Incidence of Contrast-Associated Acute Kidney Injury in Renal-Competent COVID-19 Patients Undergoing Computed Chest Angiography.

PURPOSE: COVID-19 infection poses a significant risk of both renal injury and pulmonary embolism, producing a clinical challenge, as the criterion standard examination for pulmonary embolism, computed tomography angiography (CTA), requires the use of nephrotoxic iodinated contrast agents.Our investigation evaluated whether symptomatic COVID-19-positive patients without laboratory evidence of renal impairment are at increased risk for developing contrast-associated acute kidney injury (CA-AKI). METHOD: All COVID-19-positive patients undergoing noncontrast chest computed tomography and CTA at an apex tertiary medical center between March 1 and December 10, 2020, were retrospectively evaluated. A total of 258 renal-competent (estimated glomerular filtration rate >30) patients with baseline and 48- to 72-hour postexamination creatinine measurements were identified and analyzed for incidence of acute kidney injury (AKI) meeting the criteria for CA-AKI. RESULTS: Twenty-five of 191 patients undergoing CTA (13.1%) and 9 of the 67 undergoing noncontrast computed tomography (13.4%) experienced creatinine increases meeting the criteria for CA-AKI. Univariate and multivariate analyses accounting for known AKI risk factors revealed no correlation between iodinated contrast administration and the incidence AKI meeting the criteria for CA-AKI (univariable odds ratio, 0.97 [95% confidence interval, 0.43-2.20]; multivariable odds ratio, 0.97 [95% confidence interval, 0.40-2.36]). CONCLUSIONS: Renal-competent COVID-19 patients undergoing chest CTA may not have an increased risk of AKI. Additional studies are needed to confirm this preliminary finding.

Vascular findings in CTA body and extremity of critically ill COVID-19 patients: commonly encountered vascular complications with review of literature.

The purpose of our review is to discuss the role of CT angiography (CTA) in evaluating a variety of vascular complications in critically ill COVID-19 patients. The COVID-19 pandemic continues to be a worldwide health threat. While COVID-19 pneumonia is the most common and well-recognized presentation of COVID-19, severely ill hospitalized patients often present with extrapulmonary systemic findings. Vascular complications occur not only due to known viral-induced vasculopathy, coagulopathy, and related "cytokine storm," but also due to anticoagulation medication used during hospitalization. There is a paucity of articles describing extrapulmonary vascular findings, especially in critically ill COVID-19 patients. In our article, we discuss commonly encountered vascular imaging findings in the body (chest, abdomen, and pelvis) and extremities, the importance of early radiological detection, and the role of CTA in the management of critically ill COVID-19 patients.

Ultrasound Studies of COVID-19-Positive Patients and Patient Under Investigation: Pandemic Experience of Body Imaging Division at a Tertiary Medical Center.

ABSTRACT: This retrospective study shares our departmental experience of screening of ultrasound (US) requests, triaging of studies, and abbreviated US protocols implemented during the COVID-19 pandemic. For US studies requested in April and May 2020, the following data were collected: type of study, indication, COVID-19 status (positive or patient under investigation [PUI]), decision to perform study, US findings, and location of patient. A total of 196 US studies in 150 patients were included. The median age of patients was 60 years (female: 46.7% [70/150]). At the time of study request, 83 patients (55.3%) were COVID-19-positive and 67 (44.7%) were PUI, of which 8 (11.9%) tested positive after waiting for test result. The most frequently requested study was venous extremity Doppler (51%), followed by right upper quadrant (20.4%), renal (11.7%), and liver duplex (6.6%). After radiologist screening and triage of US requests, 156 studies were performed (79.6%), 15 were postponed until COVID test result (7.6%), and 40 were not performed after discussion with ordering provider (20.4%). Notably, 40.1% of studies performed on COVID-19-positive patients yielded pathological findings, most frequently deep venous thrombosis (18.1%), medical renal disease (7.6%), and gall bladder sludge (5.7%). Abbreviated US protocols were used in 29.4% of studies. In conclusion, US study screening and triage played an important role to optimize care of COVID-19 patients and PUIs.

CT angiography of abdomen and pelvis in critically ill COVID-19 patients: imaging findings and correlation with the CT chest score.

