Performance of simultaneous multi-slice accelerated diffusion-weighted imaging for assessing focal renal lesions in pediatric patients with tuberous sclerosis complex.

BACKGROUND: Diffusion-weighted imaging (DWI) is a useful MRI technique to characterize abdominal lesions in children, but long acquisition times can lead to image degradation. Simultaneous multi-slice accelerated DWI is a promising technique to shorten DWI scan times. OBJECTIVE: To test the feasibility of simultaneous multi-slice DWI of the kidneys in pediatric patients with tuberous sclerosis complex (TSC) and to evaluate the accelerated protocol regarding image quality and quantitative apparent diffusion coefficient (ADC) values compared to standard echoplanar DWI sequence. MATERIALS AND METHODS: We included 33 children and adolescents (12 female, 21 male; mean age 10±5 years) with TSC and renal cyst or angiomyolipoma on 3-tesla (T) MRI from 2017 to 2019. All studies included both free-breathing standard echoplanar DWI and simultaneous multi-slice DWI sequences. Subjective and quantitative image quality was evaluated using a predefined 5-point scale. ADC values were obtained for all renal cysts and angiomyolipomas ≥5 mm. All statistical analysis was performed using Stata/SE v15.1. RESULTS: Simultaneous multi-slice DWI ADC values were slightly lower compared to standard echoplanar DWI for both renal cysts and angiomyolipomas (mean difference 0.05×10-3 mm2/s, 95% confidence interval [CI] 0.40-0.50 and 0.024×10-3 mm2/s, 95% CI 0.17-0.21, respectively, with P>0.1). Our results showed that renal lesions with ADC values >1.69×10-3 mm2/s were all cysts, whereas lesions with values <1.16×10-3 mm2/s were all angiomyolipomas. However, ADC values could not discriminate between lipid-rich and lipid-poor angiomyolipomas (P>0.1, for both sequences). CONCLUSION: A 55% reduction in scan time was achieved using simultaneous multi-slice DWI for abdominal imaging in children with TSC, with near identical image quality as standard DWI. These results suggest that multi-slice techniques should be considered more broadly as an MRI acceleration technique in children.

Reducing Radiation Dose and Contrast Medium Volume With Application of Dual-Energy CT in Children and Young Adults.

OBJECTIVE. The purpose of this study was to assess if dual-source dual-energy CT (DS-DECT) can be used with lower radiation doses and contrast material volumes than single-energy CT (SECT) in children and young adults. MATERIALS AND METHODS. This retrospective study included 85 consecutive children and young adults (age range, 1 month old to 19 years old; 81 male, 70 female) who underwent contrast-enhanced DS-DECT of the chest (n = 41) or the abdomen and pelvis (n = 44) on second- or third-generation dual-source CT scanners (Somatom Flash or Force, Siemens Healthineers) for clinically indicated reasons. We included 66 age-, sex-, body region-, and weight-matched patients who underwent SECT on the same scanner. Patients were scanned with either SECT (with automatic exposure control using both CARE kV [Siemens Healthineers] and CARE Dose 4D [Siemens Healthineers]) or DS-DECT (with CARE Dose 4D). Two pediatric radiologists assessed clinical indications, radiologic findings, image quality, and any study limitations (noise or artifacts). Patient demographics (age, sex, weight), scan parameters (tube voltage, tube current-time product, pitch, section thickness), CT dose descriptors (volume CT dose index, dose-length product, size-specific dose estimate [SSDE]), and contrast material volume were recorded. Descriptive statistics, paired t test, and Cohen kappa test were performed. RESULTS. Mean patient ages and weights ± SD in DS-DECT (10 ± 6 years old, 38 ± 23 kg) and SECT (11 ± 7 years old, 43 ± 29 kg) groups were not significantly different (p > 0.05). Respective SSDEs for chest DS-DECT (4.0 ± 2.1 mGy), chest SECT (6.1 ± 4.4 mGy), abdomen-pelvis DS-DECT (5.0 ± 5.0 mGy), and abdomen-pelvis SECT (8.3 ± 4.0 mGy) were significantly different (p = 0.003-0.005). Contrast material volume for DS-DECT examinations was 19-22% lower compared with the weight- and body region-matched scans obtained with SECT. Image quality of DECT was acceptable in all patients. CONCLUSION. In children and young adults, chest and abdomen-pelvis DS-DECT enables substantial radiation dose and contrast volume reductions compared with weight- and region-matched SECT.

