title: [Image analysis in the differential diagnosis of renal parenchyma lesions].
abstract: OBJECTIVE
  Visual analysis of echo intensity is of importance for the differential diagnosis of focal renal lesions. Quantification of the echo intensity and of other parameters might help with differential diagnosis.
  
  
  METHODS
  In 145 patients with focal renal lesions, digitized images were evaluated (40 angiomyolipomas [group A], 70 renal cell carcinomas [group B], 20 pseudo-tumors [group C] and 15 other focal lesions in group D). With Photoshop®, the average grayscale values of the lesion (defined as echo intensity focal, EF) and its variance s2 (as expression of the inhomogeneity focal, IF) were measured. These measurements were compared to the renal cortex (echo intensity renal cortex=ER, inhomogeneity renal renal cortex=I R). Other calculated parameters: Echo intensity quotient, echo intensity index, inhomogeneity quotient and inhomogeneity index.
  
  
  RESULTS
  Angiomyolipomas had a higher echo intensity quotient EQ and echo intensity index EI than renal cell carcinomas, pseudo-tumors and other lesions (p<0.001). Pseudo-tumors had a lower inhomogeneity quotient than angiomyolipomas (p<0.001), renal cell carcinomas (p<0.05). Echo intensity quotient EQ≥2.0 and echo intensity index EI≥0.5 were typical for angiomyolipomas with a sensitivity of 96.4 % and a specificity of 97.3 % for tumors<3 cm.
  
  
  CONCLUSIONS
  Quantitative echo intensity measurements enhance the differential diagnosis of focal renal lesions. The differentiation of typical angiomyolipomas to other lesions could be improved.
authors.affiliation: Die Institutsangaben sind am Ende des Beitrags gelistet, Innere Medizin 2, Caritas-Krankenhaus, Bad Mergentheim.
authors.forename: J
authors.initials: J
authors.lastname: Tuma
authors.forename: B
authors.initials: B
authors.lastname: Novakova
authors.forename: H R
authors.initials: HR
authors.lastname: Schwarzenbach
authors.forename: K-P
authors.initials: KP
authors.lastname: Jungius
authors.forename: A
authors.initials: A
authors.lastname: Hollerweger
authors.forename: F
authors.initials: F
authors.lastname: Zatura
authors.forename: M
authors.initials: M
authors.lastname: Kuchta
authors.forename: C F
authors.initials: CF
authors.lastname: Dietrich
mesh_terms: D018207:Angiomyolipoma / Q000000981:diagnostic imaging* / Q000473:pathology; D002292:Carcinoma, Renal Cell / Q000000981:diagnostic imaging* / Q000473:pathology; D003937:Diagnosis, Differential; D006801:Humans; D007089:Image Enhancement; D007091:Image Processing, Computer-Assisted; D007672:Kidney Cortex / Q000000981:diagnostic imaging / Q000473:pathology; D007674:Kidney Diseases / Q000000981:diagnostic imaging / Q000473:pathology; D007680:Kidney Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology; D012680:Sensitivity and Specificity; D012984:Software; D014057:Tomography, X-Ray Computed; D014463:Ultrasonography