkel cell carcinoma (MCC) is a rare and aggressive cutaneous neuroendocrine tumor with a higher mortality rate than melanoma. Approximately 40% of MCC patients have nodal or distant metastasis at initial presentation, and one-third of patients will develop distant metastatic disease over their clinical course. Although MCC is rare, its incidence has been steadily increasing. Furthermore, the immunogenicity of MCC and its diagnostic and therapeutic application have made MCC one of the most rapidly developing topics in dermatology and oncology. Owing to the aggressive and complex nature of MCC, a multidisciplinary approach is necessary for management of this tumor, including dermatologists, surgeons, radiation oncologists, medical oncologists, pathologists, radiologists, and nuclear medicine physicians. Imaging plays a crucial role in diagnosis, planning for surgery or radiation therapy, and assessment of treatment response and surveillance. However, MCC is still not well recognized among radiologists and nuclear medicine physicians, likely owing to its rarity. The purpose of this review is to raise awareness of MCC among imaging experts by describing the epidemiology, pathophysiology, and clinical features of MCC and current clinical management with a focus on the role of imaging. The authors highlight imaging findings characteristic of MCC, as well as the clinical significance of CT, MRI, sentinel lymph node mapping, fluorine 18 fluorodeoxyglucose PET/CT, and other nuclear medicine studies such as bone scintigraphy and somatostatin receptor scintigraphy. ©RSNA, 2019.

Pattern Recognition: A Mechanism-based Approach to Injury Detection after Motor Vehicle Collisions.

Motor vehicle collisions cause substantial mortality, morbidity, and expense worldwide. Certain types of injuries are more likely to result from frontal versus side-impact collisions, and knowledge of these specific patterns and why they occur aids in accurate and efficient diagnosis of traumatic injuries. Although the proper use of seat belts decreases crash-related mortality during frontal impact, certain injury patterns to the torso are directly attributed to restraint use. The spectrum of seat belt-related injuries ranges from mild skin and soft-tissue contusions to traumatic bowel injuries and unstable spine injuries that require surgery. Impact with the steering wheel or windshield during a frontal crash can cause characteristic injuries to the head, neck, torso, and distal upper extremity. Steering wheel deformity is an independent predictor of serious thoracic and abdominal injury among front-seat passengers. Impact of a flexed knee with the dashboard during a frontal collision can cause knee, thigh, and hip injuries. Distal lower extremity injuries are encountered frequently when the floorboard is driven into the foot. Lateral impact crashes often result in traumatic brain, thoracic, abdominal, and pelvic injuries, which are more often fatal to occupants on the side of the impact. The specific mechanism-based injury patterns are reviewed to establish a structured systematic search pattern that enables the radiologist to identify traumatic injuries with greater accuracy and speed, thereby improving the care of patients who experience acute trauma. ©RSNA, 2019 See discussion on this article by Ballard and Mellnick .

Placental abruption and hemorrhage-review of imaging appearance.

Placental and periplacental bleeding are common etiologies for antepartum bleeding. Placental abruption complicates approximately 1% of pregnancies and is associated with increased maternal, fetal, and neonatal morbidity and mortality. This article reviews the normal placental appearance on ultrasound, computed tomography (CT), and magnetic resonance imaging (MRI) and then discusses the different morphological appearance of placental and periplacental hematomas along with their mimics. Hematomas are classified based on the location as retroplacental, marginal subchorionic, preplacental (subamniotic), or intraplacental. Placenta-related bleeding is a common finding during first trimester ultrasound and its detection can help triage the pregnant females into low- and high-risk groups. This article reviews placenta related bleeding in the setting of trauma. Trauma can complicate pregnancy with potential severe maternal and fetal outcomes. CT is usually performed as part of the trauma workup and it can be challenging for placental evaluation. MRI can characterize the age of the hematomas and can differentiate hematomas from tumors.

Diagnosing Polyps on Transvaginal Sonography: Is Sonohysterography Always Necessary?

BACKGROUND: Endometrial polyps are localized overgrowth of glands, stroma, and blood vessels and reported in 13% to 50% of women with dysfunctional uterine bleeding. Transvaginal ultrasound (TVUS) is the initial noninvasive modality of choice for the evaluation of endometrial polyps. The addition of intrauterine contrast by adding saline during saline infusion sonohysterography (SIS) has been reported to improve diagnostic accuracy in detecting of endometrial polyps. Given all the technical advances in ultrasound instrumentation and technology over the last 10 years, we wanted to revisit the diagnostic accuracy and associated confidence level of TVUS and SIS for detecting endometrial polyps. OBJECTIVE: The aims of this study was to determine the diagnostic accuracy of TVUS in detecting endometrial polyps in patients with abnormal uterine bleeding or infertility and to determine if SIS is necessary when the level of confidence that a polyp is present is high. MATERIALS AND METHODS: A total of 144 patients who underwent both TVUS and SIS for the evaluation of abnormal uterine bleeding and infertility were retrospectively identified and independently reviewed by 2 blinded readers. Examinations were graded as polyps absent, equivocal for polyps, and polyps definitely present. Interreader agreement for TVUS grade was assessed using Cohen kappa. Hysteroscopy and histopathology were used as the reference standard for the final diagnosis. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value were calculated, and confidence intervals (CIs) were computed. RESULTS: From the combined assessments of both readers (288 reads), 24.7% were definitively positive for polyps, 47.2% were negative, and 28.1% were equivocal by TVUS. Interreader agreement was good with a kappa of 0.66 (95% CI, 0.56-0.76). Among the 108 reads where hysteroscopy/histopathology results were available, even when diagnostic confidence for the presence of polyps was high, TVUS had a PPV of 65.2% (95% CI, 42.1%-88.9%). This PPV was significantly lower than the corresponding PPV of SIS of 88.5% (95% CI, 77.4-100.0%; P = 0.021 for the difference). CONCLUSION: Saline infusion sonohysterography has better diagnostic accuracy for the detection and exclusion of endometrial polyps than TVUS, even in cases where the diagnostic confidence for the presence of polyps is high. Saline infusion sonohysterography may still be needed to confirm a TVUS diagnosis for polyps to limit the number of negative hysteroscopies.