Pharmacokinetic-guided hydroxyurea to reduce transfusions in Ugandan children with sickle cell anemia: study design of the Alternative Dosing And Prevention of Transfusions (ADAPT) trial.

INTRODUCTION: People with sickle cell anemia (SCA) may require frequent blood transfusions to treat acute and chronic complications. Hydroxyurea is a life-saving treatment for SCA that could also decrease the need for blood transfusions. Inadequate medication access and challenges in dose optimization limit the widespread use of hydroxyurea in Africa. If feasible, pharmacokinetic (PK) dosing might improve dose determination to minimize toxicities and maximize clinical benefits. The Alternative Dosing And Prevention of Transfusions (ADAPT, NCT05662098) trial will analyze the impact of hydroxyurea on transfusion rate and serve as a pilot study to evaluate the feasibility of PK-guided hydroxyurea dosing in Uganda. METHODS: Herein we describe the rationale and design of ADAPT, a prospective cohort study of ~100 children with SCA in Jinja, Uganda. The primary hypothesis is that hydroxyurea will decrease blood transfusion use by ≥50%, comparing the transfusion incidence rate ratio between a 3-month pre-treatment and a 12-month treatment period. A key secondary hypothesis is that our PK-dosing approach will generate a suitable hydroxyurea dose for ≥80% of participants. Every ADAPT participant will undergo hydroxyurea PK testing, and if a dose is generated within 15-35 mg/kg/day participants will start on their individualized dose. If not, they will start on a default dose of 20 mg/kg/day. Hydroxyurea dose optimization will occur with periodic dose adjustments. CONCLUSION: Overall, demonstrating the reduction in blood transfusion utilization with hydroxyurea treatment would provide leverage to increase hydroxyurea access, and PK-guided hydroxyurea dosing should optimize the safe and effective treatment of SCA across sub-Saharan Africa.

Rapid, free-breathing non-contrast MRI for first-line imaging evaluation of ovarian torsion in the emergency department.

BACKGROUND: Transabdominal ultrasound (US) is first-line imaging to evaluate ovaries in girls presenting to the emergency department (ED) with suspected ovarian torsion. Ovaries may be difficult to visualize sonographically; therefore, prompt diagnosis using US alone can be challenging. Rapid MRI as first-line imaging may help streamline patient throughput, especially with increasing MRI availability in the ED. OBJECTIVE: To assess feasibility of rapid MRI for diagnosis of ovarian torsion. MATERIALS AND METHODS: A retrospective, single-center IRB approved study of MRI performed in female pediatric patients presenting with abdominopelvic pain from August 2022 to January 2023. Imaging occurred according to one of three clinical pathways (US-first approach vs MRI-first approach vs US + MRI-second-line approach). A rapid three-sequence free-breathing MRI protocol was utilized. Frequency of ovarian torsion and secondary diagnoses was recorded. Length of MR scan time, time from ED arrival to time of diagnosis, and whether patient had US prior to MR exam were obtained. A historical cohort of patients with US only performed for assessment of ovarian torsion were evaluated for length of the US examination and time from ED arrival to time of diagnosis. Intervals were compared using the uncorrected Fisher's least significant difference and Turkey's multiple comparison tests. RESULTS: A total of 140 MRI exams (mean age 14.6 years) and 248 historical US exams (mean age 13.5 years) were included. Of the patients with MRI, 41 (29%) patients were imaged with US + MRI and 99 (71%) imaged with MRI only; 4% (6/140) MR exams were suspicious for ovarian torsion, with one true positive case (1/6 TP) and 5 false positive cases (5/6 FP); 26.4% (37/140) of exams had secondary diagnoses. Median MRI scan time was 11.4 min (4.4) vs median historical US scan time was 24.1 min (19.7) (P<0.001). Median time from arrival in ED to MRI read was 242 (140). Median time from arrival in ED to US only read was 268 min (148). This was not a statistically significant difference when compared to the MRI only cohort. CONCLUSION: First-line MRI imaging for evaluation of ovarian torsion is a rapid and feasible imaging modality for female patients in the emergent setting.

Stroke Prevention with Hydroxyurea Enabled through Research and Education: A Phase 2 Primary Stroke Prevention Trial in Sub-Saharan Africa.

