ObjectiveApparent diffusion coefficient (ADC) values calculated through magnetic resonance imaging have been proposed as a useful tool to distinguish benign from malignant liver lesions. Most studies however included simple cysts in their analysis. Liver cysts are easy to diagnose, have very high ADC values and their inclusion facilitates differentiation in the ADC values between benign and malignant liver lesions groups. We prospectively evaluated the ability of ADC values to differentiate metastatic liver lesions from all benign or only solid benign liver lesions.Material and MethodsSixty-seven adult cancer patients with 188 liver lesions were evaluated. Lesions were categorized as metastatic or benign throughout imaging and clinical evaluation. One hundred and five (105) metastatic lesions and 83 benign lesions including hemangiomas (37), cysts (42), adenomas (2) and focal nodular hyperplasias (2) were evaluated. ADC values were calculated for each lesion utilizing two b values (0 and 600 sec/mm2).ResultsThe average ADC value for cysts was 2.4×10−3 mm2/sec (CI: 2.1–2.6), for solid benign lesions was 1.4×10−3 mm2/sec (CI: 1.1–1.7) and for metastases was 1.0×10−3 mm2/sec (CI: 0.8–1.3). There was a difference between the ADC values of metastases and benign solid lesions (p<0.0001). With the ADC value of 1.5×10−3 mm2/sec as a cut off it is possible to distinguish metastatic from benign liver lesions, including cysts, with an accuracy of 78%. But to distinguish metastatic from benign solid liver lesions the best ADC cut off value was 1.2×10−3 mm2/sec and the accuracy drops to 71%.ConclusionsADC values proved to be helpful in the distinction between metastasis and benign solid hepatic lesions. But the exclusion of cysts in the analysis point out to a lower cut off value and lower accuracy than previously reported.

Enucleation is typically performed for the treatment of advanced retinoblastoma in children. After enucleation, the orbit undergoes abnormal development. In this study, orbital asymmetry was calculated using computed tomography measurements obtained from patients who experienced enucleation for unilateral retinoblastoma. Influence factors analyzed included: type of treatment, use of orbital implants, and patient's age at diagnosis. A total of 42 children underwent enucleation with a mean follow-up period of 4.8 years. For 28 patients, treatment included enucleation alone, 14 patients received enucleation plus radiation therapy. Thirty patients kept orbital implants long term. The mean orbital volume asymmetry for treated versus contralateral orbits was 16.8%. Mean asymmetry in orbital volume was greater for patients who underwent enucleation combined to radiation therapy (23.7% vs. 13.3%, P=0.05) and for patients without long-term maintenance of the prosthetic implants (29.3% vs. 11.8%, P<0.01). In conclusion, orbital volume is abnormally affected in children after enucleation of 1 eye for the treatment of retinoblastoma, and computed tomography can precisely quantify the asymmetry that develops. Orbital implants improve volumetric growth after enucleation, with 2-fold greater orbital asymmetry achieved without an implant.

The authors report a case where a quantitative assessment of the apparent diffusion coefficient (ADC) of liver metastasis in a patient undergoing chemotherapy has shown to be an effective early marker for predicting therapeutic response, anticipating changes in tumor size. A lesion with lower initial ADC value and early increase in such value in the course of the treatment tends to present a better therapeutic response.