Understanding provider cost of MRI for appendicitis in children: A Time-Driven Activity-Based Costing Analysis.

OBJECTIVE: To use time driven activity-based costing (TDABC) to characterize the provider cost of rapid MRI for appendicitis compared to other MRI examinations billed with the same current procedural technology (CPT) codes commonly used for MRI appendicitis examinations. METHODS: Rapid MRI appendicitis examination was compared to MRI pelvis without intravenous contrast, MRI abdomen/pelvis without intravenous contrast, and MRI abdomen/pelvis with intravenous contrast. Process maps for each examination were created through direct shadowing of patient procedures (n=20) and feedback from relevant healthcare professionals. Additional data were collected from the electronic medical record for 327 MRI examinations. Practical capacity cost rates were calculated for personnel, equipment, and facilities. The cost of each step was calculated by multiplying the capacity cost rate with the mean duration of each step. Stepwise costs were summed to generate a total cost for each MRI examination. RESULTS: The mean duration and costs for MRI examination type were as follows: MRI appendicitis: 11 (range: 6-25) min, $20.03 (7.80-44.24); MRI pelvis without intravenous contrast: 55 (29-205) min, $105.99 (64.18-285.13); MRI abdomen/pelvis without intravenous contrast: 65 (26-173) min, $144.83 (61.16-196.50; MRI abdomen/pelvis with intravenous contrast: 128 (39-303) min, $236.99 (102.62-556.54). CONCLUSION: The estimated cost of providing a rapid appendicitis MRI examination is significantly less than other MRI examinations billed using CPT codes typically used for appendicitis MRI. Mechanisms to appropriately bill rapid MRI examinations with limited sequences are needed to improve cost efficiency for the patient, and to enable wider use of limited MRI examinations in the pediatric population.

Magnetic resonance imaging T1 mapping of the liver, pancreas and spleen in children.

PURPOSE: To characterize T1 relaxation times of the pancreas, liver, and spleen in children with and without abdominal pathology. METHODS: This retrospective study included pediatric patients (< 18-years-old). T1 mapping was performed with a Modified Look-Locker Inversion Recovery sequence. Patients were grouped based on review of imaging reports and electronic medical records. The Kruskal-Wallis test with Dunn's multiple comparison was used to compare groups. RESULTS: 220 participants were included (mean age: 11.4 ± 4.2 years (1.5 T); 10.9 ± 4.5 years (3 T)). Pancreas T1 (msec) was significantly different between subgroups at 1.5 T (p < 0.0001). Significant pairwise differences included: normal (median: 583; IQR: 561-654) vs. acute pancreatitis (731; 632-945; p = 0.0024), normal vs. chronic pancreatitis (700; 643-863; p = 0.0013), and normal vs. acute + chronic pancreatitis (1020; 897-1099; p < 0.0001). Pancreas T1 was also significantly different between subgroups at 3 T (p < 0.0001). Significant pairwise differences included: normal (779; 753-851) vs. acute pancreatitis (1087; 910-1259; p = 0.0012), and normal vs. acute + chronic pancreatitis (1226; 1025-1367; p < 0.0001). Liver T1 was significantly different between subgroups only at 3 T (p = 0.0011) with pairwise differences between normal (818, 788-819) vs. steatotic (959; 848-997; p = 0.0017) and normal vs. other liver disease (882; 831-904; p = 0.0455). Liver T1 was weakly correlated with liver fat fraction at 1.5 T (r = 0.39; 0.24-0.52; p < 0.0001) and moderately correlated at 3 T (r = 0.64; 0.49-0.76; p < 0.0001). There were no significant differences in splenic T1 relaxation times between subgroups. CONCLUSION: Pancreas T1 relaxation times are higher at 1.5 T and 3 T in children with pancreatitis and liver T1 relaxation times are higher in children with steatotic and non-steatotic chronic liver disease at 3 T.

Visibility and Size of the Pancreatic Duct and Common Bile Duct on Routine 2D MRI Sequences in Children Without Pancreaticobiliary Disease.

