T2-weighted Fat-saturated Sequences Research Articles

“Bone marrow edema” in the differential diagnosis of traumatic injuries of the knee

Bone marrow edema is MR images is defined by the presence of hypointense infiltration on T1-weighted images and clear high signal intensity on fat-saturated T2-weighted sequences (T2 FSE FAT SATURATED, T2-weighted short-tau inversion recovery (T2w-STIR)).Aim: To demonstrate the features of manifestation of “bone marrow edema” at different severity and character of traumatic injury of the knee.Materials and Methods. A series of clinical cases with subchondral bone involvement in the form of “bone marrow edema” resulting from trauma is presented using the example of the knee joint as the most common area of MRI for differential diagnosis.Results. The features of “marrow edema” of the femoral and tibial condyles were analyzed using clinical examples. It was shown that the severity and nature of injury can be judged by the nature of the edema, presence of linear hypointensities, articular surface deforms and the bone defects.Conclusion. Evaluation of “bone marrow edema” revealed on MRI examination in case of pain syndrome after a knee joint injury allows timely clarification of the diagnosis and adequate treatment.

Diagnosis and monitoring denosumab therapy of giant cell tumors of bone: radiologic-pathologic correlation.

To determine the value of CT and dynamic contrast-enhanced (DCE-)MRI for monitoring denosumab therapy of giant cell tumors of bone (GCTB) by correlating it to histopathology. Patients with GCTB under denosumab treatment and monitored with CT and (DCE-)MRI (2012-2021) were retrospectively included. Imaging and (semi-)quantitative measurements were used to assess response/relapse. Tissue samples were analyzed using computerized segmentation for vascularization and number of neoplastic and giant cells. Pearson's correlation/Spearman's rank coefficient and Kruskal-Wallis tests were used to assess correlations between histopathology and radiology. Six patients (28 ± 8years; five men) were evaluated. On CT, good responders showed progressive re-ossification (+7.8HU/month) and cortical remodeling (woven bone). MRI showed an SI decrease relative to muscle on T1-weighted (-0.01 A.U./month) and on fat-saturated T2-weighted sequences (-0.03 A.U./month). Time-intensity-curves evolved from a type IV with high first pass, high amplitude, and steep wash-out to a slow type II. An increase in time-to-peak (+100%) and a decrease in Ktrans (-71%) were observed. This is consistent with microscopic examination, showing a decrease of giant cells (-76%), neoplastic cells (-63%), and blood vessels (-28%). There was a strong statistical significant inverse correlation between time-to-peak and microvessel density (ρ = -0.9, p = 0.01). Significantly less neoplastic (p = 0.03) and giant cells (p = 0.04) were found with a time-intensity curve type II, compared to a type IV. Two patients showed relapse after initial good response when stopping denosumab. Inverse imaging and pathological findings were observed. CT and (DCE-)MRI show a good correlation with pathology and allow adequate evaluation of response to denosumab and detection of therapy failure.

Comparison of a STIR- and T1-based radiomics model to differentiate between plexiform neurofibromas and malignant peripheral nerve sheath tumors in neurofibromatosis type 1 (NF1) (S17.010)

Comparison of a STIR- and T1-based radiomics model to differentiate between plexiform neurofibromas and malignant peripheral nerve sheath tumors in neurofibromatosis type 1 (NF1) (S17.010)

Quantitative MR Neurography in Multifocal Motor Neuropathy and Amyotrophic Lateral Sclerosis

The aim of this study was to assess the phenotype of multifocal motor neuropathy (MMN) and amyotrophic lateral sclerosis (ALS) in quantitative MR neurography. In this prospective study, 22 patients with ALS, 8 patients with MMN, and 10 healthy volunteers were examined with 3T MR neurography, using a high-resolution fat-saturated T2-weighted sequence, diffusion-tensor imaging (DTI), and a multi-echo T2-relaxometry sequence. The quantitative biomarkers fractional anisotropy (FA), radial and axial diffusivity (RD, AD), mean diffusivity (MD), cross-sectional area (CSA), T2-relaxation time, and proton spin density (PSD) were measured in the tibial nerve at the thigh and calf, and in the median, radial, and ulnar nerves at the mid-upper arm. MMN showed a characteristic imaging pattern of decreased FA (p = 0.018), increased RD (p = 0.014), increased CSA (p < 0.001), increased T2-relaxation time (p < 0.001), and increased PSD (p = 0.025) in the upper arm nerves compared to ALS and controls. ALS patients did not differ from controls in any imaging marker, nor were there any group differences in the tibial nerve (p > 0.05). MMN shows a characteristic pattern of quantitative DTI and T2-relaxometry parameters in the upper-arm nerves, primarily indicating demyelination. Peripheral nerve changes in ALS seem to be below the detection level of current state-of-the-art quantitative MR neurography.

