Accuracy of radiography in grading and tissue-specific diagnosis--a study of 200 consecutive bone tumors of the hand

Diffusion weighted imaging of extremity bone tumors-inter-reader analysis and incremental value over conventional MR imaging

OBJECTIVE

To determine whether the addition of diffusion-weighted imaging (DWI) to conventional MRI improves diagnostic accuracy of bone tumor characterization with the hypothesis that the DWI has incremental value in the diagnosis of osseous tumors.

METHODS

In this multireader cross-sectional validation study, four musculoskeletal radiologists evaluated osseous tumors blinded to final diagnosis in two rounds-first without DWI or apparent diffusion coefficient (ADC) maps, then months later with these available. Each reader recorded a binary result as to whether the lesion is benign or malignant. Intraclass correlation (ICC) and Conger's κ were used. Diagnostic performance measures including area under the receiver operating curve (AUC) were reported.

RESULTS

133 osseous tumors of the extremities (76 benign, 57 malignant) were tested. Blinded to DWI, average reader sensitivity, specificity, positive-predictive value, and negative-predictive value were 0.83, 0.92, 0.94, and 0.82, respectively. With DWI, the values were 0.85, 0.92, 0.94, and 0.83, respectively. Interreader agreement was good for both rounds (0.67 and 0.71, respectively, p-value > 0.05). Average reader confidence was 4.1 and 4.4, respectively (p-value < 0.001). ADC values and DWI/ADC ratios showed significant differences between benign and malignant tumors.

CONCLUSION

DWI and ADC show statistically significantly different values of benign from malignant osseous tumors and mildly increased radiologist confidence with similar interreader reliability. However, given similar diagnostic accuracy, conventional MR imaging is adequate for bone tumor characterization and incremental value of DWI is limited.

ADVANCES IN KNOWLEDGE

This paper is the first of its kind to report the use of DWI/ADC ratio for the diagnosis of bone tumors.

Osseous-Tissue Tumor Reporting and Data System With Diffusion-Weighted Imaging of Bone Tumors-An Interreader Analysis and Whether It Adds Incremental Value on Tumor Grading Over Conventional Magnetic Resonance Imaging

OBJECTIVE

The aim of the study is to determine whether the use of diffusion-weighted imaging (DWI) provides incremental increase in performance in the osseous-tissue tumor reporting and data system (OT-RADS) with the hypothesis that use of DWI improves interreader agreement and diagnostic accuracy.

METHODS

In this multireader cross-sectional validation study, multiple musculoskeletal radiologists reviewed osseous tumors with DW images and apparent diffusion coefficient maps. Four blinded readers categorized each lesion using the OT-RADS categorizations. Intraclass correlation (ICC) and Conger κ were used. Diagnostic performance measures including area under the receiver operating curve were reported. These measures were then compared with the previously published work that validated OT-RADS but did not include incremental value assessment of DWI.

RESULTS

One hundred thirty-three osseous tumors of the upper and lower extremities (76 benign, 57 malignant) were tested. Interreader agreement for OT-RADS with DWI (ICC = 0.69) was slightly lower (not statistically different) from the previously published work that did not incorporate DWI (ICC = 0.78, P > 0.05). The mean sensitivity, specificity, positive predictive value, negative predictive value, and area under the receiver operating curve including DWI of the 4 readers were 0.80, 0.95, 0.96, 0.79, and 0.91, respectively. In the previously published work without DWI, the mean values of the readers were 0.96, 0.79, 0.78, 0.96, and 0.94, respectively.

CONCLUSIONS

The addition of DWI to the OT-RADS system does not allow significantly improved area under the curve diagnostic performance measure. Conventional magnetic resonance imaging can be prudently used for OT-RADS for reliable and accurate characterization of bone tumors.

