Publications by authors named "Amy B Kolbe"

31 Publications

Preparing for the next pandemic: It is more than just about numbers.

Clin Imaging 2021 May 29;79:179-182. Epub 2021 May 29.

Mayo Clinic, Department of Radiology, 200 First Street SW, Rochester, MN 55905, United States of America.

The COVID-19 pandemic has brought enormous hardships to our country and healthcare system. We present our experience navigating through this pandemic with emphasis on reactivating our practice while keeping patients and staff safe. It is hoped that the methods and thought processes provided in this manuscript will help those who are in various stages of managing their practice or provide lessons learned as our country eventually moves beyond this pandemic. Lastly, we aspire to provide a guide for those who are in a position to prepare for the next pandemic.
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http://dx.doi.org/10.1016/j.clinimag.2021.05.017DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8164499PMC
May 2021

Reproducibility of Lung and Liver Volume Measurements on Fetal Magnetic Resonance Imaging in Left-Sided Congenital Diaphragmatic Hernia.

Fetal Diagn Ther 2021 23;48(4):258-264. Epub 2021 Mar 23.

Division of Maternal-Fetal Medicine, Department of Obstetrics and Gynecology, Mayo Clinic College of Medicine, Rochester, Minnesota, USA,

Introduction: Congenital diaphragmatic hernia (CDH) affects 1 in 3,000 live births and is associated with significant morbidity and mortality.

Methods: A review of fetal magnetic resonance imaging (MRI) examinations was performed for fetuses with left CDH and normal lung controls. Image review and manual tracings were performed by 4 pediatric radiologists; right and left lung volumes in the coronal and axial planes as well as liver volume above and below the diaphragm in the coronal plane were measured. Intra- and interreviewer reproducibility was assessed using intraclass correlation coefficient (ICC) and Bland-Altman analysis.

Results: Excellent intra- and interreviewer reproducibility of the right and left lung volume measurements was observed in both axial planes (interreviewer ICC: right lung: 0.97, 95% CI: 0.95-0.99; left lung: 0.97, 95% CI: 0.95-0.98) and coronal planes (interreviewer ICC: right lung: 0.97, 95% CI: 0.95-0.98; left lung: 0.96, 95% CI: 0.93-0.98). Moderate-to-good interreviewer reproducibility was observed for liver volume above the diaphragm (ICC 0.7, 95% CI: 0.59-0.81). Liver volume below the diaphragm had a good-to-excellent interreviewer reproducibility (ICC 0.88, 95% CI: 9.82-0.93).

Conclusions: The present study demonstrated an excellent intra- and interreviewer reproducibility of MRI lung volume measurements and good-to-moderate inter- and intrareviewer reproducibility of liver volume measurements after standardization of the methods at our fetal center.
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http://dx.doi.org/10.1159/000512491DOI Listing
March 2021

Pediatric scurvy MRI appearance.

Radiol Case Rep 2021 May 10;16(5):1148-1152. Epub 2021 Mar 10.

Division of Radiology, Mayo Clinic, 200 1st St SW; Rochester, MN 55905, USA.

We present a rare case of pediatric scurvy in a 9-year-old male who presented with nontraumatic knee pain. MRI was obtained due to the puzzling presentation. MRI demonstrated a systemic bone marrow abnormality which led to a conversation with the clinician and further elucidation of an extremely narrow diet lacking sufficient vitamin C (ascorbic acid). Diagnosis was confirmed biochemically with undetectable ascorbic acid level and clinically with compatible exam and history. This case highlights a thought process for unexpected bone marrow abnormality on MRI.
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http://dx.doi.org/10.1016/j.radcr.2021.02.045DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7960501PMC
May 2021

Asymptomatic macrocephaly: to scan or not to scan.

Pediatr Radiol 2021 May 5;51(5):811-821. Epub 2021 Jan 5.

Department of Radiology, Mayo Clinic, 200 1st Street SW, Rochester, MN, 55905, USA.

Background: Macrocephaly is a common finding in infants and is often idiopathic or familial. In the absence of clinical signs and symptoms, it can be difficult to determine when concern for underlying pathology is justified.

Objectives: The objectives of this study were to determine the utility of screening head ultrasound (US) in asymptomatic infants with macrocephaly and to identify clinical factors associated with significant US findings.

Materials And Methods: A 20-year retrospective review was performed of infants undergoing head US for macrocephaly or rapidly increasing head circumference. Data collected included age, gender, head circumference at birth and at the time of US, specialty of the ordering physician, US findings, computed tomography (CT) or magnetic resonance imaging (MRI) findings, and clinical course including interventions.

Results: Four hundred and forty infants met inclusion criteria. Two hundred and eighty studies (64%) were found to be normal, 137 (31%) had incidental findings, 17 (3.8%) had indeterminate but potentially significant findings, and 6 (1.4%) had significant findings. Twenty of the 23 infants with indeterminate or significant findings had subsequent CT or MRI. This confirmed significant findings in eight infants (1.8%): three subdural hematomas, two intracranial tumors, two aqueductal stenoses, and one middle fossa cyst. Five of the eight infants required surgical procedures. The only statistically significant association found with having a significant finding on head US was head circumference at birth.

Conclusion: Ultrasound is a useful initial study to evaluate infantile macrocephaly, identifying several treatable causes in our study and, when negative, effectively excluding significant pathology.
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http://dx.doi.org/10.1007/s00247-020-04907-7DOI Listing
May 2021

Sequential Minimally Invasive Fetal Interventions for Two Life-Threatening Conditions: A Novel Approach.

Fetal Diagn Ther 2021 20;48(1):70-77. Epub 2020 Oct 20.

Division of Pediatric Surgery, Department of Surgery, Mayo Clinic College of Medicine, Rochester, Minnesota, USA.

Introduction: In utero interventions are performed in fetuses with "isolated" major congenital anomalies to improve neonatal outcomes and quality of life. Sequential in utero interventions to treat 2 anomalies in 1 fetus have not yet been described.

