HARVARD

MEDICAL SCHOOL

MASSACHUSETTS

GENERAL HOSPITAL

Oncological Applications of

Dual Energy CT in the Abdomen

Avinash Kambadakone, MD FRCR

Disclosures

• Avinash Kambadakone – Nothing to Disclose

Aims and Objectives

• To review the technical aspects of DECT with particular focus on

oncology and tips for protocol optimization

• Discuss the potential role and limitations of DECT in oncology

• Describe our experience with integration of DECT in oncologic imaging

practice

• Case-based discussion on clinical value of DECT in cancer patients

I- I+ I- I+

SECT: Limitations

Need for non-contrast scans

Presence of Artifacts

(Beam hardening, metal

streak artifacts)

Post treatment assessment

Small lesion evaluation

Need for multiphasic scans

Courtesy: Dushyant Sahani, MD

DECT: Advantages in Oncology 1. Improved lesion Characterization

a. hemorrhagic cysts vs solid renal masses

b. hepatic cysts vs hypodense metastases

2. Improve lesion detection

a. Virtual precontrast (water density) images

b. Reduced beam hardening

c. Low kVp/ monochromatic Kev images

3. Reduce dose

a. Eliminate non-contrast exams

b. Decrease follow-up CT of indeterminate lesions

4. Metal Artifact Reduction

DECT in Oncology

• Tumor Detection

• Tumor Characterization

• Treatment Planning

• Monitoring Treatment Response

DECT: Tumor Detection • Low energy virtual mono-chromatic images improve detection of both

hypervascular and hypovascular lesions

• Iodine-specific maps improve detection of hypovascular lesions in the liver,

pancreas and kidney

• DECT improves depiction of hepatocellular carcinoma and hypervascular liver

metastases

• Improves detection and staging of pancreatic cancer

140 keV

DECT- Improved Detection

• DECT allows improved detection of small hypervascular HCC lesions

• Low keV and iodine images can be exploited to enable superior lesion

evaluation

70 keV 50 keV

Improved visualization of multifocal HCC on low keV images

CECT

MD iodine MD iodine

DECT - Improved Detection

Iodine specific images improve detection of hypovascular lesions

DECT: Tumor Characterization

• Iodine specific images demonstrate iodine in tissues and aid in

lesion characterization

• Iodine specific images can help differentiate renal cysts from

solid neoplasms

• DECT allows characterization of adrenal nodules

• Iodine maps may help differentiate between blood clot and

tumors e.g. bland versus tumor thrombus

Small

cyst

MD Iodine

Renal

mass

TNC Iodine map TNC CECT

DECT: Tumor Characterization

Virtual unenhanced images and Iodine images, helps differentiate

renal masses from cystic lesions

DECT: Treatment Planning

Adenocarcinoma of the pancreas: Hypoattenuating lesion in the tail of the pancreas

(arrow) with margins unclearly defined in CECT image. The VMC image at 50 keV

and iodine map can better define the margins of the lesion as well as its relationship

with vessels, contributing to a better treatment planning.

CECT 50 keV Iodine map

Coursey, C. A. et al. Radioghraphics 30(4), 1037–1055, Silva, A. C et al. Radiographics 31(4), 1031–1046, Kulkarni N et al. JVIR 2012

DECT: Monitoring Response

Iodine maps obtained from dual energy acquisition allows detection of enhancement in

ablation zone to identify residual tumor/ recurrence in HCC

Iodine map Color overlay image

Dual energy CT

• Qualitative and quantitative

iodine extraction from processed

DECT data sets enables more

accurate detection of

residual/recurrent tumor.

• Vascular or parenchymal

complications

• Quantitative response monitoring

using tissue iodine values

HCC: RFA + TACE

HCC: post RFA

• Establish the image series to be sent to PACS

Our Practice Cancer follow up protocol CT

Limit DECT scans/day to cause minimal impact on workflow

140kVp (5mm) 65keV (5mm) MD-W (5mm) MD-I (5mm) Cor/Sag (3mm)

– Cancer follow up scans

– Renal-mass

– CTU

– Liver (HCC/hypervascular tumors)

– Pancreatic mass/staging

Oncology DECT Protocols

• Needs specialized hardware and software (Cannot upgrade

a SECT)

• Cost

• Accessibility

• Workflow constraints

• Patient body habitus

Oncology DECT Protocols

Conclusion

• Dual-energy CT has immense potential applications in

oncology in the abdomen

• DECT data sets not only allow enhanced lesion detection

and characterization but also permit treatment planning and

monitoring of treatment response