Evaluation of a numerical observer to determine the influence of JPEG data compression on the diagnostic quality of computed tomography images

BackgroundSkeletal muscle dysfunction is a common feature in patients with severe lung diseases. Although lung transplantation aims to save these patients, the surgical procedure and disuse may cause additional deterioration and prolonged functional disability. We investigated the postoperative course of antigravity muscle condition in terms of quantity and quality using chest computed tomography.Methods35 consecutive patients were investigated for 12 months after living-donor lobar lung transplantation (LDLLT). The erector spinae muscles (ESMs), which are antigravity muscles, were evaluated, and the cross-sectional area (ESMCSA) and mean attenuation (ESMCT) were analysed to determine the quantity and quality of ESMs. Functional capacity was evaluated by the 6-min walk distance (6MWD). Age-matched living donors with lower lobectomy were evaluated as controls.ResultsRecipient and donor ESMCSA values temporarily decreased at 3 months and recovered by 12 months post-operatively. The ESMCSA of recipients, but not that of donors, surpassed baseline values by 12 months post-operatively. Increased ESMCSA (ratio to baseline ≥1) may occur at 12 months in patients with a high baseline ESMCT. Although the recipient ESMCT may continuously decrease for 12 months, the ESMCT is a major determinant, in addition to lung function, of the postoperative 6MWD at both 3 and 12 months.ConclusionThe quantity of ESMs may increase within 12 months after LDLLT in recipients with better muscle quality at baseline. The quality of ESMs is also important for physical performance; therefore, further approaches to prevent deterioration in muscle quality are required.

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ALADA Dose Optimization in the Computed Tomography of the Temporal Bone: The Diagnostic Potential of Different Low-Dose CT Protocols

Diagnostics ◽

10.3390/diagnostics11101894 ◽

2021 ◽

Vol 11 (10) ◽

pp. 1894

Author(s):

Barbara Kofler ◽

Laura Jenetten ◽

Annette Runge ◽

Gerald Degenhart ◽

Natalie Fischer ◽

...

Keyword(s):

Computed Tomography ◽

Temporal Bone ◽

Cone Beam Ct ◽

Ct Scanner ◽

Diagnostic Quality ◽

Diagnostic Potential ◽

Incudostapedial Joint ◽

Bone Structures

Objective: Repeated computed tomography (CT) is essential for diagnosis, surgical planning and follow-up in patients with middle and inner ear pathology. Dose reduction to “as low as diagnostically acceptable” (ALADA) is preferable but challenging. We aimed to compare the diagnostic quality of images of subtle temporal bone structures produced with low doses (LD) and reference protocols (RP). Methods: Two formalin-fixed human cadaver heads were scanned using a 64-slice CT scanner and cone-beam CT (CBCT). The protocols were: RP (120 kV, 250 mA, CTDIvol 83.72 mGy), LD1 (100 kV, 80 mA, CTDIvol 26.79 mGy), LD2 (100 kV, 35 mA, CTDIvol 7.66 mGy), LD3 (80 kV, 40 mA, CTDIvol 4.82 mGy), and CBCT standard protocol. Temporal bone structures were assessed using a 5-point scale. Results: A median score of ≥2 was achieved with protocols such as the tendons of m. tensor tympani (RP/LD1/LD2/CBCT) and m. stapedius (CBCT), the incudostapedial joint (RP/LD1/CBCT), the incudomalleolar joint (RP/LD1/LD2/CBCT), the stapes feet (RP/LD1/CBCT), the stapes head (RP/LD1/LD2/CBCT), the tympanic membrane (RP/LD1/LD2/CBCT), the lamina spiralis ossea (none), the chorda tympani (RP/LD1/CBCT), and the modiolus (RP/LD1/LD2/CBCT). Adaptive statistical iterative reconstructions did not show advantages over the filtered back projection. Conclusions: LD protocols using a CTDIvol of 7.66 mGy may be sufficient for the identification of temporal bone structures.

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