What’s New in Ultrasonography – October 2021

3 weeks ago

ACORE US Blog – October 2021

Abdominal Imaging

Contrast-enhanced Ultrasonography Promotes Differential Diagnosis of Ureteral Neoplasms

Bai Y, Lin J, Chen A, et al.

British Journal of Radiology. 2021.

doi:10.1259/bjr.20210078

 

  • Background: Early detection of urothelial carcinoma can be difficult and result in poor prognosis. Contrast-enhanced US (CEUS) can be a helpful tool in distinguishing urothelial carcinomas from benign lesions.
  • Question: Is CEUS a helpful imaging modality in evaluating ureteral neoplasms?
  • Inclusion criteria: Patients with suspected ureteral neoplasms at a single institution who underwent CT urography initially.
  • Design: This retrospective study analyzed the clinical presentations, imaging appearances, and imaging results of US and CEUS in patients with ureteral neoplasms. CT urography was done to confirm the presence of these neoplasms.
  • Results: There were 39 patients included in this study. The patients underwent US, CEUS, and CT urography to confirm the presence of ureteral neoplasms. There were 27 ureteral malignancies confirmed on pathologic examinations. CEUS features of malignancy included hyperenhancement, large width, and hyperenhancing ureteric wall.
  • Conclusion and remarks: Ureteral neoplasms exhibit microvessels on CEUS, which can be useful in diagnosing urothelial carcinomas.

 

Role of Contrast-enhanced Ultrasound in Assessing Indeterminate Renal Lesions and Bosniak 2F Complex Renal Cysts Found Incidentally on CT or MRI

Como G, Valotto C, Di Franco FT, et al.

British Journal of Radiology. 2021.

doi:10.1259/bjr.20210707

 

  • Background: CT and MRI can sometimes be unhelpful in distinguishing Bosniak 2F versus Bosniak 3 renal cysts. Differentiating these categories can impact patient management. Contrast-enhanced US (CEUS) can potentially serve to distinguish these two categories.
  • Question: Can CEUS help reclassify indeterminate lesions (IL) or Bosniak 2F complex renal cysts (CRC) initially found on CT or MRI?
  • Inclusion criteria: Patients who underwent CEUS to further assess incidentally found renal lesions on prior CT or MRI.
  • Design: This retrospective study included 44 patients who underwent CEUS assessing 48 IL and CRC that were incidentally found on CT or MRI. One radiologist performed the CEUS, retrospectively reviewed the CEUS images, and categorized the findings by Bosniak classification. The CEUS-related reclassification rate was calculated. Histologic examination or a 24 month follow-up served as the standard of reference.
  • Results: CEUS reclassified 24 out of 48 findings, including 12/12 IL and 12/36 CRC. CEUS demonstrated a 96% sensitivity and 82.6% specificity compared to CT/MRI with a 44% sensitivity and 60.9% specificity.
  • Conclusion and remarks: CEUS can help accurately reclassify CT and MRI incidental renal lesions.

 

Cystic Artery Velocity as a Predictor of Acute Cholecystitis

Perez MG, Tse JR, Bird KN, et al.

Abdominal Radiology. 2021.

doi:10.1007/s00261-021-03020-z

 

  • Background: The sensitivity and specificity of US for acute cholecystitis is variable. Since gallbladder hyperemia is seen with acute cholecystitis, an increased cystic artery velocity may serve as an objective and quantitative biomarker for acute cholecystitis.
  • Question: Can angle-corrected peak systolic cystic artery velocity (CAv) serve as a predictor for acute cholecystitis in patients presenting with right upper quadrant pain?
  • Inclusion criteria: Adult patients who presented to the emergency department with right upper quadrant pain and who underwent cystic artery measurement and definitive treatment. Control group included patients undergoing abdominal US without clinical suspicion for acute cholecystitis or other biliary disease.
  • Design: This retrospective study evaluated 73 patients, 43 who underwent definitive treatment with cholecystectomy or percutaneous cholecystostomy and 30 control patients without clinical suspicion for cholecystitis. Three radiologists evaluated the common bile duct (CBD) diameter, cholelithiasis, impacted stone in the neck, sludge, gallbladder wall thickness >3 mm, gallbladder transverse dimension 4 cm, longitudinal dimension 8 cm, tensile gallbladder fundus sign, pericholecystic fluid, pericholecystic echogenic fat, and sonographic Murphy sign.
  • Results: Out of the 43 patients who underwent definitive treatment, 25 had acute cholecystitis and 18 had chronic cholecystitis. The average CAv measurements were 50 ± 16 cm/sec (acute), 28 ± 8 cm/sec (chronic), and 22 ± 8 cm/sec (control). Acute cholecystitis was associated with CAv 40 cm/sec, gallbladder wall thickening, stone impaction, gallbladder long dimension 8 cm, and elevated WBC.
  • Conclusion and remarks: CAv 40 cm/sec is highly associated with acute cholecystitis. This can serve as a helpful biomarker for this disease.

