Bone scintigraphy with SPECT/CT in paediatric patients with neck and back pain in comparison with other imaging modalities: the experience of a tertiary paediatric referral centre.

OBJECTIVE: Retrospective review of the additional clinical value provided by single photon emission computed tomography-computed tomography (SPECT/CT) in children and adolescents with back pain. METHODS: A total of 207 consecutive paediatric patients (94 males, 113 females, age range 5-17 years, median age 14 years) were reviewed after referral to the spinal surgery clinic of a paediatric teaching hospital between November 2009 and February 2021. All patients had either only whole spine X-rays or whole spine x-rays and MRI, along with bone scan with planar whole-body images and SPECT/CT (with spot views of painful area). RESULTS: X-ray identified the pain generator in 23 of 177 (13.0%) cases. MRI identified the pain generator in 49 of 165 (29.7%) cases. SPECT/CT reported relevant positive findings which identified the pain generator in 107 of 185 (57.8%) cases. SPECT/CT changed patients' management in 72 of 185 (38.9%) cases. SPECT/CT was most effective at identifying the pain generator in cases of facet arthropathy, previous vertebral fracture and patients with previous deformity correction, where the pain generator was identified in 76.5% (13 of 17), 71.4% (5 of 7) and 63.4% (26 of 41) of cases, respectively. CT settings were adjusted to minimise the radiation burden (50 mAs/80kVp under 8 years, 24 mAs/110 kVp over 8 years). CONCLUSION: The role of SPECT/CT in diagnosing back pain is justified in selected paediatric patients, particularly with diagnostic uncertainty using conventional imaging. The CT component of the SPECT/CT study produced a lower radiation dose than conventional CT imaging, whilst producing bone images of diagnostic quality.

Small Bowel Transit Scintigraphy in Children With Pediatric Intestinal Pseudo-Obstruction.

INTRODUCTION: Objective evidence of small intestinal dysmotility is a key criterion for the diagnosis of pediatric intestinal pseudo-obstruction (PIPO). Small bowel scintigraphy (SBS) allows for objective measurement of small bowel transit (SBT), but limited data are available in children. We aimed to evaluate the utility of SBS in children suspected of gastrointestinal dysmotility. METHODS: Patients undergoing gastric emptying studies for suspected foregut dysmotility, including PIPO, from 2016 to 2022 at 2 tertiary children's hospitals were recruited to an extended protocol of gastric emptying studies to allow for assessment of SBT. PIPO was classified based on antroduodenal manometry (ADM). SBT was compared between PIPO and non-PIPO patients. Scintigraphic parameters were assessed and correlated against ADM scores. RESULTS: Fifty-nine patients (16 PIPO and 43 non-PIPO diagnoses) were included. SBS was performed with liquid and solid meals in 40 and 26 patients, respectively. As compared to the non-PIPO group, PIPO patients had a significantly lower median percentage of colonic filling at 6 hours, with both liquid (48% vs 83%) and solid tests (5% vs 65%). SBT in PIPO patients with myopathic involvement was significantly slower than in patients with neuropathic PIPO, both for liquid and solid meal. A significant correlation was found between solid SBT and ADM scores (r = -0.638, P = 0.036). DISCUSSION: SBS provides a practically feasible assessment of small intestinal motility. It shows a potential utility to help diagnose and characterize PIPO. SBS seems most discriminative in PIPO patients with myopathic involvement. Studies in a larger pediatric population and across different ages are required.

Shockwaves and the Rolling Stones: An Overview of Pediatric Stone Disease.

Urinary stone disease is a common problem in adults, with an estimated 10% to 20% lifetime risk of developing a stone and an annual incidence of almost 1%. In contrast, in children, even though the incidence appears to be increasing, urinary tract stones are a rare problem, with an estimated incidence of approximately 5 to 36 per 100,000 children. Consequently, typical complications of rare diseases, such as delayed diagnosis, lack of awareness, and specialist knowledge, as well as difficulties accessing specific treatments also affect children with stone disease. Indeed, because stone disease is such a common problem in adults, frequently, it is adult practitioners who will first be asked to manage affected children. Yet, there are unique aspects to pediatric urolithiasis such that treatment practices common in adults cannot necessarily be transferred to children. Here, we review the epidemiology, etiology, presentation, investigation, and management of pediatric stone disease; we highlight those aspects that separate its management from that in adults and make a case for a specialized, multidisciplinary approach to pediatric stone disease.

