Vaios Hatzoglou MD, Presenter: Nothing to Disclose

Sasan Karimi MD, Abstract Co-Author: Nothing to Disclose

The describe the presence and frequency of T1 shortening (T1s) unrelated to hemorrhage that is observed in the region of enhancing neoplastic disease when primary CNS lymphoma (PCNSL) undergoes treatment.

We retrospectively identified 221 patients with pathologically confirmed PCNSL and reviewed their imaging studies and treatment histories. All relevant CT scans and MRI sequences, including fast spin echo T2, gradient echo, pre- and post-contrast T1, were assessed in order to identify the frequency of post-treatment T1 shortening that was not due to blood products.

Out of 221 patients, only 119 (60 men, 59 women) met the eligibility criteria. The median age was 65 at the time of the last scan prior to treatment initiation. All of the patients were immunocompetent. Methotrexate was the most commonly administered drug (98%) followed by steroids (92%). Seventeen patients (17%) received radiation therapy. Seventy five patients (63%) developed non-hemorrhagic T1 shortening after treatment. The median time until T1 shortening was 39 months (26 – 51), and the duration of T1 shortening was 7.1 months (6 days – 58.4 months). All of the patients that developed non-hemorrhagic T1 shortening received methotrexate.

The development of non-hemorrhagic T1 shortening in patients treated for PCNSL has not been described before in the literature. The etiology of the T1 shortening is indeterminate but may reflect the cellular response to treatment on a biochemical scale. For example, methotrexate results in homocysteine accumulation which leads to oxidative stress and free radicals causing paramagnetic T1 shortening. Methotrexate also leads to stimulation of NMDA receptors with high calcium influx causing cell death and additional T1 shortening.

Non-hemorrhagic T1s in treated PCNSL is possibly related to methotrexate treatment response and merits additional studies focusing on patient outcome and assessment of prognostic significance.

Hatzoglou, V, Karimi, S, Post Treatment T1 Shortening in Primary CNS Lymphoma.  Radiological Society of North America 2010 Scientific Assembly and Annual Meeting, November 28 - December 3, 2010 ,Chicago IL. http://archive.rsna.org/2010/9012907.html