Diffusion-Weighted Imaging in the Differential Diagnosis of Simple and Hydatid Cysts of the Liver

• Published in: American journal of roentgenology (1976) Vol. 189; no. 5; pp. 1031 - 1036
• Main Authors: Inan, Nagihan, Arslan, Arzu, Akansel, Gur, Anik, Yonca, Sarisoy, H. Tahsin, Ciftci, Ercument, Demirci, Ali
• Format: Journal Article
• Language: English
• Published: Leesburg, VA Am Roentgen Ray Soc 01.11.2007; American Roentgen Ray Society
• Subjects: Adolescent; Adult; Aged; Biological and medical sciences; Child; Cysts - diagnosis; Diagnosis, Differential; Diffusion Magnetic Resonance Imaging - methods; Diseases caused by cestodes; Echinococcoses; Echinococcosis, Hepatic - diagnosis; Female; Helminthic diseases; Humans; Image Interpretation, Computer-Assisted - methods; Infectious diseases; Investigative techniques, diagnostic techniques (general aspects); Liver - pathology; Male; Medical sciences; Middle Aged; Parasitic diseases; Reproducibility of Results; Sensitivity and Specificity; Performance evaluation; Human; Nuclear medicine; Liver; Diffusion imaging; Parasitosis; Hydatid cyst; Helminthiasis; Cestode disease; Infection; Sensitivity; Specificity; Radiology; Diagnosis; Diffusion coefficient; Predictive factor; Echinococciasis
• ISSN: 0361-803X; 1546-3141
• DOI: 10.2214/AJR.07.2251

The purpose of our study was to evaluate the value of diffusion-weighted imaging (DWI) in the differential diagnosis of simple and hydatid cysts of the liver, particularly in the completely liquid type of hydatid cyst. Eighty-two cysts (43 simple cysts, 39 hydatid cysts) were included in this prospective study. DWI was performed using a breath-hold single-shot echo-planar spin-echo sequence, and apparent diffusion coefficients (ADCs) were calculated. On DW trace images, the signal intensity of cysts was visually compared with the signal intensity of the liver using a 3-point scale: 0, isointense; 1, moderately hyperintense; and 2, significantly hyperintense. Quantitatively, signal intensity of the cysts, cyst-to-liver signal intensity ratios, ADC of the cysts, and cyst-to-liver ADC ratios were compared between the groups. The statistical significance was determined using the Mann-Whitney U test. On trace DWI (b = 1,000 s/mm2), most hydatid cysts (37/39, 95%) were hyperintense, whereas most simple cysts (40/43, 93%) were isointense with the liver. Three simple cysts (7%) were moderately hyperintense and two hydatid cysts (5%) were isointense. Quantitatively, both the signal intensity and cyst-to-liver signal intensity ratio of the hydatid cysts were significantly higher than those for simple cysts (p < 0.001). The cutoff value at 1.5 yielded a sensitivity of 77%, a specificity of 86%, and positive predictive value of 83% for the cyst-to-liver signal intensity ratio. The ADC and cyst-to-liver ADC ratio of the hydatid cysts were significantly lower than those of simple cysts (p < 0.005). For the completely liquid type in particular, we observed statistically significant differences in signal intensity, signal intensity ratio, ADC, and ADC ratios from those of simple cysts (p < 0.005). With a cutoff value of 1.5, signal intensity ratio had a sensitivity of 81%, specificity of 86%, and positive predictive value of 74%. DWI may help in the differential diagnosis of hydatid and simple cysts of the liver.