Is it Possible to Differentiate Types of Breast Implants by Imaging in the Era of Implant-associated Lymphoma?

Breast implant-associated anaplastic large-cell lymphoma (BIA-ALCL) has been recognised in recent years, and there is extensive ongoing research. Although the exact mechanism and cause are still unclear, we now know that the disease is more associated with textured implants. To the best of our knowledge, no previous studies investigating the radiological differential of various implants have been conducted. In this essay, we aimed to demonstrate dicriminating in vitro and in vivo imaging features of variuos types of breast implant devices using mammography, ultrasound, and Magnetic Resonance Imaging (MRI). Five different implant devices from various manufacturers with various surface textures, including smooth, micro-textured, regular macro-textured, lightweight macro-textured, and polyurethane- coated were used. In vitro mammography was performed with a digital mammogram (Amulet Innovality, Fuji, Japan), and in vitro and in vivo sonography were performed with Esaote MyLab9 using a 7.5 MHz linear probe. In vitro MRI was performed with a 1.5T magnet (Symphony TIM upgrade and Aera, Siemens Healthcare, Erlangen, Germany) with a 7-channel breast coil (Sense coil, Innova, Germany). MRI studies included fat sat T2 weighted sequences (T2WS), non-fat sat T2WS, and silicone only sequences. Each imaging technique had different contributions to dealing with this challenge. Mammography and MRI were limited to identifying the capsule's double bands. We could only differentiate the lightweight macro-textured implant on the mammogram as the borosilicate microspheres were represented by tiny, round lucencies within the gel. Ultrasound imaging with the proper technique was very helpful in identifying the surface. The inner capsule (implant shell) was identified as parallel double echogenic bands on the in vitro sonogram. Bands of the smooth implant were better delineated compared to the textured implants. The double echogenic bands of the polyurethane-coated implant were not even identified individually. The reverberation artifact caused by the smooth implant was the main discriminating in vivo sonographic feature of smooth implants. The hyperintense polyurethane-coated capsule was identified on fat-saturated T2WS and non-fat-saturated T2WS via in vitro MRI. The tiny hypointense microspheres of the lightweight implant were also identified on the silicone-only sequence of the in vitro MRI. In this study, we have shown that breast implant material and type may differ with the help of in vitro and in vivo imaging characteristics on different radiological modalities. These different imaging features could be used for recognising and labelling the implant type, especially macrotextured implants that are reported to be more associated with breast implant-associated anaplastic large-cell lymphoma (BIA-ALCL) compared to other types. We believe evaluating these imaging characteristics during daily practice will help radiologists become aware of the implant type and possible complications or diseases associated with that type.

MRI evaluation of soft tissue tumors: comparison of a fast, isotropic, 3D T2-weighted fat-saturated sequence with a conventional 2D T2-weighted fat-saturated sequence for tumor characteristics, resolution, and acquisition time.

To test whether a 4-fold accelerated 3D T2-weighted (T2) CAIPIRINHA SPACE TSE sequence with isotropic voxel size is equivalent to conventional 2DT2 TSE for the evaluation of intrinsic and perilesional soft tissue tumors (STT) characteristics. For 108 patients with histologically-proven STTs, MRI, including 3DT2 (CAIPIRINHA SPACE TSE) and 2DT2 (TSE) sequences, was performed. Two radiologists evaluated each sequence for quality (diagnostic, non-diagnostic), tumor characteristics (heterogeneity, signal intensity, margin), and the presence or absence of cortical involvement, marrow edema, and perilesional edema (PLE); tumor size and PLE extent were measured. Signal-to-noise (SNR) and contrast-to-noise (CNR) ratios and acquisition times for 2DT2 in two planes and 3DT2 sequences were reported. Descriptive statistics and inter-method agreement were reported. Image quality was diagnostic for all sequences (100% [108/108]). No difference was observed between 3DT2 and 2DT2 tumor characteristics (p < 0.05). There was no difference in mean tumor size (3DT2: 2.9 ± 2.5 cm, 2DT2: 2.8 ± 2.6 cm, p = 0.4) or PLE extent (3DT2:0.5 ± 1.2 cm, 2DT2:0.5 ± 1.0 cm, p = 0.9) between the sequences. There was no difference in the SNR of tumors, marrow, and fat between the sequences, whereas the SNR of muscle was higher (p < 0.05) on 3DT2 than 2DT2. CNR measures on 3DT2 were similar to 2DT2 (p > 0.1). The average acquisition time was shorter for 3DT2 compared with 2DT2 (343 ± 127 s vs 475 ± 162 s, respectively). Isotropic 3DT2 MRI offers higher spatial resolution, faster acquisition times, and equivalent assessments of STT characteristics compared to conventional 2DT2 MRI in two planes. 3DT2 is interchangeable with a 2DT2 sequence in tumor protocols. • Isotropic 3DT2 CAIPIRINHA SPACE TSE offers higher spatial resolution than 2DT2 TSE and is equivalent to 2DT2 TSE for assessments of soft tissue tumor intrinsic and perilesional characteristics. • Multiplanar reformats of 3DT2 CAIPIRINHA SPACE TSE can substitute for 2DT2 TSE acquired in multiple planes, thereby reducing the acquisition time of MRI tumor protocols. • 3DT2 CAIPIRINHA SPACE TSE and 2DT2 TSE had similar CNR of tissues.

