Role of diffusion-weighted MRI in differentiation of hepatic abscesses from non-infected fluid collections

Diffusion-Weighted Imaging Distinguishes Between Osteomyelitis, Bone Marrow Edema, and Healthy Bone on Forefoot Magnetic Resonance Imaging

BACKGROUND

Diagnosis of osteomyelitis by imaging can be challenging. The feasibility of diffusion-weighted imaging (DWI) as ancillary sequence was evaluated in this study.

PURPOSE

To evaluate DWI for differentiation between osteomyelitis, bone marrow edema, and healthy bone on forefoot magnetic resonance imaging (MRI).

STUDY TYPE

Prospective.

SUBJECTS

A total of 60 consecutive patients undergoing forefoot MRI divided into three study groups (20 subjects each): osteomyelitis, bone marrow edema, and healthy bone.

FIELD STRENGTH/SEQUENCE

A 1.5T and 3T MRI scanners; readout-segmented multishot echo planar DWI.

ASSESSMENT

Two independent radiologists measured apparent diffusion coefficient (ADC) values within abnormal or healthy bone.

STATISTICAL TESTS

ADC values were compared between groups (pairwise t-test with Bonferroni-Holm correction for multiple testing). Intraclass correlation coefficient (ICC) was calculated to assess inter-reader agreement. Threshold ADC values were determined as the cutoffs that maximized the sum of sensitivity and specificity. Receiver operating characteristic (ROC) analysis was performed with statistical threshold of P < 0.05.

RESULTS

Inter-reader agreement was 0.92 in the healthy bone group and 0.78 in both the edema and osteomyelitis groups. Average ADC values were significantly different between groups: 1432 ± 222 × 10^-6  mm² /sec (osteomyelitis), 1071 ± 196 × 10^-6  mm² /sec (bone marrow edema), and 277 ± 89 × 10^-6  mm² /sec (healthy bone). A threshold ADC value of 534 × 10^-6  mm² /sec distinguishes between healthy and abnormal bone with specificity and sensitivity of 100% each. For distinction between osteomyelitis and bone marrow edema, two cutoff values were determined: a 95%-specificity cutoff indicating osteomyelitis (>1320 × 10^-6  mm² /sec) and a 95%-sensitivity cutoff indicating bone marrow edema (<1155 × 10^-6  mm² /sec). Diagnostic accuracy of 95% was achieved for 73% (29/40) of the subjects.

DATA CONCLUSION

DWI with ADC maps distinguishes between healthy and abnormal bone on forefoot MRI. Calculated cutoff values allow confirmation or exclusion of osteomyelitis in a high proportion of subjects.

EVIDENCE LEVEL

2 TECHNICAL EFFICACY: Stage 2.

Correlation Analysis of Ultrasound Elastography Score with Invasive Breast Cancer and Biological Prognostic Factors

Invasive breast cancer (IBC) is a kind of malignant tumor in which cancer cells have broken through the basement membrane of breast ducts or lobular acini and invaded the stroma. Although ultrasound elastography score (UES) has shown unique advantages in the diagnosis of IBC, its value in the prognosis is not clear. Here, we explored the correlation of UES with IBC and biological prognostic factors. The datum of 86 patients with suspected IBC from January 2018 to December 2021 was collected. UE was applied in the examination of all patients. The lesion tissue of the malignant group was punctured to detect and analyze the expression of biological prognostic factors, including estrogen receptor (E receptor), progesterone receptor (P receptor), and human epidermal growth factor 2 (HER factor 2) and Ki67. The differences in UES under different biological prognostic factors were compared. The receiver operating characteristic (ROC) curve was applied to analyze the diagnostic value of UES of IBC and the expression of biological prognostic factors. Based on the pathological diagnosis results, the sensitivity, specificity, accuracy, positive predictive value, and negative predictive value of UES in the diagnosis of IBC were analyzed. The correlation of UES with IBC and biological prognostic factors was analyzed by multiple linear regression and Spearman method. ROC analysis showed that the area under the curve of UES for diagnosing IBC and evaluating the expression of P receptor, HER factor 2, and Ki67 were 0.877, 0.704, 0.763, and 0.820, respectively (P＜0.05). The sensitivity, specificity, accuracy, positive predictive value, and negative predictive value of UES when diagnosing IBC were 92.42%, 90.00%, 91.86%, 96.83%, and 78.26%, respectively. The UES of E receptor expression (positive and negative group) showed no obvious variance ( $P$  > 0.05). The UES of P receptors (positive and negative), HER factor 2 (positive and negative), and Ki67 (high and low expression) showed obvious differences ( $P$  < 0.05). Multiple linear regression and Spearman indicated UES was significantly correlated with the expression of P receptor, HER factor 2, and Ki67 (P＜0.05). UES has a certain diagnostic value for IBC and is significantly correlated to the expression of P receptor, HER factor 2, and Ki67, which is helpful for evaluating the prognosis of patients with IBC.

