Introduction
Modern day clinical radiology imaging demands a wide variety of clinical depictions, such as the nature of the tumor, the chemical composition of the material, and imaging moving structures, etc. Fulfilling these imaging demands requires both technical and clinical capabilities in the acquiring systems. The ultimate aim of such technology is to enhance patient outcomes and clinical procedures. A dual-source dual-energy system, equipped with imaging techniques powered by native temporal resolution and sub-second scanning rotation speed, along with the highest pitch acquisition techniques, helps confidently attain images in challenging clinical conditions.
The scan technique
Patients were scanned on a SOMATOM Force DSCT scanner (Siemens Healthineers, Munich, Germany) using a variable AI-based acquisition technique that includes Turbo Flash protocols and dual-energy protocol. AI-based algorithms, combined with DE&DSCT techniques, ensure the highest image quality with the lowest possible dose. Automatic exposure control facilitates tube current modulation in kV and mA, adjusting according to patient size, and it is key to reducing contrast amount and patient dose.
Study discussion – Clinical Case 1
Spectral imaging with bilateral pulmonary thromboembolism and a hypodense filling defect, distending and filling the cranial aspect of the inferior vena cava (IVC) and extending into the right atrium.
Case Presentation
A 38-year-old male patient with a known history of pulmonary embolism and a follow-up study.
Imaging Protocol
• PE DECT 90/Sn150 kV, mAs 31/25 low-dose protocol with CareDose4D for automatic mAs and dose reduction.
• Collimation: 2 x 192 x 0.6 mm. TOTAL DLP 121 mGy·cm, CTDIvol for the specific series 1.66 mGy.
• Ultra-high-pitch acquisition with a rotation time of 0.25 sec. Dual-energy pulmonary angiography with multiplanar reformatted images revealed a few small hypodense thrombi within the right interlobar pulmonary artery. A hypodense filling defect is distending and filling the cranial aspect of the inferior vena cava and extending into the right atrium. Spectral virtual non-contrast and iodine-map depict and delineate the vascular nature of the embolism and the hypodense filling defect.
Conclusion
DECT acquisition and postprocessing techniques facilitate the ability of CT images in various clinical manners, such as material decomposition, iodine map, virtual known contrast, and monoenergetic imaging, which are useful in the evaluation of any contrast-enhancing lesion in the body. We can obtain a plain scan out of contrast scan (virtual non-contrast), leading to omit one scan and reduce patient dose. DE perfusion maps are to be generated for the evaluation of pulmonary thromboembolism. Dual-energy iodine maps also improve visualization of filling
defects in a small segmental or subsegmental artery. DECT follow-up studies seem to be more beneficial in terms of evaluating the treatment outcome in patients who are treated with anticoagulants.
Study discussion – Clinical Case 2
Case Presentation
A 40-year-old male presented with a history of severe lower abdominal pain. Ultrasound revealed multiple stones and suggested a dual-energy scan to identify the type of the stone for further clinical management.
Imaging Protocol
• DEUT 100/Sn150 kV, mAs 152/76 with CareDose4D for automatic mAs and dose reduction.
• Collimation: 2 x 192 x 0.6 mm. TOTAL DLP 707 mGy·cm, CTDIvol for the specific series 8.89 mGy, rotation time of 0.5 sec.
Dual-energy of the renal stone depicts the chemical composition of the stone. An automated renal stone characterization and analysis application color codes the stones according to their composition and measures the volume automatically. Colorcoded multiple variable-sized dense stones are seen within the urinary bladder resting on the posterior wall. The largest one measures about 1.8 x 1.8 x 1.8 cm. The system-generated characterization graph of the stone reveals the composition as a uric acid stone.
Contact
Professor of Radiology, Cairo University