Identification of intracranial liqor metastases of experimental stereotactically implanted brain tumors by the tumor-selective MRI contrast agent MnTPPS

Abstract

Two cases of stereotactically induced and spontaneously metastasizing neoplasms in the rat and the cat brain are reported. In the rat, a malignant Schwannoma derived from initially supratentorially implanted RN6 cells developed a second tumor in the posterior cranial fossa. In the cat, a highly malignant polymorphous anaplastic glioma induced by implantation of cloned rat glioma cells (F98) into the left internal capsule developed small tumor cell nests along the ependyma of the ipsilateral ventricle. In precontrast magnetic resonance imaging (MRI) of both cases, the primary tumor was detectable only by a very weak hypointensity and through a shift of the midline. No metastases were apparent. Application of the metallated paramagnetic porphyrin derivative manganese(III) tetraphenylporphine sulfonate (MnTPPS) resulted in a remarkable contrast enhancement between tumoral and normal tissue, which was evident not only in the primary tumor but also in the small metastases. These observations demonstrate for the first time that MnTPPS is an efficient MRI contrast agent for the detection of metastases from primary brain neoplasms and, in consequence, support the hypothesis of its selective binding to tumor cells.

In Vivo1H‐NMR microimaging with respiratory triggering for monitoring adoptive immunotherapy of metastatic mouse lymphoma

“…In numerous studies good contrast between normal tissue and tumors, lesions, or metastases was generally obtained with the help of contrast agents, especially at low fields (B, 5 2 T). Also, in an animal model study at 4.7 T, it was shown that metastases from brain tumors could not be detected without contrast agent (35). On the other hand, in a previous liver study at 9.4 T (3) and in our study of kidney and liver at 7 T, sufficient contrast is obtained simply with T, weighting and a TE of about 30 ms.…”

Rat brain tumor models in experimental neuro-oncology: the C6, 9L, T9, RG2, F98, BT4C, RT-2 and CNS-1 gliomas

“…Finally, F98 cells also are capable of growing as i.c. xenografts in cats [119], but since these cells can evoke a xenoimmune response, this model is of limited usefulness. It is important to note that, what may be therapeutically effective in the rat, may not be in the human.…”

In vivo models of primary brain tumors: pitfalls and perspectives

“…44 Murine, 45 canine, 46 and feline 47 models also exist but have gained less popularity. Spontaneous brain tumors are rarely reported in animals, except in dogs, where the incidence and malignancy types are similar to those seen in humans.…”