Assessment of infant gonadal dose irradiated from urine-contaminated diapers during diuretic renal scintigraphy.

OBJECTIVE: To estimate the gonadal doses irradiated from urine- contaminated diapers during diuretic renal scintigraphy. METHODS: Images of 31 patients (18 males and 13 females) with urine-contaminated diapers during 99m Tc-MAG3 renal scintigraphy were analyzed. The count rate of the diapers was converted into a time-activity curve based on the calibrated factor of the gamma camera system. The cumulative activity was determined from the area under the curve. By incorporating dose per unit cumulative activity pre-calculated from Monte Carlo simulation with 0-year phantom, the gonadal dose irradiated from diaper was calculated. To assess the degree of this additionally introduced dose from diapers, the calculated gonadal dose was compared to the internal gonadal dose from injected radiotracer activity. RESULTS: The cumulative activities irradiated from urine-contaminated diapers were 1.12 E04 ±â€…1.29E04 MBq.s in male infants, which was nearly half of the 1.94 E04 ±â€…1.80E04 MBq.s ( P  = 0.15) in female infants. However, the absorbed doses for testes in male infants were 7.37E-01 ±â€…8.50E-01 mGy, which was approximately 10 times the 6.38E-02 ±â€…5.94E-02 mGy for ovaries in female infants ( P  < 0.01). The diaper-introduced dose for testes and ovaries was 91.7% and 3.9% of the gonadal doses from the injected activity in patients with normal renal function, and 99.0% and 4.3% of those in patients with abnormal renal function. CONCLUSION: Urine-contaminated diapers introduced additional radiation doses to infant patients during 99m Tc-MAG3 renal scintigraphy. The gonadal doses were of significance in male infants who had nearly double the absorbed dose for the testes.

Mesenchymal Stromal Cells Facilitate Tip Cell Fusion Downstream of BMP-Mediated Venous Angiogenesis-Brief Report.

BACKGROUND: The goal of this study was to identify and characterize cell-cell interactions that facilitate endothelial tip cell fusion downstream of BMP (bone morphogenic protein)-mediated venous plexus formation. METHODS: High resolution and time-lapse imaging of transgenic reporter lines and loss-of-function studies were carried out to study the involvement of mesenchymal stromal cells during venous angiogenesis. RESULTS: BMP-responsive stromal cells facilitate timely and precise fusion of venous tip cells during developmental angiogenesis. CONCLUSIONS: Stromal cells are required for anastomosis of venous tip cells in the embryonic caudal hematopoietic tissue.

Technical note: Evaluation of a V-Net autosegmentation algorithm for pediatric CT scans: Performance, generalizability, and application to patient-specific CT dosimetry.

PURPOSE: This study developed and evaluated a fully convolutional network (FCN) for pediatric CT organ segmentation and investigated the generalizability of the FCN across image heterogeneities such as CT scanner model protocols and patient age. We also evaluated the autosegmentation models as part of a software tool for patient-specific CT dose estimation. METHODS: A collection of 359 pediatric CT datasets with expert organ contours were used for model development and evaluation. Autosegmentation models were trained for each organ using a modified FCN 3D V-Net. An independent test set of 60 patients was withheld for testing. To evaluate the impact of CT scanner model protocol and patient age heterogeneities, separate models were trained using a subset of scanner model protocols and pediatric age groups. Train and test sets were split to answer questions about the generalizability of pediatric FCN autosegmentation models to unseen age groups and scanner model protocols, as well as the merit of scanner model protocol or age-group-specific models. Finally, the organ contours resulting from the autosegmentation models were applied to patient-specific dose maps to evaluate the impact of segmentation errors on organ dose estimation. RESULTS: Results demonstrate that the autosegmentation models generalize to CT scanner acquisition and reconstruction methods which were not present in the training dataset. While models are not equally generalizable across age groups, age-group-specific models do not hold any advantage over combining heterogeneous age groups into a single training set. Dice similarity coefficient (DSC) and mean surface distance results are presented for 19 organ structures, for example, median DSC of 0.52 (duodenum), 0.74 (pancreas), 0.92 (stomach), and 0.96 (heart). The FCN models achieve a mean dose error within 5% of expert segmentations for all 19 organs except for the spinal canal, where the mean error was 6.31%. CONCLUSIONS: Overall, these results are promising for the adoption of FCN autosegmentation models for pediatric CT, including applications for patient-specific CT dose estimation.

