Low b-value (50-100) diffusion-weighted images detect significantly more hyperintense liver lesions in children than T2-weighted images.

BACKGROUND: Low b-value (50-100 s/mm2) diffusion-weighted images (low b-value DWI) have been shown to be superior to T2-weighted fast spin echo sequence (T2-W) in detecting liver lesions in adults. There are no such studies assessing this difference in children. OBJECTIVE: The purpose of the study was to compare the sensitivity of low b-value DWI images and T2-W images in detecting focal liver lesions in children. MATERIALS AND METHODS: A retrospective review of liver magnetic resonance imaging (MRI) to assess focal liver lesions in 50 children (22 males, 28 females; age: 2 months to 17 years [mean: 10.9 years]) was performed. Two radiologists reviewed both low b-value DWI and T2-W sequences independently on different occasions to note lesions, the smallest lesion size and the location. A consensus reading of the entire MRI examination and a correlation with follow-up, other imaging modalities and pathology in available cases were used to determine the final number of lesions as a reference standard. The average number of lesions per patient detected by both readers on each sequence was compared with each other and with the reference standard using the signed-rank test. The smallest lesions detected by each sequence were compared using the paired t-test. RESULTS: One hundred seventy hyperintense lesions were identified on consensus review to serve as the reference standard. The average number of lesions identified by both readers on low b-value DWI was 134 (79%) and on T2-W was 95 (56%). There was excellent interobserver agreement for detection of lesions on low b-value DWI (intraclass correlation coefficient [ICC]=0.96 [0.93-0.98]) and T2-W (ICC=0.85 [0.75-0.91]), with slightly better agreement on low b-value DWI. Both readers identified significantly more number of lesions on low b-value DWI compared to T2-W (Reader 1: P=0.0036, Reader 2: P=0.0001). Compared to the reference standard (mean number of lesions: 3.45), T2-W detected significantly fewer lesions (mean number of lesions: 1.91; P=0.0001) while there was no significant difference in lesion detection on low b-value DWI (mean number of lesions: 2.68; P=0.1527). Low b-value DWI and T2-W were not significantly different in identifying the smallest lesion size (Reader 1: P=0.19, Reader 2: P=0.47). CONCLUSION: Low b-value DWI images are more sensitive than T2-W sequences in detecting hyperintense focal liver lesions in children.

ACR Appropriateness Criteria® Imaging for Transcatheter Aortic Valve Replacement.

Aortic stenosis is a common valvular condition with increasing prevalence in aging populations. When severe and symptomatic, the downstream prognosis is poor without surgical or transcatheter aortic valve replacement. Transcatheter aortic valve replacement is now considered a viable alternative to surgical aortic valve replacement in patients considered high and intermediate risk for surgery. Pre-intervention imaging with echocardiography and CT are essential for procedure planning and device selection to help optimize clinical outcomes with MR angiography playing largely a complementary role. Modern 3-D cross-sectional imaging has consistently shown to help reduce procedural complications from vascular access injury to paravalvular regurgitation and coronary obstruction. 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.

Abnormalities of the Coronary Arteries in Children: Looking beyond the Origins.

Coronary arterial abnormalities are uncommon findings in children that have profound clinical implications. Although anomalies of the coronary origins are well described, there are many other disease processes that affect the coronary arteries. Immune system-mediated diseases (eg, Kawasaki disease, polyarteritis nodosa, and other vasculiditides) can result in coronary arterial aneurysms, strictures, and abnormal tapering of the vessels. Because findings at imaging are an important component of diagnosis in these diseases, the radiologist's understanding of them is essential. Congenital anomalies may present at varying ages, and findings in hemodynamically significant anomalies, such as fistulas, are key for both diagnosis and preoperative planning. Pediatric heart surgery can result in wide-ranging postoperative imaging appearances of the coronary arteries and also predisposes patients to a multitude of complications affecting the heart and coronary arteries. In addition, although rare, accidental trauma can lead to injury of the coronary arteries, and awareness and detection of these conditions are important for diagnosis in the acute setting. Patients with coronary arterial conditions at presentation may range from being asymptomatic to having findings of myocardial infarction. Recognition of the imaging findings is essential to direct appropriate treatment. ©RSNA, 2017.

Rapid non-contrast magnetic resonance imaging for post appendectomy intra-abdominal abscess in children.