Comparison of CT enterography and MR enterography imaging features of active Crohn disease in children and adolescents.

BACKGROUND: Assessment for active Crohn disease by CT enterography and MR enterography relies on identifying mural and perienteric imaging features. OBJECTIVE: To evaluate the performance of established imaging features of active Crohn disease in children and adolescents on CT and MR enterography compared with histological reference. MATERIALS AND METHODS: We included patients ages 18 years and younger who underwent either CT or MR enterography from 2007 to 2014 and had endoscopic biopsy within 28 days of imaging. Two pediatric radiologists blinded to the histological results reviewed imaging studies and scored the bowel for the presence or absence of mural features (wall thickening >3 mm, mural hyperenhancement) and perienteric features (mesenteric hypervascularity, edema, fibrofatty proliferation and lymphadenopathy) of active disease. We performed univariate analysis and multivariate logistic regression to compare imaging features with histological reference. RESULTS: We evaluated 452 bowel segments (135 from CT enterography, 317 from MR enterography) from 84 patients. Mural imaging features had the highest association with active inflammation both for MR enterography (wall thickening had 80% accuracy, 69% sensitivity and 91% specificity; mural hyperenhancement had 78%, 53% and 96%, respectively) and CT enterography (wall thickening had 84% accuracy, 72% sensitivity and 91% specificity; mural hyperenhancement had 76%, 51% and 91%, respectively), with perienteric imaging features performing significantly worse on MR enterography relative to CT enterography (P < 0.001). CONCLUSION: Mural features are predictors of active inflammation for both CT and MR enterography, while perienteric features can be distinguished better on CT enterography compared with MR enterography. This likely reflects the increased conspicuity of the mesentery on CT enterography and suggests that mural features are the most reliable imaging features of active Crohn disease in children and adolescents.

Abdominal ultrasonography of the pediatric gastrointestinal tract.

Ultrasound is an invaluable imaging modality in the evaluation of pediatric gastrointestinal pathology; it can provide real-time evaluation of the bowel without the need for sedation or intravenous contrast. Recent improvements in ultrasound technique can be utilized to improve detection of bowel pathology in children: Higher resolution probes, color Doppler, harmonic and panoramic imaging are excellent tools in this setting. Graded compression and cine clips provide dynamic information and oral and intravenous contrast agents aid in detection of bowel wall pathology. Ultrasound of the bowel in children is typically a targeted exam; common indications include evaluation for appendicitis, pyloric stenosis and intussusception. Bowel abnormalities that are detected prenatally can be evaluated after birth with ultrasound. Likewise, acquired conditions such as bowel hematoma, bowel infections and hernias can be detected with ultrasound. Rare bowel neoplasms, vascular disorders and foreign bodies may first be detected with sonography, as well. At some centers, comprehensive exams of the gastrointestinal tract are performed on children with inflammatory bowel disease and celiac disease to evaluate for disease activity or to confirm the diagnosis. The goal of this article is to review up-to-date imaging techniques, normal sonographic anatomy, and characteristic sonographic features of common and uncommon disorders affecting the gastrointestinal tract in children.

Value of diffusion-weighted imaging when added to magnetic resonance enterographic evaluation of Crohn disease in children.

