The Diagnostic Performance of Magnetic Resonance Imaging in the Categorization of Pediatric Neck Lymph Nodes: Radiologic and Pathologic Correlations.

BACKGROUND/AIM: To present MRI features of neck lymph nodes in benign and malignant conditions in the pediatric population. MATERIALS AND METHODS: MRIs of the neck of 51 patients 1 to 18 years old (40 boys, 11 girls [10.08±4.73]) with lymph node biopsy were retrospectively analyzed. Those were grouped as benign including reactive (27 [52.9%]) and lymphadenitis (11 [21.6%]), and malignant (13 [25.5%]). The groups were evaluated multiparametrically in terms of quantitative and qualitative variables. RESULTS: The long axis, short axis, area, and apparent diffusion coefficient (ADC) values of the largest lymph node were 21 (17 to 24) mm, 14 (12 to 18) mm, 228.60 (144.79 to 351.82) mm 2 , 2531 (2457 to 2714) mm 2 /s for reactive, 24 (19 to 27) mm, 15 (11 to 20) mm, 271.80 (231.43 to 412.20) mm 2 , 2534 (2425 to 2594) mm 2 /s for lymphadenitis, 27 (23.50 to 31.50) mm, 20 (15 to 22) mm, 377.08 (260.47 to 530.94) mm 2 , 2337 (2254 to 2466) mm 2 /s for malignant, respectively. Statistical analysis of our data suggests that the following parameters are associated with a higher likelihood of malignancy: long axis >22 mm, short axis >16 mm, area >319 cm 2 , ADC value <2367 mm 2 /s, and supraclavicular location. Perinodal and nodal heterogeneity, posterior cervical triangle location are common in lymphadenitis ( P <0.001). Reactive lymph nodes are distributed symmetrically in both neck halves ( P <0.001). CONCLUSION: In the MRI-based approach to lymph nodes, not only long axis, short axis, surface area, and ADC, but also location, distribution, perinodal, and nodal heterogeneity should be used.

Coexistence of longitudinally extensive transverse myelitis and diffuse midline glioma in the brainstem in an adolescent boy with acute flaccid paralysis.

We present the case of a previously healthy 13-year-old boy who was admitted to the emergency department with acute flaccid paralysis. Magnetic resonance imaging revealed radiological evidence of longitudinally extensive transverse myelitis. Additionally, homogeneous T2 signal increase was observed in the pons and medulla oblongata, initially indicating brainstem encephalitis. Subsequent evaluations confirmed a coexistence of diffuse midline glioma (DMG) in the brain stem alongside acute transverse myelitis (ATM). Children with ATM generally have a more favorable prognosis than adults. However, despite the implementation of advanced treatment methods, the patient's quadriplegia did not improve and resulted in spinal cord sequela atrophy. DMG exhibits an aggressive growth pattern and lacks a known curative treatment. This case represents an exceedingly rare synchronous occurrence of aggressive conditions, underscoring the importance of raising awareness among physicians. Furthermore, we aim to discuss the radiologic differential diagnosis, as this is the first documented instance in the literature.

Quantitative analysis of distal femoral epiphysis blood supply in healthy infants with superb microvascular imaging: a pilot study

Background/aim: This study aimed to determine the blood supply of the distal femoral epiphysis (DFE) using superb microvascular imaging in newborns and infants, and to investigate the correlation with ossification center (OC) length, sex, and age. Materials and methods: A total of 140 cases were evaluated in this study. The cases were divided into 2 groups of less than 90 days and over 90 days. Cartilage blood supply was measured with vascularity index (%) (VI). Results: The mean OC length and median VI values were measured as 10.20 ± 3.72 mm and 0.80% (0.58­1.50) for boys and 10.03 ± 3.36 mm and 0.70% (0.30­1.40) for girls, respectively. There was no significant difference in OC length and VI between sexes. The mean OC length in Group II was significantly higher than in Group I (12.14 ± 3.14 vs 8.09 ± 2.64) (p < 0.001). The median VI in Group I was higher than in Group II (1.40% vs 0.40%) (p < 0.001). There were positive correlations between age and OC length (r = 0 .716), negative correlations between age and VI (r = ­0.822), and between VI and OC length (r = ­0.657). Conclusion: Quantitative reference values for DFE blood supply and OC length can guide the diagnosis and follow-up of many skeletal diseases.