INTRODUCTION: Stroke is a severe complication of sickle cell anemia (SCA), with devastating sequelae. Transcranial Doppler (TCD) ultrasonography predicts stroke risk, but implementing TCD screening with suitable treatment for primary stroke prevention in low-resource environments remains challenging. SPHERE (NCT03948867) is a prospective phase 2 open-label hydroxyurea trial for SCA in Tanzania. METHODS: After formal training and certification, local personnel screened children 2-16 years old; those with conditional (170-199 cm/s) or abnormal (≥200 cm/s) time-averaged mean velocities (TAMVs) received hydroxyurea at 20 mg/kg/day with dose escalation to maximum tolerated dose (MTD). The primary study endpoint is change in TAMV after 12 months of hydroxyurea; secondary endpoints include SCA-related clinical events, splenic volume and function, renal function, infections, hydroxyurea pharmacokinetics, and genetic modifiers. RESULTS: Between April 2019 and April 2020, 202 children (average 6.8 ± 3.5 years, 53% female) enrolled and underwent TCD screening; 196 were deemed eligible by DNA testing. Most had numerous previous hospitalizations and transfusions, with low baseline hemoglobin (7.7 ± 1.1 g/dL) and %HbF (9.3 ± 5.4%). Palpable splenomegaly was present at enrollment in 49 (25%); average sonographic splenic volume was 103 mL (range 8-1,045 mL). TCD screening identified 22% conditional and 2% abnormal velocities, with hydroxyurea treatment initiated in 96% (45/47) eligible children. CONCLUSION: SPHERE has built local capacity with high-quality research infrastructure and TCD screening for SCA in Tanzania. Fully enrolled participants have a high prevalence of elevated baseline TCD velocities and splenomegaly. SPHERE will prospectively determine the benefits of hydroxyurea at MTD for primary stroke prevention, anticipating expanded access to hydroxyurea treatment across Tanzania.

Diagnostic performance of ultrasound hepatorenal index for the diagnosis of hepatic steatosis in children.

BACKGROUND: Non-alcoholic fatty liver disease (NAFLD) is increasing in prevalence and is the most common cause of pediatric chronic liver disease. Objective US-based measures of hepatic steatosis are an unmet clinical need. OBJECTIVE: To evaluate the diagnostic performance of quantitative measurement of liver echogenicity (hepatorenal index, or HRI) for hepatic steatosis in a pediatric cohort. MATERIALS AND METHODS: We identified pediatric patients (≤18 years old) who underwent both clinically indicated abdominal US and MRI with liver proton-density fat fraction (PDFF) within the 3-month period during the timeframe of July 2015-April 2020 (n=69). Using ImageJ, we drew small circular regions of interest (ROIs) and large freehand ROIs in the liver and right kidney on single longitudinal and transverse images to measure echogenicity (arbitrary units). We calculated four HRIs (liver-to-kidney ratio) as well as liver histogram features. Five pediatric radiologists independently reported the qualitative presence/absence of hepatic steatosis. We used Pearson correlation (r) to assess associations and receiver operating characteristic (ROC) curve analyses to evaluate diagnostic performance. Multivariable logistic regression was used to further assess relationships. RESULTS: Mean patient age was 11.6 (standard deviation [SD] 4.7, range 0.3-18) years; 27/69 (39.1%) were female. Mean PDFF was 12.5% (SD 13.1%, range 1-48%); 34/69 (49.3%) patients were classified as having hepatic steatosis by MRI (PDFF ≥6%). There were significant, positive correlations between all four US HRI methods and PDFF (r=0.51-0.61); longitudinal freehand ROIs exhibited the strongest correlation (r=0.61; P<0.0001). Longitudinal freehand ROI HRI had moderate diagnostic performance for the binary presence of steatosis (area under the curve [AUC]=0.80, P<0.0001), with an optimal cut-off value >1.75 (sensitivity=70.6%, specificity=77.1%). Radiologists' sensitivity for detecting hepatic steatosis ranged from 79.4% to 97.1%, and specificity ranged from 91.2% to 100%. Significant multivariable predictors of PDFF ≥6% included HRI (P=0.002; odds ratio [OR]=34.2), body mass index (BMI) percentile (P=0.005; OR=1.06), and liver gray-scale echogenicity standard deviation (P=0.02; OR=0.79) (receiver operating characteristic AUC = 0.92). CONCLUSION: Quantitative US HRI has moderate diagnostic performance for detecting liver fat in children and positively correlates with MRI PDFF. Incorporation of BMI-percentile and gray-scale echogenicity standard deviation improved diagnostic performance.