BACKGROUND: MR enterography is increasingly utilized for noninvasive evaluation of disease activity in young patients with Crohn disease and has great impact on clinical management. Diffusion-weighted imaging (DWI) is a rapid MR imaging technique that measures molecular diffusion of water and is sensitive to the inflammatory process; however, its value to MR enterography has not been rigorously evaluated. OBJECTIVE: To determine whether the addition of DWI to MR enterography is helpful in evaluating Crohn disease activity in young patients when compared to a histological reference. MATERIALS AND METHODS: In this single-institution retrospective study, we searched an imaging database for the period January 2010 to December 2012 to identify patients age 19 years and younger who had MR enterography with diffusion-weighted imaging (DWI). We used an electronic medical record search to identify those who had MR enterography and colonoscopy performed within 28 days of each other. All MR enterography scans were performed on a 1.5-T or 3-T clinical MR scanner with phased-array torso coil configuration using standard pulse sequences as well as axial DWI with b values of 50, 400 and 800. Bowel segments were evaluated for disease activity based on standard MR enterography sequences; in addition, segmental apparent diffusion coefficient (ADC) values were calculated based on DWI. Histological reference for disease activity was based on assessment for mucosal inflammatory changes on endoscopic biopsy. MR enterography and DWI evaluation were performed in a blinded fashion with respect to histological results. RESULTS: We included imaging of 78 bowel segments from 27 patients (mean age 14.5 ± 3.02 years) with known Crohn disease in the study. The mean ADC for bowel segments with active disease was 1.56 ± 0.7 × 10(3) mm(2)/s compared with 2.58 ± 1.4 × 10(3) mm(2)/s for segments without active disease, a difference that was statistically significant (P < 0.01, Student's t-test). Using a threshold value of 2.0 × 10(3) mm(2)/s, DWI demonstrated lower accuracy (64.1%) but higher sensitivity (78.8%) for detecting active disease compared with standard MR enterography (69.2% and 54.6%, respectively). Combining DWI with MR enterography, using DWI as the initial screen and MR enterography afterward to reduce false negativity, led to a significant increase in accuracy (76.9%; P = 0.03, McNemar's test) compared with either imaging technique alone. CONCLUSION: Although DWI does not perform as well as standard MR enterography for detection of active Crohn disease, the combination of DWI and MR enterography increases imaging accuracy for determining disease activity compared with either technique alone. These results indicate that DWI adds value to MR enterography and supports the incorporation of DWI into MR enterography protocols for evaluation of Crohn disease in young patients.

Feasibility study to assess clinical applications of 3-T cine MRI coupled with synchronous audio recording during speech in evaluation of velopharyngeal insufficiency in children.

BACKGROUND: In the past decade, there has been increased utilization of magnetic resonance imaging (MRI) in evaluating and understanding velopharyngeal insufficiency (VPI). To our knowledge, none of the prior studies with MRI has simultaneously linked the audio recordings of speech during cine MRI acquisition with the corresponding images and created a video for evaluating VPI. OBJECTIVE: To develop an MRI protocol with static and cine sequences during phonation to evaluate for VPI in children and compare the findings to nasopharyngoscopy and videofluoroscopy. MATERIALS AND METHODS: Five children, ages 8-16 years, with known VPI, who had previously undergone nasopharyngoscopy and videofluoroscopy, were included. MRI examination was performed on a 3-T Siemens scanner. Anatomical data was obtained using an isotropic T2-weighted 3-D SPACE sequence with multiplanar reformation capability. Dynamic data was obtained using 2-D FLASH cine sequences of the airway in three imaging planes during phonation. Audio recordings were captured by a MRI compatible optical microphone. RESULTS: All five cases had MRI and nasopharyngoscopy and four had videofluoroscopy performed. VPI was identified by MRI in all five patients. The location and severity of the velopharyngeal gap, closure pattern, velar size and shape and levator veli palatini (LVP) muscle were identified in all patients. MRI was superior in visualizing the integrity of the LVP muscle. MRI was unable to identify hemipalatal weakness in one case. In a case of stress-induced VPI, occurring only during clarinet playing, cine MRI demonstrated discordant findings of a velopharyngeal gap during phonatory tasks but not with instrument playing. Overall, there was satisfactory correlation among MRI, nasopharyngoscopy and videofluoroscopy findings. CONCLUSION: Cine MRI of the airway during speech is a noninvasive, well-tolerated diagnostic imaging tool that has the potential to serve as a guide prior to and after surgical correction of VPI. MRI provided superior anatomical detail of the levator musculature. The creation of a video with recorded phonation allowed correlation between palatal movements and specific phonatory tasks.