Evaluation of renal oxygenization in laparoscopic pediatric surgery by near infrared spectroscopy.

PURPOSE: Increased intraabdominal pressure IAP may reduce renal blood flow (RBF). The study aims to evaluate the pneumoperitoneum effect on RBF by comparing renal regional oxygen saturation index (rSrO2) measured by near-infrared spectroscopy (NIRS) in pediatric patients having laparotomy and laparoscopy. METHODS: Of 58 patients having laparoscopy and laparotomy, 18 were excluded due to renal pathologies, combined open surgical procedures, and administration of inotropic drugs. Hemodynamic parameters and rSrO2 were recorded in laparoscopy (n = 20) and laparotomy (n = 20) groups before induction and with 5 min intervals up to 60 min and at post-extubation. RESULTS: Decrease in right renal rSrO2 at 45th and 60th min and 30th, 45th and 60th min in left were significant in the laparoscopy group compared to laparotomy group. In the laparoscopy group, reductions at T25, T30, T45, and T60 were significant in both renal rSrO2. Renal rSO2 increased to normal with desufflation. CONCLUSION: IAP with pneumoperitoneum may lead to renal hypoxia in children. Renal rSO2 returns to normal with desufflation. Renal NIRS monitorization might be needed in patients with renal parenchymal and vascular pathologies, solitary kidney, and multiorgan pathologies that may affect renal oxygenation.

Severe Multisystem Involvement of Chronic Granulomatous Disease in a Pediatric Patient.

Chronic granulomatous disease (CGD) is a rare primary immunodeficiency disorder identified by recurrent pyogenic and fungal infections infections secondary to defective nicotinamide adenine dinucleotide phosphate oxidase enzyme. In the present study, we demonstrated a case with a history of multiple segmental lung resections because of invasive bronchopulmonary aspergillosis, multifocal hepatic and splenic granulomas, bilateral adnexal calcific foci presumed to be related with old granulomatous infection and finally gastric outlet obstruction secondary to the involvement of the stomach wall thickening with granulomatous tissue. This is an extremely severe case of CGD with multiorgan involvement within a 10-year period after the diagnosis. Gastric antral involvement may mimic inflammatory bowel diseases in such cases, and intestinal involvement can reliably be demonstrated via ultrasonography. Spontaneous resolution of the antral involvement was observed in the follow-up.

Shear wave elastography of parotid glands in pediatric patients with HIV infection.

OBJECTIVES: Parotid gland (PG) involvement is common among the patients with HIV infection. Shear wave elastography (SWE) is a noninvasive method used to measure the tissue stiffness of several organs including PG. The aim of this study was to evaluate the tissue stiffness values of PGs of HIV-infected children via SWE and compare the results with the counterparts of healthy subjects. MATERIALS AND METHODS: This single-center, prospective study included the PG examinations of 23 pediatric HIV patients and 40 healthy children via grayscale ultrasound and SWE. Independent sample T test and Mann-Whitney U test were used in statistical analysis. RESULTS: Stiffness of both PGs was significantly higher in patients' group when compared with control subjects. In addition, when the patients were separated into two groups according to the appearance of PG on grayscale ultrasound as homogeneous and heterogeneous, stiffness values were increased in the patients with homogeneous parenchymal appearance. No significant difference was achieved in terms of median CD4 and CD8 counts, HIV RNA levels or median duration of illnesses. CONCLUSIONS: PG examination of HIV-infected children via SWE reveals increased tissue stiffness when compared with healthy subjects. SWE can be used as an ultrasound-assisted noninvasive technique in this manner.