Comparing the blood oxygen level–dependent fluctuation power of benign and malignant musculoskeletal tumors using functional magnetic resonance imaging

Purpose

The aim of this study is to compare the blood oxygen level–dependent (BOLD) fluctuation power in 96 frequency points ranging from 0 to 0.25 Hz between benign and malignant musculoskeletal (MSK) tumors via power spectrum analyses using functional magnetic resonance imaging (fMRI).

Materials and methods

BOLD-fMRI and T1-weighted imaging (T1WI) of 92 patients with benign or malignant MSK tumors were acquired by 1.5-T magnetic resonance scanner. For each patient, the tumor-related BOLD time series were extracted, and then, the power spectrum of BOLD time series was calculated and was then divided into 96 frequency points. A two-sample t-test was used to assess whether there was a significant difference in the powers (the “power” is the square of the BOLD fluctuation amplitude with arbitrary unit) of each frequency point between benign and malignant MSK tumors. The receiver operator characteristic (ROC) analysis was used to assess the diagnostic capability of distinguishing between benign and malignant MSK tumors.

Results

The result of the two-sample t-test showed that there was significant difference in the power between benign and malignant MSK tumor at frequency points of 58 (0.1508 Hz, P = 0.036), 59 (0.1534 Hz, P = 0.032), and 95 (0.247 Hz, P = 0.014), respectively. The ROC analysis of mean power of three frequency points showed that the area of under curve is 0.706 (P = 0.009), and the cutoff value is 0.73130. If the power of the tumor greater than or equal to 0.73130 is considered the possibility of benign tumor, then the diagnostic sensitivity and specificity values are 83% and 59%, respectively. The post hoc analysis showed that the merged power of 0.1508 and 0.1534 Hz in benign MSK tumors was significantly higher than that in malignant ones (P = 0.014). The ROC analysis showed that, if the benign MSK tumor was diagnosed with the power greater than or equal to the cutoff value of 1.41241, then the sensitivity and specificity were 67% and 68%, respectively.

Conclusion

The mean power of three frequency points at 0.1508, 0.1534, and 0.247 Hz may potentially be a biomarker to differentiate benign from malignant MSK tumors. By combining the power of 0.1508 and 0.1534 Hz, we could better detect the difference between benign and malignant MSK tumors with higher specificity.

Osseous Tumor Reporting and Data System-Multireader Validation Study

OBJECTIVE

To develop and validate an Osseous Tumor Reporting and Data System (OT-RADS) with the hypothesis that the proposed guideline is reliable and assists in separating benign from malignant osseous tumors with a good area under the curve, and that could assist further patient management.

METHODS

In this multireader cross-sectional validation study, an agreement was reached for OT-RADS categories based on previously described magnetic resonance imaging features and consensus of expert musculoskeletal radiologists. World Health Organization classification was used, and a wide spectrum of benign and malignant osseous tumors was evaluated. Magnetic resonance imaging categories were as follows: OT-RADS 0-incomplete imaging; OT-RADS I-negative; OT-RADS II-definitely benign; OT-RADS III-probably benign; OT-RADS IV-suspicious for malignancy or indeterminate; OT-RADS V-highly suggestive of malignancy; and OT-RADS VI-known biopsy-proven malignancy or recurrent malignancy in the tumor bed. Four blinded readers categorized each tumor according to OT-RADS classification. Intraclass correlation (ICC) and Conger κ were used. Diagnostic performance measures including area under the receiver operating curve were reported. Osseous Tumor Reporting and Data System was dichotomized as benign (I-III) and malignant (IV and V) for calculating sensitivity and specificity.

RESULTS

Interreader agreement for OT-RADS (ICC = 0.78) and binary distinction of benign versus malignant (κ = 0.67) were good to excellent, while agreement for individual tumor feature characteristics were poor to fair (ICC = 0.25-0.36; κ = 0.16-0.39). The sensitivities, specificities, and area under the receiver operating curve of the readers ranged from 0.93-1.0, 0.71-0.86, and 0.92-0.97, respectively.