Predictors of Clinical Outcomes in Pediatric Appendicitis: Role of the Individual Sonographer and Radiologist When Using a First-Line Ultrasound Approach.

OBJECTIVE: To determine if differences between individual sonographers and radiologists performing and interpreting appendix ultrasound affect clinically important outcomes in children with suspected acute appendicitis. METHODS: Patients <18 years of age who presented to our emergency department (ED) with suspected acute appendicitis and underwent an appendix ultrasound were identified. Sonographers who performed fewer than 100 examinations and radiologists who interpreted fewer than 100 examinations during the study period were excluded. Multivariable logistic regression was performed to assess the effect of sonographer, radiologist, clinical variables, and system factors on key clinical outcomes, including hospital admission and appendectomy. RESULTS: In all, 9,283 appendix ultrasounds (mean age, 9.9 ± 4.2 years; 5,400 [58.2%] boys) performed by 31 sonographers (mean number of examinations, 299 ± 140 [range, 115-610]) and interpreted by 31 radiologists (mean number of examinations, 299 ± 157 [range, 101-845]) were included. Mean admission frequency per sonographer was 34.0% ± 3.3% (range, 27.8%-42.6%) and per radiologist was 33.5% ± 3.9% (range, 23.7%-41.6%). Mean appendectomy frequency per sonographer was 20.3% ± 2.6% (range, 14.9%-27.0%) and per radiologist was 20.3% ± 3.1% (range, 15.2%-28.7%). Significant multivariable predictors of hospital admission included temperature (P < .0001), white blood cell count (P < .0001), male sex (P = .002), imaging performed at the main hospital (versus satellite hospital) (P = .001), abdominal tenderness with ultrasound transducer compression (P < .0001), presence of rebound tenderness (P = .001), and presence of acute appendicitis by ultrasound (P < .0001), but not sonographer or radiologist. Predictors of appendectomy included weight (P < .0001), white blood cell count (P < .0001), male sex (P = .0004), abdominal tenderness with ultrasound transducer compression (P < .0001), and the presence of acute appendicitis by ultrasound (P < .0001), but not sonographer or radiologist. CONCLUSION: Differences in individual sonographers and radiologists did not predict clinically important outcomes in children undergoing ultrasound in the ED for suspected acute appendicitis.

Variation in imaging outcomes associated with individual sonographers and radiologists in pediatric acute appendicitis: a retrospective cohort of 9271 examinations.

OBJECTIVE: To determine if individual sonographers and radiologists impact appendix visualization by ultrasound and utilization of computed tomography (CT) in children with suspected acute appendicitis. MATERIALS AND METHODS: Appendix ultrasound examinations performed at Cincinnati Children's Hospital Medical Center on Emergency Department patients ≤ 18 years old were retrospectively identified. Examinations performed/interpreted by sonographers/radiologists with fewer than 100 examinations were excluded. Multivariable logistic regression was used to assess the effect of sonographer, radiologist, clinical variables, and system factors on imaging outcomes, including appendix visualization and subsequent CT utilization. RESULTS: A total of 9271 ultrasound examinations (mean [SD] patient age, 9.9 [4.2] years; 5392 [58.2%] boys) performed by 31 sonographers (mean number examinations, 299 [139]; range, 115-610) and interpreted by 31 radiologists (mean number examinations, 299 [157]; range, 101-845) were included. The mean frequency of appendix visualization per sonographer was 57.8% [8.7%] (range, 40.9-76.0%) and per radiologist was 59.5% [4.1%] (range, 51.7-66.3%). The mean rate of CT utilization per sonographer was 9.2% [2.0%] (range, 5.9-14.0%) and per radiologist was 9.2% [1.8%] (range, 3.4-12.1%). Predictors of appendix visualization by ultrasound included patient weight (p < 0.0001), sex (p = 0.0003), white blood cell count (p < 0.0001), temperature (p = 0.002), abdominal tenderness (p = 0.004), presence of appendicitis (p < 0.0001), sonographer (p < 0.0001), and radiologist (p = 0.02). Predictors of CT utilization included patient weight (p < 0.0001), white blood cell count (p < 0.0001), abdominal tenderness (p < 0.0001), rebound tenderness (p = 0.0003), and presence of appendicitis (p < 0.0001), but not sonographer or radiologist. CONCLUSION: Individual sonographers and radiologists were associated with appendix visualization by ultrasound in children with suspected acute appendicitis; neither was associated with CT utilization. KEY POINTS: • Individual sonographers and radiologists are significantly and independently associated with appendix visualization by ultrasound in children with suspected acute appendicitis. • Frequency of appendix visualization per sonographer demonstrated significant and wide variability across 31 sonographers, ranging from 40.9 to 76.0%. • Fewer than 10% of patients with an ultrasound examination for suspected acute appendicitis underwent CT imaging within the following 24 h. Individual radiologists and sonographers were not predictive of CT utilization within 24 h.

