Diffusion and Perfusion MRI to Differentiate Treatment-Related Changes Including Pseudoprogression from Recurrent Tumors in High-Grade Gliomas with Histopathologic Evidence

Abstract

BACKGROUND AND PURPOSE Treatment-related changes and recurrent tumors often have overlapping features on conventional MR imaging. The purpose of this study was to assess the utility of DWI and DSC perfusion imaging alone and in combination to differentiate treatment-related effects and recurrent high-grade gliomas. MATERIALS AND METHODS We retrospectively identified 68 consecutive patients with high-grade gliomas treated by surgical resection followed by radiation therapy and temozolomide, who then developed increasing enhancing mass lesions indeterminate for treatment-related changes versus recurrent tumor. All lesions were diagnosed by histopathology at repeat surgical resection. ROI analysis was performed of the enhancing lesion on the ADC and DSC maps. Measurements made by a 2D ROI of the enhancing lesion on a single slice were recorded as ADCLesion and rCBVLesion, and measurements made by the most abnormal small fixed diameter ROI as ADCROI and rCBVROI. Statistical analysis was performed with Wilcoxon rank sum tests with P = .05. RESULTS Ten of the 68 patients (14.7%) had treatment-related changes, while 58 patients (85.3%) had recurrent tumor only (n = 19) or recurrent tumor mixed with treatment effect (n = 39). DWI analysis showed higher ADCLesion in treatment-related changes than in recurrent tumor (P = .003). DSC analysis revealed lower relative cerebral blood volume (rCBV)Lesion and rCBVROI in treatment-related changes (P=.003 andP=.011, respectively). Subanalysis of patients with suspected pseudoprogression also revealed higher ADCLesion (P = .001) and lower rCBVLesion (P = .028) and rCBVROI (P = .032) in treatment-related changes. Applying a combined ADCLesion and rCBVLesion model did not outperform either the ADC or rCBV metric alone. CONCLUSIONS Treatment-related changes showed higher diffusion and lower perfusion than recurrent tumor. Similar correlations were found for patients with suspected pseudoprogression.

Pseudoprogression, radionecrosis, inflammation or true tumor progression? challenges associated with glioblastoma response assessment in an evolving therapeutic landscape

“…Some studies conclude that specific relative thresholds are helpful, with lesion-to-normal white matter rCBV ratio thresholds ranging from 1.2 to 2.0 for delineation of pseudoprogression (low rCBV) from recurrent disease (high rCBV) [35][36][37][38]. This is supported by studies in brain metastases demonstrating high reliability of detecting tumor progression (high rCBV) from radionecrosis (low rCBV) using a lesion to normal white matter rCBV ratio higher than 1.5-2.0 [39,40] and studies showing that rCBV can reliably differentiate radionecrosis from true progression in malignant gliomas [38,41].…”

MR perfusion-weighted imaging in the evaluation of high-grade gliomas after treatment: a systematic review and meta-analysis

“…26,33,35 There were a total of 937 cases (54%) of tumor progression and 806 cases (46%) of treatment change. Investigators reported that pseudoprogression was the specific treatment effect under evaluation in 13 studies, 14,17,18,[29][30][31]33,34,[36][37][38][39][40] radiation necrosis in 4 studies, 15,16,19,21 and both in 2 studies. 25,34 Patients meeting inclusion criteria for pseudoprogression developed a new lesion during concurrent radiation and chemotherapy 29 out to 6 months after treatment completion.…”

“…The remaining 28 studies met eligibility criteria for the systematic review. Seventeen studies evaluated DSC, [13][14][15]17,18,20,[23][24][25][27][28][29][30][31]34,36,39 8 evaluated DCE, 16,19,21,22,32,37,38,40 and 3 evaluated both DSC and DCE. 26,33,35 There were a total of 937 cases (54%) of tumor progression and 806 cases (46%) of treatment change.…”

Intrakraniyal Tumörlerin Tedaviye Yanitinin Radyolojik Olarak Degerlendirilmesi

“…DSC-MR perfüz-yon incelmesinde, damar yoğunluğundaki artı-şın bir göstergesi olan CBV (cerebral blood volume-serebral kan akımı)'nin artması, tümöral neo-anjiogenezin dolaylı bir göstergesi olarak kabul edilmektedir [24,25]. Psödoprogresyon-da ise neo-anjiogenezin olmaması nedeniyle CBV değerleri düşüktür.…”