Transpyloric propagation and liquid gastric emptying in children with foregut dysmotility.

BACKGROUND/OBJECTIVES: Gastric emptying (GE) requires precise antropyloroduodenal coordination for effective transpyloric flow, the mechanisms of which are still unclear. We aimed to correlate gastric antral function assessed by antroduodenal manometry (ADM) with GE scintigraphy (GES) for liquid feeds in children with suspected gastrointestinal dysmotility. METHODS: Children who underwent both ADM and GES over a five-year period were reviewed. ADM tracings were re-analyzed to assess antral frequency, amplitude, and motility index (MI) pre-prandially and postprandially. Transpyloric propagation (TPP) was defined as antegrade propagated antral activity preceding duodenal phase III of the migrating motor complex (MMC). TPP was defined as "poor" if occurring in <50% of all presented duodenal phases III. For GES, regions of interest over the whole stomach, fundus, and antrum were drawn to calculate GE half-time (GE-T1/2 ) and retention rate (RR) in each region at 1 and 2 h. RESULTS: Forty-seven children (median age: 7.0 years) were included. Twenty-two had PIPO, 14 functional GI disorders, and 11 gastroparesis. Children with poor TPP had longer GE-T1/2 (113.0 vs 66.5 min, p = 0.028), higher RR of the whole stomach and fundus at 1 h (79.5% vs 63.5%, p = 0.038; 60.0% vs 41.0%, p = 0.022, respectively) and 2 h (51.0% vs 10.5%, p = 0.005; 36.0% vs 6.5%, p = 0.004, respectively). The pre-prandial antral amplitude of contractions inversely correlated with GE-T1/2 , RR of the whole stomach, and fundus at 2 h. CONCLUSIONS: TPP during phase III of the MMC correlated with gastric emptying of liquid and its assessment on ADM might predict abnormalities in postprandial gastric function.

Abdominal US in Pediatric Inflammatory Multisystem Syndrome Associated with SARS-CoV-2 (PIMS-TS).

Background Children with pediatric inflammatory syndrome temporally associated with SARS-CoV-2 (PIMS-TS), also known as multisystem inflammatory syndrome in children, present with abdominal pain among other nonspecific symptoms. Although initial imaging features of PIMS-TS have been reported, the duration of sonographic features remains unknown. Purpose To describe the abdominal US features of PIMS-TS at initial presentation and follow-up. Materials and Methods A retrospective review of children and young adults presenting with clinical features suspicious for PIMS-TS between April 2020 and June 2021 was carried out. US features were documented and reviewed at initial presentation and follow-up. Descriptive statistics were used and interobserver variability was calculated. Results Of 140 children and young adults presenting with suspected PIMS-TS, 120 had confirmed PIMS-TS (median age, 9 years; interquartile range, 7-12 years; 65 male patients) and 102 underwent abdominal US at presentation. PIMS-TS was present as a single abnormality in 109 of the 120 patients (91%) and abdominal symptoms were present in 104 of the 109 (95%). US examinations were abnormal in 86 of 102 patients (84%), with ascites being the most common abnormality in 65 (64%; 95% CI: 54, 73). Bowel wall thickening was present at US in 14 of the 102 patients (14%; 95% CI: 7, 20) and mesenteric inflammation was present in 16 (16%; 95% CI: 9, 23); all of these patients presented with abdominal symptoms. Among the patients with bowel wall thickening, the distal and terminal ileum were most involved (eight of 14 patients, 57%). Abdominal symptoms decreased to seven of 56 patients (13%) in those followed up at 6 months. Thirty-eight patients underwent follow-up US, and the presence of bowel inflammation had decreased to three of 27 patients (11%; 95% CI: -1, 23) in those followed up for less than 2 months and 0 of 17 (0%) in those followed up for more than 2 months. Conclusion Of 102 patients with pediatric inflammatory multisystem syndrome temporally associated with SARS-CoV-2 who underwent US at presentation, 14 (14%) had abdominal US findings of bowel inflammation and 16 (16%) had mesenteric edema. All US abnormalities resolved after 2 months. © RSNA, 2022 Online supplemental material is available for this article. See also the editorial by van Rijn and Pajkrt in this issue.

