Use of intraoperative bone scintigraphy for resection of spinal osteoid osteoma.

BACKGROUND: The location and proximity to the spinal cord in spinal osteoid osteoma can increase the likelihood of an incomplete resection. Intraoperative bone scintigraphy (IOBS) can be used to verify location and complete surgical resection. OBJECTIVE: To review our experience using IOBS for resection of intraspinal osteoid osteoma. METHODS: IRB approved, retrospective review of IOBS-guided resection over 10 years. Patients underwent injection of 200 uCi/kg (1-20 mCi) 99mTc-MDP 3-4 h prior surgery. Portable single-headed gamma camera equipped with a pinhole collimator (3- or 4-mm aperture) was used. Images were obtained pre-operatively, at the start of the procedure, and intraoperatively. Operative notes were reviewed. Evaluation of recurrence and clinical follow-up was performed. RESULTS: Twenty IOBS-guided resections were performed in 18 patients (median age 13.5 years, 6-22 years, 12 males). Size ranged 5-16 mm, with 38.9% (7/18) cervical, 22.2% (4/18) thoracic, 22.2% (4/18) lumbar, and 16.7% (3/18) sacral. In all cases, IOBS was able to localize the lesion. After suspected total excision, IOBS altered the surgical plan in 75% of cases (15/20), showing residual activity prompting further resection. Median length of follow-up was 6 months (range 1-156 months) with 90% (18/20) showing complete resection without recurrence. Two patients had osteoid osteoma recurrence at 7 and 10 months following the original resection, requiring re-intervention. CONCLUSIONS: IOBS is a useful tool for real-time localization and assessment of spinal osteoid osteoma resection. In all cases, IOBS was able to localize the lesion and changed surgical planning in 75% of cases. Ninety percent of patients achieved complete resection and remain recurrence free.

Pediatric Solid Gastric Emptying Scintigraphy: Normative Value Guidelines and Nonstandard Meal Alternatives.

INTRODUCTION: Adult standards for gastric emptying scintigraphy, including the type of meal and range of normative values for percent gastric emptying, are routinely used in pediatric practice, but to date have not been validated. The purpose of this study is to determine whether the use of adult criteria for gastric emptying scintigraphy is valid for children and whether alternative nonstandard meals can also be offered based on these criteria. METHODS: This retrospective study analyzed patients (n = 1,151 total) who underwent solid-phase gastric emptying scintigraphy. Patients were stratified into normal and delayed gastric emptying cohorts based on adult criteria, i.e., with normal gastric emptying defined as ≤10% gastric retention at 4 hours. Patients were further stratified based on the type of meal, namely complete or partial adult standard meals or alternative cheese-based meals. Percent gastric retention values at 1, 2, 3, and 4 hours were compared. RESULTS: The median (95% upper reference limit) percentage gastric retention values for the complete standard meal were 72% (93%) at 1 hour, 39% (65%) at 2 hours, 15% (33%) at 3 hours, and 6% (10 %) at 4 hours. By comparison, the values for cheese-based meals were 60% (87%) at 1 hour, 29% (61%) at 2 hours, 10% (30%) at 3 hours, and 5% (10%) at 4 hours. Consumption of at least 50% of the standard meal yielded similar retention percentages; 68% (89%) at 1 hour, 32% (57%) at 2 hours, 10% (29%) at 3 hours, and 5% (10%) at 4 hours. There were no significant age- or sex-specific differences using the adult criteria. DISCUSSION: The adult normative standards for gastric emptying scintigraphy are applicable for use in the pediatric population. These same standards can be also be applied to nonstandard meal options, including cheese-based alternative meals and partial standard meals.

Gastric emptying of milk in infants and children up to 5 years of age: normative data and influencing factors.

BACKGROUND: Gastric emptying scintigraphy is widely used in infants and children, but there is a lack of age-specific normative data. OBJECTIVE: The objectives of this retrospective study were: 1) to establish a range of gastric emptying of milk or formula as a surrogate for normal gastric emptying in infants and young children ≤5 years of age, and 2) to investigate the effects of patient age, feeding volume, feeding route and gastroesophageal reflux on gastric emptying. MATERIALS AND METHODS: The reports of 5,136 gastric emptying studies of children ≤5 years of age performed at Children's National Medical Center from January 1990 to August 2012 were reviewed. Demographic data, 1-h and 3-h gastric emptying values and gastroesophageal reflux status of all patients were stored in a database. Using stringent inclusion and exclusion criteria, the studies of patients as similar to healthy children as possible were selected for this study. RESULTS: The study group included 2,273 children (57% male) ages 0-59 months (median: 4.6 months). The median 1-h gastric emptying was 43% (interquartile range [IQR] 34-54%). The median 3-h gastric emptying was 91% (IQR 79-98%). Sixty-one percent of patients with 1-h gastric emptying value of <50% had 3-h gastric emptying ≥80%. Gastric emptying was significantly faster in children ≤6 months as compared with all older age groups. In each age group, the median gastric emptying decreased with increasing feeding volume. Gastric emptying was significantly faster in patients fed via combined nasogastric tube and oral routes as compared with those fed exclusively orally. There was no significant difference in gastric emptying of children with and without gastroesophageal reflux. CONCLUSION: Although there are statistically significant differences in gastric emptying based on age, volume and route of feeding, the data suggest that overall normal liquid gastric emptying in infants and children ≤5 years of age is ≥80% at 3 h. One-hour emptying measurements are not reliable for detecting delayed gastric emptying.

