Clinical Utility of Diffusion-Weighted Imaging in Spinal Infections

PURPOSE

Both laboratory markers and radiographic findings in the setting of spinal infections can be nonspecific in determining the presence or absence of active infection, and can lag behind both clinical symptoms and antibiotic response. Magnetic resonance imaging (MRI) with diffusion-weighted imaging (DWI) has been shown to be helpful in evaluating brain abscesses but has not been commonly used in evaluating spinal infections. We aimed to correlate findings on DWI of the spine to results of microbiological sampling in patients with suspected spinal infections.

METHODS

Patients who underwent MRI with DWI for suspicion of spinal infections and microbiological sampling from 2002 to 2010 were identified and reviewed retrospectively in this institutional review board approved study. In addition to DWI, scans included sagittal and axial T1, fast-spin echo (FSE) T2, and post-gadolinium T1 with fat saturation. Regions of interest were drawn on apparent diffusion coefficient (ADC) maps in the area of suspected infections, and ADC values were correlated with microbiological sampling.

RESULTS

Of 38 patients with suspected spinal infections, 29 (76%) had positive microbiological sampling, and 9 (24%) had negative results. The median ADC value was 740 × 10^-6 mm²/s for patients with positive microbiological sampling and 1980 × 10^-6 mm²/s for patients with negative microbiological sampling (p < 0.001). Using an ADC value of 1250 × 10^-6 mm²/s or less as the cut-off value for a positive result for spinal infection, sensitivity was 66%, specificity was 88%, positive predictive value was 95%, negative predictive value was 41% and accuracy was 70%.

CONCLUSION

In patients with suspected spine infection, ADC values on DWI are significantly reduced in those patients with positive microbiological sampling compared to patients with negative microbiological sampling. The DWI of the spine correlates well with the presence or absence of spinal infection and may complement conventional magnetic resonance imaging (MRI).

PathBot: A Radiology-Pathology Correlation Dashboard

Pathology is considered the "gold standard" of diagnostic medicine. The importance of radiology-pathology correlation is seen in interdepartmental patient conferences such as "tumor boards" and by the tradition of radiology resident immersion in a radiologic-pathology course at the American Institute of Radiologic Pathology. In practice, consistent pathology follow-up can be difficult due to time constraints and cumbersome electronic medical records. We present a radiology-pathology correlation dashboard that presents radiologists with pathology reports matched to their dictations, for both diagnostic imaging and image-guided procedures. In creating our dashboard, we utilized the RadLex ontology and National Center for Biomedical Ontology (NCBO) Annotator to identify anatomic concepts in pathology reports that could subsequently be mapped to relevant radiology reports, providing an automated method to match related radiology and pathology reports. Radiology-pathology matches are presented to the radiologist on a web-based dashboard. We found that our algorithm was highly specific in detecting matches. Our sensitivity was slightly lower than expected and could be attributed to missing anatomy concepts in the RadLex ontology, as well as limitations in our parent term hierarchical mapping and synonym recognition algorithms. By automating radiology-pathology correlation and presenting matches in a user-friendly dashboard format, we hope to encourage pathology follow-up in clinical radiology practice for purposes of self-education and to augment peer review. We also hope to provide a tool to facilitate the production of quality teaching files, lectures, and publications. Diagnostic images have a richer educational value when they are backed up by the gold standard of pathology.

Apparent Diffusion Coefficient Histogram Analysis for the Preoperative Evaluation of Ki-67 Expression in Pituitary Macroadenoma

PURPOSE

To explore the value of an apparent diffusion coefficient (ADC) histogram in predicting the Ki-67 proliferation index in pituitary macroadenomas.

MATERIAL AND METHODS

This retrospective study analyzed the pathological and imaging data of 102 patients with pathologically confirmed pituitary macroadenoma. Immunohistochemistry staining was used to assess Ki-67 expression in tumor tissue samples, and a high Ki-67 labeling index was defined as 3%. The ADC images of the maximum slice of tumors were selected and the region of interest (ROI) of each slice was delineated using the MaZda software (version 4.7, Technical University of Lodz, Institute of Electronics, Łódź, Poland) and analyzed by ADC histogram. Histogram characteristic parameters were compared between the high Ki-67 group (n = 42) and the low Ki-67 group (n = 60). The important parameters were further analyzed by receiver operating characteristic (ROC).

RESULTS

The mean value, and the 1st, 10th, 50th, 90th, and 99th percentiles were found to be negatively correlated with Ki-67 expression (all P < 0.05), with correlation coefficients of -0.292, -0.352, -0.344, -0.289, -0.253 and -0.267, respectively. The mean ADC and the 1st, 10th, 50th, 90th, and 99th quantiles extracted from the histogram were significantly lower in the high Ki-67 group than in the low Ki-67 group (all P < 0.05). The area under the ROC curve was 0.699-0.720; however, there were no significant between-group differences in variance, skewness and kurtosis (all P > 0.05).

CONCLUSION

An ADC histogram can be a reliable tool to predict the Ki-67 proliferation status in patients with pituitary macroadenomas.