Evaluation of non-contrast magnetic resonance imaging as an imaging surveillance tool for hepatocellular carcinoma in at-risk patients.

This study aimed to evaluate the potential of non-contrast-enhanced magnetic resonance (MR) imaging as an imaging surveillance tool for detection of hepatocellular carcinoma (HCC) in at-risk patients and to compare the performance of non-contrast MR imaging with ultrasonography (US) as a screening modality for the same. In this retrospective study, patients diagnosed with HCC between 1 January 2010 and 31 December 2015 were selected from our institution's cancer registry. Patients who underwent MR imaging and had US performed within three months of the MR imaging were included. For each MR imaging, two non-contrast MR imaging sequences - T2-weighted fat-saturated (T2-W FS) sequence and diffusion-weighted imaging (DWI) - were reviewed for the presence of suspicious lesions. A non-contrast MR image was considered positive if the lesion was seen on both sequences. The performance of non-contrast MR imaging was compared to that of hepatobiliary US for the detection of HCC. A total of 73 patients with 108 HCCs were evaluated. Sensitivity of non-contrast MR imaging for the detection of HCC using T2-W FS and DWI was 93.2%, which was significantly higher than that of US, which was 79.5% (p = 0.02). In a subgroup of 55 patients with imaging features of liver cirrhosis, the sensitivity of non-contrast MR imaging was 90.9%, which was also significantly higher than that of US, which was 74.5% (p = 0.02). Our pilot study showed that non-contrast MR imaging, using a combination of T2-W FS and DWI, is a potential alternative to US as a screening tool for surveillance of patients at risk for HCC.

Spindle Cell Carcinoma of the Breast: Investigation of Magnetic Resonance Imaging Features of 26 Cases

The aim of the study was to retrospectively investigate the fat-saturated T2-weighted sequences (FST2WI) and 3-dimensional dynamic contrast-enhanced sequence (DCE) of magnetic resonance imaging (MRI) findings of breast spindle cell carcinoma (SpCC). Twenty-six women with surgically confirmed breast SpCC, who underwent breast MRI in 2 institutions, were enrolled in this study (mean age, 54 years; range, 27-81 years). Two breast radiologists determined the MRI findings by consensus after independent interpretations. Each MRI finding was analyzed. Most lesions of SpCC showed a solitary mass (92.2%). Most masses were round/oval (76.0%), had an irregular margin (88.0%), rim enhancement (72.0%), washout kinetic analysis (96.0%), hyperintensity on FST2WI (84%), hyperintensity on FST2WI and fast enhancing component on DCE (56%), and hypointense rim on FST2WI (72.0%). Most breast SpCC showed a solitary mass, round/oval shape, irregular margin, rim enhancement, washout kinetics, and intratumoral hyperintensity on FST2WI; a hypointense rim on FST2WI; and hyperintensity on FST2WI and fast enhancing component on DCE.

Contrast-enhanced MRI of the wrist: Intravenous application of gadolinium improves diagnosis in ulnar-sided injuries of the TFCC

