Does adding FDG-PET to MRI improve the differentiation between primary cerebral lymphoma and glioblastoma? Observer performance study

Objective

It is sometimes difficult to distinguish between primary central nervous system lymphomas (PCNSL) and glioblastoma multiforme (GBM). The aim of this study was to investigate whether the addition of ¹⁸F-2-fluoro-2-deoxy-d-glucose positron emission tomography ([¹⁸F]FDG-PET) and apparent diffusion coefficients (ADC) to conventional MRI improves diagnostic accuracy for distinguishing between PCNSL and GBM with similar MRI findings.

Methods

We used conventional- and diffusion-weighted MRI and FDG-PET scans of 21 patients with histologically confirmed brain tumors exhibiting similar MRI findings (PCNSL, n?=?14, GBM, n?=?7) in our observer performance study that consisted of 3 interpretation sessions. ADC and maximum standard uptake values (SUV_max) of the tumors were calculated. Three radiologists first interpreted conventional MRI (1st session), then they read images to which the ADC value had been added (2nd session), and finally they interpreted images supplemented with SUV_max (3rd session). Observer performance was evaluated using ?? statistic and receiver operating characteristics analyses.

Results

The addition of ADC values to conventional MRI failed to improve the differentiation between PCNSL and GBM. The addition of SUV_max at the third session improved the diagnostic accuracy of all 3 readers and resulted in higher interobserver agreement; mean accuracy was 95% (range 93?C100%). In one observer the accuracy of tumor differentiation was significantly improved at the third compared to the second session (p?=?0.017).

Conclusions

In a selected group of PCNSL and GBM with similar MRI findings, the addition of quantitative FDG-PET to MRI may improve their differentiation. ADC measurement did not allow further discrimination.     

Apparent diffusion coefficient vale of the brain in patients with Gaucher’s disease type II and type III

Introduction  

The aim of this work is to assess the usefulness of apparent diffusion coefficient (ADC) value of the brain for diagnosis of patients with Gaucher’s disease type II and type III.     

What is the significance of haemosiderin in the lungs of deceased infants?

In infants, pulmonary haemosiderin has been put forward as a marker of previous asphyxic abuse and possible grounds for suspicion of homicide. Review of the available literature does not provide a strong enough evidence base to support this claim. Further research is needed before instigation of criminal proceedings can be justified on this pathological finding.     

Imaging the heart’s brain: Simultaneous innervation/perfusion analysis in the era of new CZT cameras

Journal of Nuclear Cardiology -     

Diagnosis of perfusion abnormality of the pulmonary artery in Takayasu’s arteritis using contrast-enhanced MR perfusion imaging

To determine the clinical efficacy of contrast-enhanced magnetic resonance (MR) perfusion imaging in the diagnosis of perfusion abnormality in the pulmonary artery (PA) in Takayasu’s arteritis (TA). Twenty-one patients were evaluated. Pulmonary MR perfusion images were acquired using a 2-dimensional (2D) fast spoiled gradient echo sequence with single-slice technique (TR/TE, 5.3/1.3; flip angle, 30°; receiver bandwidth, 31.2 kHz/pixel; acquisition time, 0.7 s; and total acquisition time, 49 s). Seventy continuous subtracted MR images were evaluated, and the presence of perfusion abnormality was determined in lobe-based (n=126) and patient-based (n=21) analyses. Sensitivity, specificity, positive predictive value (PPV), and negative predictive values (NPV) were calculated using perfusion scintigraphy as a standard reference. For lobe-based analysis, sensitivity was 91.7–95.8%, specificity was 92.2–93.7%, and PPV and NPV were 73.3–76.7% and 97.9–99.0%, respectively. For patient-based analyses, sensitivity was 100%, specificity was 72.7%, and PPV and NPV were 76.9% and 100%, respectively. Kappa values for each analysis were between 0.78–1.00. In conclusion, MR perfusion imaging appears to be a valuable, noninvasive method to estimate PA involvement in patients with TA.     

Structural and neurochemical evaluation of the brain and pons in patients with Wilson’s disease

Purpose  

The aim of this study was to examine the structural-neurochemical abnormalities of the frontal white matter (FWM), deep gray matter nuclei, and pons in patients with Wilson’s disease (WD) using proton magnetic resonance spectroscopy (MRS) and diffusion-weighted imaging (DWI).     

Imaging strategies in the management of oesophageal cancer: what’s the role of MRI?

Objectives

To outline the current role and future potential of magnetic resonance imaging (MRI) in the management of oesophageal cancer regarding T-staging, N-staging, tumour delineation for radiotherapy (RT) and treatment response assessment.