Pediatric chest-abdomen-pelvis and abdomen-pelvis CT images with expert organ contours.

PURPOSE: Organ autosegmentation efforts to date have largely been focused on adult populations, due to limited availability of pediatric training data. Pediatric patients may present additional challenges for organ segmentation. This paper describes a dataset of 359 pediatric chest-abdomen-pelvis and abdomen-pelvis Computed Tomography (CT) images with expert contours of up to 29 anatomical organ structures to aid in the evaluation and development of autosegmentation algorithms for pediatric CT imaging. ACQUISITION AND VALIDATION METHODS: The dataset collection consists of axial CT images in Digital Imaging and Communications in Medicine (DICOM) format of 180 male and 179 female pediatric chest-abdomen-pelvis or abdomen-pelvis exams acquired from one of three CT scanners at Children's Wisconsin. The datasets represent random pediatric cases based upon routine clinical indications. Subjects ranged in age from 5 days to 16 years, with a mean age of 7 years. The CT acquisition, contrast, and reconstruction protocols varied across the scanner models and patients, with specifications available in the DICOM headers. Expert contours were manually labeled for up to 29 organ structures per subject. Not all contours are available for all subjects, due to limited field of view or unreliable contouring due to high noise. DATA FORMAT AND USAGE NOTES: The data are available on The Cancer Imaging Archive (TCIA_ (https://www.cancerimagingarchive.net/) under the collection Pediatric-CT-SEG. The axial CT image slices for each subject are available in DICOM format. The expert contours are stored in a single DICOM RTSTRUCT file for each subject. The contour names are listed in Table 2. POTENTIAL APPLICATIONS: This dataset will enable the evaluation and development of organ autosegmentation algorithms for pediatric populations, which exhibit variations in organ shape and size across age. Automated organ segmentation from CT images has numerous applications including radiation therapy, diagnostic tasks, surgical planning, and patient-specific organ dose estimation.

RhoA activation-mediated vascular permeability in capillary malformation-arteriovenous malformation syndrome: a hypothesis.

Capillary malformation-arteriovenous malformation (CM-AVM) syndrome is a class of capillary anomalies that are associated with arteriovenous malformations and arteriovenous fistulas, which carry a risk of hemorrhages. There are no broadly effective pharmacological therapies currently available. Most CM-AVMs are associated with a loss of RASA1, resulting in constitutive activation of RAS signaling. However, protein interaction analysis revealed that RASA1 forms a complex with Rho GTPase-activating protein (RhoGAP), a negative regulator of RhoA signaling. Herein, we propose that loss of RASA1 function results in constitutive activation of RhoA signaling in endothelial cells, resulting in enhanced vascular permeability. Therefore, strategies aimed at curtailing RhoA activity should be tested as an adjunctive therapeutic approach in cell culture studies and animal models of RASA1 deficiency.

Pediatric abdominal and pelvic trauma: safety and efficacy of arterial embolization.

PURPOSE: Although transcatheter embolization is a well established technique to treat adults in the trauma setting, evidence is lacking in the pediatric population. This study assesses the safety and efficacy of arterial embolization for blunt abdominal and pelvic trauma in the pediatric population. MATERIALS AND METHODS: A retrospective review of abdominal and pelvic angiograms in 97 pediatric patients with blunt trauma was conducted over an 11-year period. Abdominal angiography and embolization was performed for ongoing hepatic, renal, splenic, or nonvisceral retroperitoneal injury. Pelvic angiography was performed in the setting of pelvic fracture with ongoing pelvic hemorrhage. Complications and clinical success rates of these procedures were assessed. RESULTS: Of the 97 pediatric patients who underwent angiography for acute abdominal or pelvic trauma, 54 (56%) required embolization involving 62 separate sites. Injury severity score greater than 15 was present in 94% of patients. Targets of embolization included the pelvis (n = 39), liver (n = 8), kidney (n = 7), spleen (n = 6), and retroperitoneum (n = 2). Effective hemorrhage control was achieved in 47 patients (87%). Overall mortality rate was 22% (12 of 54), with most deaths related to traumatic brain injury. Five complications occurred in four patients (7%), including three major complications (hepatic abscess, bile leak, and urinary incontinence). CONCLUSIONS: Angiography and embolization is relatively safe and potentially effective in the setting of abdominal and pelvic trauma in the pediatric population. Angiography with embolization should be considered in the treatment algorithm for this patient population.