CONCLUSIONS

Osseous Tumor Reporting and Data System lexicon is reliable and helps stratify tumors into benign and malignant categories. It can be practically used by radiologists to guide patient management, improve multidisciplinary communications, and potentially impact outcomes.

An Approach to Undiagnosed Bone Tumors

The radiographic appearance of primary bone tumors is important for initial diagnosis and often augments histopathological analysis. The original grading system relied on the radiographic analysis of the margin of the lesions to determine tumor aggression, which often corresponds with malignant potential. The recently developed, modified Lodwick-Madewell grading system also incorporates the appearance of lesion margins on radiographs but also considers the change in margins on serial radiographs and includes a category for clinically suspected, radiographically occult, aggressive lesions. This article reviews the prior and modified grading systems, and the concepts necessary for proper interpretation of the initial appearance of bone tumors which often determines the radiologist's recommendation for biopsy or follow-up imaging.

ACR Appropriateness Criteria® Primary Bone Tumors

Although primary bone tumors are relatively uncommon, appropriate imaging evaluation is essential when they are suspected or incidentally detected. In almost all cases, radiographs are the most appropriate initial imaging study for screening and characterization of primary bone tumors. Radiographs often provide sufficient information for diagnosis and to guide the treating clinician. However, when conventional radiographs alone are inadequate, they still often guide the selection of the most appropriate next step for advanced imaging. MRI and CT are typically the most appropriate next step. MRI provides excellent soft-tissue contrast allowing for evaluation of the tissue composition (such as fat, hemorrhage, fluid levels) and anatomic extent of bone tumors. CT provides complementary information, with its ability to detect subtle matrix mineralization or periosteal reaction that may not be seen on radiographs or MRI. This publication focuses on six common variants to guide diagnosis and management of primary bone tumors. In addition to conventional radiographs, appropriate use of MRI, CT, PET/CT, bone scan, and ultrasound are discussed. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Multi-modality imaging approach to bone tumors - State-of-the art

The approach to the radiographic diagnosis of bone tumors is much beyond the conventional radiographs in present era of multiplanar and functional imaging. Radiographs is still the most pertinent part of initial diagnosis of bone tumors, however, there are few limitations, like lesions in complex anatomy, marrow assessment, soft tissue resolution, which are important for staging. Diagnosis is just one aspect of the tumor evaluation, extent of marrow involvement by the tumor growth, involvement of overlying soft tissue, involvement of adjacent joint, and knowledge about skip lesions and metastasis are equally important for staging and treatment of the disease. Multimodality imaging like CT, MRI helps cover all these aspects. Emerging role of PETCT/PET MRI has further revolutionized the imaging of bone tumors by providing anatomical and morphological characteristics simultaneously and combining the whole body scan in same sitting. This article will discuss the role of various imaging modalities along with illustrative examples of few cases. Team work between radiologist with orthopedic oncologist and pathologist will help in deciding a road map for diagnosing and treatment of bone tumors. Follow up scanning with MRI and PET FDG scan has also been well established in assessing therapeutic response.

Bone Tumor Diagnosis Using a Naïve Bayesian Model of Demographic and Radiographic Features

Because many bone tumors have a variety of appearances and are uncommon, few radiologists develop sufficient expertise to guide optimal management. Bayesian inference can guide decision-making by computing probabilities of multiple diagnoses to generate a differential. We built and validated a naïve Bayes machine (NBM) that processes 18 demographic and radiographic features. We reviewed over 1664 analog radiographic cases of bone tumors and selected 811 cases (66 diagnoses) for annotation using a quantitative imaging platform. Leave-one-out cross validation was performed. Primary accuracy was defined as the correct pathological diagnosis as the top machine prediction. Differential accuracy was defined as whether the correct pathological diagnosis was within the top three predictions. For the 29 most common diagnoses (710 cases), primary accuracy was 44%, and differential accuracy was 60%. For the top 10 most common diagnoses (478 cases), primary accuracy was 62%, and differential accuracy was 80%. The machine returned relevant diagnoses for the majority of unknown test cases and may be a feasible alternative to machine learning approaches such as deep neural networks or support vector machines that typically require larger training data (our model required a minimum of five samples per diagnosis) and are "black boxes" (our model can provide details of probability calculations to identify features that most significantly contribute to truth diagnoses). Finally, our Bayes model was designed to scale and "learn" from external data, enabling incorporation of outside knowledge such as Dahlin's Bone Tumors, a reference of anatomic and demographic statistics of more than 10,000 tumors.