 

Ultrasound Liver Imaging Reporting and Data System (US LI-RADS) Visualization Score: A Reliability Analysis on Inter-reader Agreement

Tiyarattanachai T, Bird KN, Lo EC, et al.

Abdominal Radiology. 2021.

doi:10.1007/s00261-021-03067-y

 

  • Background: The ACR US LI-RADS Visualization Score helps convey the expected level of sensitivity of the examination for detecting focal liver observations in patients at risk for hepatocellular carcinoma (HCC). The inter-reader agreement of this score is unknown.
  • Question: What is the inter-reader agreement for US LI-RADS Visualization Score?
  • Inclusion criteria: Consecutive US HCC screening and surveillance studies were included and randomly sampled to include for analysis.
  • Design: This retrospective study reviewed 6998 US HCC screening and surveillance studies, of which 90 samples were randomly analyzed to include 30 studies in each Visualization category. Nine radiologists were blinded to the original categorization and independently reviewed each study and assigned a Visualization Score. Inter-reader agreement was quantified using intraclass correlation coefficient (ICC).
  • Results: The ICC among all nine radiologists was 0.70; the ICCs among senior attendings, junior attendings, and body imaging fellows were 0.68, 0.72, and 0.76, respectively. ICC was the highest for patients with normal liver parenchyma, followed by steatosis and cirrhosis.
  • Conclusion and remarks: There is good inter-reader agreement in US LI-RADS Visualization Score, which is a helpful tool to convey the expected level of sensitivity of the examination for detecting focal liver observations.

 

Pediatric Imaging

Feasibility and Safety of Neonatal Brain Contrast-Enhanced Ultrasound: A Prospective Study Using MRI as Reference Standard

Squires JH, Beluk NH, Lee VK, et al.

American Journal of Roentgenology. 2021.

doi:10.2214/AJR.21.26274

 

  • Background: MRI is the standard imaging modality for evaluating the neonatal brain; however, this can be expensive, time-consuming, and limited by availability and accessibility. Transfontanelle neonatal contrast-enhanced (CEUS) can be an excellent alternative imaging modality to assess for brain injury.
  • Question: Is CEUS a feasible, safe, and diagnostic modality to assess the neonatal brain compared to MRI?
  • Inclusion criteria: Neonates in the neonatal ICU who underwent MRI and portable brain US and CEUS.
  • Design: This prospective study included neonates who underwent MRI, portable brain US, and CEUS. Adverse events were recorded. Two radiologists independently evaluated the US and CEUS images, and another radiologist reviewed the MRI examinations. The sensitivity, specificity, and inter-reader agreement were evaluated.
  • Results: This prospective study included 26 neonates (9 boys, 17 girls). There were no adverse events. The mean examination time was significantly shorter for CEUS compared to MRI. There was excellent inter-reader agreement. CEUS demonstrated 87.5% sensitivity for acute/subacute ischemia and 100% sensitivity for chronic ischemia, and 100% specificity for acute/subacute ischemia and chronic ischemia. However, sensitivity for subdural and intraparenchymal hemorrhage was poor on both US and CEUS.
  • Conclusion and remarks: Portable brain CEUS is a safe, more rapid, and feasible imaging modality compared to MRI. It can potentially help diagnose ischemia in neonates.

 

Cranial US in Infants Exposed to Zika Virus: The NATZIG Cohort

Teixeira SR, Elias Jr, J, Coutinho CM, et al.