Fishtail deformity--a delayed complication of distal humeral fractures in children.

BACKGROUND: Concavity in the central portion of the distal humerus is referred to as fishtail deformity. This entity is a rare complication of distal humeral fractures in children. OBJECTIVE: The purpose of this study is to describe imaging features of post-traumatic fishtail deformity and discuss the pathophysiology. MATERIALS AND METHODS: We conducted a retrospective analysis of seven cases of fishtail deformity after distal humeral fractures. RESULTS: Seven children ages 7-14 years (five boys, two girls) presented with elbow pain and history of distal humeral fracture. Four of the seven children had limited range of motion. Five children had prior grade 3 supracondylar fracture treated with closed reduction and percutaneous pinning. One child had a medial condylar fracture and another had a lateral condylar fracture; both had been treated with conservative casting. All children had radiographs, five had CT and three had MRI. All children had a concave central defect in the distal humerus. Other imaging features included joint space narrowing with osteophytes and subchondral cystic changes in four children, synovitis in one, hypertrophy or subluxation of the radial head in three and proximal migration of the ulna in two. CONCLUSION: Fishtail deformity of the distal humerus is a rare complication of distal humeral fractures in children. This entity is infrequently reported in the radiology literature. Awareness of the classic imaging features can result in earlier diagnosis and appropriate treatment.

MRI predictors of treatment response for perianal fistulizing Crohn disease in children and young adults.

BACKGROUND: Magnetic resonance imaging (MRI) is considered the imaging standard for diagnosis and characterization of perianal complications associated with Crohn disease in children and adults. OBJECTIVE: To define MRI criteria that could act as potential predictors of treatment response in fistulizing Crohn disease in children, in order to guide more informed study interpretation. MATERIALS AND METHODS: We performed a retrospective database query to identify all children and young adults with Crohn disease who underwent serial MRI studies for assessment of perianal symptoms between 2003 and 2010. We examined imaging features of perianal disease including fistula number, type and length, presence and size of associated abscess, and disease response/progression on follow-up MRI. We reviewed imaging studies and electronic medical records. Statistical analysis, including logistic regression, was performed to associate MR imaging features with treatment response and disease progression. RESULTS: We included 36 patients (22 male, 14 female; age range 8-21 years). Of these, 32 had a second MRI exam and 4 had clinical evidence of complete response, obviating the need for repeat imaging. Of the parameters analyzed, presence of abscess, type of fistula according to the Parks classification, and multiplicity were not predictors of treatment outcome. Maximum length of the dominant fistula and aggregate fistula length in the case of multiple fistulae were the best predictors of treatment outcome. Maximum fistula length <2.5 cm was a predictor of treatment response, while aggregate fistula length ≥2.5 cm was a predictor of disease progression. CONCLUSION: Perianal fistula length is an important imaging feature to assess on MRI of fistulizing Crohn disease.

Relationship between radiologist training level and fluoroscopy time for voiding cystourethrography.

