Quality Assessment of Radiomics Studies on Functional Outcomes After Acute Ischemic Stroke-A Systematic Review

OBJECTIVE

Radiomics is a machine-learning method that extracts features from medical images. The objective of the present systematic review was to assess the quality of existing studies that use radiomics methods to predict functional outcomes in patients after acute ischemic stroke.

METHODS

Studies using radiomics-extracted features to predict functional outcomes among patients with acute ischemic stroke using the modified Rankin Scale were included. PubMed, Scopus, Web of Science, and Embase were screened using the terms "radiomics" and "texture" in combination with "stroke." Quality scores were calculated based on Radiomics Quality Score, the IBSI (Image Biomarkers Standardization Initiative), and the QUADAS-2 (Quality Assessment of Diagnostic Accuracy Studies 2).

RESULTS

Fourteen studies were included. The median total Radiomics Quality Score was 14.5 (13-16) out of 36. Domains 1, 5, and 6 on protocol quality and stability of imaging and segmentation, level of evidence, and use of open science and data, respectively, were poor. Median IBSI score was 2.5 (1-5) out of 6. Few studies included bias-field correction algorithms, isovoxel resampling, skull stripping, or gray-level discretization. Of 14 studies, none received +6 points, 1 received +5 points, 5 received +4 points, 1 study received +3 points, 5 received +2 points, 2 received +1 points, and none received 0 points. As per the QUADAS-2, 6/14 (42.9%) studies had a risk of bias concern and 0/14 (0%) had applicability concern.

CONCLUSIONS

The quality of the included studies was low to moderate. With increasing use of radiomics, future studies should attempt to adhere to and report established radiomics quality guidelines.

PET/CT Imaging in Treatment Planning and Surveillance of Sinonasal Neoplasms

Sinonasal cancers are uncommon malignancies with a generally unfavorable prognosis, often presenting at an advanced stage. Their high rate of recurrence supports close imaging surveillance and the utilization of functional imaging techniques. Whole-body 18F-FDG PET/CT has very high sensitivity for the diagnosis of sinonasal malignancies and can also be used as a "metabolic biopsy" in the characterization of some of the more common subgroups of these tumors, though due to overlap in uptake, histological confirmation is still needed. For certain tumor types, radiotracers, such as 11C-choline, and radiolabeled somatostatin analogs, including 68Ga-DOTATATE/DOTATOC, have proven useful in treatment planning and surveillance. Although serial scans for posttreatment surveillance allow the detection of subclinical lesions, the optimal schedule and efficacy in terms of survival are yet to be determined. Pitfalls of 18F-FDG, such as post-surgical and post-radiotherapy crusting and inflammation, may cause false-positive hypermetabolism in the absence of relapse.

High resolution 7T MR imaging in characterizing culprit intracranial atherosclerotic plaques

BACKGROUND

Current imaging modalities underestimate the severity of intracranial atherosclerotic disease (ICAD). High resolution vessel wall imaging (HR-VWI) MRI is a powerful tool in characterizing plaques. We aim to show that HR-VWI MRI is more accurate at detecting and characterizing intracranial plaques compared to digital subtraction angiography (DSA), time-of-flight (TOF) MRA, and computed tomography angiogram (CTA).

METHODS

Patients with symptomatic ICAD prospectively underwent 7T HR-VWI. We calculated: degree of stenosis, plaque burden (PB), and remodeling index (RI). The sensitivity of detecting a culprit plaque for each modality as well as the correlations between different variables were analyzed. Interobserver agreement on the determination of a culprit plaque on every imaging modality was evaluated.

RESULTS

A total of 44 patients underwent HR-VWI. Thirty-four patients had CTA, 18 TOF-MRA, and 18 DSA. The sensitivity of plaque detection was 88% for DSA, 78% for TOF-MRA, and 76% for CTA. There's significant positive correlation between PB and degree of stenosis on HR-VWI MRI (p < 0.001), but not between PB and degree of stenosis in DSA (p = 0.168), TOF-MRA (p = 0.144), and CTA (p = 0.253). RI had a significant negative correlation with degree of stenosis on HR-VWI MRI (p = 0.003), but not on DSA (p = 0.783), TOF-MRA (p = 0.405), or CTA (p = 0.751). The best inter-rater agreement for culprit plaque detection was with HR-VWI (p = 0.001).

CONCLUSIONS

The degree of stenosis measured by intra-luminal techniques does not fully reflect the true extent of ICAD. HR-VWI is a more accurate tool in characterizing atherosclerotic plaques and may be the default imaging modality in clinical practice.

Spinal subarachnoid hemorrhage secondary to ruptured artery of Adamkiewicz aneurysm: Is conservative management the first best step?

A 43-year-old woman presented to the hospital with severe low back pain and paresthesias in the bilateral lower extremities. MRI of the spine revealed spinal subarachnoid and subdural hemorrhage extending from T11 to L5-S1. A diagnostic spinal angiogram demonstrated a dissecting, partially thrombosed aneurysm of the artery of Adamkiewicz.At four weeks from the sentinel event, her symptoms had completely resolved with resolution on imaging.Isolated artery of Adamkiewicz aneurysms, which are most often dissecting, fusiform aneurysms are extremely rare and management controversial.

Assessment of knee osteoarthritis by ultrasonography and its association with knee pain

BACKGROUND

Pain is a significant cause of disability in knee osteoarthritis. Conventional radiography is widely used in the assessment of knee osteoarthritis, however radiographic findings do not correlate well with pain. Ultrasonography can be used to evaluate the soft tissue structures of the knee that can be related to pain.

OBJECTIVE

To evaluate pain-related soft tissue structures of the knee with ultrasonography.

METHODS

This cross-sectional study included a total of 198 knees from 99 patients with knee osteoarthritis. Knee pain and functional status were evaluated by performing visual analogue scale (VAS) and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). On the ultrasound, cartilaginous thickness, knee effusion and presence of Baker's cyst were assessed and the correlation to pain was investigated.

RESULTS

Baker's cyst was significantly more frequent in symptomatic knees (13.9%) compared to asymptomatic knees (2.5%). Patients with Baker's cyst had a significantly more limited degree of knee flexion, significantly higher resting VAS pain scores and worse WOMAC scores compared to patients without Baker's cyst. In log-linear analysis, presence of Baker's cyst increased the risk of pain by 2.94 times.

CONCLUSION

Ultrasound as a modality that is easily accessible, inexpensive and without radiation exposure is helpful to demonstrate factors related to pain in knee osteoarthritis by allowing assessment of soft tissue structures.