Comparative evaluation of liver, spleen, and kidney stiffness in HIV-monoinfected pediatric patients via shear wave elastography

Background/aim: This study aimed to evaluate the stiffness of the liver, spleen, and kidneys in HIV-monoinfected children via shear wave elastography (SWE). Materials and methods: Twenty-one HIV-monoinfected children and 37 healthy subjects were included in this study. Livers, spleens, and kidneys of the participants were examined via ultrasound and SWE. Patients were divided into two groups according to the presence of pathologic ultrasonographic findings. Routine laboratory tests were also recorded. Stiffness of these organs was compared between patients and control groups. Results: Liver transaminases, blood urea, and creatinine levels were normal in all subjects. Ultrasonographic examination revealed hepatosplenomegaly (n = 1, 4.7%), grade 1 hepatosteatosis (n = 1, 4.7%), and hepatosteatosis and minimal heterogeneity of the liver (n = 1, 4.7%). Ultrasonographic features were normal in 18 patients. Stiffness of the liver, spleen, and kidneys of all HIV-monoinfected children with normal laboratory parameters was significantly higher than in healthy subjects. Eighteen patients with normal ultrasonographic findings also had higher stiffness values when compared to control subjects. Conclusion: Stiffness of the liver, spleen, and kidneys in HIV-monoinfected children was increased. SWE can be used in the detection of early parenchymal changes even in patients with normal laboratory parameters and ultrasonographic findings.

Simultaneous Presentation of Wilms' Tumor and Contralateral Ganglioneuroma in a Child: Case Report and Literature Review.

We demonstrate a 4-year-old girl who presented with progressive, asymmetrical, firm abdominal distention and was diagnosed with synchronous Wilms' tumor and left para-aortic ganglioneuroma (GN). Although synchronous tumors in the pediatric population are commonly associated with malignancy-predisposing syndromes, the patient in question was found to be otherwise healthy and had no clinical evidence nor family history of a syndrome. This case is the second one in the literature diagnosed with synchronous presentation of Wilms' tumor and GN in a previously healthy child. In addition, a GN foci presumed to be a previous metastasis of a neurogenic tumor that subsequently matured to GN was depicted within a left para-aortic lymph node. We aimed to emphasize an extremely rare synchronous occurrence of these embryonal tumors, increase the awareness of physicians, and discuss the radiologic differential diagnosis and management.

Evaluation of parotid glands in healthy children and adolescents using shear wave elastography and superb microvascular imaging.

OBJECTIVES: We aim to determine parotid gland elasticity values from healthy children and adolescents using shear wave elastography (SWE). We also define the degree of vascularity using superb microvascular imaging (SMI), power Doppler (PD), and color Doppler (CD) and compare SMI with CD and PD. MATERIALS AND METHODS: A total of 100 cases, comprising 50 girls and 50 boys, with ages ranging from 3 to 17 years were included in this prospective study. SWE, SMI, PD, and CD measurements were taken from both parotid glands, and the relationships with sex, age, and body mass index (BMI) were determined. The SMI was compared with the PD and CD. RESULTS: The median elasticity values measured with SWE were 8.37 ± 2.09 kPa and 1.68 ± 0.26 m/s on the right and 8.33 ± 2.04 kPa and 1.69 ± 0.26 m/s on the left. There were significant positive correlations present for those aged below and above 10 years and for BMI with elasticity values. The median vascular spot numbers measured using SMI, PD, and CD were 5 ± 1.70, 3.5 ± 1.45, and 2 ± 1.1 on the right and 4 ± 1.7, 4 ± 1.43, and 2 ± 1.05 on the left, respectively. The median values obtained with SMI were significantly higher than the median values obtained with both PD and CD. CONCLUSION: This study determined the reference SWE, SMI, PD, and CD values for normal parotid glands in healthy children and adolescents. Elasticity values were affected by age and BMI. There was no correlation between vascularity values and age, sex, or BMI. SMI provided more detailed information about vascularity compared with the other methods.