Comparison of ultrasound versus computed tomography for the detection of kidney stones in the pediatric population: a clinical effectiveness study.

BACKGROUND: The incidence of pediatric nephrolithiasis in the United States is increasing. There is a paucity of literature comparing the diagnostic performance of computed ultrasound (US) to tomography (CT) in the pediatric population. OBJECTIVE: To determine the diagnostic performance of renal US for nephrolithiasis in children using a clinical effectiveness approach. MATERIALS AND METHODS: Institutional review board approval with a waiver of informed consent was obtained for this retrospective, HIPAA-complaint investigation. Billing records and imaging reports were used to identify children (≤18 years old) evaluated for nephrolithiasis by both US and unenhanced CT within 24 h between March 2012 and March 2017. Imaging reports were reviewed for presence, number, size and location of kidney stones. Diagnostic performance of US (reference standard=CT) was calculated per renal unit (left/right kidney) and per renal sector (four sectors per kidney). For sector analysis, US was considered truly positive if a stone was identified at CT in the same or an adjacent sector. RESULTS: There were 68 renal stones identified by CT in 30/69 patients (43%). Mean patient age was 14.7±3.6 years, and 35 were boys. For detecting nephrolithiasis in any kidney, US was 66.7% (48.8-80.8%) sensitive and 97.4% (86.8-99.9%) specific (positive predictive value=95.2% [77.3-99.8%], negative predictive value=79.2% [65.7-88.3%], positive likelihood ratio=26.0). Per renal sector, US was 59.7% (46.7-71.4%) sensitive and 97.4% (95.5-98.5%) specific (positive predictive value=72.3% [58.2-83.1%], negative predictive value=95.4% [93.2-96.9%], positive likelihood ratio=22.5). Of the 30 stones not detected by US, only 3 were >3 mm at CT. CONCLUSION: In clinical practice, US has high specificity for detecting nephrolithiasis in children but only moderate sensitivity and false negatives are common.

Normograms for the Extrahepatic Bile Duct Diameter in Children.

OBJECTIVE: The normal diameter of the extrahepatic bile duct (EHD) in children has been poorly studied. Prior studies have enrolled small subject numbers, have studied only specific pediatric age groups, or have potential bias due to loosely defined exclusion criteria. We sought to establish parameters for the normal diameter of the EHD in children from birth to late adolescence, including premature infants. METHODS: A 12½-month institutional review board-approved, Health Insurance Portability and Accountability Act-compliant, retrospective chart review of all transabdominal ultrasounds performed on children (younger than 18 years) was conducted at a single pediatric tertiary referral center. Exclusion criteria included a past medical history of any pancreaticobiliary or hepatology disorder. New abnormal findings related to the liver, biliary system, or pancreas were also excluded. Recorded EHD measurements from review of the radiology reports were compiled. Estimated mean and 95% prediction intervals of EHD were calculated and reported for 6 nonoverlapping pediatric age groups. RESULTS: A total of 1016 ultrasounds on unique patients were included within the study. Estimated mean values and calculated 95% prediction intervals (in parentheses) for the diameter of the EHD were prematurity, 0.7 (0.3-1.7) mm; 0 to 2 months, 1.0 (0.4-2.3) mm; 3 to 11 months, 1.2 (0.5-2.9) mm; 1 to 4 years, 1.4 (0.6-3.3) mm; 5 to 12 years, 1.9 (0.8-4.3) mm; 13 to 17 years, 2.3 (1.0-5.2) mm. CONCLUSIONS: Our derived data of normal predicted parameters of the EHD diameter in children of all age groups will help guide clinicians in identifying those patients outside the norm that may benefit from additional testing.

