What’s new in Ultrasonography – September 2020

Abdominal Imaging

Primary Research

Comparison of imaging findings between acute focal bacterial nephritis (acute lobar nephronia) and acute pyelonephritis: a preliminary evaluation of the sufficiency of ultrasound for the diagnosis of acute focal bacterial nephritis

Hosokawa T, Tanami Y, Sato Y, Oguma E.

Emerg Radiol. 2020;27(4):405-412.

https://doi.org/10.1007/s10140-020-01771-8

Background: Treatment duration for acute focal bacterial nephritis (AFBN) differs from acute pyelonephritis and thus accurate diagnosis can make a clinical difference.
Question: Can US differentiate AFBN from acute pyelonephritis compared to CT?
Location: Saitama, Japan
Participants and inclusion criteria: 11 children with a urinary tract infection as well as a contrast enhanced CT and US within a 24 hour period.
Design: Retrospective design, comparing CT features (focal decreased enhancement) with US features (focal hyperechogenicity, abscess formation, and diffuse nephromegaly). For analysis Fisher’s exact test was used.
Results: 8 patients had AFBN and 3 had acute pyelonephritis (n=11 total). On US, there was a statistically significant difference in corticomedullary differentiation, which was lost in 8 (100%) of the AFBN cases and none (0%) of the acute pyelonephritis patients (P=0.01). These areas corresponded with hypoenhancement on CT in all cases. Two patients had multiple lesions on CT with only one focal abnormality identified on US. Focal hyperechogenicity, abscess formation, and diffuse nephromegaly on US was not statistically different between the two groups.
Conclusions and remarks: Ultrasound alone may be useful to diagnosis acute focal bacterial nephritis based on results from this small retrospective study.

Primary Research

Effects of Contrast-Enhanced Ultrasound of Indeterminate Renal Masses on Patient Clinical Management: Retrospective Analysis from Two Institutions

Eisenbrey JR, Kamaya A, Gummadi S, Bird K, Burrowes D, Arias D, Lallas CD, Trabulsi EJ, Lyshchik A.

Journal of Ultrasound in Medicine (2020).

https://doi.org/10.1002/jum.15383

Background: Incidentally determined renal lesions are common and previous studies have validated contrast-enhanced US (CEUS) as an effective tool in renal mass characterization.
Question: How does CEUS affect long term clinical management when used to assess indeterminate renal masses?
Location: Dual institution: Stanford University; Palo Alto, CA and Thomas Jefferson University, Philadelphia, PA
Participants and inclusion criteria: 215 renal lesions in 157 patients who had documented chronic renal disease or nephrectomy and had a CEUS prior to any treatment.
Design: Retrospective design, comparing malignancy and surgical rates of lesions after CEUS.
Results: in the 215 total lesions, 154 (71.6%) were recommended to either have surgical intervention or no follow up and 61 (28.4%) to be followed up. Among those 154, 118 were thought to be benign on CEUS and therefore did not undergo intervention. 24 (15.6%) underwent surgical intervention yielding malignancy in 21/24 samples (87.5%). None of the lesions deemed benign on CEUS were later suspicious for, or confirmed as, RCC.
Conclusions and remarks: CEUS can have an important long-term clinical impact in patients with indeterminate renal masses.

Primary Research

“Pseudogestational Sac” and Other 1980s-Era Concepts in Early First-Trimester Ultrasound: Are they Still Relevant Today?

Phillips CH, Benson CB, Durfee SM, Heller HT, Doubilet PM.

Journal of Ultrasound in Medicine. 2020 Feb 11.