Radiology. 2021.

doi:10.1148/radiol.2021204150

 

  • Background: There is a wide range of central nervous system changes in infants exposed to the Zika virus. There are very few studies that evaluated infants with mild manifestations. Brain US can potentially reveal these features.
  • Question: What are the US features of prenatal Zika virus exposure? How frequent are these findings in infants exposed to Zika virus compared to control infants?
  • Inclusion criteria: Infants born to women with laboratory-confirmed Zika virus infection. Infants born to mothers not infected with Zika virus served as the control group.
  • Design: This prospective study included infants during the December 2015-July 2016 outbreak of Zika virus infection in southeast Brazil. The infants underwent US, and maternal Zika virus infection was confirmed with RNA polymerase chain testing. A control group included infants born to mothers who tested negative for Zika virus infection during pregnancy. Two radiologists independently reviewed brain US examinations for both groups and categorized their findings.
  • Results: There were 220 Zika virus-exposed infants born to 219 mothers infected with Zika virus. There were 170 control infants. Mild finding of lenticulostriate vasculopathy was frequently identified in Zika virus-exposed infants (6%) compared to control infants (1%).
  • Conclusion and remarks: Lenticulostriate vasculopathy is a common finding in infants with prenatal exposure to Zika virus.

 

 

Vascular Imaging

 

US Velocimetry in Participants with Aortoiliac Occlusive Disease

Engelhard S, van Helvert M, Voorneveld J, et al.

Radiology. 2021.

doi:0.1148/radiol.2021210454

 

  • Background: Blood flow patterns are correlated with the development and progression of atherosclerotic disease. Currently, there is no reliable method in obtaining accurate quantification of blood flow for aortoiliac stenosis. High-frame-rate contrast-enhanced US (HFR-CEUS) with particle image velocimetry (PIV) can potentially address this.
  • Question: Can HFR-CEUS and PIV help quantify blood flow in aortoiliac arteries in patients with aortoiliac stenosis?
  • Inclusion criteria: Patients with aortoiliac stenosis who underwent HFR-CEUS.
  • Design: This prospective study evaluated patients with aortoiliac stenosis and their HFR-CEUS measurements of the pre- and post-stenotic vessel segments. Quantification of blood flow was done using PIV analysis.
  • Results: There were 35 patients included in this study. Flow quantification was achieved using PIV in 41 out of 42 locations. In 25 locations, there were several issues that limited optimal flow quantification. Optimal quantification was achieved in the remaining 16 locations.
  • Conclusion and remarks: Blood flow quantification with US velocimetry can be done to assess blood flow disturbances, which can influence the development and progression of atherosclerotic disease. However, this method is not yet implemented in clinical practice due to its limitations.

 

 

Women’s Imaging

ACORE US Blog – October 2021

Axillary Nodal Metastases in Invasive Lobular Carcinoma versus Invasive Ductal Carcinoma: Comparison of Node Detection and Morphology by Ultrasound

Chung HL, Tso HH, Middleton LP, et al.

American Journal of Roentgenology. 2021.

doi:10.2214/AJR.21.26135

 

  • Background: Invasive lobular carcinoma is more often occult on imaging compared to invasive ductal carcinoma. Since they have different imaging appearances, their nodal metastases may also have different appearances on US.
  • Question: What is the detection rate of metastatic axillary lymph nodes? What are their US features in invasive lobular carcinoma compared with invasive ductal carcinoma?
  • Inclusion criteria: Women with breast cancer, biopsy-proven axillary nodal metastases, and pretreatment breast US at a single institution.
  • Design: This retrospective study included 695 women with breast cancer with a total of 723 breasts (76 lobular, 586 ductal, 61 mixed) with biopsy-proven axillary nodal metastases. They underwent pretreatment US examinations, which were reviewed by a breast radiologist. The suspicious lymph nodes were classified by node number, size, and morphology. These findings were compared between lobular and ductal carcinoma. A second radiologist independently classified the node morphology in 241 cancers.
  • Results: There were 99 total metastatic axillary nodes that were not visualized on US and diagnosed by surgical biopsy. The remaining 624 metastatic nodes (61 lobular, 520 ductal, 43 mixed) were seen on US and diagnosed with US-guided fine needle aspiration (FNA). The detection rate was 80.3% for lobular carcinoma and 88.7% for ductal carcinoma. US demonstrated a lower detection rate for axillary nodal metastases in lobular carcinoma (80.3%) than in ductal carcinoma (88.7%). Metastatic nodes exhibited diffuse cortical thickening without hilar mass effect in 68.9% of lobular carcinoma versus 28.8% of ductal carcinoma.
  • Conclusion and remarks: US detects a smaller amount of nodal metastases in lobular compared to ductal carcinoma. Lobular carcinoma nodal metastases tend to demonstrate diffuse cortical thickening and less hilar mass effect compared to that of ductal carcinoma. Therefore, biopsy should be pursued at a lower threshold for any suspicious axillary nodes in patients with lobular carcinoma.
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