A confounding rib variation: bilateral symmetric aberrant posterior rib articulations and bridgings.

INTRODUCTION: Although mild bone angulation with osseous enlargement often suggests fractures with callus formation, in some cases the diagnosis is synchondrosis. CASE REPORT: We present a rare variation of the chest wall in a 15-year-old male with a history of lymphoma. Bilateral multi-level posterior rib enlargements revealing mild 18F-fluorodeoxyglucose uptake were detected via positron-emission tomography/computed tomography. The variations were identified as healing fractures, although the more accurate diagnosis was determined to be multi-level posterior rib synchondroses with consecutive bridgings. Although variant bone anatomies are commonly seen in radiological practice, such multiple symmetrical posterior rib synchondroses associated with consecutive bridgings and articulations have not been clearly demonstrated before. CONCLUSION: Awareness of such a rare combination of a well-known variation is crucial for radiologists to exclude malignancies, possibility of fracture and suspicion of child abuse.

[Management and treatment difficulties of multi-drug resistant pulmonary tuberculosis in a pediatric case]. / Çok ilaca direçli akciger tüberkülozu olan çocuk olguda tani ve tedavi yaklasiminda yasanan güçlükler.

Tuberculosis continues to be a major health problem worldwide. Multidrug resistant tuberculosis (MDR-TB) infection that occurs in childhood is caused by adult MDR-TB agents which are in circulation and resistant to primary drugs. In this case report a 17-month-old child with MDR-TB who was cured after a 24-month therapy regimen was presented. Physical examination of a 17-month-old girl admitted to the hospital with the cause of recurrent pneumonia revealed a rubbery lymphadenopathy less than 2 cm in the right upper cervical region. Crepitant rales were detected in the right basal on auscultation of the lung. Interferon gamma release assay (IGRA) and tuberculin skin (TST) tests were negative. Computed tomography (CT) scan of the chest showed mediastinal conglomerate pathologic lymphadenopathy and air bronchograms were detected near the lower lobe of the left lung. Treatment of isoniazid, rifampicin, pyrazinamide with the diagnosis of epituberculosis was started by taking a sample of gastric aspirate culture sample. In the sixth month of the treatment patient was admitted to our clinic with enlarged cervical rubbery lymphadenopathy. It was determined that microbiological test of gastric aspirate culture specimen was positive for M.tuberculosis complex resistant to isoniazid, rifampin, ethambutol, streptomycin, ethionamide and rifabutin. Control CT showed residual peribronchial infiltrations and hilar calcific lymph nodes. Hearing test, vision control and, thyroid function tests were performed and treatment of moxifloxacin, amikacin, para-amino salicylic acid, protionamide and pyrazinamide was started based on minor drug susceptibility results of M.tuberculosis isolate which was still growing in gastric aspirate culture. Gastric aspirate culture for M.tuberculosis was still positive after 3 months of treatment and the current treatment was continued. Amikacin was stopped after 6 months. Therapy regimen was stopped after 24-months. Over the course of a follow-up period of more than 3 years, the clinical and radiological resultsof the patient has improved significantly. The clinical presentation of TB in children is often nonspecific and differs from the patterns seen in adults. MDR-TB cases can be seen in this age group since tuberculosis in children is mainly caused by transmission of drug-resistant strains from adults. This situation is particularly problematic due to the long-term treatment and the lack of specific drug formulations for children.

Apparent diffusion coefficient (ADC) measurements and morphometric evaluation of the cranium in age-matched children with central precocious puberty.

