Top-Down versus Bottom-Up Approach in Children Presenting with Urinary Tract Infection: Comparative Effectiveness Analysis Using RIVUR and CUTIE Data.

PURPOSE: The initial imaging approach to children with urinary tract infection (UTI) is controversial. Along with renal/bladder ultrasound, some advocate voiding cystourethrogram (VCUG), ie a bottom-up approach, while others advocate dimercaptosuccinic acid (DMSA) scan, ie a top-down approach. Comparison of these approaches is challenging. In the RIVUR/CUTIE trials, however, all subjects underwent both VCUG and DMSA scan. Our objective was to perform a comparative effectiveness analysis of the bottom-up vs top-down approach. MATERIALS AND METHODS: We simulated 1,000 hypothetical sets of 500 children using RIVUR/CUTIE data. In the top-down approach, patients underwent initial DMSA scan, and only those with renal scarring underwent VCUG. In the bottom-up approach, the initial study was VCUG. We assumed all children with vesicoureteral reflux (VUR) received continuous antibiotic prophylaxis (CAP). Outcomes included recurrent UTI, number of VCUGs and CAP exposure. We assumed a 25% VUR prevalence in children with initial UTI with sensitivity analysis using 40% VUR prevalence. RESULTS: Median age of the original RIVUR/CUTIE cohort was 12 months. First DMSA scan was performed at a median of 8.2 weeks (IQR 5-11.8) after the index UTI. In the simulated cohort, slightly higher yet statistically significantly recurrent UTI was associated with the top-down compared with the bottom-up approach (24.4% vs 18.0%, p=0.045). On the other hand, the bottom-up approach resulted in more VCUG (100% vs 2.4%, p <0.001). Top-down resulted in fewer CAP-exposed patients (25% vs 0.4%, p <0.001) and lower overall CAP exposure (5 vs 162 days/person, p <0.001). Sensitivity analysis was performed with 40% VUR prevalence with similar results. CONCLUSIONS: The top-down approach was associated with slightly higher recurrent UTI. Compared to the bottom-up approach, it significantly reduced the need for VCUG and CAP.

Safety and feasibility of breast lesion localization using magnetic seeds (Magseed): a multi-centre, open-label cohort study.

PURPOSE: Wire localization has several disadvantages, notably wire migration and difficulty scheduling the procedure close to surgery. Radioactive seed localization overcomes these disadvantages, but implementation is limited due to radiation safety requirements. Magnetic seeds potentially offer the logistical benefits and transcutaneous detection equivalence of a radioactive seed, with easier implementation. This study was designed to evaluate the feasibility and safety of using magnetic seeds for breast lesion localization. METHODS: A two-centre open-label cohort study to assess the feasibility and safety of magnetic seed (Magseed) localization of breast lesions. Magseeds were placed under radiological guidance into women having total mastectomy surgery. The primary outcome measure was seed migration distance. Secondary outcome measures included accuracy of placement, ease of transcutaneous detection, seed integrity and safety. RESULTS: Twenty-nine Magseeds were placed into the breasts of 28 patients under ultrasound guidance. There was no migration of the seeds between placement and surgery. Twenty-seven seeds were placed directly in the target lesion with the other seeds being 2 and 3 mm away. All seeds were detectable transcutaneously in all breast sizes and at all depths. There were no complications or safety issues. CONCLUSIONS: Magnetic seeds are a feasible and safe method of breast lesion localization. They can be accurately placed, demonstrate no migration in this feasibility study and are detectable in all sizes and depths of breast tissue. Now that safety and feasibility have been demonstrated, further clinical studies are required to evaluate the seed's effectiveness in wide local excision surgery.

The SNMMI and EANM practice guideline for renal scintigraphy in adults.

PURPOSE: The Society of Nuclear Medicine and Molecular Imaging (SNMMI) is an international scientific and professional organization founded in 1954 to promote the science, technology, and practical application of nuclear medicine. The European Association of Nuclear Medicine (EANM) is a professional nonprofit medical association that facilitates communication worldwide between individuals pursuing clinical and research excellence in nuclear medicine. The EANM was founded in 1985. SNMMI and EANM members are physicians, technologists, and scientists specializing in the research and practice of nuclear medicine. METHODS: The SNMMI and EANM will periodically define new guidelines for nuclear medicine practice to help advance the science of nuclear medicine and to improve the quality of service to patients throughout the world. Existing practice guidelines will be reviewed for revision or renewal, as appropriate, on their fifth anniversary, or sooner, if indicated. CONCLUSION: Each practice guideline, representing a policy statement by the SNMMI/EANM, has undergone a thorough consensus process in which it has been subjected to extensive review. The SNMMI and EANM recognize that the safe and effective use of diagnostic nuclear medicine imaging requires specific training, skills, and techniques, as described in each document. Reproduction or modification of the published practice guideline by entities not providing these services is not authorized.

