Faculty Bibliography

OBJECTIVE:Juvenile idiopathic arthritis (JIA) frequently affects the temporomandibular joints (TMJs) and is often undetected by history, examination, and plain imaging. Qualitative assessment of gadolinium-enhanced magnetic resonance images (MRIs) is currently the standard for diagnosis of TMJ synovitis associated with JIA. The purpose of this study is to apply a quantitative analysis of synovial enhancement to MRIs of patients with and without JIA to establish a disease threshold and sensitivity and specificity for the technique. METHODS:ROI of the longus capitis muscle was calculated. Receiver operating characteristic curves were used to determine the sensitivity and specificity. The inter- and intraexaminer reliability was evaluated with Bland-Altman plots and 2-way mixed, absolute agreement intraclass correlation coefficients. RESULTS:There were 187 and 142 TMJs included in the JIA and control groups, respectively. An ER threshold of 1.55 had a sensitivity and specificity for detecting synovitis of 91% and 96%, respectively. The inter- and intraexaminer reliability was excellent. CONCLUSION:Calculating a ratio of pixel intensity between the TMJ synovium and the longus capitis muscle is a reliable way to quantify synovial enhancement. An ER of 1.55 differentiates normal TMJs from those affected by inflammatory arthritis.

BACKGROUND:Numerous bone age estimation techniques exist, but little is known about what methods radiologists use in clinical practice. OBJECTIVE:To determine which methods pediatric radiologists use to assess bone age in children, and their confidence in these methods. MATERIALS AND METHODS/METHODS:Society for Pediatric Radiology (SPR) members were invited to complete an online survey regarding bone age assessment. Respondents were asked to identify the methods used and their confidence with their technique for the following groups: Infants (<1 year old), 1- to 3-year-olds and 3- to 18-year-olds. RESULTS:Of the 937 SPR members invited, 441 responded (47%). For infants, 70% of respondents use the hand/wrist method of Greulich and Pyle, 27% use a hemiskeleton method (e.g., Sontag or Elgenmark), and 14.4% use the knee method of Pyle and Hoerr. Of these respondents, 34% were not confident with their technique. For 1- to 3-year-olds, 86% used Greulich and Pyle, and 19% used a hemiskeleton method; 21% were not confident with their technique in this age group. For 3- to 18-year-olds, 97% used Greulich and Pyle, and only 6% of respondents were not confident with their technique in this category. A logistic regression analysis demonstrated that the chronological age of the patient had the greatest impact on reader confidence, with the odds ratios for confidence being 4 times greater in the 3- to 18-year-olds category compared to the younger groups. CONCLUSION/CONCLUSIONS:For children older than 3 years, the majority of pediatric radiologists are very confident in their use of Greulich and Pyle for bone age assessment. However a variety of methodologies are used when assessing bone age in infants and younger children, and pediatric radiologists are less confident assessing bone age in these children. This survey highlights the need for a consensus protocol on bone age assessment of younger children and infants that provides readers with a higher degree of confidence.

BACKGROUND:Bone age in infants (<1 year old) is generally estimated using hand/wrist or knee radiographs, or by counting ossification centers. The accuracy and reproducibility of these techniques are largely unknown. OBJECTIVE:To develop and validate an infant bone age estimation technique using fibular shaft length and compare it to conventional methods. MATERIALS AND METHODS/METHODS:We retrospectively reviewed negative skeletal surveys of 247 term-born low-risk-of-abuse infants (no persistent child protection team concerns) from July 2005 to February 2013, and randomized them into two datasets: (1) model development (n = 123) and (2) model testing (n = 124). Three pediatric radiologists measured all fibular shaft lengths. An ordinary linear regression model was fitted to dataset 1, and the model was evaluated using dataset 2. Readers also estimated infant bone ages in dataset 2 using (1) the hemiskeleton method of Sontag, (2) the hemiskeleton method of Elgenmark, (3) the hand/wrist atlas of Greulich and Pyle, and (4) the knee atlas of Pyle and Hoerr. For validation, we selected lower-extremity radiographs of 114 normal infants with no suspicion of abuse. Readers measured the fibulas and also estimated bone ages using the knee atlas. Bone age estimates from the proposed method were compared to the other methods. RESULTS:The proposed method outperformed all other methods in accuracy and reproducibility. Its accuracy was similar for the testing and validating datasets, with root-mean-square error of 36 days and 37 days; mean absolute error of 28 days and 31 days; and error variability of 22 days and 20 days, respectively. CONCLUSION/CONCLUSIONS:This study provides strong support for an infant bone age estimation technique based on fibular shaft length as a more accurate alternative to conventional methods.