Lung Ultrasonography: A Viable Alternative to Chest Radiography in Children with Suspected Pneumonia?

OBJECTIVE: To determine the interrater reliability (IRR) of lung ultrasonography (LUS) and chest radiography (CXR) and evaluate the accuracy of LUS compared with CXR for detecting pediatric pneumonia compared with chest computed tomography (CT) scan. STUDY DESIGN: This was a prospective cohort study of children aged 3 months to 18 years with a CXR and LUS performed between May 1, 2012, and January 31, 2014 with or without a clinical diagnosis of pneumonia. Four pediatric radiologists blinded to clinical information reported findings for the CXR and LUS images. IRR was estimated for 50 LUS and CXR images. The main outcome was the finding from CT ordered clinically or the probability of the CT finding for patients clinically requiring CT. Two radiologists reviewed CT scans to determine an overall finding. Latent class analysis was used to evaluate the sensitivity and specificity for findings (eg, consolidation) for LUS and CXR compared with CT. RESULTS: Of the 132 patients in the cohort, 36 (27%) had CT performed for a clinical reason. Pneumonia was clinically documented in 47 patients (36%). The IRR for lung consolidation was 0.55 (95% CI, 0.40-0.70) for LUS and 0.36 (95% CI, 0.21-0.51) for CXR. The sensitivity for detecting consolidation, interstitial disease, and pleural effusion was statistically similar for LUS and CXR compared with CT; however, specificity was higher for CXR. The negative predictive value was similar for CXR and LUS. CONCLUSIONS: LUS has a sufficiently high IRR for detection of consolidation. Compared with CT, LUS and CXR have similar sensitivity, but CXR is more specific for findings indicating pneumonia.

Reliability of renal length measurements made with ultrasound compared with measurements from helical CT multiplanar reformat images.

OBJECTIVE: The purpose of this article is to determine the reliability of sonographic renal length measurements compared with measurements obtained from helical CT multiplanar reformat images and compared with standard renal growth curves. MATERIALS AND METHODS: A retrospective review was performed of 76 subjects who underwent both renal ultrasound and abdominal CT within 2 weeks of one another. Renal lengths were measured using oblique coronal reformat images of helically acquired CT data by two observers on two occasions. Intraobserver and interobserver error for these measurements were calculated. Ultrasound renal length measurements were compared with CT measurements. Measurement variation was compared with standard renal growth curves. RESULTS: The mean (± SD) of the absolute value of interobserver error of CT measurements was 0.9 ± 0.8 mm. Compared with CT, individual ultrasound measurements underestimated renal length by 1.5 ± 5.6 mm on average, with a 95% CI of -12.5 to 9.5 mm. When the maximum of three ultrasound renal length measurements was used, the SD was 4.7 mm, with a 95% CI of -8.2 to 10.1 mm of the reported renal length. This corresponds to greater or less than 3.3 years of normal renal growth. CONCLUSION: Lack of renal growth can be asserted only when renal length falls below the growth curve, taking into account the corresponding measurement error limits, which we found to be greater or less than 9.3 mm. If the follow-up measurement falls within these limits, one should not infer lack of appropriate renal growth, even if the renal length measurement decreases or remains unchanged for up to 3 years.

Interaction between academic radiology and the news media: a potentially powerful and unpredictable process--five stories.

OBJECTIVE: Although articles have been published describing the relationship between news reports and the general medical literature, to our knowledge little has been published describing the relationship between radiology publications and news coverage. We present five instances of news stories centered on radiology publications or abstracts of presentations at national meetings and the effect of the media coverage within the medical community. CONCLUSION: The five examples show that news coverage can have a dramatic effect on advancing research findings and public health information published in radiology journals. Even when news coverage is inaccurate or sensationalized, the attention of the general public can drive change not only generally in medicine but also specifically in radiology.

Van Wyk and Grumbach syndrome revisited: imaging and clinical findings in pre- and postpubertal girls.