PurposeAlthough lesions of the triangular fibrocartilage complex (TFCC) frequently induce ulnar-sided wrist pain and potentially distal radioulnar joint instability, diagnosis can pose a challenge due to the intricate anatomy. This study aims to evaluate the benefits of contrast-enhanced sequences for the detection of TFCC injuries in magnetic resonance imaging of the wrist. Method94 patients underwent wrist MRI with intravenous application of gadolinium-based contrast agents. For each patient, two datasets were analysed independently by two board-certified radiologists: One set comprised only plain T1- and fat-saturated proton-density-weighted sequences, while the second dataset included contrast-enhanced T1-weighted images with fat suppression. Arthroscopy or clinical reports served as reference standard with the former being used whenever available. Diagnostic confidence and TFCC component assessability were subjectively evaluated. Contrast-to-noise ratios (CNR) were calculated serve as an objective indicator of image contrast. ResultsLesions of the articular disc, the foveal and styloid ulnar attachment were present in 24 (25.5%), 61 (64.9%) and 53 (56.4%) patients. Access to contrast-enhanced T1 images improved the diagnostic accuracy for injuries of the styloid (R1/R2, 0.68/0.73 vs. 0.86/0.88) and foveal attachment (0.68/0.72 vs. 0.90/0.89) substantially compared to plain MRI (all p < 0.001), while no benefits could be identified for lesions of the central disc (0.89/0.90 vs. 0.87/0.90). Readers’ diagnostic confidence and CNR for ulnar-sided lesions improved with contrast-enhanced T1 sequences available (p < 0.001). ConclusionsWith superior CNR in lesions of the TFCC’s foveal and styloid attachment, contrast-enhanced, fat-saturated T1-weighted sequences facilitate higher diagnostic accuracy and confidence than fat-saturated PD- and plain T1-weighted MRI.

Prognostic Assessment in High-Grade Soft-Tissue Sarcoma Patients: A Comparison of Semantic Image Analysis and Radiomics.

Simple SummarySoft-tissue sarcomas constitute a rare cancer type, with approximately 40% of patients experiencing disease recurrence. There is a need for a better identification of patients with especially aggressive tumors. Previous research demonstrated that the qualitative assessment of imaging data by radiologists (“semantic features”) and the algorithm-based analysis of imaging data (termed “radiomics”) may help to achieve a more thorough identification of patients at high risk for cancer-specific mortality. In this work, we compared the performance of predictions of patients’ survival based on semantic features extracted by radiologists with a “radiomic” approach. While some semantic features were helpful to identify high-risk patients, the radiomic approach achieved an overall improved ability to identify patients at high risk. For the radiomic prediction, only one MRI sequence was sufficient and an MRI sequence without the need for contrast agent achieved good predictive performance.Background: In patients with soft-tissue sarcomas of the extremities, the treatment decision is currently regularly based on tumor grading and size. The imaging-based analysis may pose an alternative way to stratify patients’ risk. In this work, we compared the value of MRI-based radiomics with expert-derived semantic imaging features for the prediction of overall survival (OS). Methods: Fat-saturated T2-weighted sequences (T2FS) and contrast-enhanced T1-weighted fat-saturated (T1FSGd) sequences were collected from two independent retrospective cohorts (training: 108 patients; testing: 71 patients). After preprocessing, 105 radiomic features were extracted. Semantic imaging features were determined by three independent radiologists. Three machine learning techniques (elastic net regression (ENR), least absolute shrinkage and selection operator, and random survival forest) were compared to predict OS. Results: ENR models achieved the best predictive performance. Histologies and clinical staging differed significantly between both cohorts. The semantic prognostic model achieved a predictive performance with a C-index of 0.58 within the test set. This was worse compared to a clinical staging system (C-index: 0.61) and the radiomic models (C-indices: T1FSGd: 0.64, T2FS: 0.63). Both radiomic models achieved significant patient stratification. Conclusions: T2FS and T1FSGd-based radiomic models outperformed semantic imaging features for prognostic assessment.

Deep learning with a convolutional neural network model to differentiate renal parenchymal tumors: a preliminary study.

With advancements in medical imaging, more renal tumors are detected early, but it remains a challenge for radiologists to accurately distinguish subtypes of renal parenchymal tumors. We aimed to establish a novel deep convolutional neural network (CNN) model and investigate its effect on identifying subtypes of renal parenchymal tumors in T2-weighted fat saturation sequence magnetic resonance (MR) images. This retrospective study included 199 patients with pathologically confirmed renal parenchymal tumors, including 77, 46, 34, and 42 patients with clear cell renal cell carcinoma (ccRCC), chromophobe renal cell carcinoma (chRCC), angiomyolipoma (AML), and papillary renal cell carcinoma (pRCC), respectively. All enrolled patients underwent kidney MR scans with the field strength of 1.5Tesla (T) or 3.0T before surgery. We selected T2-weighted fat saturation sequence images of all patients and built a deep learning model to determine the type of renal tumors. Receiver operating characteristic(ROC) curve was depicted to estimate the performance of the CNN model; the accuracy, precision, sensitivity, specificity, F1-score, and area under the curve (AUC) were calculated. One-way analysis of variance and χ2 tests of independent samples were used to analyze the variables. The experimental results demonstrated that the model had a 60.4% overall accuracy, a 61.7% average accuracy, and a macro-average AUC of 0.82. The AUCs for ccRCC, chRCC, AML, and pRCC were 0.94, 0.78, 0.80, and 0.76, respectively. Deep CNN model based on T2-weighted fat saturation sequence MR images was useful to classify the subtypes of renal parenchymal tumors with a relatively high diagnostic accuracy.