Background: Pancreatic duct (PD) or common bile duct (CBD) dilatation can indicate ductal pathology, but limited data describe normal pediatric duct measurements on routine 2D MR sequences. Objective: To characterize the visibility and diameter of the PD and CBD on 2D MR images in children without pancreaticobiliary disease. Methods: This retrospective study included patients who underwent abdominal MRI using a rapid protocol (comprised of noncontrast axial and coronal 2D SSFSE sequences) to assess for suspected appendicitis or ovarian torsion in the emergency department setting between January 23, 2023, and September 13, 2023, excluding patients with a pancreatic or hepatobiliary abnormality on MRI or laboratory assessment. Four radiologists independently reviewed examinations. Reviewers recorded PD visibility in each of four segments (head, neck, body, and tail) and CBD visibility, and measured PD diameter in each segment and maximal CBD diameter. Duct measurements by age were characterized by linear regression analyses. Results: The study included 177 patients [112 female, 65 female; mean age, 12.3±3.4 years (range, 5.1-17.7 years)]. The observers reported PD visibility in the head in 32.5-93.5%, neck in 18.4-71.5%, body in 22.3-69.8%, and tail in 7.3-25.7%, and in all four segments in 6.2-22.4%, of patients. Maximum PD diameter in any segment, as a mean across observers, was 1.8 mm (range across observers, 0.7-3.5 mm). Expected maximal PD diameter in any segment, in terms of the 5th and 95th percentile values of observers' mean measurements, was 1.4-2.3 mm; the prediction interval's upper limit increased from age 5 to 17 from 2.1 to 2.5 mm. All observers reported CBD visibility in all patients. Mean CBD diameter across observers was 3.1 mm (range across observers, 2.9-3.4 mm). Expected CBD diameter, in terms of the 5th and 95th percentile values of observers' mean measurements, was 2.3-4.9 mm; the prediction interval's upper limit increased from age 5 to 17 from 3.9 to 5.0 mm. Conclusion: We report expected upper limits for PD and CBD measurements on 2D MR images in children without evidence of pancreaticobiliary disease. Clinical Impact: These findings may aid radiologists' identification of pancreaticobiliary duct abnormalities on routine abdominal MRI examinations.

Partial visualization of appendix on ultrasound: What does it mean in the child with suspected appendicitis?

BACKGROUND: Visualization of the entire appendix, including the tip, is thought, but has not been demonstrated, to be important for exclusion of appendicitis by ultrasound. OBJECTIVE: To determine if incomplete visualization of the appendix has negative clinical ramifications including missed appendicitis. METHODS: Under IRB approval we retrospectively reviewed right lower quadrant ultrasound reports from January 2017 to December 2020 to identify examinations with impressions of full visualization of the normal appendix, non-visualization of the appendix with and without secondary findings of appendicitis, and partial visualization of the appendix. Electronic health records were reviewed for follow-up imaging within 48 h, and surgery with pathology reports (if available). RESULTS: 12,193 examinations were included. 4171 (34.2 %) had full visualization of a normal appendix, 5369 (44.0 %) had non-visualization with no secondary findings, and 234 (1.9 %) had non-visualization with secondary findings, The frequencies of appendicitis in these three groups were 34 (0.8 %), 283 (5.3 %), and 127 (54.3 %) respectively. The appendix was partially visualized in 338 (2.8 %) patients with secondary findings present in 53 (15.6 %). Partial visualization without secondary findings had a similar frequency (4.9 %, 14/285) of appendicitis to non-visualized appendix without secondary findings (p = 0.797) and a higher frequency than full visualization of a normal appendix (p < 0.0001). Partial visualization with secondary findings had similar rates (54.7 %, 29/53) to non-visualized appendix with secondary findings (p = 0.953). CONCLUSION: Partial visualization of the appendix with ultrasound (with and without secondary findings) is associated with similar frequencies of appendicitis as non-visualization of appendix (with and without secondary findings).

Imaging and clinical predictors of surgery in stricturing ileal Crohn's disease: a retrospective study from a large pediatric hospital.

PURPOSE: (1) To determine the frequency of surgical management in children with Crohn's Disease (CD) and a new radiologic ileal stricture, and (2) to identify imaging and clinical features that predict the need for surgery. METHODS: This retrospective study included pediatric patients (< 21 years old) with CD and a new ileal stricture diagnosed by MRE, CTE, or CT between July 2018 and June 2023. Three board-certified radiologists recorded stricture length, maximum mural thickness, minimum lumen diameter, maximum upstream diameter, and simplified magnetic resonance index of activity (sMaRIA) score. Anthropometrics, laboratory data, and surgical interventions performed after stricture diagnosis were also recorded. Multivariable logistic regression was used to identify imaging and clinical variables associated with the need for surgery. RESULTS: 44 pediatric CD patients (median age 16.5 years) presented with a new ileal stricture during the study period. 30 (68.2%) patients required surgery, with a median time of 87.5 days between stricture diagnosis and surgery. Median stricture measurements were length: 7.0 cm, maximum mural thickness: 7.3 mm, minimum lumen diameter: 0.2 cm, and maximum upstream diameter: 3.3 cm. Median sMaRIA score was 3.0, and 14 (31.8%) strictures had associated internal penetrating disease. Stricture ratio (ratio of maximum upstream lumen diameter to minimum lumen diameter) (OR = 1.15 [95% CI 1.02-1.30]; p = 0.02) and sMaRIA (OR = 2.12 [95% CI 0.87-5.17; p = 0.10) were associated with need for surgery. CONCLUSION: Surgery remains common in stricturing pediatric CD, with increasing stricture ratio and sMaRIA score associated with need for surgical management.

Patient factors affecting 18F FDG uptake in children.