PURPOSE/OBJECTIVE:We examine the performance of pure model-based iterative reconstruction with reduced-dose CT in follow-up of patients with early-stage testicular cancer. METHODS:Sixteen patients (mean age 35.6 ± 7.4 years) with stage I or II testicular cancer underwent conventional dose (CD) and low-dose (LD) CT acquisition during CT surveillance. LD data was reconstructed with model-based iterative reconstruction (LD-MBIR). Datasets were objectively and subjectively analysed at 8 anatomical levels. Two blinded clinical reads were compared to gold-standard assessment for diagnostic accuracy. RESULTS:Mean radiation dose reduction of 67.1% was recorded. Mean dose measurements for LD-MBIR were: thorax - 66 ± 11 mGy cm (DLP), 1.0 ± 0.2 mSv (ED), 2.0 ± 0.4 mGy (SSDE); abdominopelvic - 128 ± 38 mGy cm (DLP), 1.9 ± 0.6 mSv (ED), 3.0 ± 0.6 mGy (SSDE). Objective noise and signal-to-noise ratio values were comparable between the CD and LD-MBIR images. LD-MBIR images were superior (p < 0.001) with regard to subjective noise, streak artefact, 2-plane contrast resolution, 2-plane spatial resolution and diagnostic acceptability. All patients were correctly categorised as positive, indeterminate or negative for metastatic disease by 2 readers on LD-MBIR and CD datasets. CONCLUSIONS:MBIR facilitated a 67% reduction in radiation dose whilst producing images that were comparable or superior to conventional dose studies without loss of diagnostic utility.

BACKGROUND:Despite limitations of routine methods, Clinical Practice Guidelines support the assessment of bone mineral density (BMD) and vascular calcification in renal transplant recipients. Changes in fat mass also occur post-transplantation, although they are traditionally difficult to measure accurately. We report the feasibility, convenience and accuracy of measuring the above 3 parameters using a novel CT protocol. METHODS:We conducted a cross-sectional study of 64 first renal allograft recipients (eGFR > 30 ml/min/1.73 m(2)). Quantitative CT (QCT) BMD analysis was conducted using CT lumbar spine (GE Medical Systems Lightspeed VCT & Mindways QCT Pro Bone Mineral Densitometry System Version 4.2.3) to calculate spinal volumetric BMD and compared with standard DXA calculated areal BMD at the spine, hip and distal forearm. Abdominal aortic calcification was assessed by semi-quantitative Aortic Calcification Index (ACI) method and compared with lateral lumbar x-ray Kappuila score and pulse wave velocity (PWV). Visceral and subcutaneous adipose tissue volume (Osirix 16 Ver 3.7.1) was compared with BMI. RESULTS:Participants were 61 % male, had a mean age of 47 years, median ESKD duration of 5.4 years and a mean eGFR of 54 ml/min. iDXA median T-score at proximal femur was -1.2 and at lumbar spine was -0.2. Median QCT Trabecular T-score at lumbar spine was -1.2. The percent of subjects with a T-score of < 2.5 by site and method was DXA Proximal Femur: 7 %, DXA distal radius: 17 %, DXA spine: 9 %, QCT (American College of Radiology cutoffs): 9 %. CT derived ACI correlated with PWV (r = 0.29, p = 0.02), pulse wave pressure (r = 0.51, p < 0.001), QCT Trabecular (-0.31, p = 0.01) and cortical volumetric BMD and history of cardiovascular events (Mann-Whitney U, p = 0.02). Both visceral and subcutaneous adipose tissue correlated with BMI (r = 0.63 & 0.64, p < 0.001). CONCLUSIONS:Single CT scan triple assessment of BMD, vascular calcification and body composition is an efficient, accurate and convenient method of risk factor monitoring post renal transplantation.

BACKGROUND:The clinical significance of a pulmonary nodule that is detected incidentally on CT studies in children is unknown. In addition, there is limited information regarding the management of incidentally detected pulmonary nodules discovered on abdominal CT studies in children. OBJECTIVE:The purpose of this study was to investigate the clinical significance of incidental pulmonary nodules detected on abdominal CT studies in children. MATERIALS AND METHODS/METHODS:This was a retrospective study performed following institutional review board approval. Abdominal CT reports in patients younger than 18 years of age from July 2004 to June 2011 were reviewed for the terms "nodule," "nodular" or "mass" in reference to the lung bases. The study population included those pediatric patients in whom pulmonary nodules were initially detected on abdominal CT studies. The largest pulmonary nodules detected on CT studies were evaluated for their features (size, shape, margin, attenuation, location, and presence of calcification and cavitation). Follow-up CT studies and clinical records were reviewed for demographic information, history of underlying malignancies and the clinical outcome of the incidental pulmonary nodules. Comparison of malignant versus benign pulmonary nodules was performed with respect to the size of the nodule, imaging features on CT, and patient history of malignancy using the Student's t-test and Fisher exact test. Youden J-index in receiver operating characteristic (ROC) analysis was used to determine the optimal cut-off size for suggesting a high risk of malignancy of incidentally detected pulmonary nodules. RESULTS:Pulmonary nodules meeting inclusion criteria were detected in 62 (1.2%) of 5,234 patients. The mean age of patients with nodules was 11.2 years (range: 5 months-18 years). Thirty-one patients (50%) had follow-up CT studies and two of these patients (6%) were subsequently found to have malignant pulmonary nodules. Both of these patients had a history of malignancy. Of the remaining 31 patients without follow-up CT studies, none had a history of malignancy. Clinical follow-up data was available in 26 of these 31 patients (84%) and none had any evidence of malignant pulmonary nodule development. There was a significant association between history of malignancy and incidentally detected pulmonary nodules on abdominal CT studies subsequently found to be malignant (P = 0.036). The size was significantly larger for the malignant pulmonary nodules compared to the benign pulmonary nodules with a size ≥7 mm in diameter being the optimal cut-off for suggesting a high risk of malignancy (11.5 ± 6.4 mm vs. 4.7 ± 3.0 mm, P = 0.003). CONCLUSION/CONCLUSIONS:The incidence of pulmonary nodules found on pediatric abdominal CT studies is 1.2%. The incidence of malignancy in such pulmonary nodules is low (3%) and only seen in the setting of pulmonary nodules ≥7 mm in diameter in children with a history of malignancy. Therefore, further investigation is warranted for pulmonary nodules that are ≥7 mm in children with a history of malignancy while further imaging work-up may not be necessary in the remaining patients in this pediatric patient population.

