To assess the influence of gray-level discretization on inter- and intra-observer reproducibility of texture radiomics features on clinical MR images.
We studied two independent MRI datasets of 74 ...lacrymal gland tumors and 30 breast lesions from two different centers. Two pairs of readers performed three two-dimensional delineations for each dataset. Texture features were extracted using two radiomics softwares (Pyradiomics and an in-house software). Reproducible features were selected using a combination of intra-class correlation coefficient (ICC) and concordance and coherence coefficient (CCC) with 0.8 and 0.9 as thresholds, respectively. We tested six absolute and eight relative gray-level discretization methods and analyzed the distribution and highest number of reproducible features obtained for each discretization. We also analyzed the number of reproducible features extracted from computer simulated delineations representative of inter-observer variability.
The gray-level discretization method had a direct impact on texture feature reproducibility, independent of observers, software or method of delineation (simulated vs. human). The absolute discretization consistently provided statistically significantly more reproducible features than the relative discretization. Varying the bin number of relative discretization led to statistically significantly more variable results than varying the bin size of absolute discretization.
When considering inter-observer reproducible results of MRI texture radiomics features, an absolute discretization should be favored to allow the extraction of the highest number of potential candidates for new imaging biomarkers. Whichever the chosen method, it should be systematically documented to allow replicability of results.
Oncogenic fusions consisting of fibroblast growth factor receptor (FGFR) and TACC are present in a subgroup of glioblastoma (GBM) and other human cancers and have been proposed as new therapeutic ...targets. We analyzed frequency and molecular features of FGFR-TACC fusions and explored the therapeutic efficacy of inhibiting FGFR kinase in GBM and grade II and III glioma.
Overall, 795 gliomas (584 GBM, 85 grades II and III with wild-type and 126 with IDH1/2 mutation) were screened for FGFR-TACC breakpoints and associated molecular profile. We also analyzed expression of the FGFR3 and TACC3 components of the fusions. The effects of the specific FGFR inhibitor JNJ-42756493 for FGFR3-TACC3-positive glioma were determined in preclinical experiments. Two patients with advanced FGFR3-TACC3-positive GBM received JNJ-42756493 and were assessed for therapeutic response.
Three of 85 IDH1/2 wild-type (3.5%) but none of 126 IDH1/2-mutant grade II and III gliomas harbored FGFR3-TACC3 fusions. FGFR-TACC rearrangements were present in 17 of 584 GBM (2.9%). FGFR3-TACC3 fusions were associated with strong and homogeneous FGFR3 immunostaining. They are mutually exclusive with IDH1/2 mutations and EGFR amplification, whereas they co-occur with CDK4 amplification. JNJ-42756493 inhibited growth of glioma cells harboring FGFR3-TACC3 in vitro and in vivo. The two patients with FGFR3-TACC3 rearrangements who received JNJ-42756493 manifested clinical improvement with stable disease and minor response, respectively.
RT-PCR sequencing is a sensitive and specific method to identify FGFR-TACC-positive patients. FGFR3-TACC3 fusions are associated with uniform intratumor expression of the fusion protein. The clinical response observed in the FGFR3-TACC3-positive patients treated with an FGFR inhibitor supports clinical studies of FGFR inhibition in FGFR-TACC-positive patients.
Computed tomography (CT) and magnetic resonance (MR) imaging reliably demonstrate typical features of vestibular schwannomas or meningiomas in the vast majority of mass lesions in the ...cerebellopontine angle (CPA). However, a large variety of unusual lesions can also be encountered in the CPA. Covering the entire spectrum of lesions potentially found in the CPA, these articles explain the pertinent neuroimaging features that radiologists need to know to make clinically relevant diagnoses in these cases, including data from diffusion and perfusion-weighted imaging or MR spectroscopy, when available. A diagnostic algorithm based on the lesion's site of origin, shape and margins, density, signal intensity and contrast material uptake is also proposed. Part 1 describes the different enhancing extra-axial CPA masses primarily arising from the cerebellopontine cistern and its contents, including vestibular and non-vestibular schwannomas, meningioma, metastasis, aneurysm, tuberculosis and other miscellaneous meningeal lesions.