Propranolol reduces infantile hemangioma volume and vessel density.

OBJECTIVE: To evaluate changes in infantile hemangioma tissue before and after propranolol therapy, using gray-scale and color Doppler ultrasound imaging. STUDY DESIGN: Case series with chart review. SETTING: Tertiary pediatric hospital. SUBJECTS AND METHODS: Medical records and image studies of head and neck infantile hemangioma patients treated with propranolol, identified in a quality improvement database, were reviewed. Patients with imaging before and at least 4 weeks following the initiation of treatment were included. Data collected included sex, age, location, and concurrent treatment. Student t tests were used to evaluate change in cutaneous lesion area, volume, and vessel density. Logistic regression was used to compare lesion area, volume, and vessel density. RESULTS: Of the 177 patients identified, 19 met inclusion criteria. Fourteen of 19 were female, and 5 of 19 were older than 1 year. Mean lesion area change with treatment was 13.0 cm(2) (range, -2.8 to 28.9 cm(2), P = .05). Measured volume change was a mean of 10.3 cm(3) (range, 1.5-19.2 cm(3), P = .01). Mean vessel density change was 4.4 vessels per cm(2) (range, 2.5-6.3 vessels per cm(2), P < .01). Treatment decreased clinically determined hemangioma area proportionately less than gray-scale and color Doppler ultrasound measured lesion volume. Gray-scale and color Doppler ultrasound measured treatment response did not differ with sex, lesion location, or age at propranolol initiation. CONCLUSION: Gray-scale and color Doppler ultrasound imaging of propranolol-treated infantile hemangiomas detected a significant reduction in lesion volume and vessel density. Patient age at propranolol treatment and concomitant corticosteroid use did not affect lesion volume change.

Midterm follow-up of transjugular intrahepatic portosystemic shunts using polytetrafluoroethylene endografts in children.

PURPOSE: To report the initial experience of a pediatric center's use of expanded polytetrafluoroethylene (ePTFE) endografts for the creation of transjugular intrahepatic portosystemic shunts (TIPSs) in children. MATERIALS AND METHODS: Twelve consecutive patients had a TIPS created, all with ePTFE endografts. Nine were children younger than 18 years of age: one infant (age 18 mo) and eight adolescent children with a median age of 14 years, 3 months (range, 10 y, 1 mo, to 17 y, 2 mo). All had gastric or esophageal varices. Acute variceal bleeding was the primary indication in four of nine cases (44%). Mean follow-up was 20 months (range, 4 d to 32 mo). RESULTS: Technical success rate was 100%. Seven TIPSs (78%) were created with a 10-mm-diameter endograft and two (22%) were created with an 8-mm-diameter endograft. Mean portosystemic gradient was reduced from 15.9 mm Hg to 5.8 mm Hg after TIPS creation. The devices were not dilated to their nominal diameter in seven of nine cases (78%). There were no major complications or mortalities associated with TIPS creation. There was one minor complication during follow-up in which a child developed progressively increasing lethargy. Primary patency rate by ultrasound during follow-up was 100%. There were no shunt dysfunctions or repeat interventions required, and no clinical recurrences. One child received a liver transplant 4 days after TIPS creation. CONCLUSIONS: TIPSs can be created in children with the use of ePTFE endografts with an excellent midterm primary patency rate and a low complication rate.

Percutaneous drainage of intra-abdominal abscess in children with perforated appendicitis.