OBJECTIVE: The objective of our study was to determine whether voiding cystourethrography (VCUG) fluoroscopy time is related to the training level of the performing radiologist. MATERIALS AND METHODS: VCUG reports with normal findings from 2008 to 2011 at one institution were retrospectively reviewed. The average fluoroscopy time was calculated for first-year radiology residents, senior radiology residents, pediatric radiology fellows, and attending pediatric radiologists. The average fluoroscopy time was also calculated for radiologist sex, patient sex, and patient age group. The analysis of variance was used to evaluate differences in average fluoroscopy times between training levels of radiologists, patient age groups, and patient sexes. RESULTS: We reviewed 784 VCUG reports with normal findings: 340 (43.4%) were performed by first-year residents; 181 (23%), by senior residents; 161 (20.5%), by fellows; and 102 (13%), by attending pediatric radiologists. The overall average fluoroscopy time was 1.86 minutes (SD ± 0.98). The attending pediatric radiologists had the shortest average fluoroscopy time (1.63 ± 0.92 minutes), significantly shorter than senior residents (1.96 ± 1.09 minutes; p = 0.0070) and fellows (1.91 ± 0.85 minutes; p = 0.0255). There was no significant difference between attending radiologists and first-year residents (1.85 ± 1.00 minutes; p = 0.0550). The male-to-female ratio of radiologists was 54% versus 46%, with identical average fluoroscopy times: male radiologists, 1.86 ± 1.05 minutes; female radiologists, 1.86 ± 0.90 minutes. There was no significant difference in average fluoroscopy times among patient age groups: 1.93, 1.76, and 1.78 minutes, respectively, for groups A (0-1 years), B (> 1 to ≤ 5 years), and C (> 5 years) (p = 0.1750, 0.4605, 0.6303). The average fluoroscopy time for male patients (2.02 ± 1.00 minutes) was significantly longer than that for female patients (1.71 ± 0.95 minutes; p < 0.0001). CONCLUSION: Attending pediatric radiologists have the shortest fluoroscopy time; the differences between their average time compared with the average times of pediatric radiology fellows and of senior radiology residents were statistically significant. The average fluoroscopy time is longer for male patients than for female patients.

Detecting active inflammation and fibrosis in pediatric Crohn's disease: prospective evaluation of MR-E and CT-E.

Symptoms of Crohn's disease (CD) can be due to active inflammation or fibrosis. Differentiating these based on clinical presentation, endoscopy, laboratory parameters, and clinical scoring methods can be inaccurate and/or invasive. As therapy decisions are often directed based on whether active disease or fibrosis is present, a reliable and non-invasive test to distinguish these two etiologies would be a powerful clinical tool. CT enterography (CT-E) and MR enterography (MR-E) are two non-invasive imaging modalities tailored to evaluate the small bowel. The purpose of our study was to compare the ability of MR-E and CT-E to assess for active inflammation and mural fibrosis in patients with known CD as compared to a histologic reference standard. After obtaining MR-E and CT-E on the same day, a total of 61 histologic samples were obtained from twelve subjects aged 12-20 years via full-thickness bowel resection or endoscopy. These were evaluated by the pathologist for active inflammation and fibrosis. We found that while CT-E and MR-E were similar in their accuracies of depicting active inflammation, MR-E was significantly more sensitive in detecting fibrosis. Because of this and the lack of ionizing radiation from MR-E, we believe that MR-E rather than CT-E should serve as the primary imaging modality for the assessment of CD pediatric patients with non-acute clinical exacerbations.

Imaging of multifocal hepatic lesions in pediatric patients.

Imaging plays a vital role in detection and characterization of multifocal liver lesions in children. Numerous causes for these lesions exist, including benign and malignant neoplasms, infectious lesions, and congenital and inflammatory conditions. The imaging spectrum of multifocal liver lesions in children is presented with emphasis on key imaging features, differential diagnoses and helpful relevant clinical features.

The association of a dysmorphic pelvis, absence of pubic rami, hip dysplasia, and genitourinary anomalies.

BACKGROUND: There have been reports of children who had absence of the pubic rami, hip dysplasia, and genitourinary anomalies. CASE REPORT: We describe a 44-year-old woman with severe hip dysplasia, bilateral chronic congenital hip dislocations, abnormal development of the entire pelvis, and absence of the pubic rami in association with absence of the uterus. CONCLUSION: We present an individual who has abnormal development of the entire pelvis, including absence of the pubic rami, and genitourinary anomalies. We suggest that this is a rare pattern of associated anomalies confined to a localized region of the body. Potential underlying developmental abnormalities include somatic mutations which affected the mesodermal cells from which the pelvis and mullerian structures develop.

Prospective evaluation of MR enterography as the primary imaging modality for pediatric Crohn disease assessment.