Soft Tissue Masses of Hand: A Radio-Pathological Correlation

Aim. To evaluate soft tissue masses of the hand with magnetic resonance imaging (MRI) and ultrasonography (USG) and to correlate imaging findings with pathological findings. Material and Methods. Thirty-five patients with soft tissue masses of the hand were evaluated with high resolution USG and contrast enhanced MRI of the hand, prospectively over a period of 2.5 years. The radiological diagnosis was then compared with cytology/histopathology. Results. There were a total of 19 (55%) females. The mean age was 27.45 ± 14.7 years. Majority (45%) of cases were heteroechoic. Four cases were predominantly hyperechoic. These were later diagnosed as lipomas. Four cases were anechoic (diagnosed as ganglions). Only four lesions showed hyperintense signal on T1-weighted images. Out of these, 3 were lipomas and one was cavernous haemangioma. Three lesions were hypointense on T2-weighted images. All these lesions were diagnosed as giant cell tumor of the tendon sheath. A correct diagnosis was possible on MRI in 80% of cases (n = 28). Conclusion. MRI provides specific findings for diagnosis of certain soft tissue lesions of the hand. Ultrasonography allows accurate diagnosis of hemangioma/vascular malformations. However, in most conditions, imaging findings are nonspecific and diagnosis rests on pathologic evaluation.

Imaging evaluation of musculoskeletal tumors

In this chapter, we review different imaging modalities, including radiography, computed tomography (CT), magnetic resonance imaging (MRI), ultrasound, and nuclear medicine scintigraphy, and their application to musculoskeletal neoplasm. Advantages and limitations of each modality are reviewed, and suggestions for imaging approach are provided.

State-of-the-art HR-US imaging findings of the most frequent musculoskeletal soft-tissue tumors

High resolution ultrasound (HR-US) including color Doppler ultrasound (CD-US), power Doppler ultrasound (PD-US), and spectral wave analysis (SWA), is a broadly available, non-invasive and relatively low-cost modality without ionizing radiation. It is increasingly used for initial assessment of an ambiguous musculoskeletal soft-tissue lesion and for sonographically guided core biopsy. The aim of this review is to provide sonographic findings of the most frequent benign and malign soft-tissue lesions. By this essay, we can show that combined with clinical features, with information on tumor-localization and patient age, many musculoskeletal lesions may be successfully characterized by HR-US. In contrast, a mere morphologic assignment of some fibrous tumors and malignant lesions remains often impossible; however, certain CD-US signs such as anarchic vascular architecture or arteriovenous shunting may be very helpful indicators for malignancy. HR-US offers a simple, quick, and reliable first-line examination of musculoskeletal soft-tissue lesions and may have an important role in the diagnostic work-up followed by magnetic resonance or multimodality imaging and guided core biopsy.

Magnetic resonance imaging of bone tumors and joints

PURPOSE

In this invited review, the main subtypes of commoner bone tumors will be reviewed. Background and general concepts on pathology and surgery will be given with magnetic resonance imaging features of bone tumors. TEXT: The main malignant bone tumors being: osteogenic sarcoma, Ewings sarcoma, and chondrosarcoma are reviewed. Malignant intra-articular tumors are mentioned. The differential diagnoses including tumor mimickers are also reviewed.

CONCLUSION

Magnetic resonance imaging allows for basic anatomical review and characterization of tumor type for diagnosis, therapy monitoring, and preoperative planning. A team approach to tumor imaging and treatment is optimal.