To evaluate the ability of a diagnostic abbreviated magnetic resonance (MR) imaging protocol consisting of maximum intensity projections (MIPs) from diffusion-weighted imaging with background ...suppression (DWIBS) and unenhanced morphologic sequences to help predict the likelihood of malignancy on suspicious screening x-ray mammograms, as compared with an abbreviated contrast material-enhanced MR imaging protocol and a full diagnostic breast MR imaging protocol.
This prospective institutional review board-approved study included 50 women (mean age, 57.1 years; range, 50-69 years), who gave informed consent and who had suspicious screening mammograms and an indication for biopsy, from September 2014 to January 2015. Before biopsy, full diagnostic contrast-enhanced MR imaging was performed that included DWIBS (b = 1500 sec/mm(2)). Two abbreviated protocols (APs) based on MIPs were evaluated regarding the potential to exclude malignancy: DWIBS (AP1) and subtraction images from the first postcontrast and the unenhanced series (AP2). Diagnostic indexes of both methods were examined by using the McNemar test and were compared with those of the full diagnostic protocol and histopathologic findings.
Twenty-four of 50 participants had a breast carcinoma. With AP1 (DWIBS), the sensitivity was 0.92 (95% confidence interval CI: 0.73, 0.98), the specificity was 0.94 (95% CI: 0.77, 0.99), the negative predictive value (NPV) was 0.92 (95% CI: 0.75, 0.99), and the positive predictive value (PPV) was 0.93 (95% CI: 0.75, 0.99). The mean reading time was 29.7 seconds (range, 4.9-110.0 seconds) and was less than 3 seconds (range, 1.2-7.6 seconds) in the absence of suspicious findings on the DWIBS MIPs. With the AP2 protocol, the sensitivity was 0.85 (95% CI: 0.78, 0.95), the specificity was 0.90 (95% CI: 0.72, 0.97), the NPV was 0.87 (95% CI: 0.69, 0.95), the PPV was 0.89 (95% CI: 0.69, 0.97), and the mean reading time was 29.6 seconds (range, 6.0-100.0 seconds).
Unenhanced diagnostic MR imaging (DWIBS mammography), with an NPV of 0.92 and an acquisition time of less than 7 minutes, could help exclude malignancy in women with suspicious x-ray screening mammograms. The method has the potential to reduce unnecessary invasive procedures and emotional distress for breast cancer screening participants if it is used as a complement after the regular screening clarification procedure.
The purpose of this study was to apply a magnetic resonance (MR) imaging-compatible positron emission tomographic (PET) detector technology for simultaneous MR/PET imaging of the human brain and ...skull base. The PET detector ring consists of lutetium oxyorthosilicate (LSO) scintillation crystals in combination with avalanche photodiodes (APDs) mounted in a clinical 3-T MR imager with use of the birdcage transmit/receive head coil. Following phantom studies, two patients were simultaneously examined by using fluorine 18 fluorodeoxyglucose (FDG) PET and MR imaging and spectroscopy. MR/PET data enabled accurate coregistration of morphologic and multifunctional information. Simultaneous MR/PET imaging is feasible in humans, opening up new possibilities for the emerging field of molecular imaging.
BACKGROUNDThe “glymphatic system” (GS), a brain-wide network of cerebrospinal fluid microcirculation, supplies a pathway through and out of the central nervous system (CNS); malfunction of the system ...is implicated in a variety of neurological disorders. In this exploratory study, we analyzed the potential of a new imaging approach that we coined delayed T2-weighted gadolinium-enhanced imaging to visualize the GS in vivo.
METHODSHeavily T2-weighted fluid-attenuated inversion recovery (hT2w-FLAIR) magnetic resonance imaging was obtained before, and 3 hours and 24 hours after intravenous gadolinium-based contrast agent (GBCA) application in 33 neurologically healthy patients and 7 patients with an impaired blood-brain barrier (BBB) due to cerebral metastases. Signal intensity (SI) was determined in various cerebral fluid spaces, and white matter hyperintensities were quantified by applying the Fazekas scoring system.