OBJECTIVE: The objectives of this study were prospective evaluation of MR enterographic accuracy for detecting Crohn disease imaging features in pediatric patients, compared with a CT reference standard, as well as determination of MR enterographic accuracy for detecting active bowel inflammation and fibrosis using a histologic reference standard. SUBJECTS AND METHODS: The study group for this blinded prospective study included 21 pediatric subjects with known Crohn disease scheduled for clinical CT and histologic bowel sampling for symptomatic exacerbation. All subjects and their parents gave informed consent to also undergo MR enterography. CT and MR enterography examinations were independently reviewed by two radiologists and were scored for Crohn disease features. All bowel histology specimens were reviewed by a single pathologist for the presence of active mucosal inflammation and mural fibrosis, followed by correlation of imaging and histologic findings. RESULTS: All 21 subjects underwent MR enterography and histologic sampling, 18 of whom also underwent CT. MR enterography had high sensitivity for detecting Crohn disease imaging features (e.g., bowel wall thickening, mesenteric inflammation, lymphadenopathy, fistula, and abscess) compared with CT, with individual sensitivity values ranging from 85.1% to 100%. Of a total of 53 abnormal bowel segments with correlation of MRI and histologic findings, MR enterography showed 86.7% accuracy (90.0% sensitivity and 82.6% specificity) for detecting active inflammation (p < 0.001). The accuracy of MR enterography for detecting mural fibrosis overall was 64.9%, compared with histology, but increased to 83.3% (p < 0.05) for detecting fibrosis without superimposed active inflammation. CONCLUSION: MR enterography can substitute for CT as the first-line imaging modality in pediatric patients with Crohn disease, on the basis of its ability to detect intestinal pathologic abnormalities in both small and large bowel as well as extraintestinal disease manifestations. Additionally, MR enterography provides an accurate noninvasive assessment of Crohn disease activity and mural fibrosis and can aid in formulating treatment strategies for symptomatic patients and assessing therapy response.

Cine magnetic resonance imaging with simultaneous audio to evaluate pediatric velopharyngeal insufficiency.

OBJECTIVE: To develop a protocol linking cine magnetic resonance (MR) imaging to simultaneously acquired audio recordings of specific phonatory tasks to evaluate velopharyngeal insufficiency (VPI) in children. DESIGN: Institutional review board-approved development and application of a novel dynamic cine MR imaging protocol linked to simultaneously recorded audio. SETTING: A tertiary care multidisciplinary pediatric airway center. PARTICIPANTS: Three healthy adult volunteers and 5 pediatric volunteers (age range, 9.3-18.9 years; mean age, 12.4 years) from the multidisciplinary pediatric airway center with VPI who previously had undergone nasopharyngoscopy, videofluoroscopy, or both. INTERVENTIONS: Cine MR imaging with simultaneously acquired audio files was performed in 3 adult volunteers to optimize the protocol and then in 5 pediatric volunteers meeting the inclusion criteria. MAIN OUTCOME MEASURES: High-resolution cine MR images with clear intelligible audio recordings of specific phonatory tasks. RESULTS: Using 3 healthy adult volunteers, a cine MR imaging VPI protocol was developed that links simultaneously acquired cine MR images to audio recordings of specific validated phonatory tasks. Five school-aged children with VPI from our multidisciplinary pediatric airway center were then enrolled and underwent cine MR imaging using this protocol. The cine MR images and audio recordings acquired were of sufficient diagnostic quality to evaluate VPI closure patterns in school-aged children with VPI. CONCLUSION: Cine MR imaging linked to audio is a quick, safe, and well-tolerated dynamic diagnostic imaging tool that may eventually have the potential to guide more precisely the selection and application of surgical techniques for VPI.

The growing teratoma syndrome.

Growing teratoma syndrome is defined as enlarging masses of mature teratoma following chemotherapy for malignant nonseminomatous germ-cell tumors. Typically, there is associated normalization of initially elevated serum tumor markers. We describe clinical and imaging findings in a case of growing teratoma syndrome originating from immature teratoma of the ovary in a 12-year-old girl. Familiarity with this unusual entity is important to avoid confusion with advancing malignancy.