PET/MR Imaging:: Current Updates on Pediatric Applications.

PET/MR imaging is an integrated imaging system that combines the high soft tissue resolution of MR imaging with the quantitative data obtained from PET into a single system. It is a relatively new imaging technique but with potential clinical use in pediatric oncologic and nononcologic processes in additional to its role in research. It is particularly relevant in pediatric patients due to reduced radiation burden compared with PET/CT and the ability to obtain exquisite functional and anatomic imaging in a single imaging session, thereby reducing the number of anesthesia/sedations. This review article focuses on the current as well as future applications of PET/MR imaging in pediatric imaging, including both oncologic and nononcologic indications.

Chronic Acalculous Cholecystitis in Children With Biliary Symptoms: Usefulness of Hepatocholescintigraphy.

OBJECTIVES: Chronic acalculous cholecystitis (CAC) increasingly is being diagnosed as a cause of recurring biliary symptoms in children, but its clinical diagnosis remains challenging. The primary objective was to evaluate the utility of hepatocholescintigraphy in pediatric patients with suspected CAC. A secondary objective was to describe their clinical follow-up after diagnosis. METHODS: Medical records of patients (aged 9-20 years) who underwent hepatocholescintigraphy from February 2008 to January 2012 were reviewed. Patients with gallstones, and with ≤1 year of clinical follow-up, and studies without gallbladder (GB) stimulation were excluded. GB ejection fraction (GBEF) of <35% after sincalide or fatty meal (Lipomul) stimulation were considered abnormal. Diagnosis of CAC was based on histopathology after cholecystectomy. Patients with negative GB pathology, or complete resolution of symptoms without surgery, or alternative diagnoses for persistent symptoms were considered to not have CAC. RESULTS: Eighty-three patients formed the study group (median age 14.9 years), of which 81.9% were girls. Median duration of symptoms and clinical follow-up were 6 months and 2.9 years, respectively. Fifty-two patients had at least 1 study with sincalide and 36 patients had at least 1 study with Lipomul. Initial cholescintigraphy was 95.0% sensitive and 73.0% specific in diagnosing CAC, with a negative predictive value of 97.9%. Of the 31 patients with abnormal GBEF, 22 underwent cholecystectomy with improvement in pain in 72.7%, whereas all of the 9 without surgery improved. CONCLUSIONS: Hepatocholescintigraphy is useful for excluding CAC, although the clinical implications of an abnormal GBEF need to be further defined.

Esophageal transit scintigraphy in children: a user's guide and pictorial review.

Technical and clinical aspects of esophageal transit scintigraphy in pediatric patients are reviewed via several illustrative cases that highlight its utility in evaluating primary and secondary esophageal motility disorders.

The duplicated collecting system of the urinary tract: embryology, imaging appearances and clinical considerations.

Duplication anomalies of the urinary collecting system are common and can be discovered and characterized with multiple imaging modalities. The embryology, imaging manifestations and clinical ramifications of duplicated ureters and renal collecting systems vary from a normal anatomical variant to urological pathology and are discussed and illustrated in this review.

Practical Indication-Based Pediatric Nuclear Medicine Studies: Update and Review.

Pediatric nuclear medicine imaging presents unique challenges and requires a thorough understanding of the patients' developmental stages and physiology to optimize study protocols. This article provides an overview of the current practice of diagnostic pediatric nuclear medicine, including the common clinical applications and imaging protocol considerations.

Glomerular hyperfiltration in children with cancer: prevalence and a hypothesis.

