TiCEM – Mammography becomes functional technique
A new mammographic technique with dual energy and Titanium filter significantly increases the accuracy and sensitivity of mammography.
Is it possible to combine the excellent spatial resolution of mammography with a functional study based on neoangiogenesis? Yes, said Luis Pina from Pamplona, Spain, and introduced the audience to the concept of TiCEM – Titanium contrast-enhanced mammography.
Pina described TiCEM as a morpho-functional technique that is based on conventional mammography and information of neoangiogenesis. The technique uses a dual energy approach and obtains images of the breast using two different X-ray spectra. It takes advantage of the fact that tissue and iodinated contrast media show different attenuation coefficients at different tube voltages.
The shape of an X-ray spectrum depends on the peak voltage of the X-ray tube (kV), the anode material and the filtering of the X-ray beam. The mass attenuation coefficient of iodine shows a characteristic step at 33.2 keV, the so-called k-edge, explained Pina.
Therefore, TiCEM uses
- Low energy – usually 23-28 keV like in conventional digital mammography
- High energy – usually 45-49 keV
- Subtracted images
Why Titanium filter?
The Titanium filter optimizes the imaging process: It yields in a 60 percent higher tube output, substantially reduces the X-ray tube load and enables consecutive examinations without interruptions due to tube overheating.
Patients receive 1.5 ml/kg of an iodinated contrast medium at a flow rate of 3 ml/sec before the breast is compressed. Two minutes after intravenous contrast injection, craniocaudal (CC) and mediolateral oblique (MLO) views are carried out for each breast.
Indications for TiCEM
“We use TiCEM as problem solving technique”, said Pina, such as non-conclusive lesions after imaging with other modalities, and scars after conservative treatment.
Pina said that TiCEM would also be suitable for the
- Screening of intermediate-risk patients (not for high-risk patients – they require MRI)
- Preoperative staging of breast cancer
- Assessment of response to neoadjuvant chemotherapy (NAC)
- Patients contraindicated for MRI
Navarra University in Pamplona is one of three centers (Dortmund/Germany and Copenhague/Denmark) that collected a total of 200 TiCEM cases with pathological confirmation:
200 lesions in 129 patients underwent digital mammography, TiCEM, sonography, and percutaneous biopsy. Three blinded readers first evaluated the low energy images (LE), followed by the subtracted images. Additionally, they evaluated the breast density. Histopathology was used as gold standard.
118/200 lesions (59%) were malignant, 82/200 (41%) were benign. TiCEM was more accurate than LE for all readers. Sensitivities for LE vs TiCEM were 55.9% vs 83.9% for reader 1, 44.9% vs 71.2% for reader 2, and 50% vs 72% for reader 3. Specifities did not differ significantly between LE and TiCEM reading.
When Pina discussed some clinical cases, he said that TiCEM “could be superior than digital breast tomosynthesis to assess the lesion size” and showed good correlation with MRI. Furthermore, TiCEM was “not as much influenced by the ovarian cycle as MRI”.
By providing information on neoangiogenesis, TiCEM offers functional information of the breast lesions. It can be useful for the initial evaluation of a palpable lump or as a problem solver, summarized Pina. TiCEM significantly increases the accuracy and sensitivity of mammography without significant changes in specificity.
Presentation Title: TiCEM: When Mammography becomes a functional technique
Speaker: Luis Pina, University of Navarra, Pamplona, Spain
Date: February 27 2019
Session code: SY 2b