What’s new in Ultrasonography – June 2021 

1 year ago

 

Abdominal Imaging 

 

Original Research

Ultrasound-Guided Omental Biopsy: Diagnostic Yield and Association with CT Features Based on a Single-Institution 18-Year Series.  

Perez AA, Lubner MG, Pickhardt PJ. 

American Journal of Roentgenology. 2021.  

doi:10.2214/ajr.21.25545  

  • Background: The greater omentum is a common site of malignant peritoneal spread and can be a helpful target for percutaneous biopsy. CT guidance rather than US guidance is often used to assist in percutaneous omental biopsies. 
  • Question: What is the diagnostic yield of percutaneous US-guided omental biopsies? 
  • Inclusion criteria: Patients who underwent an US-guided omental biopsy and had a diagnostic abdominal CT performed prior to the biopsy. 
  • Design: This retrospective study included 163 patients who underwent US-guided omental biopsy by abdominal radiologists between 2002 and 2020 at a single institution. Imaging findings on pre-biopsy diagnostic CT and US-guided biopsy were reviewed. Biopsy results were classified as diagnostic or nondiagnostic.   
  • Results: On US, omental disease often appears as diffuse infiltrative thickening without a discrete target. Most of the omental biopsies (95%) were diagnostic. The diagnostic yield is not associated with omental morphology or echogenicity. No complications were identified. 
  • Conclusion and remarks: US-guided biopsy of omental disease that was identified on CT is safe and effective for tissue diagnosis. This approach should be considered as first-line when possible.  

 

Original Research 

Transabdominal Ultrasound for Follow-Up of Incidentally Detected Low-Risk Pancreatic Cysts: A Prospective Multicenter Study. 

Yu MH, Kim JH, Kang H-J, et al.  

American Journal of Roentgenology. 2021:1-9.  

doi:10.2214/ajr.20.22965  

  • Background: Incidental pancreatic cysts are often indolent with favorable prognosis; however, there is potential for growth and malignant transformation of intraductal papillary mucinous neoplasms or mucinous cystic neoplasms. Currently, CT, MRI, and endoscopic US are recommended for surveillance. Transabdominal US (TAUS) has a potential to serve as a follow-up imaging tool. 
  • Question: What is the detection rate of pancreatic cysts on TAUS that are incidentally detected on CT or MRI? What are the factors that influence detection? 
  • Inclusion criteria: Patients who had incidentally detected 5 mm to 3 cm pancreatic cysts on CT or MRI performed within 1 year before TAUS. This was performed at five medical institutions between September 2017 and January 2019. 
  • Design: This prospective study included 57 patients with low-risk pancreatic cysts that were incidentally found on CT or MRI. TAUS was independently performed by two radiologists on these patients, and the cysts were detected and characterized.  
  • Results: The detection rate for known low-risk pancreatic cysts was 81.8% and 83.1% on TAUS conducted by each radiologist. The detection rate is higher with large cysts (≥ 10 mm), cysts outside the tail of the pancreas, and single pancreatic cysts. 
  • Conclusion and remarks: TAUS is a helpful imaging tool for the surveillance of known low-risk pancreatic cysts. 

 

Original Research 

Contrast-enhanced ultrasound for screening hepatocellular carcinoma: an implemented program at a semi-rural academic center.  

Motz VL, White R, Lee R, Vu T, Shin B, McGillen KL.  

Abdominal Radiology. 2021.  

doi:10.1007/s00261-021-03104-w  

  • Background: While US is routinely used for hepatocellular carcinoma (HCC) screening, contrast-enhanced US (CEUS) could be a valuable HCC diagnostic adjunct.  
  • Question: Can CEUS serve as a feasible screening method along with routine US for HCC in cirrhotic patients? 
  • Inclusion criteria: Patients with cirrhosis at high risk for HCC and who were denied insurance coverage for multiphase CT or contrast-enhanced MRI. 
  • Design: This retrospective study evaluated 100 cirrhotic patients who underwent CEUS HCC screening over 2 years at a semi-rural academic medical center. Abdominal US with color Doppler was obtained for each patient. If a focal lesion was identified, subsequent CEUS was performed.  
  • Results: On average, the CEUS exams took 35 minutes to complete. Ten LI-RADS 3 or higher lesions were identified: five LI-RADS 3, two LI-RADS 4, one LI-RADS 5, and two LI-RADS M. One bland portal vein thrombus was identified.  
  • Conclusion and remarks: CEUS is a valuable imaging adjunct for screening high-risk patients for HCC. 

 

Conventional Ultrasound Combined with Contrast‐Enhanced Ultrasound in Differential Diagnosis of Gallbladder Cholesterol and Adenomatous Polyps (1–2 cm).  

Wang X, Zhu J, Liu Y, et al.  