Objectives
To determine the diagnostic performances of a single Dixon-T2-weighted imaging (WI) sequence compared to a conventional protocol including T1-, T2-, and fat-suppressed T2-weighted MRI at ...3 T when assessing thyroid eye disease (TED).
Materials and methods
This IRB-approved prospective single-center study enrolled participants presenting with confirmed TED from April 2015 to October 2019. They underwent an MRI, including a conventional protocol and a Dixon-T2WI sequence. Two neuroradiologists, blinded to all data, read both datasets independently and randomly. They assessed the presence of extraocular muscle (EOM) inflammation, enlargement, fatty degeneration, or fibrosis as well as the presence of artifacts. The Wilcoxon signed-rank test was used.
Results
Two hundred six participants were enrolled (135/206 66% women, 71/206 34% men, age 52.3 ± 13.2 years). Dixon-T2WI was significantly more likely to detect at least one inflamed EOM as compared to the conventional set (248/412 60% versus 228/412 55% eyes; (
p
= 0.02). Dixon-T2WI was more sensitive and specific than the conventional set for assessing muscular inflammation (100% versus 94.7% and 71.2% versus 68.5%, respectively). Dixon-T2WI was significantly less likely to show major or minor artifacts as compared to fat-suppressed T2WI (20/412 5% versus 109/412 27% eyes,
p
< 0.001, and 175/412 42% versus 257/412 62% eyes,
p
< 0.001). Confidence was significantly higher with Dixon-T2WI than with the conventional set (2.35 versus 2.24,
p
= 0.003).
Conclusion
Dixon-T2WI showed higher sensitivity and specificity and showed fewer artifacts than a conventional protocol when assessing thyroid eye disease, in addition to higher self-reported confidence.
Key Points
•
Dixon-T2WI has better sensitivity and specificity than a conventional protocol for assessing inflamed extraocular muscles in patients with thyroid eye disease.
•
Dixon-T2WI shows significantly fewer artifacts than fat-suppressed T2WI.
•
Dixon-T2WI is faster and is associated with significantly higher self-reported reader confidence as compared to a conventional protocol when assessing inflammatory extraocular muscles.
Objective
To determine the sensitivity and specificity of high-resolution (HR) MRI for detecting signal abnormalities of cranial nerves (CN) in giant cell arteritis (GCA) patients presenting with ...diplopia.
Methods
This IRB-approved retrospective single-center study included GCA patients who underwent 3-T HR MRI from December 2014 to January 2020. Two radiologists, blinded to all data, individually assessed for the presence of enhancement of the 3rd, 4th, and/or 6th CN on post-contrast HR imaging and high signal intensity on HR T2-WI, for signal abnormalities of extraocular muscles and the brainstem, and for inflammatory changes of the ophthalmic and extracranial arteries. A Fisher’s exact test was used to compare patients with or without diplopia.
Results
In total, 64 patients (42/64 (66%) women and 22/64 (34%) men, mean age 76.3 ± 8 years) were included. Of the 64 patients, 14 (21.9%) presented with diplopia. Third CN enhancement was detected in 7/8 (87.5%) patients with 3rd CN impairment, as compared to no patients with 4th or 6th CN impairment or to patients without diplopia (
p
< 0.001). Third CN abnormal high signal intensity on HR T2-WI was detected in 4/5 patients (80%) with 3rd CN impairment versus none of other patients (
p
< 0.001). Sensitivity, specificity, positive predictive value, and negative predictive value for detecting 3rd CN signal abnormalities were of 0.88, 1, 1, and 0.99 and 0.8, 1, 1, and 0.98 for post-contrast HR imaging and HR T2-WI, respectively.
Conclusions
HR MRI had excellent diagnostic sensitivity and specificity when detecting signal abnormalities of the 3rd CN in GCA patients presenting with 3rd CN impairment.
Key Points
•
Third cranial nerve enhancement was detected in all patients with 3rd cranial nerve impairment except for one with transient diplopia
.
•
The “check mark sign” might be useful to identify 3rd cranial nerve signal abnormalities in the orbital apex
.
•
No signal abnormalities of the 4th or 6th cranial nerves could be detected on high-resolution MRI
.
To retrospectively review the brain magnetic resonance (MR) imaging and computed tomographic (CT) findings in patients with Erdheim-Chester disease (ECD).