BACKGROUND: In 1960 Van Wyk and Grumbach described a syndrome of juvenile hypothyroidism, precocious puberty and ovarian enlargement. These findings undergo complete regression with thyroid hormone replacement therapy. This diagnosis can be made on the basis of imaging findings and thyroid function analysis, avoiding surgery. OBJECTIVE: To relate the distinctive clinical and imaging features and putative pathophysiological mechanism of a series of patients with Van Wyk and Grumbach syndrome (VWGS). MATERIALS AND METHODS: Patients with VWGS diagnosed at two large children's hospitals over a 6-year period beginning in 1999 were retrospectively reviewed. A literature review was also conducted. RESULTS: Five female patients were diagnosed with cystic ovarian enlargement and hypothyroidism at ages ranging from 9 to 17 years. Isosexual precocious puberty was found in prepubescent patients. Associated findings included delayed bone age, ascites, and pleural and pericardial effusions. Ovarian cyst involution occurred following treatment of the hypothyroidism. CONCLUSION: The association of primary hypothyroidism with cystic ovarian enlargement and precocious puberty is important to recognize. In the absence of suspected ovarian torsion, surgery is unnecessary, as cyst regression occurs after appropriate thyroid hormone replacement. Noncompliance with hormone replacement therapy should be considered when cystic ovarian enlargement is noted in patients with a history of hypothyroidism.

US findings of adnexal torsion in children and adolescents: size really does matter.

BACKGROUND: Adnexal torsion is rare, and symptoms are nonspecific. Clinicians often rely on US examinations to evaluate girls with abdominal or pelvic pain. OBJECTIVE: To determine which sonographic findings can predict adnexal torsion by comparing pediatric and adolescent patients with surgically confirmed torsion (cases) to those without torsion (controls). MATERIALS AND METHODS: Cases and controls were identified retrospectively by searching 7 years of medical record and radiology databases. An adnexal ratio was calculated as the volume of the affected adnexa divided by the volume of the unaffected adnexa. RESULTS: We identified 61 menarchal subjects: 33 cases and 28 controls. Adnexal volume was larger in cases than in controls (185 vs. 37.8 ml, P < 0.001). A volume of >75 ml was more common in cases than in controls (64 vs. 15%, P < 0.001). No cases had an adnexal volume of <20 ml (P < 0.001). The adnexal ratio was larger in cases than in controls (16.1 vs. 6.7, P < 0.001). An adnexal ratio of >15 was seen in 40% of cases and in no controls (P = 0.08). Doppler US results were not predictive of torsion. CONCLUSION: An adnexal volume of <20 ml is strong evidence against adnexal torsion in menarchal females. In this age group, the diagnosis of torsion cannot be established by US examination alone.

Water imaging (hydrography) in the fetus: the value of a heavily T2-weighted sequence.

BACKGROUND: Since the development of fast imaging sequences, MR has proved to be a helpful tool in the evaluation of fetal pathology. Because of the high water content of fetal tissues and pathology, hydrography imaging (MR fetography) can provide additional diagnostic information. OBJECTIVE: To demonstrate the benefit of MR fetography in fetal imaging. MATERIALS AND METHODS: From 2004 to 2005, 126 fetal MR examinations were performed for evaluation of an abnormality depicted on an antenatal sonogram. Single-shot fast spin-echo MR imaging and MR fetography were performed through the area of fetal pathology. The two studies were retrospectively compared. RESULTS: The primary diagnosis was not changed with the addition of MR fetography. New findings, particularly in the kidneys and spine, were identified in 9% of the patients. When fetal pathology was of high water content (80% patients), the MR fetography imaging increased diagnostic confidence. In 11% of the patients, those with cardiovascular or low water pathology, the MR fetography was not beneficial. CONCLUSION: The mainstay of fetal imaging is currently the HASTE and SSFSE sequences. However, MR fetography is an excellent adjunct that highlights fetal pathology by reinforcing the diagnosis, identifying additional findings, and providing high-contrast high-resolution images that are helpful when counseling clinicians and patients.

Twin-twin transfusion syndrome: cerebral ischemia is not the only fetal MR imaging finding.