The Burden of Ionizing Radiation Studies in Children with Ventricular Shunts.

OBJECTIVES: To quantify the number of shunt-related imaging studies that patients with ventricular shunts undergo and to calculate the proportion of computed tomography (CT) scans associated with a surgical intervention. STUDY DESIGN: Retrospective longitudinal cohort analysis of patients up to age 22 years with a shunt placed January 2002 through December 2003 at a pediatric hospital. Primary outcome was the number of head CT scans, shunt series radiograph, skull radiographs, nuclear medicine, and brain magnetic resonance imaging studies for 10 years following shunt placement. Secondary outcome was surgical interventions performed within 7 days of a head CT. Descriptive statistics were used for analysis. RESULTS: Patients (n = 130) followed over 10 years comprised the study cohort. The most common reasons for shunt placement were congenital hydrocephalus (30%), obstructive hydrocephalus (19%), and atraumatic hemorrhage (18%), and 97% of shunts were ventriculoperitoneal. Patients underwent a median of 8.5 head CTs, 3.0 shunt series radiographs, 1.0 skull radiographs, 0 nuclear medicine studies, and 1.0 brain magnetic resonance imaging scans over the 10 years following shunt placement. The frequency of head CT scans was greatest in the first year after shunt placement (median 2.0 CTs). Of 1411 head CTs in the cohort, 237 resulted in surgical intervention within 7 days (17%, 95% CI 15%-19%). CONCLUSIONS: Children with ventricular shunts have been exposed to large numbers of imaging studies that deliver radiation and most do not result in a surgical procedure. This suggests a need to improve the process of evaluating for ventricular shunt malfunction and minimize radiation exposure.

The EANM practice guidelines for bone scintigraphy.

PURPOSE: The radionuclide bone scan is the cornerstone of skeletal nuclear medicine imaging. Bone scintigraphy is a highly sensitive diagnostic nuclear medicine imaging technique that uses a radiotracer to evaluate the distribution of active bone formation in the skeleton related to malignant and benign disease, as well as physiological processes. METHODS: The European Association of Nuclear Medicine (EANM) has written and approved these guidelines to promote the use of nuclear medicine procedures of high quality. CONCLUSION: The present guidelines offer assistance to nuclear medicine practitioners in optimizing the diagnostic procedure and interpreting bone scintigraphy. These guidelines describe the protocols that are currently accepted and used routinely, but do not include all existing procedures. They should therefore not be taken as exclusive of other nuclear medicine modalities that can be used to obtain comparable results. It is important to remember that the resources and facilities available for patient care may vary.

10-Year experience regarding the reliability and morbidity of radio guided lymph node biopsy in penile cancer patients and the associated radiation exposure of medical staff in this procedure.

BACKGROUND: The guidelines of the European Association of Urologists (EAU), of the German Society of Nuclear Medicine (DGN), and the European Society for Medical Oncology (ESMO) recommend sentinel lymph node biopsy (SLNB) for lymph node staging in penile cancer with non-palpable inguinal lymph nodes as one diagnostic method. Despite this, the method is neither widely nor regularly applied in Germany - the same applies to many other countries, which may be due to insecurity in dealing with open radioactive tracers. This study aims to assess the reliability and morbidity of this method, as well as the associated radioactive burden for clinical staff. METHODS: Between 2006 and 2016, 34 patients with an invasive penile carcinoma and inconspicuous inguinal lymph node status underwent SLNB in 57 groins after application of a radiotracer (Tc-99 m nanocolloid). We collected the results prospectively. The reliability of the method was assessed by determining the false-negative rate. In addition, we evaluated complication rates and determined the radioactive burden for the clinical staff both pre- and intraoperatively. RESULTS: SLNB was performed in 34 patients with penile cancer with non-palpable inguinal lymph nodes in 57 groins. In two patients inguinal lymph node metastases were detected by means of SLNB. In one patient recurrent inguinal lymph node disease was found after negative SLNB in both groins. Thus, the false negative rate was 3.13 % per patient (1/32 patients) and 3.51 % per groin (2/57 groins). The morbidity rate was 2.94 % per patient (1/34 patients) and 1.75 % per groin (1/57 groins). Radiation exposure for the clinical staff during this procedure was low at a maximum of ca. four µSV per intervention. CONCLUSIONS: SLNB is a reliable method with low morbidity that is associated with a low radiation burden for clinical staff. Due to the enhanced methodological and logistic demands, this intervention should be performed in specialized centres and in an interdisciplinary approach.