Bone scan with SPECT/CT in children with complex foot and ankle pain: Initial experience of a paediatric tertiary referral centre.

PURPOSE: This study was designed to review the diagnostic yield of single photon emission computed tomography-computed tomography (SPECT/CT) in children with complex foot/ankle pain. METHODS: We reviewed the records of 33 patients with complex foot and ankle pain referred for SPECT/CT (36 scans) performed between 1st September 2009 to 30th September 2019. All patients had foot and ankle radiographs and 18 out of 33 patients had undergone magnetic resonance imaging (MRI) prior to SPECT/CT. The diagnostic contribution of SPECT/CT was established at the time of the scan during a multi-disciplinary team meeting. RESULTS: The patients' mean age was 13.4 years (range six to 16.5 years) and 58% were female. In total, 18 patients had undergone previous surgical treatment. SPECT/CT was found to have decisive clinical value compared with radiographs and CT/MRI in 28 out of 36 cases. In ten patients it prompted surgical management (coalition excision, arthrodesis), in seven patients it redirected conservative management, in six patients it excluded other pathology and in five patients it showed additional/unexpected focal areas of mechanical stress, thus avoiding surgery. When compared with MRI, SPECT/CT added further clinical information in 13 out of 18 cases. SPECT/CT added decisive clinical value in five out of five patients with accessory ossicles, eight out of nine patients with tarsal coalition, five out of seven patients with surgically treated Congenital Talipes Equinovarus (CTEV) and four out of five patients with neuromuscular feet. In eight out of 36 cases SPECT/CT confirmed the diagnosis without adding significant information. CONCLUSIONS: SPECT/CT can identify foci of active mechanical stress at cortical bone level in children with unexplained complex foot and ankle pain, particularly in the multiply operated foot, accessory ossicles and tarsal coalitions. LEVEL OF EVIDENCE: IV.

A comparison of thyroid blockade strategies in paediatric 123I-meta-iodobenzylguanidine scanning: a dual centre study.

OBJECTIVE: The aim of this study was to evaluate three thyroid blockade regimes to determine which protocol provides the optimal level of thyroidal protection for paediatric 123-I-meta-iodobenzylguanidine (mIBG) imaging and estimate the relative radiation dose inferred from unbound radioiodine. METHODS: A total of 231 patients were retrospectively evaluated for thyroid uptake and categorised into five subgroups depending upon the protocol of thyroid blockade received. Efficacy of thyroid blockade was established by visual scoring and image quantitation with comparison against a control group. RESULTS: Visual Likert scale responses were subjected to the Mann-Whitney U and Kruskal-Wallis tests, respectively. Statistical significance was reached for observed thyroid uptake in potassium perchlorate recipients (U = 1107, P = 0.001). No statistically significant difference was observed in thyroid uptake for iohexol blockade (U = 176, P = 0.71) or potassium iodate blockade despite variations in iodate dosage and duration (χ(2) = 0.203, P = 0.93). The analyses were repeated for the image quantitation data. A statistically significantly higher absorbed thyroid dose was observed using potassium perchlorate blockade compared with the control group (U = 719, P = 0.001). The Mann-Whitney U did not reach statistical significance in absorbed thyroid dose for iohexol blockade (U = 126, P = 0.209, r = -0.13). The Kruskal-Wallis test, conducted across the potassium iodate groups, did not reach statistical significance (χ(2) = 0.513, P = 0.774). The median absorbed thyroid dose across the iodate groups ranged from 3.58 to 3.91 mGy indicating comparable blockade effectiveness for single-dose potassium iodate. CONCLUSION: Potassium iodate blockade is more efficacious compared with potassium perchlorate within the cohort observed. Both visual and quantitative data indicate that potassium iodate given at 30-60 min before I-mIBG injection provides comparable blockade effectiveness to lengthier administrations, suggesting that a single dose is well tolerated and practical.

Paediatric nuclear medicine imaging.