BACKGROUND: Twin-twin transfusion syndrome (TTTS) is a complication of monochorionic/diamniotic twin pregnancies. An imbalance of blood flow occurs through placental anastomoses, causing potentially significant morbidity and mortality in both twins. Although the sonographic findings of TTTS are well documented, we believe that MR imaging is a valuable adjunct. OBJECTIVE: We describe the fetal MR imaging findings associated with TTTS. MATERIALS AND METHODS: From 2003 to 2005, 37 consecutive MR imaging studies were performed on multiple-gestation pregnancies. Of the 37, 25 were consistent with TTTS, correlated and confirmed by sonographic criteria. MR fetal abnormalities were documented. RESULTS: Cerebral ischemia, which could not be demonstrated by sonography, was delineated well by MR imaging. New findings noted on fetal MR imaging were enlargement of cerebral venous sinuses in both twins, dilatation of the renal collecting system in the recipient, lung lesions in the recipient and cerebral malformations in the donor. CONCLUSION: MR imaging is an important adjunct in TTTS imaging. Its benefit over sonography is its clear definition of cerebral pathology, which is important for intervention and counseling. The new findings, particularly in the urinary tract and cerebral venous sinuses, also help support the diagnosis of TTTS and might reveal additional consequences of the altered hemodynamics that occur in TTTS.

Pre-medication to block [(18)F]FDG uptake in the brown adipose tissue of pediatric and adolescent patients.

BACKGROUND: Radiopharmaceutical uptake of [(18)F]2-deoxy-2-glucose (FDG) in brown adipose tissue is noted on 15-20% of positron emission tomography (PET) scans in children and adolescents. One report suggests that moderate-dose oral diazepam can partly or completely block FDG uptake in brown adipose tissue. OBJECTIVE: To determine whether [(18)F]FDG uptake in brown adipose tissue can be adequately blocked by pre-medication other than moderate-dose oral diazepam. MATERIALS AND METHODS: One hundred and eighteen [(18)F]FDG PET body imaging studies were performed in 69 pediatric patients with a variety of solid tumors. The mean age at the time of imaging was 12.9 years (range 1.2-22.6 years), and 33 studies were performed in patients younger than 10 years old. Seventy-six were performed in boys and 42 in girls. Patients were imaged using a dedicated PET camera. Pre-medication was given in 88 studies: 45 received intravenous fentanyl (0.75-1.0 mug/kg), 34 received low-dose oral diazepam (0.06 mg/kg) and 9 received moderate-dose oral diazepam (0.10 mg/kg). Thirty patients received no pre-medication, 7 of whom were known to have received opiates for pain during the 12 h before the study. Six body regions in the neck and chest were reviewed for [(18)F]FDG uptake in brown adipose tissue. Uptake of FDG in brown fat was visually graded: 0 for no FDG uptake, 1 for low-grade uptake, 2 for moderate uptake, and 3 for intense uptake. Visual grades 2 and 3 were considered to interfere potentially with image interpretation in the neck and chest. Data were analyzed by multivariate regression using a Poisson distribution. RESULTS: [(18)F]FDG uptake in brown adipose tissue was most often seen in the lateral neck region and superior and lateral to the lungs (in 36 and 39 studies, respectively). Uptake was also seen near the costovertebral junctions (15 studies), in the superior and central neck in 7 studies and in the anterior mediastinum in 2. Brown adipose tissue uptake was thought to interfere potentially with image interpretation (visual grades 2 and 3) in 19 studies-in 6 of 23 (26.1%) studies after no pre-medication and no opiates for pain, in 10 of 34 (29.4%) after low-dose oral diazepam, in 0 of 9 (0%) after moderate-dose oral diazepam, in 3 of 45 (6.7%) after intravenous fentanyl, and in 0 of 7 (0%) after opiates prescribed for pain. Intravenous fentanyl reduced the grade of brown adipose tissue compared to no drug (P=0.0039) and low-dose diazepam (P=0.0024). Low-dose diazepam had no effect when compared to no drug (P=0.984). There were inadequate data for statistical testing of moderate-dose valium and opiates prescribed for pain. Children younger than 10 years had lower uptake grades (P=0.019) than those older than 10 years. SUMMARY: The frequency of interfering [(18)F]FDG uptake in brown adipose tissue is reduced by intravenous fentanyl pre-medication, which appears to be an effective alternative to the existing standard pre-medication, moderate-dose oral diazepam.

Cecal volvulus: a rare cause of bowel obstruction in a pediatric patient diagnosed pre-operatively by conventional imaging studies.

Cecal volvulus is an acute surgical condition that is extremely rare in children, with a mortality rate of up to 40%. The clinical symptoms are often non-specific, and pediatric patients frequently have neurological deficits with associated communication difficulties, making the clinical diagnosis extremely challenging. Conventional radiographic imaging studies play a key role in the prospective diagnosis in children. We report a rare case of cecal volvulus in a 12-year-old boy who was diagnosed pre-operatively by abdominal radiographs and a contrast enema.