OBJECTIVES: Central precocious puberty (CPP) is one of the common reasons for referral to pediatric endocrinology. Magnetic resonance imaging (MRI) is used to rule out intracranial pathologies. However, there is insufficient information in the literature about bone marrow abnormalities on MRI in CPP cases. The aim of this study was to evaluate the apparent diffusion coefficient (ADC) values obtained from bone marrow diffusion weight images (DWI) of cranial bone structures and the status of sphenooccipital synchondrosis (SOS) in CPP. METHODS: MRI data from 6-to 9-year-old girls with CPP and a healthy control group were evaluated. Anthropometric data, FSH, LH, and oestradiol tests were recorded, and the relationship between SOS status, DWI-ADC values of the clivus, parietal bone, and occipital protuberance were compared. RESULTS: The study included 146 girls, 79 CPP, and 67 healthy aged 6-9 years (median: 8 (2)). The diagnosis age was 8.30 ± 0.8 years. The ADC values were significantly lower on CPP than normal controls (p=<0.05). In the CPP group, pattern 1 was found at 2 % (n=2), pattern 2 at 3.5 % (n=3), and pattern 3 at 3.5 % (n=3) in clivus sphenooccipital synchondrosis. There was no correlation between the mean parietal, occipital, and clivus ADC values and any variable (p>0.05). CONCLUSIONS: DWI-MRI ADC analysis can be used as a quantitative radiological marker for early detection of CPP, even before changes in sphenooccipital synchondrosis.

[99mTc]Technetium-Labeled Niosomes: Radiolabeling, Quality Control, and In Vitro Evaluation.

The aim of this research was to develop technetium-99m ([99mTc]Tc)-radiolabeled niosomes and evaluate the cancer cell incorporation capacity of radiolabeled niosomes. For this purpose, niosome formulations were developed by film hydration method, and prepared niosomes were characterized to particle size, polydispersity index (PdI), ζ-potential value, and image profile. Then, niosomes were radiolabeled with [99mTc]Tc using stannous salts (chloride) as a reducing agent. The radiochemical purity (RP) and stability in different mediums of the niosomes were assessed by ascending radioactive thin-layer chromatography (RTLC) and radioactive ultrahigh-performance liquid chromatography (R-UPLC) methods. Also, the partition coefficient value of radiolabeled niosomes was determined. The cell incorporation of [99mTc]Tc-labeled niosome formulations, as well as reduced/hydrolyzed (R/H)-[99mTc]NaTcO4 in the HT-29 (human colorectal adenocarcinoma) cells, was then assessed. According to the obtained results, the spherical niosomes had a particle size of 130.5 ± 1.364 nm, a PdI value of 0.250 ± 0.023, and a negative charge of -35.4 ± 1.06 mV. The niosome formulations were effectively radiolabeled with [99mTc]Tc using 500 µg mL-1 stannous chloride for 15 min, and RP was found to be over 95%. [99mTc]Tc-niosomes showed good in vitro stability in every system for up to 6 h. The log P value of radiolabeled niosomes was found as -0.66 ± 0.02. Compared to R/H-[99mTc]NaTcO4 (34.18 ± 1.56%), the incorporation percentages of [99mTc]Tc-niosomes (88.45 ± 2.54%) were shown to be higher in cancer cells. In conclusion, the newly developed [99mTc]Tc-niosomes showed good prototype for potential use in nuclear medicine imaging in the near future. However, further investigations, such as drug encapsulation and biodistribution studies, should be performed, and our studies are continuing.

Shear wave elastography of temporomandibular joint disc and masseter muscle stiffness in healthy children and adolescents: a preliminary study.

