Ultrasound imaging in thyroid nodule diagnosis, therapy, and follow-up: Current status and future trends.

Ultrasound, the primary imaging modality in thyroid nodule management, suffers from drawbacks including: high inter- and intra-observer variability, limited field-of-view and limited functional imaging. Developments in ultrasound technologies are taking place to overcome these limitations, including three-dimensional-Doppler, -elastography, -nodule characteristics-extraction, and novel machine-learning algorithms. For thyroid ablative treatments and biopsies, perioperative use of three-dimensional ultrasound opens a new field of research. This review provides an overview of the current and future applications of ultrasound, and discusses the potential of new developments and trends that may improve the diagnosis, therapy, and follow-up of thyroid nodules.

The added value of conventional defecography and MRI defecography in clinical decision making on treatment for posterior compartment prolapse.

INTRODUCTION AND HYPOTHESIS: Conventional defecography and MRI defecography can be requested as an additional test for diagnosing and differentiating the type of posterior compartment prolapse and/or obstructive defecation disorders. The objective of this study was to determine the added value of conventional defecography, conventional defecography and MRI defecography for clinical decision-making on treatment for patients with posterior compartment prolapse. METHODS: Four gynecologists were asked to fill in their treatment plan per patient for 32 cases for three different steps. Step 1 consisted of information on the anamnesis and physical examination (POP-Q). Step 2 consisted of Step 1, including conventional defecography (group A) or MRI defecography (group B). In Step 3, all gynecologists received the information on Step 1 including both conventional defecography and MRI defecography. Data analysis solely focused on the assessment of changes in the gynecological treatment plan of the posterior compartment. RESULTS: After Step 2 a change in treatment plan occurred in 37% and 48% of the women in groups A and B, respectively. Accordingly, after Step 3 (including all imaging data), a change in treatment plan occurred in 19% and 52% of the women in groups A and B, respectively. A change within the surgery group (when a different type of surgery was selected) was seen for a total of 11 cases in group A and 20 in group B in all steps combined. CONCLUSIONS: Both conventional defecography and MRI defecography had an large effect on the treatment plan for patients with posterior compartment prolapse. The dedicated added value of the imaging modality individually cannot be concluded yet.

Yield of Screening for COVID-19 in Asymptomatic Patients Before Elective or Emergency Surgery Using Chest CT and RT-PCR (SCOUT): Multicenter Study.

OBJECTIVE: To determine the yield of preoperative screening for COVID-19 with chest CT and RT-PCR in patients without COVID-19 symptoms. SUMMARY OF BACKGROUND DATA: Many centers are currently screening surgical patients for COVID-19 using either chest CT, RT-PCR or both, due to the risk for worsened surgical outcomes and nosocomial spread. The optimal design and yield of such a strategy are currently unknown. METHODS: This multicenter study included consecutive adult patients without COVID-19 symptoms who underwent preoperative screening using chest CT and RT-PCR before elective or emergency surgery under general anesthesia. RESULTS: A total of 2093 patients without COVID-19 symptoms were included in 14 participating centers; 1224 were screened by CT and RT-PCR and 869 by chest CT only. The positive yield of screening using a combination of chest CT and RT-PCR was 1.5% [95% confidence interval (CI): 0.8-2.1]. Individual yields were 0.7% (95% CI: 0.2-1.1) for chest CT and 1.1% (95% CI: 0.6-1.7) for RT-PCR; the incremental yield of chest CT was 0.4%. In relation to COVID-19 community prevalence, up to ∼6% positive RT-PCR was found for a daily hospital admission rate >1.5 per 100,000 inhabitants, and around 1.0% for lower prevalence. CONCLUSIONS: One in every 100 patients without COVID-19 symptoms tested positive for SARS-CoV-2 with RT-PCR; this yield increased in conjunction with community prevalence. The added value of chest CT was limited. Preoperative screening allowed us to take adequate precautions for SARS-CoV-2 positive patients in a surgical population, whereas negative patients needed only routine procedures.

The Use of Laser Guidance Reduces Fluoroscopy Time for C-Arm Cone-Beam Computed Tomography-Guided Biopsies.

