OBJECTIVE: To determine the role of the unenhanced phase of abdominal computed tomography in patients without a definite diagnosis or undergoing tumor staging. MATERIALS AND METHODS: A prospective and transversal study was developed with 100 consecutive patients submitted to unenhanced and contrast-enhanced abdominal computed tomography. Two observers evaluated all the computed tomography images in the contrast-enhanced phase (first analysis) and, later, in the unenhanced phase (second analysis) in an attempt to establish the primary and secondary diagnoses as a function of the clinical indication for the study. The frequency of changes in the diagnoses resulting from a combined analysis of the images in the pre- and post-contrast phases was evaluated. Cases with changes in the diagnosis were reviewed by clinical specialists for determining possible changes in the therapeutic approach. RESULTS: Primary and secondary diagnoses were changed in respectively 1 and 18 cases (p = 1.000; p = 0.143) as follows: steatosis, adrenal nodules, nephrolithiasis, renal cysts and hepatic calcification. In the cases where the unenhanced phase changed the diagnosis, the specialists changed the therapeutic approach in 14 of the 19 patients (73%) (p = 0.038). CONCLUSION: No significant change was observed in the primary or secondary diagnosis as a result of the findings in the unenhanced phase. However, changes in secondary diagnoses affected the therapeutic approach adopted by the specialists.

Keywords: Computed tomography, Contrast media, Abdomen

OBJECTIVE: To evaluate a protocol for two-dimensional (2D) hydrogen proton (1H) magnetic resonance spectroscopy (MRS) (Siemens Medical Systems; Erlangen, Germany) in the detection of adrenal nodules and differentiation between benign and malignant masses (adenomas, pheochromocytomas, carcinomas and metastases). MATERIALS AND METHODS: A total of 118 patients (36 men; 82 women) (mean age: 57.3 ± 13.3 years) presenting with 138 adrenal nodules/masses were prospectively assessed. A multivoxel system was utilized with a 2D point-resolved spectroscopy/chemical shift imaging sequence. The following ratios were calculated: choline (Cho)/creatine (Cr), 4.0–4.3/Cr, lipid (Lip)/Cr, Cho/Lip and lactate (Lac)/Cr. RESULTS: 2D-1H-MRS was successful in 123 (89.13%) lesions. Sensitivity and specificity values observed for the ratios and cutoff points were the following: Cho/Cr > 1.2, 100% sensitivity, 98.2% specificity (differences between adenomas/pheochromocytomas and carcinomas/metastases); 4.0–4.3 ppm/Cr > 1.5, 92.3% sensitivity, 96.9% specificity (differences between carcinomas/pheochromocytomas and adenomas/metastases); Lac/Cr < –7.449, 90.9% sensitivity and 77.8% specificity (differences between pheochromocytomas and carcinomas/adenomas). CONCLUSION: Information provided by 2D-1H-MRS were effective and allowed for the differentiation between adrenal masses and nodules in most cases of lesions with > 1.0 cm in diameter.

Keywords: Adrenal gland; Magnetic resonance imaging; Spectroscopy.