https://doi.org/10.1002/jum.15243

Background: Many classic features in first-trimester OB US were described in the early days of US, including in the 1980s. A lot has changed with US in the more recent decades, including significantly improved resolution.
Question: Are classically described first-trimester sonographic features still relevant today?
Location: Brigham and Women’s Hospital, Boston, MA
Participants and inclusion criteria: 649 sonograms with an intrauterine saclike structure lacking a yolk sack or embryo, no extraovarian adnexal mass, and follow up information identifying the location of the pregnancy.
Design: Retrospective design. Sonograms were reviewed and features were recorded as present or absent including echogenic rim around the intrauterine collection, double sac sign (DSS), and intradecidual sign (IDS). The mean sac diameter was also recorded.
Results: 598 (92%) intrauterine collections had an echogenic rim, 182 (28%) had a DSS, and 347 (54%) an IDS. All 649 patients had a (later confirmed) intrauterine pregnancy, thus none of the fluid collections turned out to be a pseudogestational sac.
Conclusions and remarks: In patients with a positive bHCG and no sonographic findings of ectopic pregnancy, an intrauterine fluid collection is almost certain to be a gestational sac. The examined historical signs may not be useful today given increases in US resolution.

Primary Research

Contrast-enhanced ultrasound LI-RADS 2017: comparison with CT/MRI LI-RADS

Ding J, Long L, Zhang X, Chen C, Zhou H, Zhou Y, Wang Y, Jing X, Ye Z, Wang F.

European Radiology. 2020 Aug 15:1-8.

https://doi.org/10.1007/s00330-020-07159-z

Background: The ACR developed the CEUS liver imaging reporting and data system (LI-RADS) in 2016 and added it to version 2017 alongside CT and MRI.
Question: How does CEUS compare to CT and MRI using version 2017 LI-RADS?
Location: Tianjin, China
Participants and inclusion criteria: 239 patients with 273 nodules met the inclusion criteria of patients at high-risk for hepatocellular carcinoma (HCC) who underwent CEUS and either a CT or MRI with contrast. All patients had pathology available.
Design: Retrospective design. All imaging features were reviewed by at least two radiologists and categorized based on LI-RADS version 2017. Findings were compared to pathology as the reference standard. Intermodality agreement was calculated with Cohen’s kappa.
Results:
The agreement between CEUS and CT/MRI was fair with a kappa of 0.319 (P<0.001).

Conclusions and remarks: The inter-modality agreement between CEUS and CT/MRI using LI-RADS was only fair but with comparable positive predictive values for determining LR-5 lesions. CT/MRI is better for diagnosing LR-M (non-HCC) malignancy.

Primary Research

Differential diagnosis of liver metastases of gastrointestinal stromal tumors from colorectal cancer based on combined tumor biomarker with features of conventional ultrasound and contrast-enhanced ultrasound

Yang D, Zhuang B, Wang W, Xie X, Xie X.
Abdominal Radiology (New York) (2020).
https://doi.org/10.1007/s00261-020-02592-6

Background: Gastrointestinal stromal tumors (GIST) are the most common mesenchymal GI tumor, with around 1/5^th malignant. Liver metastasis are common and occasionally the first detected abnormality. The most common type of liver metastasis is from colorectal cancer (CRC).
Question: Using laboratory biomarkers, can US and CEUS accurately differentiate liver metastasis of GIST from CRC?
Location: Guangzhou, China
Participants and inclusion criteria: 160 total patients: 80 with GIST liver metastasis, and 80 with CRC metastasis to the liver. Patients had to have a CEUS available for analysis.
Design: Retrospective design. Sonographic features and laboratory biomarkers (CA125 and CEA) were recorded and analyzed with multivariate analysis.
Results: On US, hypoechogenicity, mixed echogenicity, and an anechoic area were each associated with GIST metastasis (P<0.05). With CEUS, capsular enhancement, washout starting at >40 seconds, and proportion of the non-enhancing area >20% were seen in GIST metastasis (P<0.05). When combining laboratory biomarkers with sonographic features the sensitivity improved to 70% and the specificity to 97.5%.
Conclusions and remarks: GIST liver metastases have sonographic features that are able to help differentiate from CRC metastasis to the liver, especially when combined with laboratory biomarkers (CA125 and CEA).

Primary Research

Contrast-enhanced US with Sulfur Hexafluoride and Perfluorobutane for the Diagnosis of Hepatocellular Carcinoma in Individuals with High Risk

Kang HJ, Lee JM, Yoon JH, Lee K, Kim H, Han JK.