Bladder augmentation (also called augmentation cystoplasty) refers to a number of surgical methods that increase the capacity and compliance of the urinary bladder. Imaging has an important role in the postoperative evaluation of bladder augmentation. The most common augmentation procedures utilize enteric segments to augment the bladder. The various types of bladder augmentation have characteristic appearances on different imaging modalities. Spontaneous bladder perforation is a complication that is seen in both early and late post-operative periods and it is one of the most important complications for radiologists to be aware of as it is life-threatening. We review the indications for bladder augmentation in children, the surgical techniques employed, the normal postoperative appearances on imaging studies and the role of imaging complications of bladder augmentation including delayed spontaneous bladder rupture, which is life-threatening.

OBJECTIVES/OBJECTIVE:The term functional gastrointestinal disorders (FGID) describes various aggregations of chronic gastrointestinal (GI) symptoms not explained by identifiable organic pathology; accordingly, their diagnosis rests on symptom-based criteria and a process of exclusion. Evidence is lacking on the appropriate use of abdominal imaging studies (AIS) in FGIDs. METHODS:We investigated the utilisation of AIS (site, modality, diagnostic yield/significance) at a tertiary FGID clinic over an 11-year period. RESULTS:Of 1,621 patients, 507 (31%; 67.5% women, mean age 43.9 ± 17.37 years) referred from primary care had 997 AIS (1.7 per patient): ultrasonography (US) 36.1%, fluoroscopy (FLS) 28.8%, computed tomography (CT) 19.6%, plain radiography (PR) 13.5%, nuclear medicine (NM) 1%). Of the 997 AIS, 55.6% (554/997) were normal. Of the AIS with positive findings, 9.9% (62/625) were deemed 'probably significant' and 14.7% (92/625) 'significant'. Of the CT and FLS studies, 12.3% and 13.6%, respectively, yielded 'significant' abnormalities compared to 2.2% of the US studies and 2.1% of the PR studies. CT identified five of seven neoplasms, associated with male sex, increasing age and symptom onset after age 50 years. CONCLUSIONS:This study confirmed low use of AIS in tertiary FGID clinics and a high proportion of normal studies. Barium swallow/meal and CT were more likely to identify 'probably significant' or 'significant' findings, including neoplasms. KEY POINTS/CONCLUSIONS:Imaging referral rates from a specialist functional gastrointestinal disorder clinic are low. Despite this, normal studies are still frequent in those who are imaged. Ultrasonography was the most frequent investigation, yet yielded significant findings infrequently. Abdominal radiographs accounted for 13.5% of investigations yet were normal in 71.8 %. CT and fluoroscopy were more likely to yield positive findings.

PURPOSE/OBJECTIVE:An integral part of realizing the enormous potential of imaging in patient care is close communication between radiologists and referring physicians. One key element of this process is the communication of unexpected significant findings. The authors examined the performance of a PACS-based alert system in the appropriate communication of reports containing unexpected significant findings to referring physicians. METHODS:A PACS-integrated key word system was developed such that an e-mail was sent to the referring clinician if a radiologist detected a significant unexpected finding. The number, source, and outcome of chest radiographic unexpected findings over a 14-month period were analyzed. The time for response of the referring physician plus time for follow-up were also examined. RESULTS:Key words were applied to 158 of the 39,665 chest radiographs (0.4%) obtained during the study period. The emergency department was the most frequent referral location (46.2%). Final diagnostic categories included malignancy (13.9%), benign lesion (49.4%), and no abnormality (20.2%). The average time to acknowledgment by clinicians of notification was 3.1 days, although 57.6% were acknowledged within 24 hours. The mean time interval to the next relevant radiologic investigation was 26 days among the 77.8% of findings that underwent radiologic follow-up. CONCLUSIONS:The development of electronic alert systems, which are integrated into PACS, can aid greatly in report communication and eliminate the risk associated with unread reports that contain significant or unexpected findings.