MR‐monitored LITT as a palliative concept in patients with high grade gliomas: Preliminary clinical experience

Abstract

The purpose of this study was to evaluate the clinical utility of laser-induced thermotherapy (LITT) as a palliative treatment for patients with high-grade gliomas. Four consenting patients with recurrent high grade III/IV gliomas near the primary language or motor areas were palliatively treated with LITT (2-5 W, 3-13 minutes; Neodym YAG Laser, Dornier, Friedrichshafen, Germany). Temperature monitoring was performed by T1-weighted turbo-fast low-angle shot (FLASH) imaging at 1.5 T (Siemens Magnetom SP 4000, Siemens, Erlangen, Germany). MRI studies before LITT included contrast-enhanced conventional scans and functional activation studies to localize the primary motor cortex or language areas using an echo-planar imaging (EPI) spin-echo (SE) sequence. Follow-up studies consisted of contrast-enhanced conventional scans as well as diffusion studies (contrast-enhanced Fourier-acquired steady-state technique and EPI-SE) and perfusion studies (EPI-SE with .2 mmol of gadolinium (Gd)/kg body weight) to differentiate post-therapeutic effects from residual or recurrent tumor growth. Local tumor control was achieved in areas with laser energy deposition with clinically stable conditions > or = 6 months. Conventional contrast-enhanced scans demonstrated strong enhancement surrounding ablated tumor components, which showed a reduction in CBV/CBF. Perfusion studies were useful to discriminate granulomatous tissue enhancement from residual or recurrent tumor growth. Careful application of LITT may evolve as an alternative palliative concept for patients with end-stage high-grade cerebral gliomas reducing clinical symptoms from circumscribed areas of pathology.

Multiplanar MR temperature‐sensitive imaging of cerebral thermal treatment using interstitial ultrasound applicators in a canine model

“…MAGNETIC RESONANCE IMAGING (MRI) guidance for thermal treatment of brain neoplasms has been examined in several clinical studies (1)(2)(3)(4)(5)(6)(7)(8). MRI is used to localize tumors for treatment planning, to guide placement of the treatment applicator within the tumor, and to provide visualization of the effects post-therapy.…”

“…Previous clinical studies used either laser (1,(3)(4)(5)(6)(7)(8) or radiofrequency (RF) (2) devices to deliver thermal energy to intracerebral tumors. Recent laboratory and in vivo studies showed that interstitial ultrasound applicators with multielement construction can provide a spatial control of thermal coagulation (12)(13)(14)(15)(16)(17), and that these applicators appeared to be compatible with the use of MRI (18).…”

Interstitial laser irradiation of cerebral gliomas – neurobiological background, technique and typical results

“…Although laser irradiation of brain tumors has been described early [8,16,17] most of the work refers to astrocytomas of WHO grade II-III and gliosarcomas [18]. In these studies, laser irradiation was performed with comparatively low irradiation doses [8,16,17] and less sophisticated application devices [8,16].…”

“…It could be shown in clinical trials that the disruption of the BBB in areas with otherwise uncompromised BBB can result in an improved clinical outcome of chemotherapy of brain tumors [18]. This is possibly due the fact that these areas of tumor infiltration into the surrounding healthy tissue with intact BBB are the most active parts of the tumor, characterized by a large fraction of cycling cells [21].…”

Image-guided thermal ablation with MR-based thermometry

“…Although requires contact with the targeted lesion, laser induced thermal therapy commonly uses fiber-optic probe, which does not produce large image artifacts caused by electromagnetic interference, as in RFA. The feasibility of performing MR guided high intensity focused ultrasound (MRgHIFU) and MR guided laserinduced thermal therapy (MRgLITT) has been established and further demonstrated by treating tumors in brain (27,(36)(37)(38)(39), prostate (40,41), and liver (30,42,43).…”