Radiology

DTI helps predict mild TBI outcomes in veterans

Posted by

0


Diffusion-tensor MRI (DTI-MRI) could play a key role in predicting military veterans’ functional postdeployment outcomes — such as how soon they return to work — following a mild traumatic brain injury (TBI) during combat, according to a new study published online March 29 in Radiology.

 Researchers from the Philadelphia Veterans Affairs (VA) Medical Center are optimistic their findings will overcome current challenges in differentiating between the effects of mild TBI, or concussion, from those of other conditions, such as post-traumatic stress disorder (PTSD).

Mild TBI has become an escalating public health issue, especially among military personnel during and after deployment. The Armed Forces Health Surveillance Center estimates that more than 300,000 U.S. service members were diagnosed with mild TBI between 2000 and 2015.

Lead author Dr. Jeffrey Ware and colleagues used DTI and MRI to study 57 military veterans who had a clinical diagnosis of mild TBI following deployment. The average length of time between injury and postdeployment evaluation was 3.8 years, with an average follow-up duration of 1.4 years (Radiology, March 29, 2016).

The researchers used DTI-MRI to detect abnormalities in the brain, particularly in the white matter, via measurements of water movement. They compared the results to clinical measures and patient outcomes six months to 2.5 years after the initial evaluation.

Ware and colleagues found significant associations between initial postdeployment DTI measurements and neurobehavioral symptoms, timing of injury, and subsequent functional outcomes. The measurements also correlated with greater use of healthcare services among veterans with mild TBI. All conventional MR images were interpreted as normal.

Brain DTI-MRI of veterans

Diffusion-tensor MR images show regions of the brain (blue) in which lower fractional anisotropy correlates with more severe neurobehavioral symptoms. Veterans with the most severe symptoms had lower microstructural integrity in these regions. Image courtesy of Radiology.

Following initial postdeployment evaluation, 34 study participants (60%) returned to work. Veterans who did not return to work displayed significantly lower fractional anisotropy and higher diffusivity, which suggest less structural integrity, in the left internal capsule, which is associated with motor stimulation to the typically dominant right side of the body.

Thus, the results may provide a connection between impairments in fine motor functioning and the injured veterans’ inability to return to work.

“Our findings suggest that differences in white-matter microstructure may partially account for the variance in functional outcomes among this population. In particular, loss of white-matter integrity has a direct, measurable effect,” Ware said in a statement.

 

DW-MRI: identifying lymph node metastases.

Posted by

0


Diffusion-weighted MRI (DW-MRI) is showing particular promise in aiding the identification of lymph node metastases, according to several recently published studies.

In a review paper published in the journal Radiology earlier this year, specialists summarized data on DW-MRI in the head and neck. This included a detailed section on nodal metastases, noting that “the general consensus appears to be that ADCs [apparent diffusion coefficients] of malignant nodes are significantly lower than those of benign nodes”.

In one study there was a clear lack of any overlap between the higher ADCs of benign lesions and the lower ADCs of malignant lesions. However, the variety of head and neck lesions that can occur means it is often impractical to establish a single ADC threshold for distinguishing between benign and malignant lesions.

The specialists wrote: “Although these results show the potential of DW imaging for characterization of head and neck lesions, given the heterogenous group of benign and malignant lesions that arise in the head and neck, there will clearly be exceptions and overlap in ADC results.” Future research should include the establishment of ADC thresholds for specific sites and for specific pathologic processes , they argued.1

Meta-analysis: squamous cell carcinoma
Meanwhile, the diagnostic accuracy of standard and DW-MRI in detecting lymph node metastases in patients with head and neck squamous cell carcinoma (HNSCC) was the subject of a meta-analysis recently published in the journal Academic Radiology.

Using data from 16 studies, the researchers in Shanghai, China, calculated that the sensitivity and specificity of standard MRI for determining cervical lymph node status were 76% and 86% respectively. MRI was similar to other diagnostic tools such as PET, CT, and ultrasound, in terms of performance, they added.