Contrast-enhanced T1-weighted Dixon water- and fat-only images to assess osteitis and erosions according to RAMRIS in hands of patients with early rheumatoid arthritis

PurposeTo assess the agreement between readers using contrast-enhanced T1-weighted Dixon water- and fat-only images and OMERACT-recommended sequences for the scoring of osteitis and erosions according to the rheumatoid arthritis (RA) MRI scoring system (RAMRIS) in hands of patients with early RA. Materials and methodsBoth hands of 24 patients (16 women, 8 men; mean age, 45.7±14.5 [SD] years; age range: 25–70 years) with early RA were prospectively imaged with fat-saturated T2-weighted sequences, non-Dixon T1-weighted imaging prior to contrast material injection and T1-weighted Dixon imaging after contrast material injection at 1.5T. There were Two radiologists separately quantified osteitis and erosions according to RAMRIS using contrast-enhanced T1-weighted Dixon water-only and fat-saturated T2-weighted images for osteitis and contrast-enhanced T1-weighted Dixon fat-only and T1-weighted images prior to contrast material injection for erosions. Intraclass correlation coefficients (ICC) were calculated to assess inter-technique, intra-observer and inter-observer agreement. ResultsMean ICC for the agreement between Dixon and non-Dixon images ranged from 0.68 (95%CI: 0.20–0.90) to 0.99 (95%CI: 0.95–1.00) for the scoring of osteitis and from 0.77 (95%CI: 0.38–0.93) to 0.99 (95%CI: 0.95–1.00) for the scoring of erosions. Mean ICC for the agreement between first and second readings ranged from 0.94 (95%CI: 0.81–0.98) to 0.97 (95%CI: 0.91–0.99) for the scoring of osteitis using Dixon and 0.91 (95%CI: 0.72–0.97) to 0.98 (95%CI: 0.92–0.99) using non-Dixon images and from 0.80 (95%CI: 0.45–0.94) to 0.97 (95%CI: 0.91–0.99) for the scoring of erosions using Dixon and 0.72 (95%CI: 0.29–0.91) to 0.98 (95%CI: 0.92–0.99) using non-Dixon images. ConclusionContrast-enhanced T1-weighted Dixon water- and fat-only images can serve as an alternative to fat-saturated T2-weighted and T1-weighted MRI sequences for the assessment of osteitis and erosions according to the RAMRIS scoring system in hands of patients with early RA.

Synthetic MRI is not yet ready for morphologic and functional assessment of patellar cartilage at 1.5 Tesla

PurposeThe purpose of this study was to compare morphologic assessment and relaxometry of patellar hyaline cartilage between conventional sequences (fast spin-echo [FSE] T2-weighted fat-saturated and T2-mapping) and synthetic T2 short-TI inversion recovery (STIR) and T2 maps at 1.5T magnetic resonance imaging (MRI). MethodThe MRI examinations of the knee obtained at 1.5T in 49 consecutive patients were retrospectively studied. There were 21 men and 28 women with a mean age of 45±17.7 (SD) years (range: 18–88 years). Conventional and synthetic acquisitions were performed, including T2-weighted fat-saturated and T2-mapping sequences. Two radiologists independently compared patellar cartilage T2-relaxation time on conventional T2-mapping and synthetic T2-mapping images. A third radiologist evaluated the patellar cartilage morphology on conventional and synthetic T2-weighted images. The presence of artifacts was also assessed. Interobserver agreement for quantitative variables was assessed using intraclass correlation coefficient (ICC). ResultsIn vitro, conventional and synthetic T2 maps yielded similar mean T2 values 58.5±2.3 (SD) ms and 58.8±2.6 (SD) ms, respectively (P=0.414) and 6% lower than the expected experimental values (P=0.038). Synthetic images allowed for a 15% reduction in examination time compared to conventional images. On conventional sequences, patellar chondropathy was identified in 35 patients (35/49; 71%) with a mean chondropathy grade of 4.8±4.8 (SD). On synthetic images, 28 patients (28/49; 57%) were diagnosed with patellar chondropathy, with a significant 14% difference (P=0.009) and lower chondropathy scores (3.7±4.9 [SD]) compared to conventional images. Motion artifacts were more frequently observed on synthetic images (18%) than on conventional ones (6%). The interobserver agreement was excellent for both conventional and synthetic T2 maps (ICC>0.83). Mean cartilage T2 values were significantly greater on synthetic images (36.2±3.8 [SD] ms; range: 29-46ms) relative to conventional T2 maps (31.8±4.1 [SD] ms; range: 26-49ms) (P<0.0001). ConclusionDespite a decrease in examination duration, synthetic images convey lower diagnostic performance for chondropathy, greater prevalence of motion artifacts, and an overestimation of T2 values compared to conventional MRI sequences.

