Diffusivity of intraorbital lymphoma vs. inflammation: comparison of single shot turbo spin echo and multishot echo planar imaging techniques.

PURPOSE

To compare the abilities of turbo spin-echo diffusion-weighted imaging (TSE DWI) and multi-shot echo planar DWI (MSh DWI) to discriminate orbital lymphoma from inflammatory lesions.

MATERIALS AND METHODS

Twenty-nine patients with pathologically confirmed lymphomas and 39 patients with inflammation were imaged with a 3.0-T system. The apparent diffusion coefficient (ADC) of each lesion was measured. Signal intensities compared to normal grey matter on conventional imaging were also measured.

RESULTS

The ADCs derived from the TSE DWI of the lymphomas (0.68 ± 0.14 × 10 mm/s) were significantly lower than those of the inflammation cases (1.04 ± 0.39 × 10 mm/s; p < 0.001). The ADCs derived from MSh DWI could not be used to separate the lymphomas from the inflammation (1.16 ± 0.43 × 10 mm/s vs. 1.36 ± 0.48 × 10 mm/s; p = 0.06). Conventional sequences also could not separate the lymphomas from the inflammation (p > 0.05). The ROC analysis showed the best diagnostic performance with ADCs derived from TSE DWI (the area under the curve: AUC = 0.831) followed by ADC derived from MSh DWI (AUC = 0.633).

CONCLUSION

The ADCs derived from TSE DWI might help to differentiate orbital lymphomas from inflammation.

KEY POINTS

• ADC of lymphoma was significantly lower than that of inflammation. • ADC derived from TSE DWI showed the best diagnostic performance. • This study was conducted by a 3-T MR scanner.