BACKGROUND: Because the surgical management of perforated appendicitis remains controversial, percutaneous catheter drainage (PCD) has gained favor for managing periappendiceal abscess in hemodynamically stable children. OBJECTIVE: To determine the safety and effectiveness of PCD in children with perforated appendicitis and to identify any variables of prognostic value. MATERIALS & METHODS: We retrospectively evaluated clinical data and imaging features for 33 children undergoing PCD for periappendiceal abscess from October 2006 to February 2010. Those with preprocedural CT studies were assigned to one of three risk categories based on imaging features. RESULTS: Appendectomy was successfully postponed for all patients. Our technical success rate was 87.9%, with three recurrences (two requiring repeat drainage, one managed conservatively) and one possible complication (enterocutaneous fistula formation). Children with large and diffuse abscesses had a 50% rate of technical failure, which was significantly increased when compared to children with large but localized abscesses (P < 0.028). Extraluminal appendicolith, extraluminal gas, leukocytosis, ileus/obstruction and procedural variables were not reliable predictors of outcome. CONCLUSION: PCD can be effective for managing perforated appendicitis in children. Children with large and ill-defined abscess might be at increased risk for complication or recurrence.

Recurrent Page kidney in a child with a congenital solitary kidney requiring capsular artery embolization.

We report an unusual case of a child with a congenital solitary functional kidney complicated by a sports-related posttraumatic Page kidney. The child developed severe hypertension and renal insufficiency requiring percutaneous intervention to preserve renal function. The literature is sparse with no definitive guidelines for the treatment of Page kidney. Following the initial unsuccessful treatment with percutaneous drainage and sclerotherapy procedures, the child ultimately required catheter-directed particle embolization of the capsular arteries to resolve a recurrent subscapsular hematoma definitively. This was successful in preserving renal function and stabilization of the clinical manifestations of the Page kidney.

Uterine artery embolization: a safe and effective, minimally invasive, uterine-sparing treatment option for symptomatic fibroids.

Leiomyomas (or fibroids) are exceedingly common lesions. The indications to initiate treatment are based on the symptoms that can arise from their presence. In general, medical therapy should be considered the first line of treatment. Currently, the treatment of fibroids is in evolution. Since uterine artery embolization (UAE) was first described by Ravina et al in 1995, it has been shown to be a safe, efficacious, and cost-effective alternative to traditional surgical options, with data from long-term studies now available. Appropriate patient evaluation and selection are vital; the ideal candidate is one who is premenopausal, has symptomatic fibroids resistant to medical therapy, no longer desires fertility, and wishes to maintain her uterus. Uterine artery embolization is primarily an angiographic procedure, but periprocedural clinical management is critical for patient satisfaction. This article discusses the various embolic materials that are commonly used and available for UAE; understanding the technical nuances is critical for long-term success.

The use of paired optionally retrievable günther tulip filters in trauma patients with anatomical variants.

Inferior vena cava (IVC) filtration is commonly performed to protect against pulmonary embolism in acutely injured patients with contraindications for anticoagulation therapy. Increasingly, optionally retrievable IVC filters are utilized, particularly in younger patients with longer life expectancies. There are well-described anatomical variants that preclude the typical infrarenal deployment of IVC filters. We describe three cases in which trauma patients with congenital anomalies required temporary prophylaxis with IVC filters. One patient had a duplication of the IVC requiring filter deployment in each IVC limb. The second patient had a low inserting accessory left renal vein, and a third patient had a megacava. Both of these patients required filter deployment in each common iliac vein. In each case, a pair of optionally retrievable Günther Tulip filters was deployed and subsequently retrieved.

Sharp recanalization of an esophageal occlusion after repair of esophageal atresia and tracheoesophageal stricture.

Esophageal atresia with an associated tracheoesophageal fistula is a congenital anomaly requiring surgical correction. Recurrent stricture is the most common complication of surgical repair and is usually treated with mechanical dilation. Rarely, a recurrent completely obstructive stricture can cause obliteration of the anastomosis, preventing passage of a wire for dilation. This condition requires operative correction. In the case presented herein, the obliterated esophageal lumen from an obstructing stricture was operatively corrected with use of a novel transluminal technique. The obstruction was successfully crossed with a modified Chiba biopsy needle covered in a dilator through a gastrostomy. After subsequent balloon dilation, the lumen has remained patent for more than 3 years without significant complication.