Back to Authors

Kummer, Tobias

https://orcid.org/0000-0002-2420-7001

Mayo Clinic

Mayo Clinic

Citations 8

1659: A DEEP LEARNING APPROACH FOR ULTRASOUND-BASED IDENTIFICATION OF PNEUMOTHORAX IN TRAUMATIC INJURY
Navarro, Sergio, Özbilen, Ege, Thorn, Michael, Williams, Alec, Chaar, Mohammed Abou, Stephens, Daniel, Navarro, Sergio M. , Williams, Alec, Kummer, Tobias , Stephens, Daniel

Critical Care Medicine | March 24, 2026 | Volume: 54 | Issue: 3S | Pages: No page available

10.1097/01.ccm.0001188632.48186.54 Get It

Shear wave elastography of the deltoid muscle in healthy volunteers – quantifying age-dependent normal values
Ivanov, David , Voelkel, Jacob E., Giambini, Hugo , Sánchez‐Sotelo, Joaquín , Dave, Jaydev K. , Kummer, Tobias , Sanchez-Sotelo, J.

Shoulder & Elbow | February 3, 2025 | Volume: 18 | Issue: 2 | Pages: 257-265

10.1177/17585732251315952 Get It

Introduction Reverse shoulder arthroplasty (RSA) is performed for various shoulder pathologies. Inadequate tensioning of the deltoid muscle can lead to complications, highlighting the need for optimization. Preoperative quantification of deltoid health may improve operative execution and outcomes. Shear wave elastography (SWE) quantifies stiffness as a marker for muscle health and tensioning. This study establishes normal reference values for the deltoid in healthy individuals. Methods 40 participants were enrolled, 10 in each 18–30, 31–40, 41–55, and 55 + age groups. Two operators performed SWE in 3 deltoid regions, and the intra- and inter-operator agreement was assessed. Results Mean values were 23.2 ± 4.6, 26.4 ± 5.6, and 17.9 ± 5.2 kPa for the anterior, lateral, and posterior regions. The posterior region did not show any age dependency. However, there were significant differences between the age groups of 18–30 and 55 + years in the anterior (19.7 ± 3.7 vs. 26.7 ± 5.3 kPa) and lateral (22.0 ± 5.4 vs. 30.2 ± 8.8 kPa). Intra-operator reliability ranged from 0.45 to 0.60, and inter-reader agreement from 0.57 to 0.85. Conclusion This study provides reference values of deltoid stiffness which could serve as a comparison with clinical measurements for RSA operative planning and execution and prediction of surgical outcomes.
Does needle positioning with magnetic field induction improve central venous catheterization performance by novice learners?
Kamphausen, Anne , Tarasova, Natalia , Bardwell, Abigail , Laack, Torrey A. , Shiue, Larissa T., Kummer, Tobias

The Journal of Vascular Access | August 7, 2023 | Volume: 25 | Issue: 6 | Pages: 1877-1884

10.1177/11297298231191374 Get It

Objective: The novel ultrasound magnetic needle navigation technique can visualize the entire needle and identify its projected trajectory. We hypothesized that this technique increases the first-attempt success rate of central venous puncture by novice learners compared with the conventional needle navigation technique. Methods: This prospective, randomized, controlled trial with a crossover design included 50 participants with limited prior experience in US-guided procedures. Participants were randomly assigned to novel or conventional technique groups and asked to perform central venous cannulation in a phantom task trainer. After the first successful attempt, participants were allocated to the other technique group. Results: Although participants in the novel technique group had a higher first-attempt success rate than did those in the conventional technique group, this difference was not statistically significant ( p = 0.17). The total number of attempts also did not significantly differ ( p = 0.16). The conventional technique group had more needle redirections ( p = 0.01) and a longer time to successful cannulation ( p = 0.01). The number of adverse effects ( p = 0.32) did not differ between groups. Participant confidence levels were higher in the novel technique group ( p < 0.001). Conclusions: Magnetic needle navigation can reduce the number of needle redirections, shorten the time to successful cannulation, and increase confidence levels by novice learners for successful US-guided central venous access.
Evaluation of Soft-Tissue Hematomas With Real-Time, Contrast-Enhanced Ultrasound
Kummer, Tobias , Mohn, Kelli J., Bardwell, Abigail , Boyum, James H.