Case Presentation: Here, we report a fetus with a large left-sided intralobar bronchopulmonary sequestration (BPS) causing mediastinal shift, a small extralobar BPS, and concomitant severe left-sided congenital diaphragmatic hernia (CDH). At 26-week gestation, the BPS was noted to be increasing in size with a significant reduction in right lung volume and progression to fetal hydrops. The fetus underwent ultrasound-guided ablation of the BPS feeding vessel leading to complete tumor regression. However, lung development remained poor (O/E-LHR: 0.22) due to the left-sided CDH, prompting fetal endoscopic tracheal occlusion therapy at 28-week gestation to allow increased lung growth. After vaginal delivery, the newborn underwent diaphragmatic repair with resection of the extralobar sequestration. He was discharged home with tracheostomy on room air at 9 months.

Discussion/conclusion: Sequential in utero interventions to treat 2 severe major anomalies in the same fetus have not been previously described. This approach may be a useful alternative in select cases with otherwise high morbidity/mortality. Further studies are required to confirm our hypothesis.
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http://dx.doi.org/10.1159/000510635DOI Listing
October 2020

Pediatric Patients and Diagnostic Thoracentesis: Utility for Identifying a Microorganism and Guiding Patient Management.

Radiology 2020 11 25;297(2):449-450. Epub 2020 Aug 25.

From the Departments of Radiology (P.G.T., A.B.K., N.C.H., K.B.T., L.A.B.) and Health Sciences Research (J.R.G.), Mayo Clinic, 200 First St SW, Rochester, MN 55905.

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http://dx.doi.org/10.1148/radiol.2020201511DOI Listing
November 2020

Acute Reactions to Gadolinium-Based Contrast Agents in a Pediatric Cohort: A Retrospective Study of 16,237 Injections.

AJR Am J Roentgenol 2021 05 20;216(5):1363-1369. Epub 2020 Jul 20.

Department of Radiology, 200 First St SW, Mayo Clinic, Rochester, MN 55905.

Incidences and risk factors for acute reactions to gadolinium-based contrast agents (GBCAs) are not fully understood, particularly in pediatric patients. The purpose of this study was to retrospectively examine allergiclike and physiologic acute reactions in pediatric patients who receive GBCAs for MRI examinations. The study cohort consisted of all pediatric patients (age < 18 years old) who underwent an MRI examination with a GBCA at our institution from June 1, 2009, to May 9, 2017. Acute reactions were identified by medical record review and classified by severity using the American College of Radiology guidelines. Potential risk factors for reactions were examined using generalized estimating equation methods accounting for rare events. A total of 16,237 GBCA injections (10,141 gadodiamide injections, 4880 gadobutrol injections, and 1216 gadobenate dimeglumine injections) were administered to a study cohort of 10,190 patients (49% [7982/16,237] girls and 51% [8255/16,237] boys). Incidences of 0.10% (17/16,237) for allergiclike and 0.14% (23/16,237) for physiologic reactions were observed. No severe reactions occurred. Allergiclike reaction incidences were significantly higher with gadobenate compared with gadodiamide (0.49% vs 0.04%; < .001) and in patients who underwent abdominal or pelvic MRI examinations (0.38%) or cardiac examinations (0.55%) compared with head examinations (0.05%; < .001 and = .006, respectively). Physiologic reaction incidences were significantly higher in older patients (0.25% in patients 12-17 years old vs 0.03% in patients 2 to < 12 years old; < .001) and in patients who underwent abdominal or pelvic examinations compared with head examinations (0.38% vs 0.10%; = .002). Of 16 MRI examinations performed in patients with a prior allergiclike reaction to GBCAs, only one resulted in a repeat reaction. In this pediatric cohort, GBCA type, patient age, and MRI type were risk factors for acute reactions. Repeat reactions were rare. Providers must weigh the risks and benefits when choosing a particular GBCA to use in their practices and must consider multiple, potentially disparate risks associated with each GBCA.
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http://dx.doi.org/10.2214/AJR.20.23602DOI Listing
May 2021

Quantitative Inflammation Assessment for Crohn Disease Using Ultrasensitive Ultrasound Microvessel Imaging: A Pilot Study.

J Ultrasound Med 2020 Sep 16;39(9):1819-1827. Epub 2020 Apr 16.

Departments of Radiology, Mayo Clinic, Rochester, Minnesota, USA.

Objectives: Crohn disease (CD) is a chronic inflammation in the digestive tract that affects millions of Americans. Bowel vascularity has important diagnostic information because inflammation is associated with blood flow changes. We recently developed an ultrasensitive ultrasound microvessel imaging (UMI) technique with high vessel sensitivity. This study aimed to evaluate the feasibility of UMI to assist CD detection and staging.

Methods: Ultrasound microvessel imaging was performed on 76 bowel wall segments from 48 symptomatic patients with CD. Clinically indicated computed tomographic/magnetic resonance enterography was used as the reference standard. The vessel-length ratio (VLR, the number of vessel pixels in the bowel wall segment normalized to the segment length) was derived in both conventional color flow imaging (CFI) and UMI to quantitatively stage disease activity. Receiver operating characteristic curves were then analyzed between different disease groups.

Results: The VLR-CFI and VLR-UMI detected similar correlations between vascularization and disease activity: severe inflammation had a higher VLR than normal/mildly inflamed bowels (P < .05). No significant difference was found between quiescent and mild CD due to the small sample size. The VLR-CFI had more difficulties in distinguishing quiescent versus mild CD compared to the VLR-UMI. After combining the VLR-UMI with thickness, in the receiver operating characteristic curve analysis, the areas under the curves (AUCs) improved to AUC = 0.996 for active versus quiescent CD, AUC = 0.978 for quiescent versus mild CD, and AUC = 0.931 for mild versus severe CD, respectively, compared to those using thickness alone (AUC = 0.968; P = .04; AUC = 0.919; P = .16; AUC = 0.857; P = .01).

Conclusions: Ultrasound microvessel imaging offers a safe and cost-effective tool for CD diagnosis and staging, which may potentially assist disease activity classification and therapy efficacy evaluation.
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http://dx.doi.org/10.1002/jum.15290DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7442589PMC
September 2020

In Utero Restoration of Hindbrain Herniation in Fetal Myelomeningocele as Part of Prenatal Regenerative Therapy Program at Mayo Clinic.