[Is medical imaging iatrogenic?]. / L'imagerie médicale diagnostique est-elle latrogène ?

Imaging is an indispensable element of modern medicine but is not without risk. Low-dose irradiation due to spinal, abdominal, pelvic or cardiac radiography, and the increasing use of CT carries an additional, albeit moderate risk of cancer. Iodinated and gadolinium-containing contrast media, besides their direct toxicity, can trigger hypersensitivity and allergic-like reactions. Spinal and articular diagnostic injections can also lead to complications. This article reviews the direct iatrogenicity of diagnostic imaging and current efforts to limit it through the use of new radiological systems, lower-dose CT non ionic contrast media, and alternative imaging techniques. The authors also examine the less known but more frequent problem of indirect iatrogenesis, which is highly dependent on the quality of the imaging personnel and technique. Finally, we propose some legislative solutions to this problem.

Colonic manometry and colonic scintigraphy as a diagnostic tool for children with severe constipation.

OBJECTIVE: In adults, colonic manometry and colonic scintigraphy are both valuable studies in discriminating normal and abnormal colonic motility. The objective of this study was to compare the diagnostic yield and tolerability of colonic manometry and colonic scintigraphy in children with severe constipation. METHODS: Twenty-six children (mean age 11.4 years, 77% boys) who had received colonic manometry and colonic scintigraphy as part of a colonic motility evaluation were included. Manometry was performed as per department protocol. After swallowing a methacrylate-coated capsule containing indium-111, images were taken at 4, 24, and 48 hours, and geometric centers were calculated. Results of both tests were categorized in 3 groups: normal, abnormal function in the distal part of the colon, and colonic inertia. Cohen κ was used for the level of agreement. Patients and parents completed a questionnaire regarding their experience. RESULTS: Colonic scintigraphy showed normal transit time in 20%, delay in the distal colon in 48%, and colonic inertia in 32% of patients. Colonic manometry was normal in 40%, abnormal in the distal colon in 40%, and colonic inertia was diagnosed in 20%. The κ score was 0.34. All 5 patients with colonic inertia during manometry had a similar result by scintigraphy. Eighty-eight percent of patients preferred scintigraphy over manometry and 28% of parents preferred colonic manometry over scintigraphy. CONCLUSIONS: Colonic manometry and colonic scintigraphy have a fair agreement regarding the categorization of constipation. Scintigraphy is well tolerated in pediatric patients and may be a useful tool in the evaluation of children with severe constipation.

Appropriate and safe use of diagnostic imaging.

Risks of diagnostic imaging include cancer from radiation exposure and nephrogenic systemic fibrosis. The increase in volume of imaging between 1980 and 2006 has led to a sixfold increase in annual per capita radiation exposure. It is predicted that 2 percent of future cancers will be caused by radiation from computed tomography (CT) exposure. Gadolinium contrast media should be avoided in patients with stage 4 or 5 chronic kidney disease because of the risk of nephrogenic systemic fibrosis. Appropriate use of imaging based on guidelines for specific clinical conditions can reduce these risks. Although noncontrast CT of the head is needed to rule out bleeding in patients with suspected stroke within the first three hours of symptom onset, diffusion-weighted imaging with magnetic resonance of the head and neck is superior to CT within three to 24 hours of symptom onset. Headache merits neuroimaging in special circumstances only. Sestamibi radioisotope has less radiation than thallium for myocardial perfusion imaging. Use of intravenous contrast media with abdominopelvic CT significantly increases the diagnostic accuracy for appendicitis. Cholescintigraphy has better discrimination to diagnose acute cholecystitis than CT in patients with equivocal ultrasonography results. Limited three-view intravenous urography is recommended in pregnancy to evaluate urolithiasis if initial ultrasonography findings are negative or equivocal. Given that many asymptomatic adults have abnormal findings on lumbar spine magnetic resonance imaging, this modality generally should not be performed for nonspecific chronic low back pain in the absence of red flags. Whole body scanning is not supported by current evidence.

