COVID-19 pneumonia and its lookalikes: How radiologists perform in differentiating atypical pneumonias.

PURPOSE: To examine the performance of radiologists in differentiating COVID-19 from non-COVID-19 atypical pneumonia and to perform an analysis of CT patterns in a study cohort including viral, fungal and atypical bacterial pathogens. METHODS: Patients with positive RT-PCR tests for COVID-19 pneumonia (n = 90) and non-COVID-19 atypical pneumonia (n = 294) were retrospectively included. Five radiologists, blinded to the pathogen test results, assessed the CT scans and classified them as COVID-19 or non-COVID-19 pneumonia. For both groups specific CT features were recorded and a multivariate logistic regression model was used to calculate their ability to predict COVID-19 pneumonia. RESULTS: The radiologists differentiated between COVID-19 and non-COVID-19 pneumonia with an overall accuracy, sensitivity, and specificity of 88% ± 4 (SD), 79% ± 6 (SD), and 90% ± 6 (SD), respectively. The percentage of correct ratings was lower in the early and late stage of COVID-19 pneumonia compared to the progressive and peak stage (68 and 71% vs 85 and 89%). The variables associated with the most increased risk of COVID-19 pneumonia were band like subpleural opacities (OR 5.55, p < 0.001), vascular enlargement (OR 2.63, p = 0.071), and subpleural curvilinear lines (OR 2.52, p = 0.021). Bronchial wall thickening and centrilobular nodules were associated with decreased risk of COVID-19 pneumonia with OR of 0.30 (p = 0.013) and 0.10 (p < 0.001), respectively. CONCLUSIONS: Radiologists can differentiate between COVID-19 and non-COVID-19 atypical pneumonias at chest CT with high overall accuracy, although a lower performance was observed in the early and late stage of COVID 19 pneumonia. Specific CT features might help to make the correct diagnosis.

Analyzing Longitudinal wb-MRI Data and Clinical Course in a Cohort of Former Smoldering Multiple Myeloma Patients: Connections between MRI Findings and Clinical Progression Patterns.

The purpose of this study was to analyze size and growth dynamics of focal lesions (FL) as well as to quantify diffuse infiltration (DI) in untreated smoldering multiple myeloma (SMM) patients and correlate those MRI features with timepoint and cause of progression. We investigated 199 whole-body magnetic resonance imaging (wb-MRI) scans originating from longitudinal imaging of 60 SMM patients and 39 computed tomography (CT) scans for corresponding osteolytic lesions (OL) in 17 patients. All FLs >5 mm were manually segmented to quantify volume and growth dynamics, and DI was scored, rating four compartments separately in T1- and fat-saturated T2-weighted images. The majority of patients with at least two FLs showed substantial spatial heterogeneity in growth dynamics. The volume of the largest FL (p = 0.001, c-index 0.72), the speed of growth of the fastest growing FL (p = 0.003, c-index 0.75), the DI score (DIS, p = 0.014, c-index 0.67), and its dynamic over time (DIS dynamic, p < 0.001, c-index 0.67) all significantly correlated with the time to progression. Size and growth dynamics of FLs correlated significantly with presence/appearance of OL in CT within 2 years after the respective MRI assessment (p = 0.016 and p = 0.022). DIS correlated with decrease of hemoglobin (p < 0.001). In conclusion, size and growth dynamics of FLs correlate with prognosis and local bone destruction. Connections between MRI findings and progression patterns (fast growing FL-OL; DIS-hemoglobin decrease) might enable more precise diagnostic and therapeutic approaches for SMM patients in the future.

Spatial Distribution of Focal Lesions in Whole-Body MRI and Influence of MRI Protocol on Staging in Patients with Smoldering Multiple Myeloma According to the New SLiM-CRAB-Criteria.