Spine MRI in Spontaneous Intracranial Hypotension for CSF Leak Detection: Nonsuperiority of Intrathecal Gadolinium to Heavily T2-Weighted Fat-Saturated Sequences.

Spine MR imaging plays a pivotal role in the diagnostic work-up of spontaneous intracranial hypotension. The aim of this study was to compare the diagnostic accuracy of unenhanced spine MR imaging and intrathecal gadolinium-enhanced spine MR imaging for identification and localization of CSF leaks in patients with spontaneous intracranial hypotension. A retrospective study of patients with spontaneous intracranial hypotension examined from February 2013 to October 2017 was conducted. Their spine MR imaging was reviewed by 3 blinded readers for the presence of epidural CSF using 3 different sequences (T2WI, 3D T2WI fat-saturated, T1WI gadolinium). In patients with leaks, the presumed level of the leak was reported. In total, 103 patients with spontaneous intracranial hypotension (63/103 [61%] women; mean age, 50 years) were evaluated. Seventy had a confirmed CSF leak (57/70 [81%] proved intraoperatively), and 33 showed no epidural CSF on multimodal imaging. Intrathecal gadolinium-enhanced spine MR imaging was nonsuperior to unenhanced spine MR imaging for the detection of epidural CSF (P = .24 and .97). All MR imaging sequences had a low accuracy for leak localization. In all patients, only 1 leakage point was present, albeit multiple suspicious lesions were reported in all sequences (mean, 5.0). Intrathecal gadolinium-enhanced spine MR imaging does not improve the diagnostic accuracy for the detection of epidural CSF. Thus, it lacks a rationale to be included in the routine spontaneous intracranial hypotension work-up. Heavily T2-weighted images with fat saturation provide high accuracy for the detection of an epidural CSF collection. Low accuracy for leak localization is due to an extensive CSF collection spanning several vertebrae (false localizing sign), lack of temporal resolution, and a multiplicity of suspicious lesions, albeit only a single leakage site is present. Thus, dynamic examination is mandatory before targeted treatment is initiated.

Four-class tumor staging for early diagnosis and monitoring of murine pancreatic cancer using magnetic resonance and ultrasound.

The widely used genetically engineered mouse LSL-KrasG12D/+; LSL-Trp53R172H/+; Pdx-1-Cre, termed KPC, spontaneously develops pancreatic cancer mirroring all phases of the carcinogenesis but in asynchronous manner. Preclinical studies need defined criteria for the enrollment of the KPC sharing the same stage of carcinogenesis. To define a tumor-staging criteria using magnetic resonance (MR) and ultrasound (US) and then to correlate the imaging stage with overall survival of KPC mice. Forty KPC (2- to 5-month-old mice) were imaged by axial fat-saturated T2-weighted sequences at MR and by brightness mode US to establish criteria for tumor staging. Immunohistopathology was used to validate imaging. A second cohort of 25 KPC was used to correlate imaging stage with survival by Kaplan-Meier analysis. We defined a four-class tumor staging system ranking from stages 1 to 4. Stage 1 was described as radiologically healthy pancreas; precursor lesions were detectable in histology only. Cystic papillary neoplasms, besides other premalignant alterations, marked stage 2 in the absence of cancer nodules. Stages 3 and 4 identified mice affected by overt pancreatic cancer with size <5 or ≥5 mm, respectively. Regarding the prognosis, this staging system correlated with disease-related mortality whatever may be the KPC age when they staged. This imaging-based four-class tumor staging is an effective and safe method to stage pancreatic cancer development in KPC. As a result, regardless of their age, KPC mice can be synchronized based on prognosis or on a specific phase of tumorigenesis, such as the early but already radiologically detectable one (stage 2).

Correlation between tumor growth and hormonal therapy with MR signal characteristics of desmoid-type fibromatosis: A preliminary study.