PURPOSE: To assess the spectrum of computed tomography angiogram (CTA) abdominal and pelvic findings in critically ill COVID-19 patients and investigate correlation with CT chest scores. METHODS: An IRB approved retrospective study of CTA of the chest, abdomen and pelvis between dates March 1st to September 15th, 2020 was performed in the hospitalized COVID-19 positive patients. CTA studies of solely the chest were excluded. Medical record review was performed to note patient demographics, CTA scan details and coagulation profile. CTA findings were reviewed to record vascular and non-vascular findings. CT chest was reviewed to calculate CT chest score. Logistic regression analyses were performed to correlate CT chest scores with odds of vascular and other abdomen-pelvis findings. A p < 0.05 was considered statistically significant. RESULTS: A total of 45 consecutive hospitalized COVID-19 positive patients with 61 years mean age and M:F (2:1) gender ratio were evaluated, out of which majority 68.9% (n = 31) had CTA chest, abdomen and pelvis. The most common vascular findings were hematoma 46.7% (n = 21), active extravasation 24.4% (n = 11) and vascular occlusion 17.8% (n = 8). Higher CT chest scores were significantly associated with hematoma/extravasation (OR 1.19, 95% CI 1.07-1.34, p < 0.01). The most common non-vascular abdomen-pelvis findings were seen in organs gallbladder 20% (n = 9), liver 20% (n = 9) followed by kidney 15.6% (n = 7). Higher CT chest scores were significantly associated with bowel findings (OR 1.28, 95% CI 1.01-1.63, p < 0.05) and cholestasis (OR 13.3, 95% CI 1.28-138.9, p < 0.05). CONCLUSION: Patients with moderate to severe COVID-19 pneumonia have significantly higher rate of vascular complications in the abdomen and pelvis.

MDCT evaluation of complications of percutaneous gastrostomy tube placement.

Percutaneous gastrostomy tube placement is a commonly performed procedure to provide enteral alimentation to patients unable to tolerate oral feeds. Percutaneous gastrostomy is a relatively safe procedure, and serious complications like gastrointestinal bleeding, perforated viscus, and adjacent organ injury are rare. The most common complications after gastrostomy tube placement occur early and are usually minor. The purpose of this review article is to describe the techniques of percutaneous gastrostomy tube insertion and imaging protocol for gastrostomy tube evaluation, and describe the early, late, and anytime complications. The article will also illustrate very rare late complications of gastrostomy tube placement like gastro-hepatic fistula, gastro-colic fistula, buried bumper syndrome, and gastrostomy site hernia.

Positron Emission Tomography-Based Assessment of Metabolic Tumor Volume Predicts Survival after Autologous Hematopoietic Cell Transplantation for Hodgkin Lymphoma.

Autologous hematopoietic cell transplantation (AHCT) is curative for 60% of patients with relapsed or refractory Hodgkin lymphoma (R/R HL). A more precise assessment of the depth of remission before AHCT may help to identify patients likely to benefit from AHCT. We aimed to determine whether positron emission tomography (PET)-based quantitative parameters of total metabolic tumor volume (TMTV), total lesion glycolysis (TLG), and maximal standardized uptake volume (SUVmax) measured before AHCT predict progression-free survival (PFS) after transplant. Pretransplant PET/computed tomography images of 96 consecutive patients with R/R HL were analyzed. Median TMTV, TLG, and SUVmax were 7.97 cm3 (range, 1.3 to 102.1), 23.7 (range, 4.0 to 813.1), and 5.23 (range, 2.7 to 23.2). Two-year PFS in patients with high TMTV (TMTVhigh; more than median; n = 17) was only 12% (95% CI, 1% to 38%) compared with 53% (95% CI, 28% to 73%; P = .05) in patients with TMTVlow (lower or equal to median; n = 17) and 63% (95% CI, 50% to 74%) in 61 patients with no metabolically active tumor (TMTV0; P > .01). In concordance, high TLG (>19) and SUVmax (>4.9) predicted inferior 2-year PFS. In multivariate analysis patients with TMTVhigh had a 3.5-fold higher risk of treatment failure compared with TMTV0/TMTVlow (HR, 3.49; 95% CI, 1.75 to 6.93; P < .01). Deauville (D)-scores of 4 to 5 before AHCT predicted worse PFS compared with D-scores of 1 to 3 (HR, 3.7; 95% CI, 1.92 to 7.28; P < .01). Yet, TMTV and D-scores were disconcordant in 12 subjects; 9 patients in the D4 group with TMTVlow had 2-year PFS of 44% (95% CI, 14% to 72%), which was 2-fold higher than predicted by D4 score. In conclusion, in patients with R/R HL and PET-positive residual disease, TMTVhigh can identify very poor AHCT responders. Patients with TMTVlow, TLG, and SUVmax before AHCT have similar outcomes to those without metabolically active disease.