The purpose of this study was to assess how different MRI protocols (spinal vs. spinal plus pelvic vs. whole-body (wb)-MRI) affect staging in patients with smoldering multiple myeloma (SMM), according to the SLiM-CRAB-criterion '>1 focal lesion (FL) in MRI'. In this retrospective study, a baseline cohort of 147 SMM patients with wb-MRI at initial diagnosis was investigated, including prognostic data regarding development of CRAB-criteria. Fifty-two patients formed a follow-up cohort with a median of three wb-MRIs. The locations of all FLs were determined and it was calculated how staging decisions regarding the criterion '>1 FL in MRI' would have been made if only a limited anatomic area (spine vs. spine plus pelvis) would have been covered by the MRI protocol. Furthermore, subgroups of patients selected by different cutoff-protocol-combinations were compared regarding their prognosis for development of CRAB-criteria. With an MRI protocol limited to spine/spine plus pelvis, only 28%/64% of patients who actually had >1 FL in wb-MRI would have been rated correctly as having '>1 FL in MRI'. Fifty-four percent/36% of patients with exactly 1 FL in spine/spine plus pelvis revealed >1 FL when the entire wb-MRI was analyzed. During follow-up, four more patients developed >1 FL in wb-MRI; both limited MRI protocols would have detected only one of these four patients as having >1 FL at the correct timepoint. Having >1 FL in spine/in spine plus pelvis/in the whole body was associated with a 43%/57%/49% probability of developing CRAB-criteria within 2 years. Patients with >3 FL in spine plus pelvis and patients with >4 FL in the whole body had an 80% probability to develop CRAB-criteria within 2 years. MRI protocols limited to the spine or to spine plus pelvis lead to substantial underdiagnoses of patients who actually have >1 FL in wb-MRI at baseline and during follow-up, which influences staging and treatment decisions according to the current SLiM-CRAB criteria. However, given the spatial distribution of FLs and the analysis on clinical course of patients indicates that the cutoff for the number of FLs should be adopted according to the MRI protocol when using MRI for staging in SMM.

3-T T2 mapping magnetic resonance imaging for biochemical assessment of normal and damaged glenoid cartilage: a prospective arthroscopy-controlled study.

This study evaluated the ability of T2 mapping to assess the glenoid cartilage using arthroscopy as the gold standard. Eighteen consecutive patients (mean age: 52.4 ± 14.72 years, including 12 men) with shoulder pain underwent T2 mapping at 3-T with subsequent shoulder arthroscopy. With correlation to cartilage-sensitive morphologic sequences regions-of-interest were placed in the corresponding T2 maps both in normal-appearing cartilage and focal cartilage lesions using a quadrant-wise approach. Inter-reader and intra-reader correlation coefficients (ICCs) between two independent radiologists as well as cut-off values with their sensitivities/specificities for the detection of cartilage damage were calculated. The mean T2 value for healthy cartilage was 23.0 ± 3 ms with significantly higher values in the superior quadrants compared to the inferior quadrants (p < 0.0001). In 5 patients with focal cartilage damage significantly higher T2 values of 44.7 ± 3.7 ms (P < 0.01) were observed. The maximum T2 value in normal cartilage (27.3 ms) was lower than the minimum value in damaged cartilage (40.8 ms) resulting in perfect sensitivities/specificities of 100% (95% confidence-interval 47.8-100.0) for all cut-off values between 27.3-40.8 ms. ICCs ranged between 0.63 and 0.99. In conclusion, T2 mapping can evaluate biochemical cartilage integrity and discriminates arthroscopy-proven healthy and damaged glenoid cartilage with high diagnostic performance.

Intraarticular Osteoid Osteoma: MRI Characteristics and Clinical Presentation Before and After Radiofrequency Ablation Compared to Extraarticular Osteoid Osteoma. / Das intraartikuläre Osteoidosteom: MRT-Charakteristik und klinisches Erscheinungsbild vor und nach Radiofrequenzablation im Vergleich zum extraartikulären Osteoidosteom.