To evaluate the impact of hormonal therapy on MRI characteristics of desmoid-type fibromatosis on T1-weighted, T2-weighted fat-saturated and post-contrast sequences. Nineteen patients with histologically-proven desmoid-type fibromatosis were prospectively followed up on MR imaging. Eight patients underwent hormonal therapy and 11 were only surveyed. Change in tumor size during follow-up was analyzed according to RECIST. Signal intensity on T1-weighted, T2-weighted fat-saturated and T1-weighted fat-saturated post-contrast images was graded from 0 to 5 using adjacent normal muscle as reference. Findings were compared with tumor growth and treatment option. There were seven men and 12 women with a mean age of 42.2±16.4 (SD) years (range: 18 - 64 years) yielding twenty-six follow-up periods: eight of tumor progression and 18 of tumor stability/regression (some tumors exhibited more than one behavior type). Hormonal therapy was associated with tumor stability or regression (P=0.0207). There was a significant reduction in enhancement among treated patients with stable/regressing disease (P=0.049). The mean variation in enhancement grade was -1.3±1.2 in these patients. All successfully treated patients presented a reduction in enhancement. Lesions with marked low enhancement or very low signal on T2-weighted images were rare in progressing lesions (0% and 13%). Hormonal therapy has an impact on desmoid-type fibromatosis signal characteristics reducing lesion enhancement.

Diagnostic Value of Magnetic Resonance Neurography in Cervical Radiculopathy: Plexus Patterns and Peripheral Nerve Lesions.

The aim of this study was to assess the imaging appearance and diagnostic value of plexus and peripheral nerve magnetic resonance neurography (MRN) in cervical radiculopathy. This prospective study was approved by our institutional ethics committee and written informed consent was obtained from all participants. A total of 24 patients were included with a diagnosis of cervical radiculopathy based on clinical examination, supporting electrophysiological examinations and spinal imaging consistent with the clinical syndrome. All patients then underwent a high-resolution MRN protocol including the brachial plexus from nerve roots to plexus cords using a 3-dimensional turbo spin echo with variable flip angle short tau inversion recovery and sagittal-oblique T2-weighted spectral adiabatic inversion recovery sequence, and ulnar, median, and radial nerves at the upper arm and elbow in T2-weighted fat saturated sequences. Two readers independently rated plexus elements regarding the presence of lesions at neuroforaminal levels, roots, trunks, and cord segments. Median, ulnar, and radial nerves were likewise rated. Findings were then compared to a referenced standard of cervical radiculopathy that was defined as the combined diagnosis of clinical syndrome including supporting electrophysiological exams and matching positive spinal imaging, and diagnostic performance parameters were calculated. Additional quantitative and qualitative analysis assessed peripheral nerve caliber and normalized T2-signal at arm level in cervical radiculopathy and compared them to 25 inflammatory neuropathy controls. Cervical radiculopathy resulted in distinct plexus lesion patterns for each level of neuroforaminal stenosis. Overall, brachial plexus MRN in cervical radiculopathy reached a sensitivity of 81%, a specificity of 96%, a positive predictive value of 87%, and overall diagnostic accuracy of 87%. Initial spinal magnetic resonance imaging showed multiple positive findings for clinically unaffected root levels and resulted in a specificity of 69%, a positive predictive value of 54%, and an overall diagnostic accuracy of 78%.T2-weighted peripheral nerve lesions were detected in 79% of cervical radiculopathy cases and imitated imaging appearance of inflammatory neuropathies both quantitatively and qualitatively. Complementing spine imaging in cervical radiculopathy with brachial plexus MRN can improve diagnostic accuracy by increasing specificity and positive predictive value. T2-weighted lesions of peripheral nerves can be caused by cervical radiculopathy, which must be considered a relevant diagnostic pitfall in MRN of peripheral neuropathies.

Sonographic-MRI Correlation After Percutaneous Sampling of Targeted Breast Ultrasound Lesions: Initial Experiences With Limited-Sequence Unenhanced MRI for Postprocedural Clip Localization.

The purpose of this study is to determine the frequency of correlation of sonographic and MRI findings after percutaneous sampling of presumed ultrasound correlates to suspicious lesions detected on breast MRI and to describe our initial experiences with limited-sequence MRI for postprocedural clip verification. Between January 1, 2014, and March 31, 2016, a total of 1947 contrast-enhanced breast MRI examinations were performed, and 245 targeted ultrasound examinations were conducted to identify correlates to suspicious MRI findings. We retrospectively identified all lesions that underwent ultrasound-guided sampling of a presumed sonographic correlate and for which a subsequent postprocedural limited-sequence unenhanced MR image for clip localization was available. This consisted of a T1-weighted non-fat-saturated and a T2-weighted fat-saturated sequence. Frequencies of sonographic-MRI correlation were quantified. The study cohort consisted of 35 patients with 38 presumed correlates that underwent ultrasound-guided sampling with postprocedural MRI for clip verification. The mean time from percutaneous sampling to postprocedural MRI examination was 1 day. Ten presumed sonographic correlates (26%) were found to localize to a site distinct from the lesion originally identified on MRI. One of these discordant cases revealed malignancy on subsequent MRI-guided biopsy, whereas the presumed sonographic correlate was found to be benign. No patient or lesion characteristics were associated with significantly different frequencies of correlation. In our initial experiences with MRI performed for postprocedural clip verification, 26% of presumed correlates to suspicious lesions detected on MRI were not the actual correlate, and 10% of these discordant cases ultimately revealed malignancy. Radiologists should take caution presuming that lesions identified on ultrasound actually represent the suspicious lesions detected on MRI. MRI for clip verification may be useful if ultrasound-guided sampling is pursued.