BACKGROUND: Glomerular hyperfiltration has recently been reported in children with malignancies and has been attributed to increased solute from breakdown of tumor tissues. OBJECTIVE: To evaluate the prevalence of hyperfiltration in the pediatric oncology population and explore its pathophysiological mechanism. MATERIALS AND METHODS: Tc-99 m diethylenetriaminepentaacetic acid (DTPA) glomerular filtration rate (GFR) examinations (437 studies) and medical records of 177 patients <21 years of age diagnosed with a malignancy between January 2005 and October 2013 were retrospectively reviewed. Hyperfiltration was defined as a GFR ≥ 160 ml/min/1.73 m2. RESULTS: Seventy-seven (43.5%) patients had hyperfiltration in at least one GFR exam. A significantly higher percentage of patients with central nervous system (CNS) tumors (63.6%) had hyperfiltration when compared to other tumor types (27.3%, P < 0.001). No association was found between hyperfiltration and age, gender, race or bone marrow involvement. There was a significant trend toward decreasing hyperfiltration after the second cycle of chemotherapy (P = 0.006) and a significant increase in subjects with low GFR (<100 ml/min/1.73 m2) with increasing number of cycles of chemotherapy (P = 0.005). CONCLUSION: Glomerular hyperfiltration is common in children with malignancies at diagnosis and during initial cycles of chemotherapy. It is particularly prevalent in patients with central nervous tumors, which are frequently smaller in volume. Therefore, the pathophysiological mechanism of hyperfiltration cannot be explained solely on the basis of large tumor volume and subsequent cell breakdown. We hypothesize that host hypermetabolic state plays an important role in pathophysiology of hyperfiltration.

Up-to-date review of nuclear medicine applications in pediatric thoracic imaging.

Nuclear medicine has an important role in the evaluation of various congenital and acquired pediatric chest diseases. Although the radiopharmaceuticals and nuclear medicine examinations used in children are broadly the same as in adults, there are some key differences in clinical indications and underlying disorders. This article provides the reader with an up-to-date review of practice of nuclear medicine as it relates to the pediatric chest, including its current role and future applications.

Imaging in laparoscopic cholecystectomy--what a radiologist needs to know.

Laparoscopic cholecystectomy is the gold standard treatment option for cholelithiasis. In order to properly assess for the complications related to the procedure, an understanding of the normal biliary anatomy, its variants and the normal postoperative imaging is essential. Radiologist must be aware of benefits and limitations of multiple imaging modalities in characterizing the complications of this procedure as each of these modalities have a critical role in evaluating a symptomatic post-cholecystectomy patient. The purpose of this article is describe the multi-modality imaging of normal biliary anatomy and its variants, as well as to illustrate the imaging features of biliary, vascular, cystic duct, infectious as well as miscellaneous complications of laparoscopic cholecystectomy. We focus on the information that the radiologist needs to know about the radiographic manifestations of potential complications of this procedure.

White matter integrity on fractional anisotropy maps in encephalopathic neonates post hypothermia therapy with normal-appearing MR imaging.

BACKGROUND: Neonatal encephalopathy (NE) is a clinically defined neurological syndrome commonly caused by ischemia. OBJECTIVE: We investigated white matter integrity in children with NE using diffusion tensor imaging (DTI) and examined the hypothesis that white matter insults not visible on conventional MRI may have abnormal fractional anisotropy (FA) on DTI. MATERIALS AND METHODS: DTI was performed on 36 term encephalopathic neonates who had hypothermia therapy. Of these, 12 neonates had normal conventional MRI findings (NNE) and 24 neonates had abnormal MRI findings (ANE). Twelve term-equivalent premature neonates with normal clinical neuroimaging and neurological function served as the control group. RESULTS: We found significant reductions in measured FA in white matter in the ANE neonates compared to the control group. There were, however, no significant differences in measured FA in white matter between the NNE and the control group. CONCLUSION: We did not find white matter changes detectable by DTI in encephalopathic neonates post hypothermia with normal conventional MRI findings. Further studies would be required to determine whether this unexpected finding is a direct result of neuroprotective effects of hypothermia, or more sophisticated measures of FA are required to detect subtle white matter injury.

Can Coronary Artery Involvement in Kawasaki Disease be Predicted?

BACKGROUND: Coronary artery involvement is seen in approximately 15-20% of children with Kawasaki disease. There is conflicting literature regarding the clinical and laboratory findings associated with coronary artery involvement. In this retrospective study, we attempt identification of predictive factors for coronary artery involvement at our institute and review the existing literature. METHODS AND RESULTS: A review of 203 patients (65% males) with Kawasaki disease was performed, of whom 33 (16.3%) had coronary artery involvement. High erythrocyte sedimentation rate, high platelet count, low hematocrit, low albumin levels, and refractory Kawasaki disease showed significant association with coronary artery involvement. High erythrocyte sedimentation rate and refractory Kawasaki disease were found to be independent predictors of coronary artery involvement. Review of literature suggested a wide range of coronary involvement (<5% to >60%), and highly conflicting clinical and laboratory associations. CONCLUSION: It remains difficult to accurately determine risk of coronary artery involvement, although some laboratory markers may provide information that is helpful for parental counseling and clinical follow up. Future identification of novel biomarkers and host predispositions may further our understanding of coronary artery risks and help personalize therapy for Kawasaki disease.