Current update on molecular cytogenetics, diagnosis and management of gastrointestinal stromal tumors

Table 1 Modified computed tomography response evaluation criteria for gastrointestinal stromal tumors

Response	Definition
Complete response	Disappearance of all lesions; No new lesions
Partial response	A decrease in size1 of ≥ 10% or decrease in tumor density (HU) ≥ 15% on CT; No new lesions; No obvious progression of nonmeasurable disease
Stable disease	Dose not meet criteria for complete response, partial response, or progressive disease; No symptomatic deterioration attributed to tumor progression
Progressive disease	An increase in tumor size of ≥ 10% and does not meet criteria of partial response by tumor density (HU) on CT; New lesions; New intratumoral nodules or increase in size of existing intratumoral nodules

¹The sum of longest diameters of target lesions as defined in RECIST. CT: Computed tomography.

Table 2 Imaging features of gastrointestinal stromal tumors

	CT	MRI
Primary and metastatic GISTs	Small: Homogeneous mass; Large: Hypervascular, enhancing masses with heterogeneity due to hemorrhage, cystic degeneration, or necrosis	Depend on the amount of hemorrhage, necrosis and cystic degeneration; solid tumor components with low T1 signal, intermediate-to-high T2 signal, and enhancement; low mean ADC values may predict high malignancy potential
Treatment response	Homogeneously hypoattenuating mass with decreased enhancing tumor nodules and intratumoral vessels	Increased T2 signal, increased cystic degeneration of solid tumoral components, increased ADC values
Disease recurrence	Development of enhancing tumor nodules within the treated hypoattenuating tumor	New peripheral thickening and enhancement of cystic tumor

CT: Computed tomography; MRI: Magnetic resonance imaging; GISTs: Gastrointestinal stromal tumors; ADC: Apparent diffusion coefficient.