BACKGROUND: Acute appendicitis, especially if perforated at presentation, is often complicated by postoperative abscess formation. The detection of a postoperative abscess relies primarily on imaging. This has traditionally been done with contrast-enhanced computed tomography. Non-contrast magnetic resonance imaging (MRI) has the potential to accurately detect intra-abdominal abscesses, especially with the use of diffusion-weighted imaging (DWI). OBJECTIVE: To evaluate our single-center experience with a rapid non-contrast MRI protocol evaluating post-appendectomy abscesses in children with persistent postsurgical symptoms. MATERIALS AND METHODS: In this retrospective, institutional review board-approved study, all patients underwent a clinically indicated non-contrast 1.5- or 3-Tesla abdomen/pelvis MRI consisting of single-shot fast spin echo, inversion recovery and DWI sequences. All MRI studies were reviewed by two blinded pediatric radiologists to identify the presence of a drainable fluid collection. Each fluid collection was further characterized as accessible or not accessible for percutaneous or transrectal drainage. Imaging findings were compared to clinical outcome. RESULTS: Seven of the 15 patients had a clinically significant fluid collection, and 5 of these patients were treated with percutaneous drain placement or exploratory laparotomy. The other patients had a phlegmon or a clinically insignificant fluid collection and were discharged home within 48 h. CONCLUSION: Rapid non-contrast MRI utilizing fluid-sensitive and DWI sequences can be used to identify drainable fluid collections in post-appendectomy patients. This protocol can be used to triage patients between conservative management vs. abscess drainage without oral/intravenous contrast or exposure to ionizing radiation.

Diseases and Syndromes That Affect the Lungs and the Kidneys: A Radiologic Review.

A number of different conditions simultaneously affect both the lungs and the kidneys. These include autoimmune disorders and genetic tumor syndromes. Although manifestations within either organ system alone may not be specific, by observing the pattern of involvement and clinical history, radiologists may be able to suggest the correct diagnosis.

Fat-containing soft-tissue masses in children.

The diagnosis of soft-tissue masses in children can be difficult because of the frequently nonspecific clinical and imaging characteristics of these lesions. However key findings on imaging can aid in diagnosis. The identification of macroscopic fat within a soft-tissue mass narrows the differential diagnosis considerably and suggests a high likelihood of a benign etiology in children. Fat can be difficult to detect with sonography because of the variable appearance of fat using this modality. Fat is easier to recognize using MRI, particularly with the aid of fat-suppression techniques. Although a large portion of fat-containing masses in children are adipocytic tumors, a variety of other tumors and mass-like conditions that contain fat should be considered by the radiologist confronted with a fat-containing mass in a child. In this article we review the sonographic and MRI findings in the most relevant fat-containing soft-tissue masses in the pediatric age group, including adipocytic tumors (lipoma, angiolipoma, lipomatosis, lipoblastoma, lipomatosis of nerve, and liposarcoma); fibroblastic/myofibroblastic tumors (fibrous hamartoma of infancy and lipofibromatosis); vascular anomalies (involuting hemangioma, intramuscular capillary hemangioma, phosphate and tensin homologue (PTEN) hamartoma of soft tissue, fibro-adipose vascular anomaly), and other miscellaneous entities, such as fat necrosis and epigastric hernia.

Pediatric Fibroblastic and Myofibroblastic Tumors: A Pictorial Review.

Pediatric fibroblastic and myofibroblastic tumors are a relatively common group of soft-tissue proliferations that are associated with a wide spectrum of clinical behavior. These tumors have been divided into the following categories on the basis of their biologic behavior: benign (eg, myositis ossificans, myofibroma, fibromatosis colli), intermediate-locally aggressive (eg, lipofibromatosis, desmoid fibroma), intermediate-rarely metastasizing (eg, inflammatory myofibroblastic tumors, infantile fibrosarcoma, low-grade myofibroblastic sarcoma), and malignant (eg, fibromyxoid sarcoma, adult fibrosarcoma). Imaging has a key role in the evaluation of lesion origin, extent, and involvement with adjacent structures, and in the treatment management and postresection surveillance of these tumors. The imaging findings of these tumors are often nonspecific. However, certain imaging features, such as low or intermediate signal intensity on T2-weighted magnetic resonance images and extension along fascial planes, support the diagnosis of a fibroblastic or myofibroblastic tumor. In addition, certain tumors have characteristic imaging findings (eg, multiple subcutaneous or intramuscular lesions in infantile myofibromatosis, plaquelike growth pattern of Gardner fibroma, presence of adipose tissue in lipofibromatosis) or characteristic clinical manifestations (eg, great toe malformations in fibrodysplasia ossificans fibroma, neonatal torticollis in fibromatosis colli) that suggest the correct diagnosis. Knowledge of the syndrome associations of some of these tumors-for example, the association between familial adenomatous polyposis syndrome and both Gardner fibroma and desmoid fibromatosis, and that between nevoid basal cell carcinoma syndrome and cardiac fibroma-further facilitate a diagnosis. The recognition of key imaging findings can help guide treatment management and help avoid unnecessary intervention in cases of benign lesions such as myositis ossificans and fibromatosis colli. In this article, we describe the various types of fibroblastic and myofibroblastic tumors in children and the characteristic clinical manifestations, imaging features, and growth patterns of these neoplasms-all of which aid in the appropriate radiologic assessment and management of these lesions. (©)RSNA, 2016.