Mayo Clin Proc 2020 04;95(4):738-746

Center for Regenerative Medicine, Mayo Clinic College of Medicine, Rochester, MN; Department of Cardiovascular Medicine, Mayo Clinic College of Medicine, Rochester, MN.

Objective: To assess our initial experience with prenatal restoration of hindbrain herniation following in utero repair of myelomeningocele (MMC).

Patients And Methods: Three consecutive patients with prenatally diagnosed MMC (between January 1, 2018 and September 30, 2018) were managed with open in utero surgery. As per institutional review board approval and following a protocol designed at the Mayo Clinic Maternal & Fetal Center, fetal intervention was offered between 19 0/7 and 25 6/7 weeks of gestation. Prenatal improvement of hindbrain herniation was the declared restorative end point. Obstetrical and perinatal outcomes were also assessed.

Results: Diagnosis of MMC was confirmed upon referral between 20 and 21 weeks' gestation by using fetal ultrasound and magnetic resonance imaging. In all cases reported here, the spinal defect was lumbosacral with evidence of hindbrain herniation. Open in utero MMC repair was performed between 24 and 25 weeks' gestation with no notable perioperative complications. Postprocedure fetal magnetic resonance imaging performed 6 weeks after in utero repair documented improvement of hindbrain herniation. Deliveries were at 37 weeks by cesarean section without complications. Most recent postnatal follow-ups were unremarkable at both 11 months (baby 1) and 3 months of age (baby 2), with mild ventriculomegaly. Antenatal and postnatal follow-up of baby 3 at 1 month of age was also unremarkable.

Conclusion: Our study highlights the prenatal restoration of hindbrain herniation following in utero MMC repair in all cases presented here as an example of a prenatal regenerative therapy program in our institution.
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http://dx.doi.org/10.1016/j.mayocp.2019.10.039DOI Listing
April 2020

Congenital hemangioma of the face-Value of fetal MRI with prenatal ultrasound.

Radiol Case Rep 2019 Nov 1;14(11):1443-1446. Epub 2019 Oct 1.

Division of Obstetrics and Gynecology, Mayo Clinic, 200 1st St SW, Rochester, MN 55905, USA.

We report the presentation, workup, and pre/perinatal management of a fetus with a large congenital hemangioma of the face. Hemangiomas are benign vascular neoplasms frequently encountered in neonates and infants. The less common congenital variant develops in utero and can present on prenatal ultrasound with diagnostic uncertainty as well as clinical implications for delivery. The differential diagnosis for these solid vascular masses when located in the head and neck includes myofibroma, kaposiform hemangioendothelioma, teratoma, and encephalocele. Potential clinical issues relate to size and location of the mass and include airway obstruction, disruption in development or compression of the globe, invasion into the cranial vault, bleeding and ulceration, and high output heart failure. Prenatal ultrasound and MRI play an important role in the diagnosis of congenital hemangiomas and planning for delivery and immediate postnatal cares.
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http://dx.doi.org/10.1016/j.radcr.2019.09.016DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6823738PMC
November 2019

Acute Adverse Events Following Gadolinium-based Contrast Agent Administration: A Single-Center Retrospective Study of 281 945 Injections.

Radiology 2019 09 2;292(3):620-627. Epub 2019 Jul 2.

From the Department of Radiology (J.S.M., C.H.H., A.B.K., J.J.S., R.P.H., D.F.K., R.J.M.), Division of Allergic Diseases (D.E.M.), and Department of Neurosurgery (D.F.K.), Mayo Clinic, 200 1st St SW, Rochester, Minn 55905.

Background Acute allergic-like and physiologic reactions occur following administration of gadolinium-based contrast agents (GBCAs) for MRI examinations. Because these reactions are uncommon, it is challenging to compare reaction rates between GBCAs and to determine risk factors. Purpose To compare reaction rates between the four GBCAs gadodiamide, gadobutrol, gadobenate dimeglumine, and gadoterate meglumine, and to determine potential risk factors for reactions. Materials and Methods This retrospective study identified all intravenous GBCA injections for MRI examinations performed at a single institution from June 1, 2009, to May 9, 2017. Reactions were identified by reviewing records from the MRI technologist, MRI nursing staff, radiologist, emergency department, and provider. Reactions were classified as allergic-like or physiologic and as mild, moderate, or severe by using American College of Radiology criteria. GBCA reaction rates and other potential risk factors were examined by using multivariable regression models with generalized estimating equations. Results Analysis included a total of 158 100 patients (median age, 55 years [interquartile range, 40-67 years], 51% women) who received a total of 281 945 GBCA injections (140 645 gadodiamide, 94 109 gadobutrol, 39 138 gadobenate, and 8053 gadoterate). At multivariate analysis, gadobenate or gadobutrol had higher rates of allergic-like reactions compared with gadodiamide (gadobenate: odds ratio [OR], 3.9 [95% confidence interval {CI}: 3.0, 5.1]; < .001; gadobutrol: OR, 2.3 [95% CI: 1.8, 2.9]; < .001) or gadoterate (gadobenate: OR, 4.8 [95% CI: 1.0, 23]; = .049; gadobutrol: OR, 2.8 [95% CI: 0.6, 14]; = .20). Physiologic reactions were more frequently observed with gadoterate (OR, 7.7 [95% CI: 2.3, 25; = .001), gadobenate (OR, 1.8 [95% CI: 1.3, 2.5; < .001), and gadobutrol (OR, 1.6 [95% CI: 1.3, 2.1; < .001) administration compared with gadodiamide. Six severe allergic-like reactions (three gadobutrol, three gadobenate) occurred requiring hospitalization. Patient age ( values .025 to < .001), sex ( < .001), location ( = .006), and MRI type ( = .003 and = .006) were associated with acute reactions. Conclusion Gadobenate and gadobutrol are associated with higher rates of allergic-like reactions compared with gadodiamide or gadoterate, and gadoterate, gadobenate, and gadobutrol are associated with higher rates of physiologic reactions compared with gadodiamide. Patient sex, age, location, and MRI type correlate with acute reaction rates. © RSNA, 2019
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http://dx.doi.org/10.1148/radiol.2019182834DOI Listing
September 2019

Comparison of two small bowel distending agents for enterography in pediatric small bowel imaging.