Fanconi anemia: correlating central nervous system malformations and genetic complementation groups.

BACKGROUND: Congenital central nervous system abnormalities in children with Fanconi anemia are poorly characterized, especially with regard to specific genetic complementation groups. OBJECTIVE: To characterize the impact of genetic complementation groups on central nervous system anatomy. MATERIALS AND METHODS: Through chart review we identified 36 patients with Fanconi anemia with available brain MRIs at the University of Minnesota (average age, 11.3 years; range, 1-43 years; M:F=19:17), which we reviewed and compared to 19 age- and sex-matched controls (average age, 7.9 years; range, 2-18 years; M:F=9:10). Genotypic information was available for 27 patients (15 FA-A, 2 FA-C, 3 FA-G, and 7 FA-D1 [biallelic mutations in BRCA2 gene]). RESULTS: Of the 36 patients, 61% had at least one congenital central nervous system or skull base abnormality. These included hypoplastic clivus (n=12), hypoplastic adenohypophysis (n=11), platybasia (n=8), pontocerebellar hypoplasia (n=7), isolated pontine hypoplasia (n=4), isolated vermis hypoplasia (n=3), and ectopic neurohypophysis (n=6). Average pituitary volume was significantly less in patients with Fanconi anemia (P<0.0001) than in controls. Basal angle was significantly greater in Fanconi anemia patients (P=0.006), but the basal angle of those with FA-D1 was not significantly different from controls (P=0.239). Clivus length was less in the Fanconi anemia group (P=0.002), but significance was only observed in the FA-D1 subgroup (P<0.0001). Of the seven patients meeting criteria for pontocerebellar hypoplasia, six belonged to the FA-D1 group. CONCLUSION: Patients with Fanconi anemia have higher incidences of ectopic neurohypophysis, adenohypophysis hypoplasia, platybasia and other midline central nervous system skull base posterior fossa abnormalities than age- and sex-matched controls. Patients with posterior fossa abnormalities, including pontocerebellar hypoplasia, are more likely to have biallelic BRCA2 mutations.

Three-dimensional Radiologic Assessment of Chemotherapy Response in Ewing Sarcoma Can Be Used to Predict Clinical Outcome.

Purpose To compare the agreement of three-dimensional (3D) tumor measurements for therapeutic response assessment of Ewing sarcoma according to the Children's Oncology Group (COG) criteria, one-dimensional (1D) Response Evaluation Criteria in Solid Tumors (RECIST), and two-dimensional (2D) measurements defined by the World Health Organization (WHO) with tumor volume measurements as the standard of reference and to determine which method correlates best with clinical outcomes. Materials and Methods This retrospective study was approved by the institutional review board of three institutions. Seventy-four patients (mean age ± standard deviation, 14.5 years ± 6.5) with newly diagnosed Ewing sarcoma treated at three medical centers were evaluated. Primary tumor size was assessed on pre- and posttreatment magnetic resonance images according to 1D RECIST, 2D WHO, and 3D COG measurements. Tumor responses were compared with the standard of reference (tumor volume) on the basis of RECIST, COG, and WHO therapeutic response thresholds. Agreement between the percentage reduction measurements of the methods was assessed with concordance correlation, Bland-Altman analysis, and Spearman rank correlation. Agreement between therapeutic responses was assessed with Kendall tau and unweighted κ statistics. Tumor responses were compared with patient survival by using the log-rank test, Kaplan-Meier plots, and Cox regression. Results Agreement with the reference standard was significantly better for 3D measurement than for 1D and 2D measurements on the basis of RECIST and COG therapeutic response thresholds (concordance correlation of 0.41, 0.72, and 0.84 for 1D, 2D, and 3D measurements, respectively; P < .0001). Comparison of overall survival of responders and nonresponders demonstrated P values of .4133, .0112, .0032, and .0027 for 1D, 2D, 3D, and volume measurements, respectively, indicating that higher dimensional measurements were significantly better predictors of overall survival. Conclusion The 3D tumor measurements according to COG are better predictors of therapeutic response of Ewing sarcoma than 1D RECIST or 2D WHO measurements and show a significantly higher correlation with clinical outcomes. (©) RSNA, 2016 Online supplemental material is available for this article.

Role of diffusion-weighted imaging in differentiating benign and malignant pediatric abdominal tumors.