Ultrasound Quarterly | February 2, 2023 | Volume: No volume available | Issue: No issue available | Pages: No page available

10.1097/ruq.0000000000000621 Get It

Abstract In this study, we investigated the feasibility of using contrast-enhanced ultrasound (CEUS) to detect active hemorrhage in patients presenting with soft-tissue hematomas. Adult patients with clinically suspected, actively bleeding hematomas were prospectively enrolled. Contrast-enhanced ultrasound was used to assess for contrast extravasation. Ultrasound results were compared with those of multidetector computed tomographic (MDCT) imaging, operative findings, and clinical course. Sixteen patients (9 women, 7 men; mean age, 69 [SD, 13] years) were enrolled. Thirteen patients underwent MDCT imaging during their initial visit, and for 11, CEUS and computed tomography (CT) findings were concordant. The remaining patients had a negative CEUS study that was consistent with their clinical course. In 8 patients, CT imaging showed active extravasation (6 arterial, 1 indeterminate, 1 slow venous). Contrast-enhanced ultrasound and CT findings were concordant for all cases of arterial bleeding. For 1 patient, CEUS provided superior diagnostic information by identifying a pseudoaneurysm. The 2 discrepant patient cases had a ≥3-hour delay between CT and CEUS, and in 1 patient, CEUS was limited by body habitus. The second patient had no active bleeding identified in the operating room. Compared with CT, CEUS had a sensitivity and specificity of 75% and 100%, respectively, and positive and negative predictive values were 100% and 71%, respectively. Diagnostic accuracy was 85% in this limited study. Contrast-enhanced ultrasound is a promising alternative to MDCT in select patients and may sometimes provide superior clinical information. Limiting factors are large hematoma size, unfavorable anatomic location, and body habitus.
Real-time Ultrasound-Guided Manual Testicular Detorsion: A Case Report
Smith, W. Ted, Midgley, S.J.E. , Kummer, Tobias , Midgley, Stephanie

Clinical Practice and Cases in Emergency Medicine | August 23, 2022 | Volume: 6 | Issue: 3 | Pages: 248-251

10.5811/cpcem2022.6.57256 Get It

Introduction: Acute testicular torsion is a surgical emergency due to acute testicular ischemia. Manual testicular detorsion is a testis-saving, bedside therapeutic when performed correctly and in a timely fashion. This procedure is most commonly performed blindly with pain relief as the endpoint for detorsion. However, up to one-third of patients continued to show signs of residual torsion in the operating room even using pain relief as the stopping point for the procedure. Case Report: We present a case demonstrating the utility of color Doppler ultrasound to confirm complete manual detorsion in a 14-year-old male with acute testicular torsion. The patient underwent 360-degree detorsion and had relief of pain; however, color Doppler demonstrated incomplete return of flow to the testis. After an additional 180-degree turn was made, color Doppler demonstrated complete return of normal vascular flow to the torsed testis. Conclusion: When it comes to testicular viability, timely restoration of blood flow to the testicle is of utmost importance. Manual detorsion is a non-invasive intervention that can be quickly and effectively performed at the bedside. Moreover, using color Doppler ultrasound guidance can ensure that physicians detorse in the proper direction and to completion, by providing instant visualization of restorative flow and ensuring reperfusion of the testis while awaiting definitive surgical management.
Ruptured Ectopic Pregnancy with an Intrauterine Device: Case Report and Sonographic Considerations
Jones, Derick D. , Kummer, Tobias , Schoen, Jessica C. , Jones, Derick

Clinical Practice and Cases in Emergency Medicine | November 17, 2020 | Volume: 4 | Issue: 4 | Pages: 559-563