Abdom Radiol (NY) 2019 10;44(10):3252-3262

Department of Radiology, Mayo Clinic, 200 1st St SW, Rochester, MN, 55905, USA.

Objective: To evaluate the ability of pediatric patients with known or suspected inflammatory bowel disease to ingest a new oral distending agent at CT or MR enterography (CTE/MRE), and to determine the impact on small bowel (SB) distension and diagnostic confidence.

Materials And Methods: The study design is that of retrospective review of pediatric patients who underwent CTE or MRE from January 2014 to June 2016. Patients ingested low-concentration barium suspension or flavored beverage containing sorbitol and mannitol. The need for nasogastric tube (NGT) administration, amount ingested, emesis, distal extent of contrast, SB distension, terminal ileum (TI) transverse dimension, and diagnostic confidence in TI disease were assessed. Three radiologists each blindly reviewed a subset of the studies.

Results: Of the total 591 scans in 504 patients, 316 scans used low-concentration barium suspension and 275 scans flavored beverage. Nearly all consumed the entire amount (97% vs. 96%). Low-concentration barium suspension exams required NGT more often (7% [23/316] vs. 1% [3/275]; p < 0.0003), and tended to have more emesis (3% [9/316] vs. 1% [3/275]; p = 0.13). Diagnostic confidence score was nearly identical (p = 0.94). Qualitative and quantitative analyses showed no difference in SB distension, except for distension of mid-ileum (flavored beverage > low-concentration barium suspension; p = 0.02). Flavored beverage exams demonstrated a slight increase in distal extent of luminal distension (p = 0.02).

Conclusions: A new flavored beverage distends small bowel as well as low-concentration barium suspension, with decreased requirement for NGT insertion and improved distal extent of luminal distension, and without any decrease in diagnostic confidence in the presence or the absence of TI disease.
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http://dx.doi.org/10.1007/s00261-019-02102-3DOI Listing
October 2019

Diffuse Adenomatosis and Hepatocellular Carcinoma Treated with Liver Transplantation in an Adolescent Female with Kabuki Syndrome with a Novel Gene Mutation.

Case Rep Pediatr 2019 24;2019:7983824. Epub 2019 Apr 24.

Department of Pediatric and Adolescent Medicine, Mayo Clinic, 200 First St. SW, Rochester, MN 55905, USA.

Kabuki syndrome (KS) is a rare disorder primarily associated with mutations in the and genes. Several tumors have been reported with KS; however, there have been no reports of hepatocellular carcinoma (HCC) or hepatic adenomatosis. We present an adolescent girl with KS and a novel mutation who developed diffuse adenomatosis, HCC, and subsequently underwent liver transplantation.
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http://dx.doi.org/10.1155/2019/7983824DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6507262PMC
April 2019

Correction to: Pediatric ileocolic intussusception: new observations and unexpected implications.

Pediatr Radiol 2019 03;49(3):429

Division of Pediatric Surgery, Mayo Clinic, Rochester, MN, USA.

In this article, the fourth author's name is misspelled. The correct spelling, as shown above, should be "Nadia F. Mahmood."
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http://dx.doi.org/10.1007/s00247-019-04343-2DOI Listing
March 2019

Pediatric ileocolic intussusception: new observations and unexpected implications.

Pediatr Radiol 2019 01 19;49(1):76-81. Epub 2018 Sep 19.

Division of Pediatric Surgery, Mayo Clinic, Rochester, MN, USA.

Background: Ileocolic intussusception occurs when the terminal ileum "telescopes" into the colon. We observed that ileocolic intussusception lengths are similar regardless of location in the colon.

Objective: To examine the uniformity of ileocolic intussusception length and its relationship to colon location, symptom duration and reducibility.

Materials And Methods: We retrospectively reviewed ultrasound-diagnosed pediatric ileocolic intussusceptions initially treated with pneumatic reduction at the Mayo Clinic or Texas Children's Hospital. We recorded demographic, imaging and surgical findings including age, gender, symptom duration, location of the ileocolic intussusception, reducibility with air enema and, if fluoroscopically irreducible, surgical findings.

Results: We identified 119 ileocolic intussusceptions (64% boys), with 81% in the right colon. There was no significant relationship between ileocolic intussusception length and colon location (P=0.15), nor ileocolic intussusception length and symptom duration (P=0.36). Ileocolic intussusceptions were more distal with increasing symptom duration (P=0.016). Successful reductions were unrelated to symptom duration (P=0.84) but were more likely with proximal versus distal locations (P=0.02).

Conclusion: Ileocolic intussusception lengths are relatively uniform regardless of location along the course of the colon where they present. Our findings suggest that most of the apparent distal propagation of ileocolic intussusceptions is not caused by increasing telescoping of small bowel across the ileocecal valve but rather by foreshortening of the right colon. This implies poor cecal fixation and confirms fluoroscopic and surgical observations of cecal displacement from the right lower quadrant with ileocolic intussusceptions. The movement of the leading edge of the ileocolic intussusception during reduction is first due to "relocating" the cecum into the right lower quadrant after which the reduction of small bowel back across the ileocecal valve then occurs.
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http://dx.doi.org/10.1007/s00247-018-4259-9DOI Listing
January 2019

Computed Tomography Enterography.

Radiol Clin North Am 2018 Sep 11;56(5):649-670. Epub 2018 Jul 11.

Department of Radiology, Mayo Clinic, 200 First Street Southwest, Rochester, MN 55905, USA.

Computed tomography (CT) enterography is a noninvasive imaging modality with superb spatial and temporal resolution, specifically tailored to evaluate the small bowel. It has several advantages over other radiologic and optical imaging modalities, all of which serve as complementary investigations to one another. This article describes CTE technique, including dose reduction techniques, special considerations for the pediatric population, common technical and interpretive pitfalls, and reviews some of the more common small bowel entities seen with CTE.
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http://dx.doi.org/10.1016/j.rcl.2018.04.002DOI Listing
September 2018

Postcontrast Acute Kidney Injury in Pediatric Patients: A Cohort Study.

Am J Kidney Dis 2018 12 21;72(6):811-818. Epub 2018 Jul 21.

