Contrast-enhanced MR imaging of postoperative scars and VX2 carcinoma in rabbits: comparison of macromolecular contrast agent and gadopentetate dimeglumine.

PURPOSE: To compare the magnetic resonance (MR) imaging enhancement patterns of a blood pool contrast agent, SH L 643A, with those of gadopentetate dimeglumine in postoperative scars and VX2 carcinomas in rabbits and to compare these enhancement patterns with microvessel density in pathologic specimens. MATERIALS AND METHODS: Eighteen rabbits with experimentally induced postoperative scars (n = 12) or VX2 carcinoma (n = 6) in the thighs underwent sequential MR imaging first with gadopentetate dimeglumine and then, 24 hours later, with SH L 643A. The enhancement ratios (ie, the ratios of postcontrast to precontrast signal intensity) and the microvessel densities of postoperative scars and VX2 carcinomas were assessed. Differences were tested for by using the Mann-Whitney U and Wilcoxon signed rank tests. RESULTS: In postoperative scars, enhancement ratios were consistently lower with injection of SH L 643A than with injection of gadopentetate dimeglumine for up to 30 minutes (P <.05). In postoperative scars, mean peak enhancement ratios were 1.29 +/- 0.15 (SD) with injection of SH L 643A and 1.61 +/- 0.31 with injection of gadopentetate dimeglumine (P <.01). In VX2 carcinomas, the enhancement ratios were not significantly different with injection of SH L 643A than with injection of gadopentetate dimeglumine at all time points. The mean difference between the enhancement ratios of the VX2 carcinomas and postoperative scars was 0.64 +/- 0.10 (range, 0.50-0.77) with SH L 643A and 0.36 +/- 0.16 (range, 0.17-0.66) with gadopentetate dimeglumine (P <.01). The mean microvessel density (in terms of vessels per field of view) was 10.7 +/- 5.5 for postoperative scars and 30.0 +/- 7.7 for VX2 carcinoma (P <.001). CONCLUSION: The difference between the enhancement ratios of postoperative scars and VX2 carcinomas with SH L 643A was greater than that with gadopentetate dimeglumine. Enhancement ratios at SH L 643A-enhanced MR imaging corresponded well with microvessel density in postoperative scars and VX2 carcinomas.

Efficacy of whole brain radiotherapy combined with fractionated stereotactic radiotherapy in metastatic brain tumors, and prognostic factors.

PURPOSE: We attempted to analyze the effectiveness of whole brain radiotherapy (WBRT) combined with fractionated stereotactic radiotherapy (FSRT) in brain metastases. METHODS: Thirty-seven metastatic brain tumors in 29 patients without previous treatment were treated with WBRT plus FSRT, from October 1996 to February 2002. Four of the patients received stereotactic radiosurgery (SRS) prior to WBRT. Non-small cell lung cancer was the most common type of primary tumor (20/29). The total dose to the whole brain ranged from 30 Gy to 40 Gy, and the boost dose from FSRT ranged from 12 Gy to 40 Gy. End points were survival rate and local control rates. Factors influencing survival were evaluated. RESULTS: Median survival was 13 months, and actuarial survival rates at one and two years were 81% and 39%, respectively. Actuarial one and two year local control rates for all lesions were 78% and 71%, respectively. Survival was significantly associated with age, tumor size, presence of active extracranial tumors, and performance status. No acute or delayed complications were observed. CONCLUSIONS: We believe that WBRT plus FSRT should be included in the treatment options for metastatic brain tumors, and we consider the effect of this non-invasive method to be quite good in patients with good prognostic factors, although other invasive modalities could also be effective in them.

Treatment Outcome of Brain Metastasis after the Cranial Radiotherapy Followed by Fractionated Stereotactic Radiotherapy and Its Prognostic Factors.

PURPOSE: To evaluate the effectiveness of whole brain radiotherapy followed by stereotactic radiotherapy for newly diagnosed brain metastasis. MATERIALS AND METHODS: Thirty-three metastatic brain tumors received radiotherapy to the whole brain and stereotactic radiotherapy in 25 patients. Lung carcinomas were the most common (17/25) primary tumor. The radiation dose was 30 to 40 Gy for the whole brain, with a 12 to 40 Gy boost to the metastatic foci. Survival and local control rates were determined, and the prognostic factors for survival were evaluated. RESULTS: The overall median survival was 15 months and the actuarial survivals at 1- and 2-year were 67% and 31%, respectively. The local tumor control rate was 79%, with a median follow-up period of 9 months (2~36 months). The prognostic factors associated with survival were age, tumor size and the existence of active extracranial metastasis, with the performance status showing marginal significance. No acute or chronic complications were observed in the patients. CONCLUSION: From our data, cranial radiotherapy followed by stereotactic radiotherapy was useful in the local control of metastatic tumors, and in the survival of patients with tumor factors, such as small size or the absence of extracranial tumor activity, and host factors, such as young age or good performance status.