PURPOSE: To characterize physiologic uptake of 18F FDG in children undergoing PET/CT as a step to informing efforts to optimize FDG PET image quality in children. METHODS: This retrospective study included 193 clinically indicated 18F FDG PET/CT examinations from 139 patients. 3D spherical regions of interest (ROIs) in the liver and in the thigh muscle (an area of uniform low-level uptake) were used to measure counts and mean standardized uptake value by body weight (SUVmean-bw). Counts, SUVs, and liver signal to noise ratio (SNR) were assessed for associations with patient-specific predictor variables using Pearson correlation and multivariable linear regression. RESULTS: Mean patient age was 11.0 ± 5.4 (SD) years, mean liver SUVmean-bw was 1.77 ± 0.60 and mean liver counts was 5387 ± 1875 Bq/mL. On univariable analysis liver SUVmean-bw and liver counts were strongly correlated with weight (r = 0.87, p < 0.0001), age (r = 0.75, p < 0.0001) and total injected activity (r = 0.85, p < 0.0001). Mean thigh counts were significantly associated only with injected activity/kilogram (r = 0.37, p < 0.0001). On multivariable analysis, body weight and age (which is collinear with body weight) were the only significant independent predictors (p < 0.0001). Liver SNR was moderately associated with all predictors apart from injected activity per kilogram (r = 0.09, p = 0.23). CONCLUSION: Liver counts on 18F FDG PET/CT have a significant positive association with age and body weight. However, liver SNR has no significant association with injected activity per kilogram suggesting that increasing dose per kilogram may not improve image quality in young children.

Computed Tomography Scanning for Sternal Wound Infections: A Systematic Review.

Background: Sternal wound infection (SWI) has always been a significant risk in patients who undergo sternotomies as part of their cardiac surgical procedures. Computed tomography (CT) imaging is often used to diagnose and assess sternal wound infections. Its purpose includes identifying and locating infection and any sternal dehiscence. Methods: A systematic literature review across PubMed, Embase, and Ovid was performed according to PRISMA guidelines to identify relevant articles that discussed the utility of CT scanning for SWI, common features identified, patient outcomes and sensitivity/specificity (Figure 1). Results: 25 papers were included. 100% (n=25) of the papers were published in peer-reviewed journals. CT scans in SWIs can be seen as a beneficial aid in diagnosing as well as determining the components of infection. Commonalities were identified such as fluid collection in the mediastinum, free gas, pleural effusions, and sternal dehiscence which point towards the presence of sternal wound infection. Conclusion: CT scanning is a novel and emerging methodology for imaging in SWI and post-sternotomy complications, hence increased research is required to expand the literature on this area as well as the creation of guidelines and cut-offs or signs for radiology professionals to identify and determine the extent of infection.

Rapid, free-breathing non-contrast MRI for first-line imaging evaluation of ovarian torsion in the emergency department.

BACKGROUND: Transabdominal ultrasound (US) is first-line imaging to evaluate ovaries in girls presenting to the emergency department (ED) with suspected ovarian torsion. Ovaries may be difficult to visualize sonographically; therefore, prompt diagnosis using US alone can be challenging. Rapid MRI as first-line imaging may help streamline patient throughput, especially with increasing MRI availability in the ED. OBJECTIVE: To assess feasibility of rapid MRI for diagnosis of ovarian torsion. MATERIALS AND METHODS: A retrospective, single-center IRB approved study of MRI performed in female pediatric patients presenting with abdominopelvic pain from August 2022 to January 2023. Imaging occurred according to one of three clinical pathways (US-first approach vs MRI-first approach vs US + MRI-second-line approach). A rapid three-sequence free-breathing MRI protocol was utilized. Frequency of ovarian torsion and secondary diagnoses was recorded. Length of MR scan time, time from ED arrival to time of diagnosis, and whether patient had US prior to MR exam were obtained. A historical cohort of patients with US only performed for assessment of ovarian torsion were evaluated for length of the US examination and time from ED arrival to time of diagnosis. Intervals were compared using the uncorrected Fisher's least significant difference and Turkey's multiple comparison tests. RESULTS: A total of 140 MRI exams (mean age 14.6 years) and 248 historical US exams (mean age 13.5 years) were included. Of the patients with MRI, 41 (29%) patients were imaged with US + MRI and 99 (71%) imaged with MRI only; 4% (6/140) MR exams were suspicious for ovarian torsion, with one true positive case (1/6 TP) and 5 false positive cases (5/6 FP); 26.4% (37/140) of exams had secondary diagnoses. Median MRI scan time was 11.4 min (4.4) vs median historical US scan time was 24.1 min (19.7) (P<0.001). Median time from arrival in ED to MRI read was 242 (140). Median time from arrival in ED to US only read was 268 min (148). This was not a statistically significant difference when compared to the MRI only cohort. CONCLUSION: First-line MRI imaging for evaluation of ovarian torsion is a rapid and feasible imaging modality for female patients in the emergent setting.