OBJECTIVES: Shear wave elastography (SWE) are promising techniques in diagnosing temporomandibular joint (TMJ) disc and masseter muscle disorders. To investigate normative stiffness values of the TMJ disc and masseter muscle by SWE in children and adolescents. METHODS: This prospective study evaluated 123 TMJ discs and masseter muscles in 123 subjects. The stiffnesses of anterior, middle, and posterior parts of the disc and the masseter muscle were measured. This study investigated differences in mean elasticity [kilopascal (kPa)] and velocity [metre/second (m/s)] values of the different disc parts and the masseter muscle in closed and open mouth positions, and the correlations of these SWE values with age, body mass index (BMI), height, and weight of the subjects. RESULTS: The median stiffness disc values of all participants were 28.7 kPa (elasticity) and 3.07 m/s (velocity) for the anterior, 29.10 kPa and 3.07 m/s for the middle, and 23.2 kPa and 2.77 m/s for the posterior parts. Posterior stiffness was significantly lower than other body regions in all subjects and across all age groups. The mean stiffness values of the muscle were 16.96 ± 9.01 kPa and 2.33 ± 1.2 m/s for the closed mouth, and 28.7 ± 10.2 kPa and 3.23 ± 1.32 m/s for the open mouth. CONCLUSION: The stiffness of the TMJ disc was significantly lower in the posterior part than in the anterior or middle parts. The mean stiffness was significantly higher in the open mouth than in the closed mouth position. Neither elasticity nor velocity were associated with age, height, weight, or BMI.

An adolescent girl with obstructive uropathy requiring nephro-ureterectomy was subsequently diagnosed with renal tuberculosis: case report.

A 15-year-old girl was followed up for 2 years in a district hospital for management of vesicoureteral reflux and, subsequently, hydronephrosis of both kidneys and required bilateral ureteroneocystostomy. Despite surgery, there was continuous progression of the left hydronephrosis. Referral to a tertiary hospital because of continued sterile pyuria prompted investigation for tuberculosis (TB): she was diagnosed with bilateral pulmonary TB and urine culture confirmed Mycobacterium tuberculosis. Despite tuberculous chemotherapy and dexamethasone, she required a left nephrectomy. Histology demonstrated necrotising granulomatous pyelonephritis. She remains well with normal function of the right kidney. Despite the rarity, chronic urinary tract disorders should always prompt investigation for tuberculosis.

Normative values of pancreas stiffness by shear wave elastography in healthy children and adolescents.

PURPOSE: To define normal pancreas elasticity and velocity values with shear wave elastography (SWE) in healthy children and assess associations with gender, age, and body mass index (BMI). METHODS: This prospective study included a total of 100 cases (male: 50; female: 50), aged 3-17 years. Preschool, school, and adolescent periods of 3-6 years (n = 27), 7-12 years (n = 30), and 13-17 years (n = 43), respectively, were created in addition to two groups representing prepubertal and postpubertal periods of 3-10 years (n = 50) and 11-18 years (n = 50), respectively. Demographic data regarding the gender, age, height, body weight, and BMI were recorded. Pancreatic head, corpus, and tail SWE measurements were performed with a convex transducer (3.5-5 MHz). Correlations and comparisons were made for stiffness values between groups. Statistical analyses used Mann-Whitney U, Kruskal-Wallis, and Spearman's correlation tests. RESULTS: Medians (25-75th percentage) of age and BMI were 7 (4.25-10) years and 15 (13-17) years and 17.47 (14.94-19.23) kg/m2 and 21.22 (17.41-24) kg/m2 in the two age groups, respectively. The median (interquartile range) elasticity and velocity values for the head, corpus, and tail sections of the pancreas were measured as 9.35 (2.9) kPa and 1.76 (0.26) m/s; 9.3 (2.5) kPa and 1.74 (0.21) m/s; and 8.75 (2) kPa and 1.69 (0.15) m/s, respectively. No significant differences were identified for stiffness values between gender and pancreatic section. Pancreatic stiffness values were significantly different among two (p = 0.001) and three (p = 0.028) age groups, and presented mild positive correlations with age (r: 0.23, p: 0.002), height (r: 0.18, p: 0.01), body weight (r: 0.38, p: 0.003), and BMI (r: 0.37, p: 0.045). CONCLUSION: Normal elasticity and velocity values were defined for the pancreas with SWE in children. Pancreatic stiffness does not significantly change among pancreas parts, but it increases with the transition from childhood to adolescence.

Normative values of thymus in healthy children; stiffness by shear wave elastography.

