Learning rate of students detecting and annotating pediatric wrist fractures in supervised artificial intelligence dataset preparations.

The use of artificial intelligence (AI) in image analysis is an intensively debated topic in the radiology community these days. AI computer vision algorithms typically rely on large-scale image databases, annotated by specialists. Developing and maintaining them is time-consuming, thus, the involvement of non-experts into the workflow of annotation should be considered. We assessed the learning rate of inexperienced evaluators regarding correct labeling of pediatric wrist fractures on digital radiographs. Students with and without a medical background labeled wrist fractures with bounding boxes in 7,000 radiographs over ten days. Pediatric radiologists regularly discussed their mistakes. We found F1 scores-as a measure for detection rate-to increase substantially under specialist feedback (mean 0.61±0.19 at day 1 to 0.97±0.02 at day 10, p<0.001), but not the Intersection over Union as a parameter for labeling precision (mean 0.27±0.29 at day 1 to 0.53±0.25 at day 10, p<0.001). The times needed to correct the students decreased significantly (mean 22.7±6.3 seconds per image at day 1 to 8.9±1.2 seconds at day 10, p<0.001) and were substantially lower as annotated by the radiologists alone. In conclusion our data showed, that the involvement of undergraduated students into annotation of pediatric wrist radiographs enables a substantial time saving for specialists, therefore, it should be considered.

Experiences with image quality and radiation dose of cone beam computed tomography (CBCT) and multidetector computed tomography (MDCT) in pediatric extremity trauma.

INTRODUCTION: Novel dedicated extremity cone beam computed tomography (CBCT) devices, recently introduced to the market, raised attention as a possible alternative in advanced diagnostic pediatric trauma imaging, today usually performed by multidetector computed tomography (MDCT). This work aimed to compare image quality and radiation dose of CBCT and MDCT. MATERIALS AND METHODS: Fifty-four CBCT-MDCT examination pairs, containing nine MDCTs acquired in parallel prospectively and 45 MDCTs matched in retrospect, were included in this study. Image quality was analyzed semi-objectively by measuring noise, contrast-to-noise ratio (CNR), and signal-to-noise ratios (SNR) and subjectively by performing image impression ratings. CT dose records were readout. RESULTS: Image noise was significantly lower in CBCT compared with MDCT, both semi-objectively and subjectively (both p < 0.001). CNR and SNRs were also in favor of CBCT, though CBCT examinations exhibited significantly more beam hardening artifacts that diminished the advantages of the superior semi-objective image quality. These artifacts were believed to occur more often in children due to numerous bone-cartilage transitions in open growth plates and may have led to a better subjective diagnostic certainty rating (p = 0.001). Motion artifacts were infrequently, but exclusively observed in CBCT. CT dose index (CTDIvol) was substantially lower in CBCT (p < 0.001). CONCLUSION: Dedicated extremity CBCT could be an alternative low-dose modality in the diagnostic pathway of pediatric fractures. At lower doses compared with MDCT and commonly affected by beam hardening artifacts, semi-objective CBCT image quality parameters were generally better than in MDCT.

Blake's Pouch Cysts and Differential Diagnoses in Prenatal and Postnatal MRI : A Pictorial Review.

PURPOSE: The clinical variability of Blake's pouch cysts (BPC) may range from asymptomatic via ataxia to sequelae of decompensated hydrocephalus. On the other hand, Dandy-Walker malformation (DWM) and cerebellar vermis hypoplasia generally correlate with less favorable neurologic development. The aim was to illustrate the potential of prenatal and postnatal neuroimaging to distinguish a BPC or persistent BP from other posterior fossa malformations. METHODS: This pictorial review addresses the inconsistent nomenclature, clinical features, and magnetic resonance imaging (MRI) patterns of BPC and five differential diagnoses. The MRI findings of 11 patients, acquired at up to 3 T in 3 institutions, are demonstrated. Furthermore, the literature was searched for recent improvements in genetic and embryological background knowledge. RESULTS: Posterior fossa malformations often resemble each other and may even be imitated by sequelae of hemorrhagic, ischemic or infectious disruptions, i.e. congenital anomalies of morphology despite normal developmental potential. Hydrocephalus is a typical, albeit not always congenital finding in BPC. It is frequently associated with cerebellar disruptions and DWM; however, it is also a rare complication of posterior fossa arachnoid cysts. A moderately elevated vermis needs follow-up to confirm persistent BP versus vermian hypoplasia or DWM. The fetal cerebellar tail, previously assumed to be specific for DWM, may be imitated in cases of persistent BP. CONCLUSION: The accurate diagnosis of isolated BPC is not always straightforward, which is especially critical in the context of fetomaternal medicine. A detailed description of posterior fossa malformations is to be preferred over unspecific terminology.