Dorsal root ganglia hypertrophy as in vivo correlate of oxaliplatin-induced polyneuropathy.

PurposeTo investigate in vivo morphological and functional correlates of oxaliplatin-induced peripheral neuropathy (OXA-PNP) by magnetic resonance neurography (MRN).MethodsTwenty patients (7 female, 13 male, 58.9±10.0 years) with mild to moderate OXA-PNP and 20 matched controls (8 female, 12 male, 55.7±15.6 years) were prospectively enrolled. All patients underwent a detailed neurophysiological examination prior to neuroimaging. A standardized imaging protocol at 3.0 Tesla included the lumbosacral plexus and both sciatic nerves and their branches using T2-weighted fat-saturated sequences and diffusion tensor imaging. Quantitative assessment included volumetry of the dorsal root ganglia (DRG), sciatic nerve normalized T2 (nT2) signal and caliber, and fractional anisotropy (FA), mean diffusivity (MD), axial (AD) and radial diffusivity (RD). Additional qualitative evaluation of sciatic, peroneal, and tibial nerves evaluated the presence, degree, and distribution of nerve lesions.ResultsDRG hypertrophy in OXA-PNP patients (207.3±47.7mm3 vs. 153.0±47.1mm3 in controls, p = 0.001) was found as significant morphological correlate of the sensory neuronopathy. In contrast, peripheral nerves only exhibited minor morphological alterations qualitatively. Quantitatively, sciatic nerve caliber (27.3±6.7mm2 vs. 27.4±7.4mm2, p = 0.80) and nT2 signal were not significantly changed in patients (1.32±0.22 vs. 1.22±0.26, p = 0.16). AD, RD, and MD showed a non-significant decrease in patients, while FA was unchanged.ConclusionOXA-PNP manifests with morphological and functional correlates that can be detected in vivo by MRN. We report hypertrophy of the DRG that stands in contrast to experimental and postmortem studies. DRG volume should be further investigated as a biomarker in other sensory peripheral neuropathies and ganglionopathies.

Relevance of MRI for management of non-displaced lateral humeral condyle fractures in children

IntroductionThe treatment for non-displaced (<2 mm displacement) fractures of the lateral humeral condyle in children is controversial. Most studies recommend non-surgical treatment. However, plain radiographs are not sufficient to evaluate extension of the fracture line through the articular cartilage. This explains the high frequency of secondary displacements and non-unions, despite well-conducted conservative treatment. We hypothesized that MRI could be used to analyse whether the fracture is complete or incomplete. This could help to determine whether surgical or conservative treatment is indicated. Material and methodsThis prospective study enrolled children being treated for a non-displaced (< 2 mm gap) fracture of the lateral humeral condyle. All patients were treated with a long-arm cast in the emergency room. An MRI was done later on without sedation. A specific protocol was used to reduce the duration of the examination. T2-weighted and proton density fat-saturated sequences were used. ResultsTwenty-seven patients were enrolled: 16 boys and 11 girls with a mean age of 5 years (2–10). The MRI was performed an average of 7 days (1–23) after the fracture. The MRI could not be interpreted in two cases because the child had moved during the examination. In the other 25 patients, the fracture was incomplete in 17 patients and complete in 8 patients. Two children had secondary displacement diagnosed 7 and 11 days after the fracture event. These two patients underwent open reduction and internal fixation. There was no correlation between patient age and the fracture being complete or incomplete. There were no cases of non-union. ConclusionMRI appears to be a reliable method for determining whether the fracture line is complete or incomplete. It can be performed without sedation, even in children as young as 2 years of age. Use of an injury-specific MRI protocol reduces the length of the examination, thereby improving its performance. We recommend that it be used to analyse non-displaced fractures of the lateral humeral condyle in children. Level of evidence3 Prospective study.