PURPOSE: To determine MRI characteristics and the clinical presentation of intraarticular osteoid osteomas (OO) before and after treatment with CT-guided radiofrequency ablation (RFA) compared with extraarticular osteoid osteomas. MATERIALS AND METHODS: In a retrospective study, n = 21 patients with an intraarticular OO were matched with a control group of n = 21 patients with an extraarticular OO at a comparable anatomical position. All patients underwent CT-guided RFA and preinterventional MRI. In n = 31 cases, follow-up MR imaging was available. MR images were analyzed for morphologic features: effusion and synovitis, bone marrow edema (BME), soft tissue edema, periosteal reaction as well as T1 / T2 signal and contrast enhancement of the nidus. Recorded clinical parameters included the initial diagnosis, the course of pain symptoms after RFA and the incidence of complications. RESULTS: The nidus was detectable in all patients on MRI. BME had the highest sensitivity in both intra- and extraarticular OO (100 %). Effusion and synovitis were only observed in the intraarticular OO group (n = 21) with a perfect sensitivity and specificity (100 %) and a high negative predictive value (85 %). Soft tissue edema was significantly more present in patients with intraarticular OO (p = 0.0143). No significant differences were present regarding periosteal reaction, T1/T2 signal and contrast enhancement of the nidus (p > 0.05). BME, contrast enhancement, soft tissue edema, periosteal reaction, effusion and synovitis, if preexisting, always decreased after RFA. In 66.7 % of patients with intraarticular OO, a false initial diagnosis was made (extraarticular: 19 %). All patients were free of pain after intervention. Complications following the RFA procedure did not occur. CONCLUSION: MRI demonstrates the nidus and thus the OO in all cases regardless of the location. The characteristic MRI morphology of an intraarticular OO includes synovitis and joint effusion, which are always present and differentiate with perfect sensitivity/specificity from an extraarticular OO. In both intra- and extraarticular OOs pathologic MRI changes at least decreased or completely normalized and the clinical results after RFA were excellent. KEY POINTS: · MRI is excellently suited for the diagnosis of intra- and extraarticular OOs.. · Joint effusion and synovitis distinguish both forms with perfect sensitivity and specificity.. · All MRI changes, which indicate activity, decreased after successful RFA.. · The clinical results after RFA are excellent in both forms.. CITATION FORMAT: · Germann T, Weber M, Lehner B et al. Intraarticular Osteoid Osteoma: MRI Characteristics and Clinical Presentation Before and After Radiofrequency Ablation Compared to Extraarticular Osteoid Osteoma. Fortschr Röntgenstr 2020; 192: 1190 - 1198.

[Radiologic diagnosis of pathologic fractures]. / Radiologische Diagnostik pathologischer Frakturen.

BACKGROUND: Pathologic fractures are fractures that occur without an adequate traumatic event due to focal benign or malignant skeletal lesions. The most common causes of pathologic fractures are cystic bone lesions, plasmocytoma or multiple myeloma, and the development of osseous metastases, which is increasing due to an aging general population and advances in cancer treatment. The differentiation of pathologic fractures from stress fractures, especially osteoporotic insufficiency fractures is crucial for correct treatment planning. OBJECTIVES: This review intends to explain the imaging characteristics of pathologic fractures. Moreover, it explains the role of imaging when pathologic fractures are suspected. In addition, the Mirels' score and the SINS (Spinal Instability Neoplastic Score), which are powerful yet easy-to-use tools for the assessment of the fracture risk of benign or malignant bony lesions of the extremities and the vertebral column, shall be introduced. MATERIALS AND METHODS: A PubMed literature search with the following terms was conducted: "pathologic fracture", "fatigue fracture", "insufficiency fracture", "treatment of pathologic fractures", "imaging of pathologic fractures", "fracture risk", "bone metastases", "MRI of pathologic fractures", "CT of pathologic fractures", "differentiation of pathologic and insufficiency fractures", "Mirels' score", "SINS" and "spinal instability neoplastic score". RESULTS: The definitions of pathologic, fatigue, and insufficiency fractures are explained. Moreover, the role of imaging in the clinical workup of suspected pathologic fractures and the differentiation of pathologic fractures from fatigue or insufficiency fractures as well as common scoring systems to assess the fracture risk of pathologic fractures are described.

MRI patterns indicate treatment success and tumor relapse following radiofrequency ablation of osteoblastoma.

Purpose: To explore the typical magnetic resonance imaging (MRI) pattern of osteoblastoma (OB) after radiofrequency ablation (RFA) treatment and to identify signs indicating treatment success or relapse.Materials and methods: Forty-four follow-up MRI examinations of 15 patients with OB who had undergone 19 RFA procedures were analyzed retrospectively. An early follow-up group (1-4 months after RFA) and a late follow-up group (8-131 months after RFA) were established. The groups were further subdivided according to treatment success. Images were analyzed for the presence of central nidus enhancement (CNE), peripheral nidus enhancement (PNE), perifocal bone marrow edema (PBME) and fatty nidus conversion (FNC).Results: The early follow-up MRI image from every patient in the treatment success group exhibited a target-like appearance with negative CNE and positive PNE or PBME. PNE and PBME were observed in 93% and 71% of the early follow-up images, respectively. A target-like appearance was observed in 25% of the late follow-up images, and PNE and PBME were each observed in 20% of these images. FNC was not observed in the early follow-up images, but was seen in 55% of the late follow-up images. All three MRI images of the patients exhibiting clinical recurrence demonstrated strong CNE, PNE and extensive PMBE, which was in contrast to the images of the patients exhibiting treatment success.Conclusion: A target-like appearance of OB in early follow-up MRI examination indicates treatment success. PNE and PBME typically reduce over time and can lead to FNC in successfully treated patients. CNE recurrence, PNE and extensive PBME are signs of relapse.