Chest CTA in children younger than two years - a retrospective comparison of three contrast injection protocols.

To obtain the highest diagnostic information with least side effects when performing thoracic CT angiography (CTA) is challenging in young children. The current study aims to compare three contrast agent (CA) injection protocols regarding image quality and CA characteristic: a standard CTA, a fixed-bolus delay protocol, and the "microbolus technique (MBT)" developed in our institution. Seventy chest CTA scans of patients (<2 years) were divided into three groups. MBT was applied in group I, the standard protocol in group II and a fixed bolus delay in group III. Objective image quality was assessed by measuring peak enhancement, image noise, signal-to-noise (SNR) and contrast-to-noise ratios (CNR). Two observers scored subjective image quality and artifacts. Significantly lower amounts of CA (mean ± SD) were used in the MBT group compared to Group II (9.0 ± 3.7 ml vs. 12.9 ± 4.5 ml). A lower, but still diagnostic (>400 HU) enhancement was registered in all major thoracic vessels in group I without significant differences regarding SNR and CNR in most regions (p < 0.05). The best scores for image quality and artifacts were reached in group I. All three chest CTA contrast injection protocols offered diagnostic vessel enhancement in young patients. MBT was associated with reduced image artifacts and less injected CA.

A rare anatomic variation of the superficial palmar branch of the radial artery causing pain.

BACKGROUND: The superficial palmar branch of the radial artery (SPBRA) normally pierces through the thenar muscles and unites with the ulnar artery to form the superficial palmar arch. Rarely, a subcutaneous course of the SPBRA is described in which the artery lies superficial to the thenar muscles. CASE REPORT: We report about a 17-year-old female patient with pain at the thenar eminence due to a unique course of the SPBRA. Duplex sonography and magnetic resonance angiography revealed a subcutaneous course of the artery over the thenar muscles. Arterial transposition by splitting of the abductor pollicis brevis muscle was performed. At 12-month follow-up, the patient is still free of symptoms. Duplex sonography confirmed patency of the SPBRA. CONCLUSION: While a subcutaneous course of the SPBRA has been described before, we present an adolescent patient with this anatomical variation causing pain. Our specifically tailored treatment strategy consisting of arterial transposition by splitting of the abductor pollicis brevis muscle was efficient and feasible in our patient and hand surgeons should be aware of this anatomical variation.

Surface radiation dose comparison of a dedicated extremity cone beam computed tomography (CBCT) device and a multidetector computed tomography (MDCT) machine in pediatric ankle and wrist phantoms.

OBJECTIVES: To evaluate and compare surface doses of a cone beam computed tomography (CBCT) and a multidetector computed tomography (MDCT) device in pediatric ankle and wrist phantoms. METHODS: Thermoluminescent dosimeters (TLD) were used to measure and compare surface doses between CBCT and MDCT in a left ankle and a right wrist pediatric phantom. In both modalities adapted pediatric dose protocols were utilized to achieve realistic imaging conditions. All measurements were repeated three times to prove test-retest reliability. Additionally, objective and subjective image quality parameters were assessed. RESULTS: Average surface doses were 3.8 ±2.1 mGy for the ankle, and 2.2 ±1.3 mGy for the wrist in CBCT. The corresponding surface doses in optimized MDCT were 4.5 ±1.3 mGy for the ankle, and 3.4 ±0.7 mGy for the wrist. Overall, mean surface dose was significantly lower in CBCT (3.0 ±1.9 mGy vs. 3.9 ±1.2 mGy, p<0.001). Subjectively rated general image quality was not significantly different between the study protocols (p = 0.421), whereas objectively measured image quality parameters were in favor of CBCT (p<0.001). CONCLUSIONS: Adapted extremity CBCT imaging protocols have the potential to fall below optimized pediatric ankle and wrist MDCT doses at comparable image qualities. These possible dose savings warrant further development and research in pediatric extremity CBCT applications.