Methods

PubMed, Embase and the Cochrane library were searched identifying all articles related to the use of MRI in oesophageal cancer. Data regarding the value of MRI in the areas of interest were extracted in order to calculate sensitivity, specificity, predictive values and accuracy for group-related outcome measures.

Results

Although historically poor, recent improvements in MRI protocols and techniques have resulted in better imaging quality and the valuable addition of functional information. In recent studies, similar or even better results have been achieved using optimised MRI compared with other imaging strategies for T- and N-staging. No studies clearly report on the role of MRI in oesophageal tumour delineation and real-time guidance for RT so far. Recent pilot studies showed that functional MRI might be capable of predicting pathological response to treatment and patient prognosis.

Conclusions

In the near future MRI has the potential to bring improvement in staging, tumour delineation and real-time guidance for RT and assessment of treatment response, thereby complementing the limitations of currently used imaging strategies.

Key Points

? MRI’s role in oesophageal cancer has been somewhat limited to date. ? However MRI’s ability to depict oesophageal cancer is continuously improving. ? Optimising TN-staging, radiotherapy planning and response assessment ultimately improves individualised cancer care. ? MRI potentially complements the limitations of other imaging strategies regarding these points.     

Discordance in the anatomical locations between morphological and perfusion changes occurring with the progression of Alzheimer’s disease

Objective

The aim of this study was to clarify the difference between the morphological and perfusion changes occurring with the progression of Alzheimer’s disease (AD).

Methods

The study focused on 37 patients who were clinically diagnosed with AD and were examined by both MRI and perfusion SPECT twice during a 1- to 2-year clinical observation period. Twenty-four of the 37 patients showed a progression of cognitive deterioration during the 1.2(±0.4)-year period of clinical observation (rapidly progressing group: initial mean MMSE score = 23.3; second mean MMSE score = 20.2), while 13 patients showed no apparent progression of cognitive deterioration (slowly progressing group: initial mean MMSE score = 21.2; second mean MMSE score = 22.2). The morphological changes were evaluated using a voxel-based morphometric technique with segmented MRI images. Cerebral perfusion was measured by Tc-99m ECD SPECT. Data analysis was performed by SPM on a MATLAB work space (2007.a).

Results

There was no significant difference in either the perfusion or gray matter density between the rapidly progressing and slowly progressing groups at the initial examination. The rapidly progressing group showed an interval decrease of perfusion in the bilateral parieto-occipital cortex and a decrease of gray matter density in the bilateral temporal and cingulate cortex. The slowly progressing group did not show a significant interval change in either the cerebral perfusion or gray matter density.

Conclusions

These results suggest that rapid symptomatic progression in AD patients accompanies rapid progression of both morphological and perfusion changes, although the regions of the changes differ between them.     

Brain MRI and SPECT in the diagnosis of early neurological involvement in Wilson’s disease

Purpose To evaluate the impact of brain MRI and single-photon emission computed tomography (SPECT) in early detection of central nervous system abnormalities in patients affected by Wilson’s disease (WD) with or without neurological involvement. Methods Out of 25 consecutive WD patients, 13 showed hepatic involvement, ten hepatic and neurological manifestations, and twp hepatic, neurological, and psychiatric symptoms, including mainly movement disorders, major depression, and psychosis. Twenty-four healthy, age–gender matched subjects served as controls. All patients underwent brain MRI and ^99mTc-ethyl-cysteinate dimer (ECD) SPECT before starting specific therapy. Voxel-by-voxel analyses were performed using statistical parametric mapping to compare differences in ^99mTc-ECD brain uptake between the two groups. Results Brain MRI showed T2-weighted hyperintensities in seven patients (28%), six of whom were affected by hepatic and neurological forms. Brain perfusion SPECT showed pathological data in 19 patients (76%), revealing diffuse or focal hypoperfusion in superior frontal (Brodmann area (BA) 6), prefrontal (BA 9), parietal (BA 40), and occipital (BA 18, BA 39) cortices in temporal gyri (BA 37, BA 21) and in caudatus and putamen. Moreover, hepatic involvement was detected in nine subjects; eight presented both hepatic and neurological signs, while two exhibited WD-correlated hepatic, neurological, and psychiatric alterations. All but one patient with abnormal MRI matched with abnormal ECD SPECT. Pathologic MRI findings were obtained in six out of ten patients with hepatic and neurological involvement while abnormal ECD SPECT was revealed in eight patients. Both patients with hepatic, neurological, and psychiatric involvement displayed abnormal ECD SPECT and one displayed an altered MRI. Discussion These findings suggest that ECD SPECT might be useful in detecting early brain damage in WD, not only in the perspective of assessing and treating motor impairment but also in evaluating better the less investigated disorders in the cognitive domain.     