Radiodiagnostic imaging in pregnancy and the risk of childhood malignancy: raising the bar.

Eduardo Franco and Guy-Anne Turgeon discuss new findings from Joel Ray and colleagues on the cancer risk following prenatal exposure to radiodiagnostic imaging, and where new research needs to be focused.

Major radiodiagnostic imaging in pregnancy and the risk of childhood malignancy: a population-based cohort study in Ontario.

BACKGROUND: The association between fetal exposure to major radiodiagnostic testing in pregnancy-computed tomography (CT) and radionuclide imaging-and the risk of childhood cancer is not established. METHODS AND FINDINGS: We completed a population-based study of 1.8 million maternal-child pairs in the province of Ontario, from 1991 to 2008. We used Ontario's universal health care-linked administrative databases to identify all term obstetrical deliveries and newborn records, inpatient and outpatient major radiodiagnostic services, as well as all children with a malignancy after birth. There were 5,590 mothers exposed to major radiodiagnostic testing in pregnancy (3.0 per 1,000) and 1,829,927 mothers not exposed. The rate of radiodiagnostic testing increased from 1.1 to 6.3 per 1,000 pregnancies over the study period; about 73% of tests were CT scans. After a median duration of follow-up of 8.9 years, four childhood cancers arose in the exposed group (1.13 per 10,000 person-years) and 2,539 cancers in the unexposed group (1.56 per 10,000 person-years), a crude hazard ratio of 0.69 (95% confidence interval 0.26-1.82). After adjusting for maternal age, income quintile, urban status, and maternal cancer, as well as infant sex, chromosomal or congenital anomalies, and major radiodiagnostic test exposure after birth, the risk was essentially unchanged (hazard ratio 0.68, 95% confidence interval 0.25-1.80). CONCLUSIONS: Although major radiodiagnostic testing is now performed in about 1 in 160 pregnancies in Ontario, the absolute annual risk of childhood malignancy following exposure in utero remains about 1 in 10,000. Since the upper confidence limit of the relative risk of malignancy may be as high as 1.8 times that of an unexposed pregnancy, we cannot exclude the possibility that fetal exposure to CT or radionuclide imaging is carcinogenic.

Predictive factors for acute renal cortical scintigraphic lesion and ultimate scar formation in children with first febrile urinary tract infection.

PURPOSE: We assessed predictive factors for acute renal cortical scintigraphic lesion and ultimate scar formation in children with a first febrile urinary tract infection. MATERIALS AND METHODS: A total of 89 girls and 138 boys with a first febrile urinary tract infection were included in the study. We analyzed radiological (ultrasound, dimercapto-succinic acid scintigraphy, voiding cystourethrogram), clinical (age, gender, peak fever, therapeutic delay time) and laboratory (complete blood count with differential count, absolute neutrophil count, blood urea nitrogen, creatinine, urinalysis, Gram's stain, culture, C-reactive protein, erythrocyte sedimentation rate) variables. Dimercapto-succinic acid scintigraphy was performed within 5 days and at 6 months after diagnosis of urinary tract infection. Voiding cystourethrogram was performed after the acute phase of the urinary tract infection. Predictive factors for acute scintigraphic lesion and ultimate scar formation were assessed using logistic regression analysis. RESULTS: Of 227 patients enrolled 140 had a refluxing and 87 a nonrefluxing urinary tract infection. On logistic regression analysis therapeutic delay time (p = 0.001) and presence of reflux (p = 0.011) were predictive of acute scintigraphic lesion and ultimate scar formation (p = 0.001 and p = 0.0001, respectively) in children with a first febrile urinary tract infection. CONCLUSIONS: Since vesicoureteral reflux is the common risk factor for acute scintigraphic lesion and ultimate scar formation, voiding cystourethrogram must be considered as an initial study in patients with acute febrile urinary tract infection.

Full report on a survey of adverse reactions to radiopharmaceuticals from 1975 to 2017 in Japan.