BACKGROUND: Solid malignant tumors are more highly cellular than benign lesions and hence have a restricted diffusion of water molecules. OBJECTIVE: To evaluate whether diffusion-weighted MR imaging (DWI) can differentiate between benign and malignant pediatric abdominal tumors. MATERIALS AND METHODS: We retrospectively analyzed DWI scans of 68 consecutive children with 39 benign and 34 malignant abdominal masses. To calculate the apparent diffusion coefficient (ADC) maps and ADC values, we used 1.5-T sequences at TR/TE/b-value of 5,250-7,500/54-64/b = 0, 500 and 3-T sequences at 3,500-4,000/66-73/b = 0, 500, 800. ADC values were compared between benign and malignant and between data derived at 1.5 tesla (T) and at 3 tesla magnetic field strength, using the Mann-Whitney-Wilcoxon test, ANOVA and a receiver operating curve (ROC) analysis. RESULTS: There was no significant difference in ADC values obtained at 1.5 T and 3 T (P = 0.962). Mean ADC values (× 10(-3) mm(2)/s) were 1.07 for solid malignant tumors, 1.6 for solid benign tumors, 2.9 for necrotic portions of malignant tumors and 3.1 for cystic benign lesions. The differences between malignant and benign solid tumors were statistically significant (P = 0.000025). ROC analysis revealed an optimal cut-off ADC value for differentiating malignant and benign solid tumors as 1.29 with excellent inter-observer reliability (alpha score 0.88). CONCLUSION: DWI scans and ADC values can contribute to distinguishing between benign and malignant pediatric abdominal tumors.

High-resolution MR imaging of the orbit in patients with retinoblastoma.

Retinoblastoma is the most common intraocular childhood malignancy, with a prevalence of one in 18,000 children younger than 5 years old in the United States. In 80% of patients, retinoblastoma is diagnosed before the age of three, and in 95% of patients, retinoblastoma is diagnosed before the age of five. Although reports exist of retinoblastoma in adults, onset beyond 6 years of age is rare. Broadly, retinoblastoma may be classified into two groups: sporadic and heritable. In either case, the origin of the tumor is a biallelic mutation in primitive neuroepithelial cells. Although their details vary, several staging schemes are used to describe the extent of retinoblastoma according to the following four general criteria: intraocular location, extraocular (extraorbital) location, central nervous system disease, and systemic metastases. In the past decade, substantial changes have taken place in terms of staging and monitoring treatment in patients with retinoblastoma. Diagnosis and treatment of retinoblastoma involve a multidisciplinary approach, for which imaging is a vital component. Increasing awareness and concerns about the effects of radiation in patients with retinoblastoma have led to a shift away from external-beam radiation therapy and toward chemotherapy and locoregional treatment, as well as the establishment of magnetic resonance imaging as the most important imaging modality for diagnosis, staging, and treatment monitoring.

Differentiation of normal thymus from anterior mediastinal lymphoma and lymphoma recurrence at pediatric PET/CT.

PURPOSE: To evaluate the role of positron emission tomography (PET)/computed tomography (CT) in the differentiation of normal thymus from mediastinal lymphoma and lymphoma recurrence in pediatric patients. MATERIALS AND METHODS: The study was approved by the institutional review board, and informed consent was waived. The study was HIPAA compliant. Two hundred eighty-two fluorine 18 fluorodeoxyglucose PET/CT studies in 75 pediatric oncology patients were reviewed retrospectively. Patients were divided into four groups: anterior mediastinal lymphoma (group A, n=16), anterior mediastinal lymphoma with subsequent recurrence (group B, n=5), lymphoma outside the mediastinum (group C, n=16), and other malignant tumors outside the thymus (group D, n=38). Analyses included measurements of the maximum anteroposterior and transverse dimensions of the anterior mediastinal mass or thymus on axial CT images and measurements of maximum standardized uptake values of anterior mediastinal mass, thymus (SUVt), and bone marrow at the level of the fifth lumbar vertebra (SUVb) on PET images. Quantitative parameters were compared by using an analysis of variance test. RESULTS: Mean prechemotherapy SUVt was 4.82 for group A, 8.45 for group B, 2.00 for group C, and 2.09 for group D. Mean postchemotherapy SUVt for group B was 4.74. Thymic rebound (mean SUVt, 2.89) was seen in 44% of patients at a mean interval of 10 months from the end of chemotherapy. The differences between prechemotherapy SUVt of mediastinal lymphoma and normal thymus and postchemotherapy SUVt of lymphoma recurrence and thymic rebound were highly significant (P<.001). CONCLUSION: SUVt is a sensitive predictor for differentiation of normal thymus or thymic rebound from mediastinal lymphoma. SUVt of 3.4 or higher is a strong predictor of mediastinal lymphoma.