Journal of Ultrasound in Medicine. 2021.  

doi:10.1002/jum.15740  

  • Background: It is important to differentiate cholesterol and adenomatous polyps due to their differing implications for management. Adenomatous polyps are premalignant and may require cholecystectomy. Conventional US (CUS) stands to gain in differentiating the two entities, and contrast-enhanced US (CEUS) may be a helpful adjunct. 
  • Question: What are the imaging characteristics that differentiate cholesterol and adenomatous polyps? What is the diagnostic efficacy of combining CUS with CEUS? 
  • Inclusion criteria: Patents with gallbladder polyps of 1 to 2 cm in diameter who will undergo cholecystectomy between January 2017 and August 2020. The polyps were all confirmed as cholesterol polyps or adenomatous polyps on pathology.  
  • Design: This prospective study included 89 patients: 55 had cholesterol polyps and 34 had adenomatous polyps. The CUS and CEUS imaging findings were characterized.  
  • Results: Findings of a single polyp, presence of vascularity on CUS, and intralesional linear vessels on CEUS were important combined predictors of adenomatous polyps. 
  • Conclusion and remarks: Using both CUS and CEUS can help differentiate cholesterol and adenomatous polyps. 

 

Pediatric Imaging 

 

Review 

Contrast-Enhanced Ultrasound in Children: Implementation and Key Diagnostic Applications.  

Squires JH, McCarville MB.  

American Journal of Roentgenology. 2021.  

doi:10.2214/ajr.21.25713  

  • Overview: Contrast-enhanced US (CEUS) has many advantages for evaluating pediatric conditions. Although CEUS is only FDA-approved for characterizing focal liver lesions currently, there are other potential diagnostic applications for pediatric patients. This review article describes the basic principles of CEUS and the current and potential applications for pediatric conditions, such as blunt abdominal trauma, complications of pneumonia, and hypoxic ischemic injury in the brain. 

 

Review 

Starting a pediatric contrast ultrasound service: made simple!  

Darge K, Back SJ, Barth RA, et al.  

Pediatric Radiology. 2021.  

doi:10.1007/s00247-021-04998-w 

  • Overview: This review article highlights the many advantages of using contrast-enhanced US (CEUS) for pediatric patients and covers the justifications that should be presented for initiating a CEUS service. Justifications include its comparable or superior diagnostic results compared to other imaging modalities, reduction in need for sedation, elimination of radiation exposure, good safety profile of US contrast agents, improved exam comfort, availability as another diagnostic option, and its status as an approved and reimbursable exam. 

 

Interventional Radiology 

 

Original Research 

Identification of the Most Important Subset of Doppler, Laboratory, and Clinical Parameters for Serial TIPS Evaluation.  

Paul RK, Vazirani R, McDermott JC, Kliewer MA.  

American Journal of Roentgenology. 2021:1-8.  

doi:10.2214/ajr.20.23186  

  • Background: Doppler US is the standard modality for monitoring for TIPS stenosis or occlusion. It is not known whether Doppler US in combination with serial liver function indices would modify the interpretation of TIPS dysfunction.  
  • Question: What are the most important Doppler, laboratory, and clinical parameters that predict TIPS dysfunction? 
  • Inclusion criteria: Patients who underwent TIPS procedures over a 7-year period. 
  • Design: This retrospective review included 189 patients who underwent TIPS procedures. Laboratory and Doppler parameters were analyzed. Doppler US was obtained during the first days after TIPS placement: at 1, 3, and 6 months, and every 6 months after. Laboratory and clinical parameters were obtained at each Doppler US study, including the model of end-stage liver disease (MELD) score, serum albumin level, fluctuating ascites, and time since last intervention. 
  • Results: The MELD score and time since last intervention were the laboratory and clinical parameters with the greatest predictive value for early TIPS dysfunction. Change in intrashunt velocity at the hepatic venous end had a great predictive value for early TIPS dysfunction. These indices became more predictive as more time elapsed since the last intervention. 
  • Conclusion and remarks: Additional consideration of the liver function tests can improve the diagnostic efficacy of Doppler parameters in diagnosing early TIPS dysfunction. 

 

Thoracic Radiology 

 

Original Research 

Lung ultrasound can predict the clinical course and the severity of COVID-19 disease.  

Ravetti CG, Vassallo PF, de Barros GM, et al.  

Ultrasound in Medicine & Biology. 2021.  

doi:10.1016/j.ultrasmedbio.2021.04.026  

  • Background: Critically ill patients with COVID-19 infection who require mechanical ventilation may transmit infection during transport for chest imaging. Bedside lung US can serve as a non-invasive imaging tool to monitor their pulmonary conditions and reduce the need for transport and its related risks.  
  • Question: Can lung US help determine the severity of illness from COVID-19? 
  • Inclusion criteria: Patients with COVID-19 infections who are admitted to the ICU and ward between April 2020 and August 2020. 
  • Design: This is a prospective study on 66 patients with COVID-19 infections admitted in the ICU and ward. Bedside lung US exams were performed at study inclusion, after 48 hours, and on the seventh day of follow-up. Lung US scores were quantified according to aeration loss in 8 zones.  
  • Results: Lung US scores were significantly higher in patients initially admitted to the ICU compared to those admitted to the ward. Lung US scores at the time of study inclusion was independently associated with need for ICU admission.  
  • Conclusion and remarks: Bedside lung US is helpful in determining the COVID-19 infection severity in patients admitted to the hospital and can minimize risk of transmission during patient transport.
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