OBJECTIVE: This pharmacovigilance-based survey was aimed at determining the prevalence of, and association between, radiopharmaceuticals and adverse reactions to radiopharmaceuticals from 1975 to 2017 in Japan. METHODS: The Subcommittee for Safety Issues of Radiopharmaceuticals of the Japan Radioisotope Association's Medical Science and Pharmaceutical Committee mailed a form for reporting adverse reactions to radiopharmaceuticals to all institutes performing nuclear medicine examinations in Japan. This investigation included adverse reactions to diagnostic radiopharmaceuticals labeled with both single-photon- and positron-emitting radionuclides and therapeutic sodium iodide labeled with 131I. Each institute returned the reporting form to the subcommittee each time an adverse reaction occurred. RESULTS: Replies were obtained from 75% of the institutions. In total, 1099 adverse reactions were reported from 46,645,580 radiopharmaceutical administrations, giving a prevalence of 2.4 adverse reactions per 100,000 administrations (95% confidence interval 2.2-2.5). Adverse reactions were most frequently observed for 131I-iodomethylnorcholesterol (230.1/105 administrations), followed by 131I-HSA (76.3/105 administrations), 131I-sodium iodohippurate (31.2/105 administrations), and 99mTc-DTPA (12.0/105 administrations). Comparison of adverse reactions between before and after 1997 revealed that prevalence dropped from 3.7/105 administrations (95% confidence interval 3.5-4.1) to 1.5/105 administrations (95% confidence interval 1.4-1.6). During the study period, vasovagal reactions accounted for 50.3% of adverse reactions, fever for 7.5%, allergic reactions for 25.7%, and other for 16.5%; 3.7% of all adverse reactions were considered severe but none were lethal. A definite, probable, possible, less likely, and uncertain causal relationship with radiopharmaceuticals was observed in 13.1%, 33.7%, 39.9%, 6.2%, and 7.1% of adverse reactions, respectively. CONCLUSIONS: These results suggest that nuclear medicine staff must be aware of the possibility of adverse reactions from radiopharmaceuticals, despite their rarity.

[Management of hemodialysis patient subject to medical-nuclear investigation].

In recent years imaging techniques that use radionuclides have become more and more clinically relevant as they can provide functional information for specific anatomical districts. This has also involved nephrology, where radionuclides are used to study patients with different degrees of renal function failure up to terminal uremia. Although chronic kidney disease, and dialysis in particular, may affect the distribution and the elimination of radiopharmaceuticals, to date there are no consistent data on the risks associated with their use in this clinical context. In addition to the lack of data on the safety of radio-exposure in dialysis patients, there is also a shortage of information concerning the risk for healthcare staff involved in conducting the dialysis sessions performed after a nuclear test. This study, performed on 29 uremic patients who underwent hemodialysis immediately after a scintigraphic examination, assessed the extent of radio-contamination of the staff and of hemodialysis devices such as monitor, kits and dialysate. The data collected has been used to quantify the radiological risk in dialysis after the exposure to the most common radionuclides.

Barriers and pathways to informed consent for ionising radiation imaging examinations: A qualitative study.

INTRODUCTION: Informed consent for ionising radiation medical imaging examinations represents a recent change to medical imaging practice. This practice has not had a definitive and authoritative integration into clinical practice, and lack of direction has caused many health care professionals to be unsure of an appropriate consent methodology. Consent practices have been undertaken inconsistently and sometimes poorly. This research sought to investigate what barriers exist to meaningful informed consent, and what pathways are suggested to overcome these barriers. These views are then discussed in the context of practical health care consent practices. METHODS: A semi-structured interview explored the views of radiographers and radiologists on the practice of disclosing the ionising radiation risk of a clinical medical imaging examination. Qualitative data was analysed using a nominal method of quantitative transformation. Responses were reviewed, and a set of definitive themes constructed. Participants considered the influences, logistics and barriers to the informed consent process. Participants were then asked what pathways might be developed that would improve the process. RESULTS: Twenty-one (21) radiographer participants and nine (9) radiologists were interviewed. The barriers to consent identified issues of time constraints, lack of a unified message, and patient presentations. Pathways suggested included limiting the scope of the consent practice, sharing the consent responsibility, and formulation of definitive consent guidelines. CONCLUSION: A unified, definitive series of guidelines for informed consent for ionising radiation examinations would alleviate many of the identified barriers. Having the consent process consistently begin with the referring doctor would facilitate more meaningful consent.