Background: Nuclear medicine imaging explores tissue viability and function by using radiotracers that are taken up at cellular level with different mechanism. This imaging technique can also be used to assess blood flow and transit through tubular organs. Nuclear medicine imaging has been used in paediatrics for decades and this field is continuously evolving. Sources of data: The data presented comes from clinical experience and some milestone papers on the subject. Areas of agreement: Nuclear medicine imaging is well-established in paediatric nephro-urology in the context of urinary tract infection, ante-natally diagnosed hydronephrosis and other congenital renal anomalies. Also, in paediatric oncology, I-123-meta-iodobenzyl-guanidine has a key role in the management of children with neuroblastic tumours. Bone scintigraphy is still highly valuable to localize the source of symptoms in children and adolescents with bone pain when other imaging techniques have failed. Thyroid scintigraphy in neonates with congenital hypothyroidism is the most accurate imaging technique to confirm the presence of ectopic functioning thyroid tissue. Areas of controversy: Radionuclide transit studies of the gastro-intestinal tract are potentially useful in suspected gastroparesis or small bowel or colonic dysmotility. However, until now a standardized protocol and a validated normal range have not been agreed, and more work is necessary. Research is ongoing on whether magnetic resonance imaging (MRI), with its great advantage of great anatomical detail and no ionizing radiations, can replace nuclear medicine imaging in some clinical context. On the other hand, access to MRI is often difficult in many district general hospitals and general anaesthesia is frequently required, thus adding to the complexity of the examination. Growing points: Patients with bone pain and no cause for it demonstrated on MRI can benefit from bone scintigraphy with single photon emission tomography and low-dose computed tomography. This technique can identify areas of mechanical stress at cortical bone level, difficult to demonstrate on MRI, which can act as pain generators. Positron emission tomography (PET) is being tested in the staging, response assessment and at the end of treatment of several paediatric malignancies. PET is becoming more widely utilized in neurology in the pre-surgical assessment of some children with drug resistant epilepsy. Areas timely for developing research: The use of PET/MRI scanners is very attractive as it combines benefits of MR imaging with the assessment of cellular viability and metabolism with PET in one examination. This imaging technique will allow important research on tumour in-vivo metabolism (possible applications include lymphomas, neuroblastomas, malignant germ cell tumours andbrain tumours), with the aim of offering a personalized biological profile of the tumour in a particular patient. Ground-breaking research is also envisaged in neurosciences, especially in epilepsy, using PET tracers that would enable a better identification of the epileptogenic focus, and in psychiatry, with the use of radiolabeled neurotransmitters. In paediatric nephro-urology, the identification of the asymptomatic child with ante-natally diagnosed hydronephrosis at risk of losing renal parenchymal function if left untreated is another area of active research involving radionuclide renography.

Nuclear Medicine in Pediatric Nephro-Urology: An Overview.

In the context of ante-natally diagnosed hydronephrosis, the vast majority of children with a dilated renal pelvis do not need any surgical treatment, as the dilatation resolves spontaneously with time. Slow drainage demonstrated at Tc-99m-mercaptoacetyltriglycine (MAG3) renography does not necessarily mean obstruction. Obstruction is defined as resistance to urinary outflow with urinary stasis at the level of the pelvic-ureteric junction (PUJ) which, if left untreated, will damage the kidney. Unfortunately this definition is retrospective and not clinically helpful. Therefore, the identification of the kidney at risk of losing function in an asymptomatic patient is a major research goal. In the context of renovascular hypertension a DMSA scan can be useful before and after revascularisation procedures (angioplasty or surgery) to assess for gain in kidney function. Renal calculi are increasingly frequent in children. Whilst the vast majority of patients with renal stones do not need functional imaging, DMSA scans with SPECT and a low dose limited CT can be very helpful in the case of complex renal calculi. Congenital renal anomalies such as duplex kidneys, horseshoe kidneys, crossed-fused kidneys and multi-cystic dysplastic kidneys greatly benefit from functional imaging to identify regional parenchymal function, thus directing further management. Positron emission tomography (PET) is being actively tested in genito-urinary malignancies. Encouraging initial reports suggest that F-18-fluorodeoxyglucose (FDG) PET is more sensitive than CT in the assessment of lymph nodal metastases in patients with genito-urinary sarcomas; an increased sensitivity in comparison to isotope bone scans for skeletal metastatic disease has also been reported. Further evaluation is necessary, especially with the promising advent of PET/MRI scanners. Nuclear Medicine in paediatric nephro-urology has stood the test of time and is opening up to new exciting developments.

