MDCT in suspected lumbar spine fracture: comparison of standard and reduced dose settings using iterative reconstruction

AIM

To compare standard (SD-) and reduced-dose computed tomography (RD-CT) in combination with iterative reconstruction (IR) in emergency patients with suspected lumbar spine fracture.

MATERIAL AND METHODS

Forty emergency patients with suspected lumbar spinal disorder who underwent RD-CT and 40 body mass index-matched patients undergoing SD-CT were enrolled in this retrospective study. Raw data for RD-CT were reconstructed using two increasing IR levels (IRL) 4 and 6, while SD-CT was reconstructed with IRL3. Two radiologists assessed image quality, image noise, and reader confidence in interpreting findings of spinal fractures in a blinded manner.

RESULTS

Effective radiation dose was reduced by 50% using RD-CT. Overall subjective image quality (SIQ) was high for both protocols and slightly superior in the RD-CT protocol for both IRL compared to SD-CT. The detection rate of spinal disorders was high for both protocols with a high interobserver agreement.

CONCLUSION

RD-CT with higher levels of IR results in substantial dose reduction of 50% in lumbar spine CT while maintaining an excellent subjective image quality resulting in a high diagnostic confidence.

Gadolinium-based relative contrast enhancement in primary sclerosing cholangitis: additional benefit for clinicians?

AIM

To evaluate the benefit of extracellular gadolinium-based contrast agent (GBCA) enhanced magnetic resonance imaging (MRI) in addition to conventional non-enhanced T2-weighted imaging (WI) for quantification of inflammatory or fibrotic alterations in the liver parenchyma of patients with primary sclerosing cholangitis (PSC).

MATERIAL AND METHODS

MRI (3 T) examinations were reviewed retrospectively by two radiologists in 27 PSC patients (age 42.9±15.6 years), and 19 controls. Regions of interest (ROIs) were drawn onto T2 hyperintense and T2 isointense areas and copied to section position matched non-enhanced and delayed-phase contrast-enhanced T1WI. Signal intensities (SI) obtained from ROIs of the multiphase T1WI were used to calculate relative liver enhancement (RLE). The interobserver agreement of RLE and quantified T2 signal was calculated using Bland-Altman analysis. RLE assessed for both T2 hyperintense (RLE_hyper) and T2 isointense (RLE_iso) areas were compared in patients and controls (RLE_healthy).

RESULTS

The interobserver agreement of RLE in affected hyperintense areas (bias -0.77, limits of agreement -51.7 to 50.1) was superior to the quantification of T2 signal only in these areas (bias -3.35, limits of agreement -162.4 to 155.7). The RLE_hyper (86.2±9.7%) was higher than the RLE_iso (59.8±6.2%, p=0.03) and the RLE_healthy (53.2±2.7%, p=0.002). The mean RLE_iso was not significantly different from the RLE_healthy (p=0.3).

CONCLUSION

The extracellular gadolinium-based RLE of T2 hyperintense areas could be a useful add-on for routine follow up MRI in the detection of early inflammatory changes, possibly preceding formation of fibrotic scarring in PSC patients, if validated in larger cohorts.