The ethics committee required neither ...institutional review board approval nor informed patient consent for retrospective analyses of the patients' medical records and imaging data. The patients' medical files were retrospectively reviewed in accordance with human subject research protocols. Three neuroradiologists in consensus analyzed the signal intensity, location, size, number, and gadolinium uptake of lesions detected on brain MR images obtained in 33 patients with biopsy-proved ECD.
Thirty patients had intracranial, facial bone, and/or orbital involvement, and three had normal neurologic imaging findings. The hypothalamic-pituitary axis was involved in 16 (53%) of the 30 patients, with six (20%) cases of micronodular or nodular masses of the infundibular stalk. Meningeal lesions were observed in seven (23%) patients. Three (10%) patients had bilateral symmetric T2 high signal intensity in the dentate nucleus areas, and five (17%) had multiple intraaxial enhancing masses. Striking intracranial periarterial infiltration was observed in three (10%) patients. Another patient (3%) had a lesion in the lumen of the superior sagittal sinus. Nine (30%) patients had orbital involvement. Twenty-four (80%) patients had osteosclerosis of the facial and/or skull bones. At least two anatomic sites were involved in two-thirds (n = 20) of the patients. Osteosclerosis of the facial bones associated with orbital masses and either meningeal or infundibular stalk masses was seen in eight (27%) patients.
Lesions of the brain, meninges, facial bones, and orbits are frequently observed and should be systematically sought on the brain MR and CT images obtained in patients with ECD, even if these patients are asymptomatic. Careful attention should be directed to the periarterial environment.
Objectives
To assess the impact of timing from visual symptoms’ onset to diffusion-weighted (DW) 3 T MRI completion to detect ischemic changes of the optic disc and optic nerve in AION patients.
...Methods
This IRB-approved retrospective single-center study included 3 T MRI data from 126 patients with AION and 111 controls with optic neuritis treated between January 2015 and May 2020. Two radiologists blinded to all data individually analyzed imaging. A senior neuroradiologist resolved any discrepancies by consensus. The primary judgment criterion was the restricted diffusion of the optic disc and/or the optic nerve assessed subjectively on the ADC maps. ADC values were also measured. Spearman rank correlations were used to examine the relationships between timing from visual symptoms’ onset to MRI completion and both the restricted diffusion and the ADC values.
Results
One hundred twenty-six patients (47/126 37.3% women and 79/126 62.7% men, mean age 69.1 ± 13.7 years) with AION were included. Restricted diffusion of the optic disc in AION eyes was more frequent in the early MRI group than in the late MRI group: 35/49 (71.4%) eyes versus 3/83 (3.6%) eyes,
p
< 0.001. ADC values of the pathological optic discs and optic nerves were lower in the early MRI group than in the late MRI group: 0.61 0.52–0.94 × 10
−3
mm
2
/s versus 1.28 1.01–1.44 × 10
−3
mm
2
/s,
p
< 0.001, and 0.74 0.61–0.88 × 10
−3
mm
2
/s versus 0.89 0.72–1.10 × 10
−3
mm
2
/s,
p
< 0.001, respectively.
Conclusions
DWI MRI showed good diagnostic performance to detect AION when performed early after the onset of visual symptoms.
Key Points
• Restricted diffusion of the optic disc in eyes affected by AION was significantly more likely to be observed in patients who had undergone MRI within 5 days after onset of visual symptoms.
•
ADC values of the pathological optic discs and optic nerves were significantly lower in patients who had undergone MRI within 5 days after onset of visual symptoms of AION: 0.61 × 10
−3
mm
2
/
s versus 1.28 × 10
−3
mm
2
/s,
p < 0.001, and 0.74 × 10
−3
mm
2
/
s versus 0.89 × 10
−3
mm
2
/s,
p < 0.001, respectively.
•
The optimal threshold for timing from visual symptoms’ onset to MRI completion to detect restricted diffusion of the optic disc and/or optic nerve was 5 days, with an AUC of 0.88
(
CI
95%
: 0.82–0.94
).
Objectives
To determine the diagnostic accuracy of MRI intravoxel incoherent motion (IVIM) when characterizing orbital lesions, which is challenging due to a wide range of locations and histologic ...types.
