Contrast ultrasound dispersion imaging (CUDI) as a diagnostic modality in the diagnosis of renal cell carcinoma.

Renal cell carcinoma (RCC) is a neoplasm that represents 2-3% of all cancers.
Nowadays, clinical diagnosis is based on a combination of physical examination,
laboratory findings, and imaging. Most kidney tumors are diagnosed by an
abdominal ultrasound, CT scan or MRI that is performed for other medical
reasons. On imaging, a highly suspicious renal mass can be diagnosed, however,
differentiating between benign or malignant is not yet possible. To reveal the
histology of a suspicious tumor, a renal tumor biopsy (RTB) can be performed.
RTB*s are performed under local anesthesia and can be performed by either core
needle or fine needle aspiration. The morbidity of RTB*s is low, but not
non-existent. Risks of the biopsy procedure include haematomas, infection and
recently there has been some discussion about possible tumor seeding in the
needle tract. Another diagnostic modality with less risks is therefore needed.

Contrast enhanced ultrasound (CEUS) is an already prior researched technique
that could fill this gap. With this technique, an ultrasound scan is made with
the support of ultrasound contrast agents, so called microbubbles. By using
those bubbles, micro vasculature can be visualised. Prior research has shown
that CEUS has a sensitivity of 93% for characterising kidney laesions. De
specificity however was mediocre, around 72.5%. Possible problems with CEUS
leading to this low specificity are the subjective and difficult
interpretation, which makes the interpretation of CEUS images difficult outside
of centres of excellence. For this reason, a more objective and reliable
interpretation by quantification of CEUS is needed.

Together with the Technische Universiteit Eindhoven, previous researchers in
Amsterdam UMC have developed a quantification method based on the diffusion or
dispersion of contrast agent in the tissue: Contrast Ultrasound Dispersion
Imaging (CUDI). The method builds on the interpretation of the contrast agent
kinetics as a convective dispersion process. By using CUDI, local parameters
kan by extracted in order to build a parametric map of dispersion that can
visualise underlying microcirculation.

The main goal of this study is to assess whether CUDI-quantification of CEUS
can successfully be correlated to malignant pathology results of kidney tissue.

This study will be set up as a prospective, mono center, pilot study. This is a
study in which patients that have already been planned for a partial or radical
nephrectomy will receive a bolus of contrast fluid, prior to the nephrectomy
and after start of anesthesia. After this bolus, CEUS-images of the kidney will
be made. Those images will be saved and, at a later moment, be quantified by
means of CUDI. Also, we will investigate whether this quantification can be
correlated to a pathology result.

There is a small anticipated risk for participants. After use in millions of
patients, adverse events to the both contrast agents appear to be transient,
mild and rare. The side effects of the ultrasound contrast agent mostly consist
of transient alteration of taste, local pain at the injection site and facial
or general flush. In rare cases allergic reaction is described. For more
information see section 6 (Ultrasound and SonoVue® contrast agent). The
additional targeted biopsies pose a minor increase in the risk of infection.
The risk of infection will be minimized by providing an antibiotic prophylaxis,
as part of the standard care, and pausing of anticoagulant medication when it
is necessary and safe (depending on the indication for anticoagulant therapy
and type of anticoagulants used).

Patients will be informed of the risk during intake, and it will be described
in the study information.
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