Candida albicans pancreatitis in a child with cystic fibrosis post lung transplantation.

We present a case of Candida albicans infection of a previously intact pancreas in a child with cystic fibrosis status post lung transplantation. Although Candida superinfection in necrotizing pancreatitis is not uncommon, this is a unique case of Candida infection of non-necrotic pancreatic parenchyma. This case presented a diagnostic dilemma for radiologists because it appeared virtually identical to acute interstitial edematous pancreatitis on imaging. Ultimately, endoscopic US-based biopsy was pursued for diagnosis. Although difficult to treat and compounded by the immunocompromised status of the child, the pancreatic infection improved with antifungal therapy.

Sclerotherapy of Diffuse and Infiltrative Venous Malformations of the Hand and Distal Forearm.

PURPOSE: Venous malformations (VM) involving the hand and forearm often lead to chronic pain and dysfunction, and the threshold for treatment is high due to the risk of nerve and skin damage, functional deterioration and compartment syndrome. The purpose of this study is to demonstrate that sclerotherapy of diffuse and infiltrative VM of the hand is a safe and effective therapy. MATERIALS AND METHODS: A retrospective review of all patients with diffuse and infiltrative VM of the hand and forearm treated with sclerotherapy from 2001 to 2014 was conducted. All VM were diagnosed during the clinical visit by a combination of physical examination and imaging. Sclerotherapy was performed under imaging guidance using ethanol and/or sodium tetradecyl sulfate foam. Clinical notes were reviewed for signs of treatment response and complications, including skin blistering and nerve injury. RESULTS: Seventeen patients underwent a total of 40 sclerotherapy procedures. Patients were treated for pain (76%), swelling (29%) or paresthesias (6%). Treatments utilized ethanol (70%), sodium tetradecyl sulfate foam (22.5%) or a combination of these (7.5%). Twenty-four percent of patients had complete resolution of symptoms, 24% had partial relief of symptoms without need for further intervention, and 35% had some improvement after initial treatment but required additional treatments. Two skin complications were noted, both of which resolved. No motor or sensory loss was reported. CONCLUSION: Sclerotherapy is a safe and effective therapy for VM of the hand with over 83% of patients experiencing relief.

Pediatric nonaccidental abdominal trauma: what the radiologist should know.

Abdominal injury in nonaccidental trauma (NAT) is an increasingly recognized cause of hospitalization in abused children. Abdominal injuries in NAT are often severe and have high rates of surgical intervention. Certain imaging findings in the pediatric abdomen, notably bowel perforation and pancreatic injury, should alert the radiologist to possible abuse and incite close interrogation concerning the reported mechanism of injury. Close inspection of the imaging study is warranted to detect additional injury sites because these injuries rarely occur in isolation. When abdominal injury is suspected in known or speculated NAT, computed tomography (CT) of the abdomen and pelvis with intravenous contrast material is recommended for diagnostic and forensic evaluation. Although the rate of bowel injury is disproportionately high in NAT, solid organs, including the liver, pancreas, and spleen, are most often injured. Adrenal and renal trauma is less frequent in NAT and is generally seen with multiple other injuries. Hypoperfusion complex is a constellation of abdominal CT findings that indicates current or impending decompensated shock and is most often due to severe neurologic impairment in NAT. Although abdominal injuries in NAT are relatively uncommon, knowledge of injury patterns and their imaging appearances is important for patient care and protection.

Imaging of juvenile idiopathic arthritis: a multimodality approach.

Juvenile idiopathic arthritis (JIA) is a heterogeneous group of diseases characterized by synovial inflammation and is the most common rheumatic complaint in children. To facilitate research and treatment, JIA has been further classified on the basis of the number of joints involved, additional symptoms, family history, and serologic findings. Imaging in patients with JIA has historically relied on radiography, which allows the accurate assessment of chronic changes of JIA, including growth disturbances, periostitis, and joint malalignment. However, radiographic findings of active inflammation are nonspecific, and, in the past, clinical evaluation has taken precedence over imaging of acute disease. Recent advances in disease-modifying therapeutic agents that can help prevent long-term disability in patients with JIA have led to greater emphasis on the detection of early joint-centered inflammation that cannot be accurately assessed radiographically and may not be evident clinically. Both contrast material-enhanced magnetic resonance (MR) imaging and Doppler ultrasonography (US) are well suited for this application and are playing an increasingly important role in diagnosis, risk stratification, treatment monitoring, and problem solving. Contrast-enhanced MR imaging is the most sensitive technique for the detection of synovitis and is the only modality that can help detect bone marrow edema, both of which indicate active inflammation. US is more sensitive than radiography for the detection of synovial proliferation and effusions and is particularly useful in the evaluation of small peripheral joints. The complexity of the temporomandibular and sacroiliac joints limits the usefulness of radiographic or US evaluation, and contrast-enhanced MR imaging is the preferred modality for evaluation of these structures.