Flushing of the vagina and the prepuce-a cause for contaminated urine cultures in children.

OBJECTIVE: An uncontaminated urine culture is a prerequisite for the diagnosis of a urinary tract infection. However, this may be difficult to obtain in small children. We have studied the frequency of ballooning of the prepuce in non-circumcised boys and vaginal reflux in girls during voiding as a possible cause of contaminated urine cultures. METHODS: All micturating cystourethrograms (MCUG) performed in our institution over the last 5 years in children aged 0-15 years were reviewed retrospectively for ballooning of the foreskin or vaginal reflux as a potential source of bacterial contamination. The voiding pictures were routinely done with the catheter present for the first voiding cycle and then removed on the second void. RESULTS: A total of 526 children (77.4 % boys, 22.6 % girls) were eligible for the study. Ballooning of the foreskin was identified on the micturition pictures of 115 (38 %) boys, with the frequency significantly higher in boys aged <12 months [odds ratio (OR) 4.1; 95 % confidence interval (CI) 2.1-7.3)] and boys with vesicoureteral reflux (OR 1.6; 95 % CI 1.06-2.4). Seventeen girls (14.3 %) showed vaginal reflux. No correlation with age or vesicoureteral reflux was found in the girls. CONCLUSION: Ballooning of the prepuce or vaginal reflux was seen on a fluoroscopic MCUG in a large proportion of children during their voiding. This normal phenomenon might cause contaminated urine cultures when the urine is obtained by bag or clean catch.

Reduced risk of pulmonary emboli in children treated with long-term parenteral nutrition.

BACKGROUND & AIMS: Pulmonary embolism (PE) is a complication of parenteral nutrition (PN) with a prevalence of 35% in children. In 2003 new intravenous lipid emulsions (ILEs) with MCT, olive and/or fish oil in addition to soybean oil were introduced. The aim was to compare the incidence of PE before and after introduction. METHODS: 327 surveillance ventilation-perfusion (V/Q) scintigraphies from 68 children aged 0.3-15 years, treated with PN from 1993 to 2010, were retrospectively reviewed. Rate of PE/1000 central venous catheter (CVC) days, number of children with PE pre- and post-introduction of ILEs were compared. Multivariate analyses were performed for risk factors. RESULTS: Twenty-two (32%) children (19/42 before 2003 and 3/26 after 2003, p = 0.007) had at least one episode of PE. Thirty seven (11%) episodes of PE were detected accounting for a mean of 0.2/1000 CVC days prior to 2003 and 0.05/1000 CVC days after 2003, p = 0.04. Regression analysis indicated that higher content of ILE/infusion (p = 0.045) and frequency of ILE of >3 nights/week were associated with more PE (p = 0.001). New ILEs were associated with lower risk (p = 0.003). CONCLUSION: With a four-fold fall in incidence with new ILE, PE remains a complication. We recommend 12-18 monthly surveillance with lung perfusion scan and anticoagulants if PE is diagnosed.

Functional lung assessment with radionuclides in paediatric respiratory diseases: a useful, underutilized test in nuclear medicine?

Ventilation/perfusion (VQ) studies have a much wider application range in paediatrics compared with the adult population and provide a noninvasive way to evaluate lung function. VQ studies can be used to determine lung function in patients with primary lung, vascular, cardiac and skeletal pathology. We have examined the literature regarding the current indications of the VQ scan in children. We report a summary of the current indications of VQ scans in paediatrics corroborated by our own experience as a paediatric tertiary referral centre.

Imaging chronic renal disease and renal transplant in children.

At Great Ormond Street Hospital we have the highest number of paediatric renal transplant patients in Europe, taking cases from across the United Kingdom and abroad. Our caseload includes many children with rare complicating medical problems and chronic renal failure related morbidity. This review aims to provide an overview of our experience of imaging children with chronic renal failure and transplants.