PURPOSE: When using laser guidance for cone-beam computed tomography (CBCT)-guided needle interventions, planned needle paths are visualized to the operator without the need to switch between entry- and progress-view during needle placement. The current study assesses the effect of laser guidance during CBCT-guided biopsies on fluoroscopy and procedure times. MATERIALS AND METHODS: Prospective data from 15 CBCT-guided biopsies of 8-65 mm thoracic and abdominal lesions assisted by a ceiling-mounted laser guidance technique were compared to retrospective data of 36 performed CBCT-guided biopsies of lesions >20 mm using the freehand technique. Fluoroscopy time, procedure time, and number of CBCT-scans were recorded. All data are presented as median (ranges). RESULTS: For biopsies using the freehand technique, more fluoroscopy time was necessary to guide the needle onto the target, 165 s (83-333 s) compared to 87 s (44-190 s) for laser guidance (p < 0.001). Procedure times were shorter for freehand-guided biopsies, 24 min versus 30 min for laser guidance (p < 0.001). CONCLUSION: The use of laser guidance during CBCT-guided biopsies significantly reduces fluoroscopy time.

Feasibility study of needle placement in percutaneous vertebroplasty: cone-beam computed tomography guidance versus conventional fluoroscopy.

OBJECTIVE: To investigate the accuracy, procedure time, fluoroscopy time, and dose area product (DAP) of needle placement during percutaneous vertebroplasty (PVP) using cone-beam computed tomography (CBCT) guidance versus fluoroscopy. MATERIALS AND METHODS: On 4 spine phantoms with 11 vertebrae (Th7-L5), 4 interventional radiologists (2 experienced with CBCT guidance and two inexperienced) punctured all vertebrae in a bipedicular fashion. Each side was randomization to either CBCT guidance or fluoroscopy. CBCT guidance is a sophisticated needle guidance technique using CBCT, navigation software, and real-time fluoroscopy. The placement of the needle had to be to a specific target point. After the procedure, CBCT was performed to determine the accuracy, procedure time, fluoroscopy time, and DAP. Analysis of the difference between methods and experience level was performed. RESULTS: Mean accuracy using CBCT guidance (2.61 mm) was significantly better compared with fluoroscopy (5.86 mm) (p < 0.0001). Procedure time was in favor of fluoroscopy (7.39 vs. 10.13 min; p = 0.001). Fluoroscopy time during CBCT guidance was lower, but this difference is not significant (71.3 vs. 95.8 s; p = 0.056). DAP values for CBCT guidance and fluoroscopy were 514 and 174 mGy cm(2), respectively (p < 0.0001). There was a significant difference in favor of experienced CBCT guidance users regarding accuracy for both methods, procedure time of CBCT guidance, and added DAP values for fluoroscopy. CONCLUSION: CBCT guidance allows users to perform PVP more accurately at the cost of higher patient dose and longer procedure time. Because procedural complications (e.g., cement leakage) are related to the accuracy of the needle placement, improvements in accuracy are clinically relevant. Training in CBCT guidance is essential to achieve greater accuracy and decrease procedure time/dose values.

3D cone-beam CT guidance, a novel technique in renal biopsy--results in 41 patients with suspected renal masses.

OBJECTIVE: To determine whether 3D cone-beam computed tomography (CBCT) guidance allows safe and accurate biopsy of suspected small renal masses (SRM), especially in hard-to-reach anatomical locations. MATERIALS AND METHODS: CBCT guidance was used to perform 41 stereotactic biopsy procedures of lesions that were inaccessible for ultrasound guidance or CT guidance. In CBCT guidance, a 3D-volume data set is acquired by rotating a C-arm flat-panel detector angiosystem around the patient. In the data set, a needle trajectory is determined and, after co-registration, a fusion image is created from fluoroscopy and a slice from the data set, enabling the needle to be positioned in real time. RESULTS: Of the 41 lesions, 22 were malignant, 17 were benign, and 2 were nondiagnostic. The two nondiagnostic lesions proved to be renal cell carcinoma. There was no growth during follow-up imaging of the benign lesions (mean 29 months). This resulted in a sensitivity, specificity, PPV, NPV, and accuracy of 91.7, 100, 100, 89.5, and 95.1%, respectively. Mean dose-area product value was 44.0 Gy·cm(2) (range 16.5-126.5). There was one minor bleeding complication. CONCLUSION: With CBCT guidance, safe and accurate biopsy of a suspected SRM is feasible, especially in hard-to-reach locations of the kidney. KEY POINTS : • Cone-beam computed tomography has potential advantages over conventional CT for interventional procedures. • CBCT guidance incorporates 3D CBCT data, fluoroscopy, and guidance software. • In hard-to-reach renal masses, CBCT guidance offers an alternative biopsy method. • CBCT guidance offers good outcome and safety and has potential clinical significance.