Department of Radiology, Mayo Clinic, Rochester, MN; Department of Neurosurgery, Mayo Clinic, Rochester, MN.

Rational & Objective: The risks of iodinated contrast material administered to pediatric patients are not well defined. The purpose of this study was to examine the rates of postcontrast acute kidney injury (AKI), dialysis therapy, and death following administration of intravenous contrast material to pediatric patients.

Study Design: Retrospective cohort study.

Setting & Participants: Pediatric (aged <18 years) patients who underwent either contrast-enhanced (contrast group) or unenhanced (noncontrast group) computed tomography (CT) at our institution from December 2001 to January 2016.

Exposure: Intravenous iodinated contrast material.

Outcomes: Postcontrast AKI based on serum creatinine-defined KDIGO criteria, dialysis therapy, and death.

Analytical Approach: Risks for AKI, dialysis therapy, and death were compared between contrast and noncontrast group patients using a propensity score analysis incorporating clinical covariates related to contrast exposure.

Results: 2,201 pediatric patients (1,773 contrast and 428 noncontrast) were identified. Rates of AKI and dialysis therapy in the contrast group were 3.3% (59/1,773) and 0.1% (2/1,773), respectively. Following propensity score adjustment, no differences in risk for AKI (stage 1 AKI: OR, 0.75 [95% CI, 0.32-1.78], P=0.5; stage 2: OR, 2.00 [95% CI, 0.18-21.9], P=0.6; stage 3: OR, 0.50 [95% CI, 0.05-5.48], P=0.6), dialysis therapy (OR, 1.00 [95% CI, 0.06-15.9], P=0.9), or death (OR, 1.50 [95% CI, 0.53-4.22], P=0.4) were observed between the contrast and noncontrast groups. All patients with post-CT stage 3 AKI diagnosed also had contrast-independent potential causes of AKI.

Limitations: The study's small sample size and low rates of postcontrast AKI, dialysis therapy, and death limited the ability to detect an effect of contrast administration on these outcomes. Unmeasured residual confounders may limit the validity of our results. Few patients had decreased kidney function at the time of CT.

Conclusions: Rates of postcontrast AKI, dialysis therapy, and death following contrast-enhanced CT were very low in this pediatric cohort. Although not detectably different, an effect of contrast on these outcomes could not be ruled out.
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http://dx.doi.org/10.1053/j.ajkd.2018.05.014DOI Listing
December 2018

Fetoscopic Therapy for Severe Pulmonary Hypoplasia in Congenital Diaphragmatic Hernia: A First in Prenatal Regenerative Medicine at Mayo Clinic.

Mayo Clin Proc 2018 06;93(6):693-700

Center for Regenerative Medicine, Mayo Clinic, Rochester, MN.

Objective: To introduce the prenatal regenerative medicine service at Mayo Clinic for fetal endoscopic tracheal occlusion (FETO) care for severe congenital diaphragmatic hernia (CDH).

Patients And Methods: Two cases of prenatal management of severe CDH with FETO between January and August 2017 are reported. Per protocol, FETO was offered for life-threatening severe CDH at between 26 and 29 weeks' gestation. Regenerative outcome end point was fetal lung growth. Gestational age at procedure and maternal and perinatal outcomes were additional monitored parameters.

Results: Diagnosis by ultrasonography of severe CDH was based on extremely reduced lung size (observed-to-expected lung area to head circumference ratio [o/e-LHR], eg, o/e-LHR of 20.3% for fetus 1 and 23.0% for fetus 2) along with greater than one-third of the liver herniated into the chest in both fetuses. Both patients underwent successful FETO at 28 weeks. At the time of intervention, no maternal or fetal complications were observed. Postintervention, fetal lung growth was observed in both fetuses, reaching an o/e-LHR of 62.7% at 36 weeks in fetus 1 and 52.4% at 32 weeks in fetus 2. The balloons were removed successfully at 35 weeks and 4 days by ultrasound-guided puncture in the first patient and at 32 weeks and 3 days by ex utero intrapartum therapy-to-airway procedure in the second patient. Postnatal management followed standard of care with patch CDH therapy. At discharge, one patient was breathing normally, whereas the other required minimal nasal cannula oxygen support.

Conclusion: The successful launch of the first fetoscopic therapy for CDH at Mayo Clinic reveals its feasibility and safety, with early signs of benefit documented by fetal lung growth and reversal of severe pulmonary hypoplasia.

Trial Registration: clinicaltrials.gov Identifier: G170062.
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http://dx.doi.org/10.1016/j.mayocp.2018.02.026DOI Listing
June 2018

Predictors of Durability of Radiological Response in Patients With Small Bowel Crohn's Disease.

Inflamm Bowel Dis 2018 07;24(8):1815-1825

Division of Gastroenterology and Hepatology, Rochester, Minnesota.

Background: The long-term significance of radiological transmural response (TR) as a treatment goal at the first follow-up scan in small bowel Crohn's disease (CD) has been previously shown. We examined the durability of a long-term strategy of treating to a target of radiological TR and the influence of baseline predictors on the maintenance of TR.

Methods: Small bowel CD patients between January 1, 2002, and December 31, 2014, were identified with serial computed tomography enterography (CTE)/magnetic resonance enterography (MRE) before and after initiation of therapy or on maintenance therapy. Overall TR (inflammatory lesions with/without strictures) w1as characterized by abdominal radiologists in up to 5 small bowel lesions per patient at each serial scan until last follow-up or small bowel resection, as response, partial response, or nonresponse. The rate of conversion between TR states and transition to surgery, including the effect of baseline patient/disease characteristics, was examined using a multistate model (mstate R-package).

Results: CD patients (n = 150, 705 CTE/MRE) with a median of 4 CTE/MRE during 4.6 years of follow-up, 49% with ileal-only distribution, had 260 examined bowel segments. Conversion from response to partial response/nonresponse was 37.4% per year of follow-up with no transitions seen directly from response to surgery. Current smoking status (hazard ratio [HR], 2.2; 95% confidence interval [CI], 1.1-4.3) and internal penetrating disease at baseline scan (HR, 2.2; 95% CI, 1.2-4.1) were associated with a 2-fold increased risk of transition from partial response/nonresponse to surgery.

