Comparing the clinical utility of single-shot, readout-segmented and zoomit echo-planar imaging in diffusion-weighted imaging of the kidney at 3 T

Multi-orientation and prone-position ZOOMit diffusion-weighted imaging for predicting T stage in distal gastric cancer

PURPOSE

To compare the image quality of ZOOMit diffusion-weighted imaging (ZOOMit DWI) of distal gastric cancer in prone vs supine positioning and to determine whether multi-orientation ZOOMit DWI (M-ZOOMit) offers additional diagnostic value over axial ZOOMit DWI (A-ZOOMit).

METHODS AND MATERIALS

This two-phase study enrolled patients with biopsy-confirmed distal gastric cancer who underwent pre-treatment MRI. In phase 1 (November 2021 to February 2022), participants underwent ZOOMit DWI in both standard supine and prone positions. Two radiologists independently evaluated image quality on supine and prone ZOOMit DWI using a 5-point Likert scale. In phase 2 (March 2022 to September 2023), participants were imaged solely in the prone position; they subsequently underwent radical surgery. Histopathological findings served as the reference standard. The accuracy of T staging based on uni-orientation (axial, coronal, and sagittal) vs M-ZOOMit was assessed by four additional radiologists. Reader consistency and agreement on image quality scores were evaluated using κ-agreement and Kendall W analyses.

RESULTS

Phase 1 enrolled 30 patients (mean age, 62.0 years ± 11.5 [standard deviation]; 19 men); phase 2 enrolled 134 patients (mean age, 60.9 years ± 11.7; 81 men). Image quality scores assigned by both readers were significantly higher for prone ZOOMit DWI than for supine ZOOMit DWI (p < 0.001). Regarding overall T staging, M-ZOOMit and coronal ZOOMit DWI (C-ZOOMit) demonstrated significantly better performance relative to A-ZOOMit (both p < 0.05).

CONCLUSION

ZOOMit DWI in the prone position provides superior image quality. M-ZOOMit and C-ZOOMit enhance T staging accuracy compared to A-ZOOMit for distal gastric cancer.

KEY POINTS

Question DWI is a powerful technique, but poor image quality has remained a key limitation, hindering diagnostic accuracy for distal gastric cancer. Findings The prone-position ZOOMit DWI improved the image quality. Besides, multi-orientation and coronal ZOOMit DWI demonstrated superior performance relative to A-ZOOMit DWI for T staging. Clinical relevance The prone-position and M-ZOOMit DWI is a better imaging protocol for the T staging assessment of distal gastric cancer patients, replacing the conventional supine-position and axial DWI.

Probing Renal Microstructure and Function with Advanced Diffusion MRI: Concepts, Applications, Challenges, and Future Directions

Diffusion measurements in the kidney are affected not only by renal microstructure but also by physiological processes (i.e., glomerular filtration, water reabsorption, and urine formation). Because of the superposition of passive tissue diffusion, blood perfusion, and tubular pre-urine flow, the limitations of the monoexponential apparent diffusion coefficient (ADC) model in assessing pathophysiological changes in renal tissue are becoming apparent and motivate the development of more advanced diffusion-weighted imaging (DWI) variants. These approaches take advantage of the fact that the length scale probed in DWI measurements can be adjusted by experimental parameters, including diffusion-weighting, diffusion gradient directions and diffusion time. This forms the basis by which advanced DWI models can be used to capture not only passive diffusion effects, but also microcirculation, compartmentalization, tissue anisotropy. In this review, we provide a comprehensive overview of the recent advancements in the field of renal DWI. Following a short introduction on renal structure and physiology, we present the key methodological approaches for the acquisition and analysis of renal DWI data, including intravoxel incoherent motion (IVIM), diffusion tensor imaging (DTI), non-Gaussian diffusion, and hybrid IVIM-DTI. We then briefly summarize the applications of these methods in chronic kidney disease and renal allograft dysfunction. Finally, we discuss the challenges and potential avenues for further development of renal DWI. LEVEL OF EVIDENCE: 5 TECHNICAL EFFICACY: Stage 2.

Explore the Value of Multi-Parameter MRI in Non-Invasive Assessment of Prognostic Risk and Oxford Classification in Children with IgAN or IgAVN

PURPOSE

To explore the Oxford classification and prognostic risk stratification of the non-invasive evaluation of immunoglobulin A nephropathy (IgAN) or immunoglobulin A vasculitis with nephritis (IgAVN) in children using multiparametric magnetic resonance imaging (MRI).

MATERIALS AND METHODS

Forty-four children diagnosed with IgAN or IgAVN were included. Patients with 80-month risk scores >10% were categorized as the high-risk group, while others constituted the low-risk group. The T2* and apparent diffusion coefficient (ADC) values of the renal cortex and medulla were measured. Clinical and pathological parameters were also assessed. Univariate and multivariate logistic regression analyses were performed to identify the indicators associated with the high-risk group. Receiver operating characteristic (ROC) curves were drawn and the areas under the curve (AUCs) were calculated to evaluate the diagnostic performance variables for differentiating the high-risk group from the low-risk group.

RESULTS

Only the T2*Cortex and mean arterial pressure (MAP) were independently reliable in both the univariate and multivariate analyses. The AUCs for differentiating the high-risk group from the low-risk group of T2*Cortex, MAP, and their combination model were 0.907, 0.881, and 0.947, respectively.

CONCLUSIONS

Multiparametric MRI parameters, especially T2* values, could be used as new biomarkers to provide a new dimension in chronic kidney disease-related research and could play an important role in the non-invasive prognosis of children with IgAN or IgAVN.

Comparison between ZOOMit DWI and conventional DWI in the assessment of foot and ankle infection: a prospective study

OBJECTIVE

The study aimed to compare ZOOMit diffusion-weighted imaging (DWI) MRI with conventional DWI MRI for visualizing small bones in the foot, soft tissue abscesses, and osteomyelitis.

MATERIALS AND METHODS

The cohort consisted of a consecutive series of patients with potential foot and ankle infections referred for MR imaging. Patients were imaged using both conventional and ZOOMit DWI in the same setting. Blinded reads were then conducted in separate settings and independent of known clinical diagnosis by two expert radiologists. The results from the reads were compared statistically using paired t-tests and with biopsy specimen analysis, both anatomopathological and microbiological.

RESULTS

There was improvement in fat suppression using ZOOMit sequence compared to conventional DWI (p = .001) with no significant difference in motion artifacts (p = .278). ZOOMit had a higher rate of concordance with pathology findings for osteomyelitis (72%, 31/43 cases) compared with conventional DWI (60%, 26/43 cases). ZOOMit also identified 46 additional small bones of the foot and ankle (405/596, 68.0%) than conventional DWI (359/596, 60.2%). Conventional DWI however exhibited a more negative contrast-to-noise ratio (CNR) than ZOOMit (p = 0.001).

CONCLUSION

ZOOMit DWI improves distal extremity proton diffusion assessment and helps visualize more bones in the foot, with less image distortion and improved fat saturation at the expense of reduced CNR. This makes it a viable option for assessing lower extremity infections.

CLINICAL RELEVANCE STATEMENT

This study highlights the novel utilization of ZOOMit diffusion-weighted imaging (DWI) for the assessment of lower extremity lesions compared to conventional DWI.

KEY POINTS

• Distal extremity diffusion-weighted imaging (DWI) is often limited. • ZOOMit DWI displayed improved fat suppression with less motion artifacts and better visualization of the lower extremity bones than conventional DWI. • ZOOMit shows decreased contrast-to-noise ratio than conventional DWI.