Methods
This IRB-approved prospective single-center study enrolled participants presenting with an orbital lesion undergoing a 3-T MRI prior to surgery from December 2015 to July 2019. An IVIM sequence with 15
b
values ranging from 0 to 2000 s/mm
2
was performed. Two neuroradiologists, blinded to clinical data, individually analyzed morphological MRIs. They drew one region of interest inside each orbital lesion, providing apparent diffusion coefficient (ADC), true diffusion coefficient (
D
), perfusion fraction (
f
), and pseudodiffusion coefficient (
D
*) values.
T
test, Mann-Whitney
U
test, and receiver operating characteristic curve analyses were performed to discriminate between orbital lesions and to determine the diagnostic accuracy of the IVIM parameters.
Results
One hundred fifty-six participants (84 women and 72 men, mean age 54.4 ± 17.5 years) with 167 orbital lesions (98/167 59% benign lesions including 54 orbital inflammations and 69/167 41% malignant lesions including 32 lymphomas) were included in the study.
ADC and
D
were significantly lower in malignant than in benign lesions: 0.8 × 10
−3
mm
2
/s 0.45 versus 1.04 × 10
−3
mm
2
/s 0.33,
p
< 0.001, and 0.75 × 10
−3
mm
2
/s 0.40 versus 0.98 × 10
−3
mm
2
/s 0.42,
p
< 0.001, respectively.
D
* was significantly higher in malignant lesions than in benign ones: 12.8 × 10
−3
mm
2
/s 20.17 versus 7.52 × 10
−3
mm
2
/s 7.57,
p
= 0.005. Area under curve was of 0.73, 0.74, 0.72, and 0.81 for ADC,
D
,
D
*, and a combination of
D
,
f
, and
D
*, respectively.
Conclusions
Our study showed that IVIM might help better characterize orbital lesions.
Key Points
• Intravoxel incoherent motion (IVIM) helps clinicians to assess patients with orbital lesions.
• Intravoxel incoherent motion (IVIM) helps clinicians to characterize orbital lymphoma versus orbital inflammation.
• Management of patients becomes more appropriate.
Objectives
To compare the diagnostic accuracy of 3D versus 2D contrast-enhanced vessel-wall (CE-VW) MRI of extracranial and intracranial arteries in the diagnosis of GCA.
Methods
This prospective ...two-center study was approved by a national research ethics board and enrolled participants from December 2014 to October 2017. A protocol including both a 2D and a 3D CE-VW MRI at 3 T was performed in all patients. Two neuroradiologists, blinded to clinical data, individually analyzed separately and in random order 2D and 3D sequences in the axial plane only or with reformatting. The primary judgment criterion was the presence of GCA-related inflammatory changes of extracranial arteries. Secondary judgment criteria included inflammatory changes of intracranial arteries and the presence of artifacts. A McNemar’s test was used to compare 2D to 3D CE-VW MRIs.
Results
Seventy-nine participants were included in the study (42 men and 37 women, mean age 75 (± 9.5 years)). Fifty-one had a final diagnosis of GCA. Reformatted 3D CE-VW was significantly more sensitive than axial-only 3D CE-VW or 2D CE-VW when showing inflammatory change of extracranial arteries: 41/51(80%) versus 37/51 (73%) (
p
= 0.046) and 35/50 (70%) (
p
= 0.03). Reformatted 3D CE-VW was significantly more specific than 2D CE-VW: 27/27 (100%) versus 22/26 (85%) (
p
= 0.04). 3D CE-VW showed higher sensitivity than 2D CE-VW when detecting inflammatory changes of intracranial arteries: 10/51(20%) versus 4/50(8%),
p
= 0.01. Interobserver agreement was excellent for both 2D and 3D CE-VW MRI: κ = 0.84 and 0.82 respectively.
Conclusions
3D CE-VW MRI supported more accurate diagnoses of GCA than 2D CE-VW.
Key Points
• 3D contrast-enhanced vessel-wall magnetic resonance imaging is a high accuracy, non-invasive diagnostic tool used to diagnose giant cell arteritis.
• 3D contrast-enhanced vessel-wall imaging is feasible for clinicians to complete within a relatively short time, allowing immediate assessment of extra and intracranial arteries.
• 3D contrast-enhanced vessel-wall magnetic resonance imaging might be considered a diagnostic tool when intracranial manifestation of GCA is suspected.
PDF