Gadolinium-free MR in coarctation-can contrast-enhanced MR angiography be replaced?

OBJECTIVE: To determine the difference in vessel measurements, signal-to-noise ratio (SNR), and voxel size between contrast-enhanced and noncontrast magnetic resonance techniques in patients with coarctation of the aorta (CoA). MATERIALS AND METHODS: In 39 patients, vessel size, SNR, and voxel size were compared in cine magnetic resonance imaging (MRI), gadolinium-free magnetic resonance angiography (Gd-free MRA), and contrast-enhanced MRA (ce-MRA). RESULTS: There was no significant difference in measurement and SNR, but there was a significant difference in voxel size (P<.001). CONCLUSIONS: Our results show that, in CoA patients, monitoring of vessel size using cine MRI and Gd-free MRA is equivalent to ce-MRA while being less invasive.

Huge Congenital Segmental Dilatation of the Sigmoid Colon in a Neonate: A "Rarity to Meet" and a "Challenge to Treat".

Only ten cases of neonatal congenital segmental dilatation (CSD) of the colon have been described so far. We present a full-term female newborn with trisomy 21, ventricular septal defect, and gross abdominal distension. Plain abdominal radiographs revealed a huge cystic lesion occupying the left hemiabdomen. Upon laparotomy on day 4 a CSD of the distal sigmoid and proximal rectum was confirmed and resected. The proximal colon was exteriorized and the distal part closed as a Hartmann pouch. Histology confirmed a huge segmental dilatation of the sigmoid without dysganglionosis or pseudodiverticula, but normal intestinal architecture. After correction of the ventricular septal defect a low rectal end-to-end anastomosis could be performed at an age of 5 months. The postoperative course was uneventful. CSD of the sigmoid colon is extremely "rare to meet" and a "challenge to treat" in the newborn period, but clinical awareness of this entity prompts pediatric surgical success.

European Guidelines for AP/PA chest X-rays: routinely satisfiable in a paediatric radiology division?

OBJECTIVES: Accurate collimation helps to reduce unnecessary irradiation and improves radiographic image quality, which is especially important in the radiosensitive paediatric population. For AP/PA chest radiographs in children, a minimal field size (MinFS) from "just above the lung apices" to "T12/L1" with age-dependent tolerance is suggested by the 1996 European Commission (EC) guidelines, which were examined qualitatively and quantitatively at a paediatric radiology division. METHODS: Five hundred ninety-eight unprocessed chest X-rays (45% boys, 55% girls; mean age 3.9 years, range 0-18 years) were analysed with a self-developed tool. Qualitative standards were assessed based on the EC guidelines, as well as the overexposed field size and needlessly irradiated tissue compared to the MinFS. RESULTS: While qualitative guideline recommendations were satisfied, mean overexposure of +45.1 ± 18.9% (range +10.2% to +107.9%) and tissue overexposure of +33.3 ± 13.3% were found. Only 4% (26/598) of the examined X-rays completely fulfilled the EC guidelines. CONCLUSIONS: This study presents a new chest radiography quality control tool which allows assessment of field sizes, distances, overexposures and quality parameters based on the EC guidelines. Utilising this tool, we detected inadequate field sizes, inspiration depths, and patient positioning. Furthermore, some debatable EC guideline aspects were revealed. KEY POINTS: • European Guidelines on X-ray quality recommend exposed field sizes for common examinations. • The major failing in paediatric radiographic imaging techniques is inappropriate field size. • Optimal handling of radiographic units can reduce radiation exposure to paediatric patients. • Constant quality control helps ensure optimal chest radiographic image acquisition in children.

Serum Bile Acids in Repaired Tetralogy of Fallot: A Marker for Liver and Heart?