FINDINGSDelayed hT2w-FLAIR showed GBCA entry into the CNS via the choroid plexus and the ciliary body, with GBCA drainage along perineural sheaths of cranial nerves and along perivascular spaces of penetrating cortical arteries. In all patients and all sites, a significant SI increase was found for the 3 hours and 24 hours time points compared with baseline. Although no significant difference in SI was found between neurologically healthy patients and patients with an impaired BBB, a significant positive correlation between Fazekas scoring system and SI increase in the perivascular spaces 3 hours post injection was shown.
INTERPRETATIONDelayed T2-weighted gadolinium-enhanced imaging can visualize the GBCA pathway into and through the GS. Presence of GBCAs within the GS might be regarded as part of the natural excretion process and should not be mixed up with gadolinium deposition. Rather, the correlation found between deep white matter hyperintensities, an imaging sign of vascular dementia, and GS functioning demonstrated feasibility to exploit the pathway of GBCAs through the GS for diagnostic purposes.
Summary
The definition of multiple myeloma (MM) was updated in 2014, with the intent to enable earlier treatment and thereby avoid appearance of end‐organ damage at progression from smouldering ...multiple myeloma (SMM) to MM. The purpose of this study was to investigate to which extent the development of end‐organ damage at progression to MM was reduced under the updated guidelines. In this prospective observational cohort study (ClinicalTrials.gov Identifier: NCT01374412), between 2014 and 2020, 96 SMM patients prospectively underwent whole‐body magnetic resonance imaging (wb‐MRI) and serological follow‐up at baseline and every 6 months thereafter. A total of 22 patients progressed into MM during follow‐up, of which seven (32%) showed SLiM‐criteria only but no end‐organ damage. Four (57%) of the seven patients who progressed by SLiM‐criteria only progressed with >1 focal lesion (FL) or a growing FL, and three (43%) due to serum free light‐chain‐ratio ≥100. Fifteen (68%) out of 22 patients who progressed still suffered from end‐organ damage at progression. The updated disease definition reduced the proportion of SMM patients suffering from end‐organ damage at progression to MM by one third. wb‐MRI is an important tool for detection of SMM patients who progress to MM without end‐organ damage.
•Report of late MRI findings after prostate HIFU hemiablation in non-recurrent patients.•Common were shrinkage, residual prostate tissue, fluid-filled cavities and fibrosis.•Considerable number of ...cases with rim-like or diffuse contrast enhancement.
Focal therapy with high-intensity focused ultrasound (HIFU) is an emerging option for the treatment of prostate cancer and often followed up by MRI. Image assessment of treatment failure, however, requires proper knowledge about typical procedure-related changes in prostate MRI, which is sparse, in particular for unilateral HIFU treatment and late follow up (beyond 6 months). The goal of this study was therefore to compile the type and frequency of such MRI findings in selected patients without recurrent cancer 12 months after prostate hemiablation.
Data from a prospective multicenter trial on HIFU hemiablation were reviewed retrospectively. Trial patients have had a late follow-up by MRI (at around 12 months) and either MRI/transrectal ultrasound (TRUS) fusion or standard TRUS-guided biopsy. This work deliberately included patients with non-recurrent cancer in the treated prostate lobe in per-protocol biopsy leaving 30 men with initial International Society of Urological Pathology (ISUP) Grade Group of 1 or 2. Six categories of potential HIFU-related MRI features were assessed by an expert committee and then evaluated by two readers in consensus: 1. shrinkage of the treated lobe, 2. residual prostate tissue, 3. fluid-filled cavity, 4. fibrosis, 5. hematoma residuals (in the prostate or seminal vesicles) and 6. contrast enhancement of the ablated area.