Conclusions: Achievement and maintenance of radiological response is associated with avoidance of small bowel surgery. Continued follow-up with CTE/MRE is recommended to identify loss of response, especially in current smokers and patients with internal penetrating disease at baseline CTE/MRE.
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http://dx.doi.org/10.1093/ibd/izy074DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6391864PMC
July 2018

Endoscopic Skipping of the Terminal Ileum in Pediatric Crohn Disease.

AJR Am J Roentgenol 2017 Jun 5;208(6):W216-W224. Epub 2017 Apr 5.

1 Division of Pediatric Gastroenterology and Hepatology, Mayo Clinic, 200 First St SW, Rochester, MN 55905.

Objective: Pediatric small-bowel (SB) Crohn disease (CD) may be missed if the terminal ileum (TI) appears normal at endoscopy and SB imaging is not performed. We sought to estimate the prevalence and clinical characteristics of pediatric patients with CD and endoscopic skipping of the TI-that is, pediatric patients with active SB or upper gut inflammation and an endoscopically normal TI.

Materials And Methods: This retrospective study included pediatric patients with CD who underwent both CT enterography (CTE) or MR enterography (MRE) and ileocolonoscopy within a 30-day period between July 2004 and April 2014. The physician global assessment was used as the reference standard for SB CD activity. Radiologists reviewed the CTE and MRE studies for inflammatory parameters; severity, length, and multifocality of SB inflammation; and the presence of penetrating complications.

Results: Of 170 patients who underwent ileal intubation, the TI was macroscopically normal or showed nonspecific inflammation in 73 patients (43%). Nearly half (36/73, 49%) of the patients with normal or nonspecific findings at ileocolonoscopy had radiologically active disease with a median length of SB involvement of 20 cm (range, 1 to > 100 cm). Seventeen (47%) of these patients had multifocal SB involvement and five (14%) had penetrating complications. Overall, endoscopic TI skipping was present in 43 (59%) patients with normal or nonspecific ileocolonoscopic findings: 20 with histologic inflammation (17 with positive imaging findings), 14 with inflammation at imaging only, and nine with proximal disease (upper gut, jejunum, or proximal ileum). There were no significant differences in the clinical parameters of the patients with and those without endoscopic TI skipping.

Conclusion: Ileocolonoscopy may miss SB CD in pediatric patients that is due to isolated histologic, intramural, or proximal inflammation. Enterography is complementary to ileocolonoscopy in the evaluation of pediatric CD.
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http://dx.doi.org/10.2214/AJR.16.16575DOI Listing
June 2017

Update on Magnetic Resonance Imaging and Ultrasound Evaluation of Crohn's Disease.

Gastroenterol Hepatol (N Y) 2016 Apr;12(4):226-36

Dr Deepak is an instructor in medicine and fellow and Dr Bruining is an associate professor of medicine and consultant in the Division of Gastroenterology and Hepatology at the Mayo Clinic College of Medicine in Rochester, Minnesota. Dr Kolbe is an assistant professor of radiology and senior associate consultant, Dr Fidler and Dr Fletcher are professors of radiology and consultants, and Dr Knudsen is an assistant professor of radiology and consultant in the Department of Radiology at the Mayo Clinic College of Medicine.

Magnetic resonance enterography (MRE) and abdominal ultrasound are integral parts of multimodality assessments for patients with inflammatory bowel disease. Applications include assessing Crohn's disease (CD) extent and severity, differentiating CD from ulcerative colitis, detecting CD complications, evaluating response to therapy, and demonstrating postoperative recurrence. Magnetic resonance imaging protocols are being developed that may reduce or eliminate the need for intravenous contrast agents and better differentiate inflammatory from fibrotic strictures. MRE scoring systems have been created to objectively quantify disease activity and response to therapy. By utilizing advanced sonographic imaging techniques, including ultrasound contrast and Doppler assessments, the role of abdominal ultrasonography in the evaluation and management of CD continues to expand. Abdominal ultrasound may function as a low-cost, point-of care assessment tool, especially in CD restricted to the terminal ileum and ileocolic anastomosis.
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4872852PMC
April 2016

Radiological Response Is Associated With Better Long-Term Outcomes and Is a Potential Treatment Target in Patients With Small Bowel Crohn's Disease.

Am J Gastroenterol 2016 07 10;111(7):997-1006. Epub 2016 May 10.

Division of Gastroenterology and Hepatology, Mayo Clinic College of Medicine, Rochester, Minnesota, USA.

Objectives: Crohn's disease (CD) management targets mucosal healing on ileocolonoscopy as a treatment goal. We hypothesized that radiologic response is also associated with better long-term outcomes.

Methods: Small bowel CD patients between 1 January 2002 and 31 October 2014 were identified. All patients had pre-therapy computed tomography enterography (CTE)/magnetic resonance enterography (MRE) with follow-up CTE or MRE after 6 months, or 2 CTE/MREs≥6 months apart while on maintenance therapy. Radiologists characterized inflammation in up to five small bowel lesions per patient. At second CTE/MRE, complete responders had all improved lesions, non-responders had worsening or new lesions, and partial responders had other scenarios. CD-related outcomes of corticosteroid usage, hospitalization, and surgery were assessed using Kaplan-Meier survival analysis and multivariable Cox models.

Results: CD patients (n=150), with a median disease duration of 9 years, had 223 inflamed small bowel segments (76 with strictures and 62 with penetrating, non-perianal disease), 49% having ileal distribution. Fifty-five patients (37%) were complete radiologic responders, 39 partial (26%), and 56 non-responders (37%). In multivariable Cox models, complete and partial response decreased risk for steroid usage by over 50% (hazard ratio (HR)s: 0.37 (95% confidence interval (CI), 0.21-0.64); 0.45 (95% CI, 0.26-0.79)), and complete response decreased the risk of subsequent hospitalizations and surgery by over two-thirds (HRs: HR, 0.28 (95% CI, 0.15-0.50); HR, 0.34 (95% CI, 0.18-0.63)).

Conclusions: Radiological response to medical therapy is associated with significant reductions in long-term risk of hospitalization, surgery, or corticosteroid usage among small bowel CD patients. These findings suggest the significance of radiological response as a treatment target.
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http://dx.doi.org/10.1038/ajg.2016.177DOI Listing
July 2016

Evaluation of Patient Tolerance and Small-Bowel Distention With a New Small-Bowel Distending Agent for Enterography.