Diagnostic performance of 3D-multi-Echo-data-image-combination (MEDIC) for evaluating SLAP lesions of the shoulder.

BACKGROUND: Superior labral anterior to posterior (SLAP) lesions remain a clinical and diagnostic challenge in routine (non-arthrographic) MR examinations of the shoulder. This study prospectively evaluated the ability of 3D-Multi-Echo-Data-Image-Combination (MEDIC) compared to that of routine high resolution 2D-proton-density weighted fat-saturated (PD fs) sequence using 3 T-MRI to detect SLAP lesions using arthroscopy as gold standard. METHODS: Seventeen consecutive patients (mean age, 51.6 ± 14.8 years, 11 males) with shoulder pain underwent 3 T MRI including 3D-MEDIC and 2D-PD fs followed by arthroscopy. The presence or absence of SLAP lesions was evaluated using both sequences by two independent raters with 4 and 14 years of experience in musculoskeletal MRI, respectively. During arthroscopy, SLAP lesions were classified according to Snyder's criteria by two certified orthopedic shoulder surgeons. Sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of 3D-MEDIC and 2D-PD fs for detection of SLAP lesions were calculated with reference to arthroscopy as a gold standard. Interreader agreement and sequence correlation were analyzed using Cohen's kappa coefficient. Figure 1 demonstrates the excellent visibility of a proven SLAP lesion using the 3D-MEDIC and Fig. 2 demonstrates a false-positive case. RESULTS: Arthroscopy revealed SLAP lesions in 11/17 patients. Using 3D-MEDIC, SLAP lesions were diagnosed in 14/17 patients by reader 1 and in 13/17 patients by reader 2. Using 2D-PD fs, SLAP lesions were diagnosed in 11/17 patients by reader 1 and 12/17 patients for reader 2. Sensitivity, specificity, PPV, and NPV of 3D-MEDIC were 100.0, 50.0, 78.6, and 100.0% for reader 1; and 100.0, 66.7, 84.6, and 100% for reader 2, respectively. Sensitivity, specificity, PPV, and NPV of 2D-PD fs were 90.9, 83.3, 90.9, and 83.3% for reader 1 and 100.0, 83.3, 91.7, and 100.0% for reader 2. The combination of 2D-PD fs and 3D-MEDIC increased specificity from 50.0 to 83.3% for reader 1 and from 66.7 to 100.0% for reader 2. Interreader agreement was almost perfect with a Cohen's kappa of 0.82 for 3D-MEDIC and 0.87 for PD fs. CONCLUSIONS: With its high sensitivity and NPV, 3D-MEDIC is a valuable tool for the evaluation of SLAP lesions. As the combination with routine 2D-PD fs further increases specificity, we recommend incorporation of 3D-MEDIC as an additional sequence in conventional shoulder protocols in patients with non-specific shoulder pain.

Towards quantitative imaging biomarkers of tumor dissemination: A multi-scale parametric modeling of multiple myeloma.

The advent of medical imaging and automatic image analysis is bringing the full quantitative assessment of lesions and tumor burden at every clinical examination within reach. This opens avenues for the development and testing of functional disease models, as well as their use in the clinical practice for personalized medicine. In this paper, we introduce a Bayesian statistical framework, based on mixed-effects models, to quantitatively test and learn functional disease models at different scales, on population longitudinal data. We also derive an effective mathematical model for the crossover between initially detected lesions and tumor dissemination, based on the Iwata-Kawasaki-Shigesada model. We finally propose to leverage this descriptive disease progression model into model-aware biomarkers for personalized risk-assessment, taking all available examinations and relevant covariates into account. As a use case, we study Multiple Myeloma, a disseminated plasma cell cancer, in which proper diagnostics is essential, to differentiate frequent precursor state without end-organ damage from the rapidly developing disease requiring therapy. After learning the best biological models for local lesion growth and global tumor burden evolution on clinical data, and computing corresponding population priors, we use individual model parameters as biomarkers, and can study them systematically for correlation with external covariates, such as sex or location of the lesion. On our cohort of 63 patients with smoldering Multiple Myeloma, we show that they perform substantially better than other radiological criteria, to predict progression into symptomatic Multiple Myeloma. Our study paves the way for modeling disease progression patterns for Multiple Myeloma, but also for other metastatic and disseminated tumor growth processes, and for analyzing large longitudinal image data sets acquired in oncological imaging. It shows the unprecedented potential of model-based biomarkers for better and more personalized treatment decisions and deserves being validated on larger cohorts to establish its role in clinical decision making.