Shrinkage of the ablated lobe was seen in 93% of the cases with an average percent volume change of −37% (range: −70% to +108%). In the contralateral lobe, the volume remained practically the same (–2% on average, p = 0.804). In the ablated lobe, the frequency of fibrosis was 97%. Residual prostate tissue was seen in 93% of the cases. The frequency for fluid-filled cavities was 97%, with the wide majority (90%) contiguous with the urethra. Hematoma residuals in the prostate and in seminal vesicles were found in 47% and 10% of the patients, respectively. Contrast enhancement was both rim-like (50%) as well as diffuse (33%) within the ablated area.
In our case series of HIFU hemiablation in the prostate, shrinkage, residual prostate tissue, fluid-filled cavities contiguous with the urethra and fibrosis were very common late MRI findings of the ablated lobe in non-recurrent patients. Rim-like contrast enhancement or diffuse one within the ablated area were less frequent.
Substantial cortical gray matter tissue damage, which correlates with clinical disease severity, has been revealed in multiple sclerosis (MS) using advanced magnetic resonance imaging (MRI) methods ...at 3 T and the use of ultra‐high field, as well as in histopathology studies. While clinical assessment mainly focuses on lesions using
T1‐ and
T2‐weighted MRI, quantitative MRI (qMRI) methods are capable of uncovering subtle microstructural changes. The aim of this ultra‐high field study is to extract possible future MR biomarkers for the quantitative evaluation of regional cortical pathology. Because of their sensitivity to iron, myelin, and in part specifically to cortical demyelination,
T1,
T2,
R2*, and susceptibility mapping were performed including two novel susceptibility markers; in addition, cortical thickness as well as the volumes of 34 cortical regions were computed. Data were acquired in 20 patients and 16 age‐ and sex‐matched healthy controls. In 18 cortical regions, large to very large effect sizes (Cohen's d ≥ 1) and statistically significant differences in qMRI values between patients and controls were revealed compared with only four regions when using more standard MR measures, namely, volume and cortical thickness. Moreover, a decrease in all susceptibility contrasts (
χ,
χ+,
χ−) and
R2* values indicates that the role of cortical demyelination might outweigh inflammatory processes in the form of iron accumulation in cortical MS pathology, and might also indicate iron loss. A significant association between susceptibility contrasts as well as
R2* of the caudal middle frontal gyrus and disease duration was found (adjusted R2: 0.602, p = 0.0011). Quantitative MRI parameters might be more sensitive towards regional cortical pathology compared with the use of conventional markers only and therefore may play a role in early detection of tissue damage in MS in the future.
The aim of this ultra‐high field study extracts MR biomarkers for the quantitative evaluation of regional cortical pathology in MS. In 18 cortical regions, effect sizes of 1 and higher and statistically significant differences in qMRI values between patients and controls were found. Decreasing susceptibility contrasts and
R2* values indicate that cortical demyelination might outweigh inflammatory processes in cortical MS pathology. Multiple linear regression showed that the susceptibility (
χ,
χ+,
χ−) and
R2* of the caudal middle frontal gyrus predicted disease duration.
Purpose To determine the effect of at least five serial injections of the macrocyclic gadolinium-based contrast agent (GBCA) gadoterate meglumine on the signal intensity (SI) of the dentate nucleus ...(DN) of the pediatric brain on nonenhanced T1-weighted magnetic resonance (MR) images. Materials and Methods In this retrospective, institutional review board-approved study, 41 pediatric patients (age range, 3-17 years) who were imaged in at least five consecutive 1.5-T MR examinations with the exclusive use of gadoterate meglumine (plus a final additional nonenhanced MR imaging examination) were evaluated. SI ratio differences between the first and last MR examination were calculated for DN-to-pons and DN-to-middle cerebellar peduncle (MCP) ratios in a region-of-interest-based analysis, and one-sample t tests were used to examine if the SI ratio differences differed from 0. Bayes factors were calculated to quantify the strength of evidence for each test. Results Patients underwent a mean of 8.6 ± 3.9 GBCA administrations (mean accumulated dose, 32.07 mmol ± 17.62, with an average of 16.7 weeks ± 7.9 between every administration). Both ratio differences did not differ significantly from 0 (DN-to-pons ratio: -0.0012 ± 0.0101, P = .436; DN-to-MCP ratio: 0.0007 ± 0.0088, P = .604), and one-sided Bayes factors provided substantial evidence against an SI ratio increase (0.10 for DN-to-pons ratio; 0.27 for DN-to-MCP ratio). Conclusion No increase of the SI in the DN was found after a mean of 8.6 serial injections of the macrocyclic GBCA gadoterate meglumine in pediatric patients, confirming previous studies that did not find this effect after serial injections of macrocyclic GBCAs in adults.