AJR Am J Roentgenol 2016 May 21;206(5):994-1002. Epub 2016 Mar 21.

1 Division of Radiology, Mayo Clinic, 200 1st St SW, Rochester, MN 55905.

Objective: The objective of our study was to compare a flavored beverage containing a thickening agent for enterography with a low-Hounsfield-value barium suspension for side effects, taste, subjects' willingness to repeat the drinking protocol, and small-bowel distention.

Subjects And Methods: The following five drinking protocols were administered to 10 volunteers: 1000 mL of flavored beverage followed by 350 mL of water, 1500 mL of flavored beverage, 900 mL of low-Hounsfield-value barium suspension followed by 450 mL of water, 1350 mL of low-Hounsfield-value barium suspension followed by 150 mL of water, and 1500 mL of water. MR images were obtained 50 and 60 minutes after initiation of drinking. Subjects completed a questionnaire evaluating the side effects, the taste of the drink, and their willingness to repeat the drinking protocol. Reviewers assigned scores evaluating small-bowel distention and ranked the examinations in order of preference.

Results: There was no significant difference in nausea or vomiting among the protocols (p = 0.20 and 0.42, respectively), but larger volumes of flavored beverage and low-Hounsfield-value barium suspension resulted in more cramping and diarrhea (p = 0.001 and 0.002, respectively). The taste of the low-Hounsfield-value barium suspension was rated the worst (p < 0.0001). The subjects' willingness to repeat the drinking protocol was highest for the 1000 mL of flavored beverage or water alone (p < 0.05). There were no significant differences in subjective small-bowel distention except that water was rated the worst by two of the three readers (p < 0.02). There was no significant difference in the diameter of the most dis-tended small bowel for any segment or reader (p > 0.23).

Conclusion: A flavored beverage containing a thickening agent has a similar side effect profile and results in equivalent small-bowel distention compared with a low-Hounsfield-value barium suspension, but subjects rate taste and their willingness to repeat the drinking protocol higher for this new agent.
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http://dx.doi.org/10.2214/AJR.15.15260DOI Listing
May 2016

Pediatric appendiceal ultrasound: accuracy, determinacy and clinical outcomes.

Pediatr Radiol 2015 Dec 18;45(13):1934-44. Epub 2015 Aug 18.

Department of Emergency Medicine, Mayo Clinic, Rochester, MN, USA.

Background: Ultrasonography is considered the most appropriate initial imaging study in the evaluation of acute appendicitis in children but has recently come under criticism with reports of low specificity and high indeterminate study rates, particularly when used in obese patients and patients early in the course of their disease, or when performed by sonographers with limited experience.

Objective: To (1) assess the impact of patient factors (gender, age, body mass index, and symptom duration) and system factors (call status or year of exam) on pediatric appendiceal US accuracy and indeterminate study rate, (2) assess the impact of indeterminate study results on follow-up CT and negative laparotomy rates and (3) present strategies to reduce the rate of indeterminate US studies and improve accuracy.

Materials And Methods: We retrospectively reviewed all US reports performed for the assessment of acute appendicitis in children <18 years old at Mayo Clinic Rochester from January 2010 to June 2014.

Results: A total of 790 US examinations were performed in 452 girls (57%) and 338 boys (43%). The prevalence of appendicitis was 18.5% (146/790). There were 109 true-positive, 440 true-negative, 17 false-positive, 6 false-negative, 218 equivocal and 41 technically inadequate US studies. A definitive interpretation was made in 72% of the studies, with an accuracy, sensitivity and specificity of 0.960, 0.948 and 0.963, respectively. No patient or system factors significantly affected US accuracy. Indeterminate studies (28%) had significantly higher CT utilization (46% vs. 11%) and normal appendectomy rates (6.9% vs. 3.5%).

Conclusion: US should be the initial imaging study of choice for pediatric appendicitis. When a definitive interpretation was given, the accuracy was 96%, was independent of patient and system factors and resulted in reduced follow-up CTs and negative laparotomies. Accuracy can be increased by requiring the presence of periappendiceal inflammatory changes prior to interpreting a mildly distended appendix as positive for acute appendicitis. The indeterminate study rate can be reduced by not requiring visualization of the normal appendix for the exclusion of acute appendicitis.
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http://dx.doi.org/10.1007/s00247-015-3432-7DOI Listing
December 2015

Appendiceal ultrasound: the importance of determinacy.

Pediatr Radiol 2015 Dec 18;45(13):1932-3. Epub 2015 Aug 18.

Department of Emergency Medicine, Mayo Clinic, Rochester, MN, USA.

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http://dx.doi.org/10.1007/s00247-015-3429-2DOI Listing
December 2015

Upright Biplanar Slot Scanning in Pediatric Orthopedics: Applications, Advantages, and Artifacts.

AJR Am J Roentgenol 2015 Jul;205(1):W124-32

2 Division of Pediatric Orthopedics, Department of Orthopedic Surgery, Mayo Clinic, Rochester, MN.

Objective: Digital slot scanning is a relatively new technology that has been used for imaging of pediatric orthopedic conditions such as scoliosis and leg-length discrepancies. This article will review the clinical applications, advantages, and unique artifacts of this new technology.

Conclusion: Upright biplanar slot scanners acquire high-resolution radiographs simultaneously in two orthogonal planes with reduced radiation dose. Other advantages include a more physiologic weightbearing imaging position, improved Cobb angle measurements, and 3D modeling.
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http://dx.doi.org/10.2214/AJR.14.14022DOI Listing
July 2015

CT enterography: technical and interpretive pitfalls.