Volumetry based biomarker speed of growth: Quantifying the change of total tumor volume in whole-body magnetic resonance imaging over time improves risk stratification of smoldering multiple myeloma patients.

The purpose of this study was to improve risk stratification of smoldering multiple myeloma patients, introducing new 3D-volumetry based imaging biomarkers derived from whole-body MRI. Two-hundred twenty whole-body MRIs from 63 patients with smoldering multiple myeloma were retrospectively analyzed and all focal lesions >5mm were manually segmented for volume quantification. The imaging biomarkers total tumor volume, speed of growth (development of the total tumor volume over time), number of focal lesions, development of the number of focal lesions over time and the recent imaging biomarker '>1 focal lesion' of the International Myeloma Working Group were compared, taking 2-year progression rate, sensitivity and false positive rate into account. Speed of growth, using a cutoff of 114mm3/month, was able to isolate a high-risk group with a 2-year progression rate of 82.5%. Additionally, it showed by far the highest sensitivity in this study and in comparison to other biomarkers in the literature, detecting 63.2% of patients who progress within 2 years. Furthermore, its false positive rate (8.7%) was much lower compared to the recent imaging biomarker '>1 focal lesion' of the International Myeloma Working Group. Therefore, speed of growth is the preferable imaging biomarker for risk stratification of smoldering multiple myeloma patients.

Oblique Sagittal Images Prevent Underestimation of the Neuroforaminal Stenosis Grade Caused by Disc Herniation in Cervical Spine MRI.

PURPOSE: To identify whether standard sagittal MRI images result in underestimation of the neuroforaminal stenosis grade compared to oblique sagittal MRI images in patients with cervical spine disc herniation. MATERIALS AND METHODS: 74 patients with a total of 104 cervical disc herniations compromising the corresponding nerve root were evaluated. Neuroforaminal stenosis grades were evaluated in standard and oblique sagittal images by one senior and one resident radiologist experienced in musculoskeletal imaging. Oblique images were angled 30° towards the standard sagittal plane. Neuroforaminal stenosis grades were classified from 0 (no stenosis) to 3 (high grade stenosis). RESULTS: Average neuroforaminal stenosis grades of both readers were significantly lower in standard compared to oblique sagittal images (p < 0.001). For 47.1 % of the cases, one or both readers reported a stenosis grade, which was at least 1 grade lower in standard compared to oblique sagittal images. There was also a significant difference when looking at patients who had neurological symptoms (p = 0.002) or underwent cervical spine surgery subsequently (p = 0.004). Interreader reliability, as measured by kappa value, and accordance rates were better for oblique sagittal images (0.94 vs. 0.88 and 99 % vs. 93 %). CONCLUSION: Standard sagittal images tend to underestimate neuroforaminal stenosis grades compared to oblique sagittal images and are less reliable in the evaluation of disc herniations within the cervical spine MRI. In order to assess the potential therapeutic consequence, oblique images should therefore be considered as a valuable adjunct to the standard MRI protocol for patients with a radiculopathy. KEY POINTS: · Neuroforaminal stenosis grades are underestimated in standard compared to oblique sagittal images. · Interreader reliability is higher for oblique sagittal images. · Oblique sagittal images should be performed in patients with a cervical radiculopathy. CITATION FORMAT: · Kintzele L, Rehnitz C, Kauczor H et al. Oblique Sagittal Images Prevent Underestimation of the Neuroforaminal Stenosis Grade Caused by Disc Herniation in Cervical Spine MRI. Fortschr Röntgenstr 2018; 190: 946 - 954.