PURPOSE: Thymus grows after birth, reaches maximal size after the first few years and involutes by puberty. Because of the postnatal developmental and involutional duration, we aimed toinvestigate normal stiffness values of mediastinal thymus by shear wave elastography (SWE) in different age groups of children and discuss imaging findings of thymus. METHODS: We prospectively examined 146 children (90 girls, 56 boys) who underwent a thyroid or neck ultrasound examination. All subjects underwent ultrasound and SWE evaluation of mediastinal thymus by parasternal and suprasternal approach. We subdivided the subjects based on the ages as 0 to 2 months (group 1), >2 to 6 months (group 2); >6 months to 2 years (group 3), >2 to 5 years (group 4), >5 to 8 years (group 5), and greater than 8 years old (group 6).We investigated differences of mean shear wave elasticity (kPa) and shear wave velocity (m/sec) values among age groups and the association of SWE values with age, body mass index (BMI), height, and weight of the patients. RESULTS: Medians and ranges of age, height, weight, and BMI were 24 (2-84) months, 85 (55-120) cm, 12(4.55-22) kg, 15.37 (13.92-17.51) kg/m2, 11 (2.64-23.15) cc, respectively. Mean shear wave elasticity of thymus when all participants were included was 6.76±1.04 kPa. Differences of mean elasticity values among age groups and also gender groups were not statistically significant. There were highly significant negative correlations among age (r:0.3), height (r:0.26), weight (r:0.3) with elasticity and also velocity values (p<0.001). The thymus elasticity is negatively correlated with age. CONCLUSION: Quantitative evaluation of the thymus by SWE provides normative stiffness values based on age and gender groups. The thymus elasticity decreases with increased age, height and weight.

Utility of lung radiodensity ratios in diagnosis of radiolucent foreign body aspiration in children: a practical approach.

OBJECTIVE: To evaluate the utility of radiodensity ratio between lungs on chest X-ray for the diagnosis of radiolucent foreign body aspiration (FBA) in children. METHODS: X-rays of 33 patients with confirmed diagnosis of FBA by bronchoscopy were compared to 66 control patients. We divided the study group into three subgroups: symmetric (13-patients), right-oblique (RO;12-patients) and left-oblique (LO;8-patients). RESULTS: When we compared FBA-symmetric-subgroup to symmetric-control-group, FBA-RO-subgroup to RO-control-group and FBA-LO-subgroup to LO-control-group, radiodensity ratios were significantly higher in the FBA subgroups. CONCLUSION: The calculated radiodensity ratio between lungs on X-ray would be a useful and practical tool for the diagnosis of radiolucent FBA in children.

Effects of static stretching duration on muscle stiffness and blood flow in the rectus femoris in adolescents.

AIMS: To compare the effects of 2 and 5 min of passive static stretching (SS) on stiffness and blood flow in the rectus femoris in adolescent athletes using shear wave elastography (SWE) and superb microvascular imaging (SMI).Material and methods: This prospective study included 20 male athletes with median age of 14.5 (12.5-16.5) years. The subjects were divided into two groups based on the SS duration as follows: 2 min (n=10) and 5 min (n=10). At rest and after 2 and 5 min of SS, stiffness and blood flow values were compared in the rectus femoris for each group. Inter-operator reliability was also analysed. RESULTS: There was no significant difference between resting and 2 min of SS in terms of stiffness. The stiffness values decreased significantly from resting to 5 min of SS. The blood flow increased significantly from resting to 2 and 5 min of SS. Inter-operator reliability was moderate to perfect for SWE and SMI measurements (ICC: 0.52-0.83). CONCLUSIONS:  SWE and SMI can be used to acquire reliable quantitative data about muscle stiffness and blood flow in adolescents. While stiffness parameters significantly decreased from resting after only 5 min, blood flow significantly increased both after 2 and 5 min. For physical rehabilitation protocols, 5 min of SS may be chosen to reduce stiffness. For competitions, 2 min of SS may be sufficient for warm-up exercise because it increases the blood flow optimally. Five min of SS may be preferred for the cool-down exercise to enhance recovery.