RSNA, 2017.
Background
The value of cerebral susceptibility‐weighted imaging (SWI) in malignant melanoma (MM) patients remains controversial and the effect of melanin on SWI is not well understood.
Purpose
To ...systematically analyze the spectrum of intracerebral findings in MM brain metastases (BM) on SWI and to determine the diagnostic value of SWI.
Study Type
Retrospective.
Population/Subjects
In all, 100 patients with melanoma BM (69 having received radiotherapy RT and 31 RT‐naïve) and a control group of 100 melanoma patients without BM were included. For detailed analysis of signal characteristics, 175 metastases were studied.
Field Strength/Sequence
Gradient echo SWI sequence at 1.5, 3.0, and 9.4 T.
Assessment
Signal characteristics from melanotic and amelanotic BMs on SWI with a focus on blooming artifacts were analyzed, as well as the presence and longitudinal dynamics of isolated SWI blooming artifacts in patients with and without BM.
Statistical Tests
Chi‐squared and Student's t‐test were used for contingency table measures and group data of signal and clinical characteristics, respectively.
Results
Melanotic and amelanotic metastases did not show significant differences of SWI blooming artifacts (38% vs. 43%, P = 0.61). Most metastases without an initial SWI artifact developed a signal dropout during follow‐up (80%; 65/81). Isolated SWI artifacts were detected more frequently in patients with BM (20 vs. 9, P = 0.03), of which the majority were found in patients who had received RT (17 vs. 3, P = 0.08). None of these isolated SWI blooming artifacts turned into overt metastases over time (median follow‐up: 8.5 months). Similar findings persisted as remnants of successfully treated metastases (88%; 7/8).
Data Conclusion
We conclude that SWI provides little additional diagnostic benefit over standard T1‐weighted imaging, as melanin content alone does not cause diagnostically relevant SWI blooming. Signal transition of SWI may rather indicate secondary phenomena like microbleeding and/or metal scavenging. Our results suggest that isolated SWI artifacts do not constitute vital tumor tissue but represent unspecific microbleedings, RT‐related parenchymal changes or posttherapeutic remnants of former metastatic lesions.
Level of Evidence: 3
Technical Efficacy Stage: 5
J. Magn. Reson. Imaging 2019;50:1251–1259.
Objectives
To define terms and processes and agree on a minimum dataset in relation to transperineal prostate biopsy procedures and enhanced prostate diagnostics.
To identify the need for further ...evaluation and establish a collaborative research practice.
Patients and Methods
A 19‐member multidisciplinary panel rated 66 items for their appropriateness and their definition to be incorporated into the international databank using the Research and Development/University of California Los Angeles Appropriateness Method.
The item list was developed from interviews conducted with healthcare professionals from urology, radiology, pathology and engineering.
Results
The panel agreed on 56 items that were appropriate to be incorporated into a prospective database. In total, 10 items were uncertain and were omitted. These items were within the categories: definitions (n = 2), imaging (n = 1), surgical protocols (n = 2) and histology (n = 5).
Conclusions
The components of a minimum dataset for transperineal prostate biopsy have been defined.
This provides an opportunity for multicentre collaborative data analysis and technique development.
The findings of the present study will facilitate prospective studies into the application and outcome of transperineal prostate biopsies.
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