Radiology, 200115.

https://doi.org/10.1148/radiol.2020200115

Background: Sulfur hexafluoride (SHF) is a purely intravascular US contrast agent that is widely used. Perfluorobutane (PFB) is a less widely available contrast that allows liver parenchyma evaluation in the Kupffer-phase by uptake of contrast into the Kupffer cells.
Question: How well do SHF and PFB contrasts compare in evaluating for HCC using LI-RADS version 2017?
Location: Seoul National University, Seoul, Korea
Participants and inclusion criteria: 59 participants, high risk for HCC and with non-treated LR-3 or greater observations.
Design: Prospective design. Patients underwent CEUS with PFB and SHF performed on the same day. Arterial phase hyperenhancement (APHE), time and degree of washout, and echogenicity during Kupffer phase for PFB were recorded. McNemar test was used for analysis.
Results: Mild and late washout (≥ 60 seconds) of HCC was more often seen using PFB (79%) than in SHF (53%) (P=0.04). Kupffer phase hypoenhancement using PFB was more common in malignant lesions (92%), than in benign lesions (33%). Sensitivity was 79% using PFB and 54% with SHF, while specificity was 100% for both.
Conclusions and remarks: Using LI-RADS version 2017, perfluorobutane CEUS had a higher diagnostic performance than sulfur hexafluoride.

Interventional Radiology

Primary Research

US guidance for portal vein access and percutaneous wire placement into the portal vein are associated with shorter procedure times and lower radiation doses during TIPS placement

Cam I, Gencturk M, Shrestha P, Golzarian J, Flanagan S, Lim N, Young S.

AJR Am J Roentgenol. 2020.

https://doi.org/10.2214/AJR.20.23846

Background: Transjugular intrahepatic portosystemic shunt (TIPS) can effectively treat many of the complications of portal hypertension and can be performed in a few different ways.
Question: Which treatment method is most efficient when performing TIPS?
Location: University of Minnesota, Minneapolis, MN
Participants and inclusion criteria: 264 patients who had a tips completed in 1 of 3 ways:
Group 1 (G1): Transabdominal US-guided
Group 2 (G2): Fluoroscopic guided with wedged-hepatic portography
Group 3 (G3): Percutaneous portal vein guidewire approach with fluoroscopy
Design: Retrospective design evaluating the fluoroscopic time, anesthesia time, contrast volume used, and number of intrahepatic needle passes.
Results:
See table for values and significant differences. Unlisted differences were not significant based on P≤0.005).
When complications from G1 and G3 were pooled, G2 had more complications (p=0.013)

Conclusions and remarks: US-guided (group 1) and percutaneous guidewire approach portal vein access (group 3) for TIPS may have shorter fluoroscopic and anesthesia times as well as potentially fewer complications.

Thoracic Radiology

Lung Ultrasound Findings in Patients with Coronavirus Disease (COVID-19)

Zhang Y, Xue H, Wang M, He N, Lv Z, Cui L.

AJR Am J Roentgenol. 2020;1-5.

https://doi.org/10.2214/AJR.20.23513

Background: CT findings of COVID-19 pneumonia have been well described but findings on lung US are less well documented.
Question: What are typical lung sonographic findings in COVID-19 pneumonia and is there a relationship with disease severity and duration?
Location: Capital Medical Center, Beijing, China
Participants and inclusion criteria: 28 patients (14 men and 14 women) who had a positive PCR test for SARS-CoV-2 and lung US.
Design: Retrospective design with the lung sonographic features evaluated and documented. Fisher’s exact test was used to compare with disease duration and severity.
Results: All 28 (100%) of patients had abnormal lung findings on US. The most common was B-lines in all 28 patients (100%), consolidation in 19 patients (67.9%), and thickened pleural lines in 17 patients (60.7%). Thickened pleural lines were associated with longer duration of disease and consolidation was more frequent in patients with severe cases (both p≤0.05).
Conclusions and remarks: B-lines, consolidation, and thickened pleural line are common sonographic findings in COVID-19 pneumonia with consolidation and thickened pleural line able to predict disease severity and duration, respectively.

Common Abbreviations:

US: Ultrasound
CEUS: Contrast-enhanced ultrasound
HCC: Hepatocellular carcinoma
CT: Computed tomography
MRI: Magnetic resonance imaging