A subgroup analysis, however, showed that DW-MRI had a significantly higher sensitivity (86%) than standard MRI. The researchers noted that more data are needed, concluding: “A limited number of small studies suggest DW imaging is superior to conventional imaging for nodal staging of HNSCC”.2

Prospective study in breast cancer
Finally, in the October issue of the Journal of Magnetic Resonance Imaging, specialists reported the findings of a prospective study of the accuracy of DW-MRI in distinguishing between metastatic and benign axillary lymph nodes in patients with breast cancer.

The researchers compared two groups, divided according to histology findings: 19 lymph nodes with a metastasis at least 5 mm in diameter and 24 lymph nodes with no malignant cells (nodes with metastases smaller than 5 mm were excluded from the study).

Overall, the ADC values were significantly lower for the lymph nodes with metastases, compared with the benign lymph nodes (p < 0.001). The researchers identified a threshold for ADC values that resulted in a high sensitivity, specificity, and accuracy (94.7%, 91.7%, and 93%, respectively) for this series of patients.

They concluded: “From these preliminary data, DW imaging seems a promising method in the differential diagnosis between metastatic and benign axillary lymph nodes in patients with breast cancer.”3

References:
1. Thoeny HC, et al. Radiology. 2012;263:19-32.
2. Wu LM, et al. Acad Radiol. 2012;19:331-40.
3. Fornasa F, et al. J Magn Reson Imaging. 2012;36:858-64.

Source: http://www.getinsidehealth.com

 

MRI in thoracic outlet syndrome.

Posted by

0


Thoracic outlet syndrome (TOS) arises from dynamic compression of the subclavian artery (SA) or subclavian vein (SV) or brachial plexus (BPL) in the cervicothoracobrachial region, in combination or separately. Patients sustain symptoms depending on the compressed components…

Abstract

We discuss MRI findings in patients with thoracic outlet syndrome (TOS). A total of 100 neurovascular bundles were evaluated in the interscalene triangle (IS), costoclavicular (CC), and retropectoralis minor (RPM) spaces. To exclude neurogenic abnormality, MRIs of the cervical spine and brachial plexus (BPL) were obtained in neutral. To exclude compression on neurovascular bundles, sagittal T1W images were obtained vertical to the longitudinal axis of BPL from spinal cord to the medial part of the humerus, in abduction and neutral. To exclude vascular TOS, MR angiography (MRA) and venography (MRV) of the subclavian artery (SA) and vein (SV) in abduction were obtained. If there is compression on the vessels, MRA and MRV of the subclavian vessels were repeated in neutral. Seventy-one neurovascular bundles were found to be abnormal: 16 arterial-venous-neurogenic, 20 neurogenic, 1 arterial, 15 venous, 8 arterial-venous, 3 arterial-neurogenic, and 8 venous-neurogenic TOS. Overall, neurogenic TOS was noted in 69%, venous TOS in 66%, and arterial TOS in 39%. The neurovascular bundle was most commonly compressed in the CC, mostly secondary to position, and very rarely compressed in the RPM. The cause of TOS was congenital bone variations in 36%, congenital fibromuscular anomalies in 11%, and position in 53%. In 5%, there was unilateral brachial plexitis in addition to compression of the neurovascular bundle. Severe cervical spondylosis was noted in 14%, contributing to TOS symptoms. For evaluation of patients with TOS, visualization of the brachial plexus and cervical spine and dynamic evaluation of neurovascular bundles in the cervicothoracobrachial region are mandatory.

Ayse Aralasmak1, Can Cevikol2, Kamil Karaali2, Utku Senol2, Rasul Sharifov1, Rukiye Kilicarslan1 and Alpay Alkan1

1 Department of Radiology, Bezmialem Vakif University, Fatih/Istanbul, Turkey.
2 Department of Radiology, Akdeniz University, Antalya, Turkey.

Source: www. getinsidehealth.com