What’s in a Name? Report of the ACR Task Force on General Radiology and Multi-Subspecialization

The ACR Council passed Resolution 47 at its 2020 annual meeting establishing a representative task force (TF) to explore the concept of the “multispecialty radiologist,” previously proposed in 2012. The TF held eight virtual meetings over 8 months, considered data from a 2020 ACR Membership Tracking Survey, conducted a review of current literature, and collected anecdotal experience from TF members and ACR leadership. ACR legal counsel and a cross-section of ACR Commissions and Committees also provided input. The TF concluded that there is scant interest from the radiology community in the multispecialty radiologist title and no agreed-upon definition for the term. Radiologists may identify as diagnostic or subspecialty radiologists; however, the roles they fill in clinical practice include general, multispecialty, and subspecialized radiology. The TF proposes definitions for each of these terms to support radiologist recruitment aligned with optimal patient care in the practice community and to improve the quality of data collection about the field. To reduce ambiguity, the TF proposes adoption of the defined terms by the radiology community, including radiologist recruiters and employers, and suggests ways in which resident training and the ABR board examination can be adapted to support this new structure. Additionally, as part of an exploration of hyperspecialization and trainee preparedness for clinical practice, the TF discussed the challenges faced by community-based practices seeking to provide a full range of high-quality, radiologist-delivered diagnostic and interventional services to their patient populations.     

Distinct patterns of medial temporal impairment in degenerative dementia: a brain SPECT perfusion study in Alzheimer’s disease and frontotemporal dementia

Purpose

Medial temporal impairment can be detected clinically and by morphological imaging during Alzheimer’s disease (AD), but the existence of a functional impairment in this area seems to be less well established. Yet such functional impairment is classically found in other degenerative cortical dementias, such as the frontal variant of frontotemporal dementia (fv-FTD). The aim of this study was to characterize and compare brain SPECT perfusion of the medial temporal lobe in AD and fv-FTD.

Methods

Voxel-based comparisons were performed using SPM8 between cerebral SPECT images from 85 AD patients, 25 fv-FTD patients and 12 healthy controls at the whole-brain level and the medial temporal lobe level using a region of interest approach (p?<?0.001, corrected for the cluster).

Results

In the free and cued selective reminding test, used to evaluate medial temporal memory function, AD patients had significantly lower scores than the fv-FTD patients (p?<?0.005). AD and fv-FTD patients showed hypoperfused medial temporal structures in comparison to normal controls. However, fv-FTD patients had more pronounced hypoperfusion in this area, with a different topography, more anterior and more parahippocampal.

Conclusion

These results show that medial temporal hypoperfusion can be detected in degenerative dementias by SPECT. Paradoxically, the hypoperfusion is more severe in fv-FTD than in AD patients, even though the mnesic profile of AD is more altered, suggesting the existence of inefficient compensatory mechanisms.     

Diagnosis of Alzheimer’s disease using brain perfusion SPECT and MR imaging: which modality achieves better diagnostic accuracy?

Purpose The purpose of this study was to compare the accuracy of MR imaging and brain perfusion single-photon emission tomography (SPECT) in diagnosing Alzheimers disease (AD).Methods The transaxial section display of brain perfusion SPECT, three-dimensional stereotactic surface projection (3D-SSP) SPECT image sets, thin-section MR imaging of the hippocampus and perfusion MR imaging were evaluated in 66 subjects comprising 35 AD patients and 31 subjects without AD. SPECT and MR imaging were visually interpreted by two experts and two novices, and the diagnostic ability of each modality was evaluated by receiver operating characteristic (ROC) analysis.Results In the experts interpretations, there was no significant difference in the area under the ROC curve ( A_z) between 3D-SSP and thin-section MR imaging, whereas the A_z of transaxial SPECT display was significantly lower than that of 3D-SSP (3D-SSP: 0.97, thin-section MR imaging: 0.96, transaxial SPECT: 0.91), and the A_z of perfusion MR imaging was lowest (0.63). The sensitivity and specificity of each modality were, respectively, 80.0% and 96.8% for 3D-SSP, 77.1% and 96.8% for thin-section MR imaging, 60.0% and 93.5% for transaxial SPECT display and 34.3% and 100% for perfusion MR imaging. In the novices interpretations, the A_z, sensitivity and specificity of 3D-SSP were superior to those of thin-section MR imaging.Conclusion Thin-section hippocampal MR imaging and 3D-SSP image sets had potentially equivalent value for the diagnosis of AD, and they were superior to transaxial SPECT display and perfusion MR imaging. For avoidance of the effect of interpreters experience on image evaluation, 3D-SSP appears to be optimal.