Abdom Imaging 2015 Jun;40(5):1081-96

Department of Radiology, Mayo Clinic, 200 First Street SW, Rochester, MN, 55905, USA,

CT enterography is a first-line test at many institutions to investigate potential small bowel disorders. While numerous articles have focused on the ability of CT enterography to diagnose and stage Crohn's disease, small bowel neoplasia, and malabsorptive or vascular disorders, this article reviews CT enterography limitations, technical and interpretive pitfalls, image review tactics, and complementary radiologic and endoscopic examinations to improve diagnostic accuracy. CT enterography limitations include its inability to demonstrate isolated mucosal abnormalities such as aphthous ulcers and its use of ionizing radiation. The most common technical pitfall of CT enterography is inadequate small bowel distention resulting from inadequate ingestion, gastric retention, or rapid small bowel transit of a large volume of neutral enteric contrast material. Additionally, segments of jejunum are frequently collapsed. Interpretive pitfalls commonly result from peristaltic contractions, transient intussusception and opaque intraluminal debris. Opaque debris is especially problematic during multiphasic CT enterography performed to identify potential small bowel sources of obscure gastrointestinal bleeding. False-negative examinations may result from inadequate radiation dose. Examinations complementary to CT enterography include small bowel follow through, enteroclysis, CT enteroclysis, MR enterography, MR enteroclysis, capsule endoscopy, and balloon-assisted endoscopy. Properly performed and accurately interpreted CT enterography contributes to the diagnosis and management of small bowel disease by itself and as a complement to other radiologic and optical small bowel imaging examinations.
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http://dx.doi.org/10.1007/s00261-015-0364-5DOI Listing
June 2015

The impact of hepatocyte phase imaging from infancy to young adulthood in patients with a known or suspected liver lesion.

Pediatr Radiol 2015 Mar 23;45(3):354-65. Epub 2014 Sep 23.

Department of Radiology, Cincinnati Children's Hospital Medical Center, 3333 Burnet Ave., MLC 5031, Cincinnati, OH, 45229, USA.

Objective: Hepatocyte-specific contrast agents are used to help characterize liver lesions. However, there are no studies evaluating the utility of these agents in detecting or diagnosing pediatric liver lesions. The purpose of this study is to assess the impact of the hepatocyte phase of imaging on lesion detection, tumor staging and diagnostic confidence.

Materials And Methods: All patients undergoing an MRI between September 2010 and August 2012 using gadoxetate disodium as the contrast agent were included in this study. Each exam was duplicated so that one copy contained all sequences, including the hepatocyte phase of imaging, and the other copy contained all sequences except the hepatocyte phase of imaging. One reviewer evaluated all exams in a blinded, random fashion. Data tracked included imaging diagnosis, confidence in diagnosis, number of lesions and PRETEXT grade. The imaging diagnosis was compared to histopathology, when available. Data were analyzed for the study population as well as the subset of patients diagnosed with focal nodular hyperplasia (FNH).

Results: There were 112 patients (56 male; mean age: 9.25 years) included in this study. A total of 33 patients had a malignant tumor and the remainder had either a benign lesion or no lesion. The addition of the hepatocyte phase of imaging significantly improved the diagnostic confidence for all patients (P < 0.0001) as well as specifically for patients diagnosed with FNH (P = 0.003). In nearly a quarter of patients, the hepatocyte phase of imaging allowed the reviewer to detect additional lesions (P = 0.005). In the patients with a malignant tumor, the addition of the hepatocyte phase of imaging changed the PRETEXT grade in 7/30 patients although the results were not significant (P = 0.161).

Conclusion: The addition of the hepatocyte phase of imaging helps to improve lesion detection and increase the diagnostic confidence for all liver tumors, as well as for FNH in particular.
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http://dx.doi.org/10.1007/s00247-014-3160-4DOI Listing
March 2015

Premedication of patients for prior urticarial reaction to iodinated contrast medium.

Abdom Imaging 2014 Apr;39(2):432-7

Department of Radiology, Mayo Clinic, 200 1st Street SW, Rochester, MN, 55905, USA,

Purpose: The purpose of this study was to determine whether premedication of patients with a history of urticaria after low osmolality contrast media (LOCM) results in fewer subsequent reactions, and if a benefit is seen, to determine which premedication regimen results in the fewest reactions.

Materials And Methods: The subsequent contrast enhanced studies of patients who experienced urticaria after intravenous LOCM between 2002 and 2009 were reviewed to determine whether an additional reaction occurred. Patients undergoing subsequent studies received either no premedication, or premedication with diphenhydramine alone, corticosteroid alone, or corticosteroid plus diphenhydramine. Reactions occurring without premedication were termed repeat reactions and reactions occurring after premedication were termed breakthrough reactions.

Results: Fifty patients with a history of urticaria after LOCM met the inclusion criteria and underwent 133 subsequent contrast enhanced studies. Repeat reactions occurred in 7.6% (5/66) of subsequent studies in patients receiving no premedication. Breakthrough reactions occurred in 8% (2/25), 46% (12/26), and 44% (7/16) of subsequent studies in patients receiving premedication with diphenhydramine, corticosteroid, and corticosteroid plus diphenhydramine, respectively. All subsequent reactions consisted of urticaria as the most severe manifestation; no hemodynamic instability or respiratory compromise occurred. In multivariate analysis, premedication with corticosteroid was significantly associated with higher rate of breakthrough reaction relative to no premedication (OR 14.3, 95% CI: 4.1-50.4), as was premedication with corticosteroid plus diphenhydramine (OR 8.3, 95% CI: 1.8-37.9).

Conclusion: The results suggest that premedication of patients with a history of urticaria after LOCM may not be necessary.
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http://dx.doi.org/10.1007/s00261-013-0058-9DOI Listing
April 2014

Tips and tricks for MR angiography of pediatric and adult congenital cardiovascular diseases.

AJR Am J Roentgenol 2013 May;200(5):980-8

Department of Radiology, Mayo Clinic, Rochester, MN 55905, USA.

Objective: The use of contrast-enhanced MR angiography (MRA) as an alternative to CT angiography or conventional angiography to assess pediatric and adult patients with cardiovascular diseases has the potential to significantly reduce patients' lifetime exposure to ionizing radiation. However, imaging this group of patients can be challenging because of a number of factors, including small size, difficulty timing the contrast bolus to the territory of interest, and the presence of metallic susceptibility artifact resulting from stents or clips.

Conclusion: We present some suggestions to overcome many of these obstacles to MRA in these patients, highlighted with illustrations from clinical cases.
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http://dx.doi.org/10.2214/AJR.12.9632DOI Listing
May 2013
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