BACKGROUND AND AIMS: Patients with repaired tetralogy of Fallot may develop chronic right ventricular dysfunction and hepatic congestion over time. We hypothesized that bile acid metabolism is altered in repaired tetralogy of Fallot patients and therefore sought to correlate right ventricular indices with serum bile acid levels. METHODS: Indexed right ventricular end diastolic volume, as assessed by cardiac magnetic-resonance imaging, was classified as <100ml/m2 (Group 1, n = 5), 100-150ml/m2 (Group 2, n = 18), and >150ml/m2 (Group 3, n = 6) in 29 patients with repaired tetralogy of Fallot. Pulmonary regurgitation fraction and right ventricular ejection fraction were calculated. The serum bile acid profile, including 15 species, in these patients was determined by liquid chromatography coupled with mass spectrometry. RESULTS: Serum bile acid levels increased from Group 1 to Group 3 (2.5 ± 0.7; 4.1 ± 2.5; 6.0 ± 2.8 µmol/l, respectively) with significantly increased bile acid values in Group 3 compared to Group 1 (p≤0.05). In Group 3, but not in Group 1 and 2, a significant increase in glycine-conjugated bile acids was observed. Pulmonary regurgitation fraction increased (12 ± 1; 28 ± 16; 43 ± 3%, Groups 1-3, respectively) and right ventricular ejection fraction decreased (48.4 ± 6.4; 48.5 ± 6.5; 42.1 ± 5.3%, Groups 1-3, respectively) with rising indexed right ventricular end diastolic volume. CONCLUSIONS: These preliminary results suggest that serum bile acid levels are positively correlated with indexed right ventricular end-diastolic volume in patients with repaired tetralogy of Fallot; however, this needs to be confirmed in a larger patient cohort.

Cardiac MRI assessment of right ventricular function: impact of right bundle branch block on the evaluation of cardiac performance parameters.

OBJECTIVES: Right ventricular (RV) function represents a prognostic marker in patients with corrected congenital heart disease. In up to 80 % of these patients, right branch bundle block (RBBB) exists and leads to asynchronous ventricular contraction. The aim of this retrospective study was to evaluate the change of RV performance parameters considering delayed RV end-systolic contraction. METHODS: RV volumes of 33 patients were assessed twice: 1) not taking account of RBBB (group I), and 2) considering RBBB (group II). According to the RV ejection fraction (EF) for both groups, RV function was classified in different categories (>50 % = normal, 40-50 % = mildly-, 30-40 % = moderately-, <30 % = severely-reduced). RESULTS: The mean time difference between maximal systolic contraction of the septum and RV free wall was 90.7 ms ± 42.6. Consequently, RV end-systolic volume was significantly decreased in group II (p < 0.001). Accordingly, RV stroke volume and RV EF were significantly higher in group II (p < 0.001). There was also a significant change in the assessment of RV function (p < 0.02). CONCLUSIONS: RBBB induced delayed RV contraction can be detected at CMR. Ignoring the RV physiology in RBBB patients leads to a statistically significant underscoring of RV performance parameters. KEY POINTS: • Right branch bundle block leads to an asynchronous ventricular contraction • In CMR, a delayed right ventricular contraction due to RBBB can be detected • Ignoring RV physiology in RBBB patients leads to underscoring of RV performance.

The pediatric knee: diagnosis and management of ligament injuries.

In the last few decades, sports injuries in pediatric and adolescent athletes have increased dramatically, with ∼ 38 million young athletes participating in organized sports annually in the United States. Starting at the age of 2 years, an increase of the incidence of knee injuries until adulthood with a peak at 6 and at 13 years of age has been observed. Due to a physiologic laxity of the ligaments, ligament injuries are uncommon in these patients, but they are getting more frequent. In the growing knee, open physis are the points of minor resistance. Therefore apophyseal injuries of the pediatric knee are more common. Diagnostics and treatment of ligament injuries of the pediatric and adolescent knees are challenging. This article presents an overview of ligament injuries in the pediatric and adolescent knee, their diagnostic work-up, and their treatment in the growing patient.

Diagnosis and treatment of apophyseal injuries of the pelvis in adolescents.

An avulsion fracture occurs when the growth plate of an apophysis is injured due to a sudden and forceful contraction of the attaching musculotendinous unit. Usually it is adolescents who sustain these injuries, and a significant male preponderance has been found. Even though apophyseal fractures have been described in a variety of locations, the apophyses of the pelvis and hip are more prone to these injuries. Due to their rarity, avulsion fractures of the pelvis are often misdiagnosed. Additionally, patients can present late, and other pathologies are suspected initially. In most acute cases conservative treatment is successful. However, some cases require operative intervention. To plan an optimal treatment regimen, it is important to be familiar with the typical pathomechanism, the typical clinical findings, and the most commonly applied imaging modalities of these injures. The present review analyzes the currently available literature on the most frequently encountered apophyseal injuries of the pelvis in adolescent patients. Some case examples are also presented.