Pulmonary masses: initial results of cone-beam CT guidance with needle planning software for percutaneous lung biopsy.

PURPOSE: To evaluate the outcome of percutaneous lung biopsy (PLB) findings using cone-beam computed tomographic (CT) guidance (CBCT guidance) and compared to conventional biopsy guidance techniques. METHODS: CBCT guidance is a stereotactic technique for needle interventions, combining 3D soft-tissue cone-beam CT, needle planning software, and real-time fluoroscopy. Between March 2007 and August 2010, we performed 84 Tru-Cut PLBs, where bronchoscopy did not provide histopathologic diagnosis. Mean patient age was 64.6 (range 24-85) years; 57 patients were men, and 25 were women. Records were prospectively collected for calculating sensitivity, specificity, positive predictive value, negative predictive value, and accuracy. We also registered fluoroscopy time, room time, interventional time, dose-area product (DAP), and complications. Procedures were divided into subgroups (e.g., location, size, operator). RESULTS: Mean lesion diameter was 32.5 (range 3.0-93.0) mm, and the mean number of samples per biopsy procedure was 3.2 (range 1-7). Mean fluoroscopy time was 161 (range 104-551) s, room time was 34 (range 15-79) min, mean DAP value was 25.9 (range 3.9-80.5) Gy·cm(-2), and interventional time was 18 (range 5-65) min. Of 84 lesions, 70 were malignant (83.3%) and 14 were benign (16.7%). Seven (8.3%) of the biopsy samples were nondiagnostic. All nondiagnostic biopsied lesions proved to be malignant during surgical resection. The outcome for sensitivity, specificity, positive predictive value, negative predictive value, and accuracy was 90% (95% confidence interval [CI] 86-96), 100% (95% CI 82-100), 100% (95% CI 96-100), 66.7% (95% CI 55-83), and 91.7% (95% CI 86-96), respectively. Sixteen patients (19%) had minor and 2 (2.4%) had major complications. CONCLUSION: CBCT guidance is an effective method for PLB, with results comparable to CT/CT fluoroscopy guidance.

Effective dose during needle interventions: cone-beam CT guidance compared with conventional CT guidance.

PURPOSE: To determine effective radiation dose to patients during needle interventions with cone-beam computed tomography (CT) guidance and compare it with the dose during conventional CT-guided interventions. MATERIALS AND METHODS: Cone-beam CT guidance is a recently developed technique with image acquisition on a flat-panel detector digital angiography system. It is based on a combination of acquired three-dimensional soft-tissue cone-beam CT, dedicated needle trajectory software, and fluoroscopy, providing stereotactic needle guidance. To analyze effective dose, we prospectively recorded all contributing parameters necessary to calculate it in 92 needle interventions (in 88 patients [60 men]; mean age, 63.9 y) using a Monte Carlo program. For CT guidance, we retrospectively scored the necessary parameters during 137 needle interventions (118 patients [81 men]; mean age, 59.5 y) to calculate effective dose with a CT patient dosimetry calculator. The needle interventions were categorized in four regions. RESULTS: Total mean effective doses with cone-beam CT guidance were 7.6 mSv in the upper thorax, 12.3 mSv in the lower thorax, 16.1 mSv in the upper abdomen, and 13.4 mSv in the lower abdomen. Effective doses with uncollimated cone-beam CT alone were 2.0, 2.9, 4.2, and 3.5 mSv in the respective regions. Effective doses with CT-guided interventions were 13.0, 15.1, 20.4, and 15.4 mSv in the respective regions. Cone-beam CT guidance results in a reduction of 13%-42% of total effective dose compared with conventional CT guidance. The dose reduction is mainly attributable to cone-beam CT, not to fluoroscopy. CONCLUSIONS: A new needle intervention technique with cone-beam CT guidance results in a considerable effective dose reduction for patients compared with conventional CT guidance.