Letter to the editor

Re: Distinguishing adrenal adenomas from non-adenomas with multidetector CT: evaluation of percentage washout values at a short time delay triphasic enhanced CT

We are writing to you about the original article published in November issue of BJR titled “Distinguishing adrenal adenomas from non-adenomas with multidetector CT: evaluation of percentage washout values at a short time delay triphasic enhanced CT”. The study retrospectively evaluated use of a short time delay CT protocol to distinguish adrenal adenomas from non-adenomas. As discussed in manuscript document, there are inconsistencies in CT protocol that we think requires further clarification from authors.

We thank you for your time and consideration.

It was with great interest that we read the paper published in November issue of The British Journal of Radiology titled “Distinguishing adrenal adenomas from non-adenomas with multidetector CT: evaluation of percentage washout values at a short time delay triphasic enhanced CT”.

The article presents an important advance in CT imaging of adrenal glands. The authors retrospectively evaluated use of triphasic CT with short delayed phase of 200 secs. The authors mention limitations of study however further clarification of the study protocol would be helpful.

A routine triphasic CT protocol with short delayed Phase is not performed routinely and it’s unlikely to be the case at the institution where this study was conducted. It only stands to reason that patients undergoing CT for surveillance of metastatic disease would be subjected to a different protocol than those with suspicion of or known history of adrenal masses. This could have been mitigated by tabulating clinical indications of all scans.

This is additionally complicated by statement in discussion section that “most cases of adenomas carried out both unenhanced and enhanced CT scans” implying that not all cases were subjected to the same triphasic protocol. This requires clarification.

Response to letter: “Distinguishing adrenal adenomas from non-adenomas with multidetector CT: evaluation of percentage washout values at a short time delay triphasic enhanced CT” by Khan et al

Liu et al., Department of Radiology, China-Japan Friendship Hospital

We appreciate the comments of Dr Khan et al, and we thank them for the interest in our recent publication in the British Journal of Radiology. We would like to make further clarification of the CT scan protocol in our study. Firstly, the unenhanced CT and enhanced CT are carried out separately at different time in our institution. It means that some patients receive unenhanced CT only, whereas others first receive unenhanced CT, then receive enhanced CT for further differential diagnosis. Secondly, abdomen enhanced CT use the same triphasic scan protocol after the bolus administration of the contrast agent in our institution, and this protocol is not specialized for adrenal lesions. Finally, this is a retrospective study, so we reviewed the patients with adrenal masses and selected cases carrying out both unenhanced and enhanced CT scans. Most of the adrenal lesions were discovered incidentally (incidentalomas) for other clinical problems. Some of the patients took only unenhanced CT and then underwent surgical operation or imaging follow-up. These patients were excluded in our study. Others took unenhanced CT at first and enhanced CT later, not only for differential diagnosis of adrenal lesions, but also for assessment of lesions in other organs, especially for detecting metastatic spread in patients with prior history of malignant diseases. We reviewed and analyzed these adrenal lesions in our article.