Imaging and Clinical Parameters for Distinction between Infected and Non-Infected Fluid Collections in CT: Prospective Study Using Extended Microbiological Approach

The aim of this investigation was to evaluate predictive CT imaging features and clinical parameters to distinguish infected from sterile fluid collections. Detection of infectious agents by advanced microbiological analysis was used as the reference standard. From April 2018 to October 2019, all patients undergoing CT-guided drainages were prospectively enrolled, if drainage material volume was at least 5 mL. Univariate analysis revealed attenuation (p = 0.001), entrapped gas (p < 0.001), fat stranding (p < 0.001), wall thickness (p < 0.001) and enhancement (p < 0.001) as imaging biomarkers and procalcitonin (p = 0.003) as clinical predictive parameters for infected fluid collections. On multivariate analysis, attenuation > 10 HU (p = 0.038), presence of entrapped gas (p = 0.027) and wall enhancement (p = 0.028) were independent parameters for distinguishing between infected and non-infected fluids. Gas entrapment had high specificity (93%) but low sensitivity (48%), while wall enhancement had high sensitivity (91%) but low specificity (50%). CT attenuation > 10 HU showed intermediate sensitivity (74%) and specificity (70%). Evaluation of the published proposed scoring systems did not improve diagnostic accuracy over independent predictors in our study. In conclusion, this prospective study confirmed that CT attenuation > 10 HU, entrapped gas and wall enhancement are the key imaging features to distinguish infected from sterile fluid collections on CT.

Diagnosis and Treatment for Acute Focal Bacterial Nephritis With Renal Abscess Based on Magnetic Resonance Imaging Evaluation

A 5-year-old boy was diagnosed with left acute focal bacterial nephritis (AFBN) complicated with renal abscess (RA) on magnetic resonance imaging (MRI). MRI is useful for diagnosing AFBN and RA complications. He was administered antibiotics for 3 weeks on evaluation of MRI findings. Evaluation of apparent diffusion coefficient values over time may be useful as an index of treatment of RA.

The Clinical Value of Diffusion-Weighted Magnetic Resonance Imaging in Diabetic Foot Infection

BACKGROUND

Osteomyelitis is a common complication in the diabetic foot that can conclude with amputation. The purpose of this study was to evaluate the role of diffusion-weighted magnetic resonance imaging (DWI) in the diagnosis of osteomyelitis in diabetic foot ulcer (DFU).

METHODS

Thirty patients with type 2 diabetes mellitus and a DFU were enrolled. Both DWIs and conventional MRIs were obtained. Apparent diffusion coefficient (ADC) measurements were made by transferring the images to a workstation. The measurements were made both from bone with osteomyelitis, or nearest to the injured area if osteomyelitis is not available, and from the adjacent soft tissue.

RESULTS

The patients comprised nine women (30%) and 21 men (70%) with a mean age of 58.7 years (range, 41-78 years). The levels of ADC were significantly low (P = .022) and the erythrocyte sedimentation rates were significantly high (P = .014) in patients with osteomyelitis (n = 9) compared with patients without osteomyelitis (n = 21). The mean ± SD bone ADC value (0.75 ± 0.16 × 10^-3 mm²/sec) was significantly lower than the adjacent soft-tissue ADC value (0.90 ± 0.15 × 10^-3 mm²/sec) in patients with osteomyelitis (P = .04).

CONCLUSIONS

It is suggested that DWI contributes to conventional MRI with short imaging time and no requirement for contrast agent. Therefore, DWI may be an alternative diagnostic method for the evaluation of DFU and the detection of osteomyelitis.