Clinical and hematologic benefits of partial splenectomy for congenital hemolytic anemias in children.

OBJECTIVE: To assess the role of partial splenectomy for symptomatic children with various congenital hemolytic anemias. SUMMARY BACKGROUND DATA: The use of total splenectomy for symptomatic children with congenital hemolytic anemias is restricted by concern of postsplenectomy sepsis. A partial splenectomy is an alternative procedure, although its utility remains incompletely defined. METHODS: This longitudinal cohort study followed 25 symptomatic children with various congenital anemias who underwent partial splenectomy. Sixteen children had hereditary spherocytosis (HS), and nine children had other erythrocyte disorders. Outcome measures were clinical and laboratory hemolysis, splenic phagocytic and immune function, and splenic regrowth as measured by ultrasonography. Discrete parameters were compared using the Student test. RESULTS: Partial splenectomy was successful in all 25 children, with minimal morbidity. Follow-up ranged from 7 months to 6 years (mean 2.3 +/- 1.5 years). Following surgery, children with HS had increased hemoglobin values, decreased reticulocyte and bilirubin levels, and preserved splenic function. Most children without HS had decreased symptoms of hypersplenism and splenic sequestration. Over time, variable rates of splenic regrowth were noted, although regrowth did not necessarily correlate with recurrent hemolysis. CONCLUSIONS: In children with hereditary spherocytosis, a partial splenectomy appears to control hemolysis while retaining splenic function. In children with other congenital hemolytic anemias, a partial splenectomy appears to control symptoms of hypersplenism and splenic sequestration.

Asymmetrical closure of epiphyses in a patient with sickle cell anemia.

There is a high incidence of delayed sexual development and short stature during childhood in children with sickle cell anemia (SCA). We report a 15 year-old male with SCA who presented with significant short stature after a near death event (involving seizures and prolonged hypoxia). His evaluation showed growth hormone (GH) deficiency with low insulin-like growth factor-I (IGF-I), low IGF binding protein-3, and low GH response to stimulation. He was started on GH replacement with poor response in height gain although with normal response in terms of elongation of his arm span. Further studies showed premature closure of the epiphyses of the femora and tibiae bilaterally. This report demonstrates that children with SCA may present with growth failure not only due to nutritional and GH abnormalities but also due to abnormal growth plates, probably due to local anoxic events. Children with SCA should always have their arm span measured carefully.

Optimal timing of initial postnatal ultrasonography in newborns with prenatal hydronephrosis.

PURPOSE: Conflicting data exist concerning optimal timing for initial postnatal ultrasound in newborns with prenatal hydronephrosis. To determine whether timing significantly affects the accuracy of postnatal ultrasound, we conducted a prospective study comparing ultrasound within 48 hours of birth and at 7 to 10 days of life. MATERIALS AND METHODS: A total of 21 consecutive newborns with prenatal hydronephrosis were enrolled in 14 months. Prenatal hydronephrosis was defined as a pelvic diameter 4 mm. or greater before 33 weeks and 8 mm. or greater beginning at 33 weeks of gestation. Postnatal hydronephrosis was assessed using the Society for Fetal Urology grading system. Patients were subsequently followed with serial ultrasound and adjunctive imaging studies. RESULTS: Of the 32 evaluable renal units a majority had a change in the degree of hydronephrosis between the first and second ultrasound. An increase in hydronephrosis was found in 14 (44%) renal units with an increase of 2 or greater grades in 8 (25%). At a median followup of 15 months only 3 renal units had a persistent increase in hydronephrosis. None had greater than grade 2 hydronephrosis or required therapeutic intervention. A decrease in hydronephrosis between the first and second ultrasound was noted in 8 (25%) renal units. Seven renal units were excluded from analysis due to unequivocal obstruction, and none of these demonstrated a change between the 2 sonograms. CONCLUSIONS: The degree of hydronephrosis varied between scans performed in the first 48 hours and 7 to 10 days of life in most newborns. The initial ultrasound more commonly underestimated the degree of hydronephrosis but this difference was not clinically significant at further followup. We recommend initial postnatal sonogram at 7 to 10 days of life for routine prenatal hydronephrosis but earlier scans may be appropriate in select cases.