10.5811/cpcem.2020.7.48258 Get It

Introduction: Ectopic pregnancy carries a high morbidity and mortality; patients are at risk for rupture and life-threatening hemorrhage. Case Report: We present a rare case of ruptured abdominal ectopic pregnancy in a patient with a well-positioned intrauterine device (IUD) and discuss the diagnostic utility that transabdominal point-of-care ultrasound (POCUS) can have when performed at the bedside. Conclusion: While pregnancy with an IUD in place is rare, when it is encountered the emergency provider should maintain a high degree of suspicion for extrauterine pregnancy and perform prompt evaluation for hemorrhagic shock using diagnostic POCUS.
Increased body mass index is associated with decreased imaging quality of point‐of‐care abdominal aortic ultrasonography
Jeeji, Archana K., Ekstein, Samuel F. , Ifelayo, Oluwatomilona I., Oyemade, Kafayat A. , Tawfic, Sarah, Hyde, Robert J. , Laughlin, Michael J., Lohse, Christine M. , Kummer, Tobias , Bellamkonda, Venkatesh R. , Ifelayo, Oluwatomilona , Tawfic, Sarah S, Bellamkonda, Venkatesh R , Mullan, Aidan F.

Journal of Clinical Ultrasound | September 28, 2020 | Volume: 49 | Issue: 4 | Pages: 328-333

10.1002/jcu.22929 Get It

AbstractBackgroundGiven that abdominal aorta is a retroperitoneal structure, increased body mass index (BMI) may have an adverse effect upon the quality of aortic ultrasonographic imaging.PurposeTo assess the hypothesis that increased BMI is associated with worsening point‐of‐care abdominal aortic ultrasonographic image quality.MethodsThis is a retrospective single‐center study of point‐of‐care abdominal aortic ultrasound examinations performed in an academic emergency department (ED) with fellowship‐trained emergency ultrasonography faculty performing quality assurance review.ResultsMean ± SD BMI was 27.4 ± 6.2, among the 221 included records. The overall quality rating decreased as BMI increased (correlation coefficient − 0.24; P < .001) and this persisted after adjustment for age and sex (P < .001). Although BMI was higher on average in the records that were of insufficient quality for clinical decisions when compared with those of sufficient quality (mean BMI 28.7 vs 27.0), this did not reach statistical significance in a univariable setting (P = .11) or after adjusting for age and sex (P = .14).ConclusionThis study data shows a decrease in point‐of‐care abdominal aorta ultrasound imaging quality as BMI increases, though this difference did not result in a statistically significant impairment in achieving the minimum quality for clinical decisions. This finding may help ameliorate some clinician concerns about ultrasonography for patients with high BMI.
Increased body mass index does not impact the imaging quality of focused assessment with sonography in trauma
Ifelayo, Oluwatomilona I., Oyemade, Kafayat A. , Tawfic, Sarah, Jeeji, Archana K., Ekstein, Samuel F. , Smoot, William A. , Voelkel, Jacob E., Laughlin, Michael J., Lohse, Christine M. , Kummer, Tobias , Bellamkonda, Venkatesh R. , Ifelayo, Oluwatomilona , Tawfic, Sarah S

Journal of Clinical Ultrasound | June 19, 2020 | Volume: 48 | Issue: 8 | Pages: 452-456

10.1002/jcu.22884 Get It

AbstractBackgroundMany clinicians believe that a patient's body mass index (BMI) affects the likelihood of obtaining high quality ultrasound images.ObjectivesTo assess the hypothesis that increased BMI is associated with worsening focused assessment with sonography in trauma (FAST) image quality.MethodsWe conducted a retrospective single‐center study of FAST examinations performed in a large academic emergency department (ED) with fellowship‐trained emergency ultrasonography faculty performing quality assurance review.ResultsMean (SD) BMI was 28.0 (6.6) among the 302 included studies. The overall quality rating tended to decrease as BMI increased but did not achieve statistical significance in a univariable setting (P = .06) or after adjustment for age and sex (P = .06). Operators perception of image adequacy was largely unaffected by BMI, with the exception of the pericardial view.ConclusionThis study did not identify a statistically significant difference in FAST quality with increased BMI. This result may help assuage clinician concerns about ultrasonography for patients in the ED.