Radiologic-pathologic Correlation-An Advanced Fourth-year Elective: How We Do It

Traditionally, the radiology elective has been designed to teach medical students the fundamentals of radiologic interpretation. When questioned, many students state that they want to take a radiology elective so they can "interpret images." For the students on radiology, rotation/elective education was often passive, consisting of didactic conferences and observational shadowing of radiologists as they interpreted images. Students had only a superficial appreciation of how radiologists interacted with clinical services, multidisciplinary teams, and pathology. There was very little emphasis on imaging appropriateness or the most efficient and effective imaging for various clinical problems. With the expansion of numerous imaging modalities and the emphasis on patient-centered care, including imaging safety and dose reduction, it is important to change the focus of radiology education from interpretation to the optimal integration of imaging into clinical medicine. Radiology-pathology (rad path) electives were created at Allegheny General Hospital and the Medical University of South Carolina as a new option to provide a high-quality advanced elective for fourth-year medical students. These electives enable students to correlate radiologic images with gross and microscopic pathology specimens, thus increasing their knowledge and understanding of both. The rad path elective combines aspects of surgery, radiology, and pathology and requires students to be active learners. The implementation of this elective is an exciting work in progress that has been evolving over the past 2 and 4 years at Medical University of South Carolina and Allegheny General Hospital, respectively. We will discuss the historical basis for the elective, the advantages and challenges of having such an integrated course, and some different strategies for creating a rad path elective.

Radiology-pathology correlation of endometrial carcinoma assessment on magnetic resonance imaging

Endometrial carcinoma is the most common gynaecological cancer in developed countries. Most cases are low-volume/low-grade tumour at presentation; however, high-grade subtypes may present with locally advanced disease with higher propensity for spread outside of the pelvis. MRI has a role in local staging of the tumour and helping the clinicians in treatment decision making. This pictorial essay gives examples of endometrial carcinoma at different stages with histological correlation. It also explores the potential limitations and pitfalls of imaging in this context.

Radiology Field Trips-A List of "Must Sees" in the Radiology Department for Medical Students: How We Do It

RATIONALE AND OBJECTIVE

Traditionally, the radiology elective has been designed to teach medical students the fundamentals of radiologic interpretation, typically through passive means, such as didactic conferences and observational shadowing of radiologists as they interpret images. In doing so, the importance of noninterpretive skills and active learning has been minimized. Additionally, in the traditional model, students typically only gain a superficial appreciation of radiologists' role in patient care and their interactions with clinical services, multidisciplinary teams, and patients. With the emphasis on value-focused, team-based, patient-centered care, it is important to expand the focus of radiology education beyond interpretive skills alone such that these future physicians can most effectively utilize imaging to care for patients.

MATERIALS AND METHODS

A list of integrated radiology field trips was created for medical students from two institutions, Allegheny Health Network and the University of Kentucky, representing a consolidation of the instructional strategies utilized at these institutions. This paradigm uses active observation to extend learning beyond the reading room.

RESULTS

It targets noninterpretive skills that will be of vital importance in the majority of students' future clinical practice, such as patient safety and appropriate ordering practices.

CONCLUSION

This article describes the integration of nine field trip experiences into a 4-week radiology clerkship and its effect on learning outcomes and student satisfaction.

Radiology-pathology correlation for bone and soft tissue tumors or tumor-like masses: single institutional experience after implementation of a weekly conference

OBJECTIVES

To determine the frequency of non-diagnostic and discordant results from bone and soft tissue biopsies performed at our institution over a 3-year period and to investigate whether implementation of a weekly musculoskeletal radiology-pathology correlation conference decreased the time to appropriate patient management in cases of discordance.

METHODS

Consecutive image-guided core needle biopsy results obtained over a 12 month period of time were reviewed in a retrospective fashion. Following implementation of the correlation conference, subsequent consecutive image-guided core needle biopsy results obtained over a 26 month period of time were reviewed in a prospective fashion. For non-diagnostic and discordant cases, the time in days from date of availability of the biopsy result to date of documentation of a specific follow-up action plan was recorded.

RESULTS

Diagnostic yield was 96.5% and 94.9% for the retrospective and prospective periods, respectively. There were four discordant results in the retrospective cohort (1.7%) and seven discordant results in the prospective cohort (2.1%). Following implementation of the weekly correlation conference, there was significant decrease (p < 0.05) in median time from a discordant biopsy result to follow-up action plan. There were no unnecessary surgeries, litigation, or other unfavorable consequences in either cohort.

CONCLUSION

Image-guided core needle biopsies of bone and soft tissue provide high diagnostic yield, often with specific diagnoses. The statistically significant decrease in number of days to follow-up action plan for discordant results suggests radiology-pathology review has a positive impact on patient care. Subjective benefits from communication and educational standpoints are also noteworthy.

Rad Path in a Flash: Creation of the First AMSER Sponsored Digital Flashcard Deck and a Review of Digital Flashcard Use among? Medical Students

RATIONALE AND OBJECTIVES

Digital flashcards are an increasingly popular study method for medical students today. The purpose of this study is to assess students' opinions on digital flashcards and to evaluate the need for radiology-focused digital flashcards. We created the first official Radiology-Pathology (Rad-Path) Correlation course digital flashcard deck sponsored by the Alliance of Medical Student Educators in Radiology (AMSER), and evaluated its effectiveness in increasing medical students' confidence levels of understanding Rad-Path concepts.

MATERIALS AND METHODS

A 16-question survey was developed and publicly shared with medical students to assess the need for a high-quality radiology deck. In addition, students who trialed the AMSER Rad-Path Anki deck were assessed on their confidence of radiology pathology concepts prior to and after using these digital flashcards.

RESULTS

185 survey responses were received for the first survey about digital flashcard use. Overall, 87.6% of medical student respondents had used digital flashcards during medical school, and 33.5% had used digital flashcards to study radiology topics specifically. 67.6% of respondents stated they would use a digital flashcard deck if sponsored by an academic radiology society. Regarding the survey of the students who used the AMSER Rad-Path flashcards, 31 responses were received in the pre- and follow-up survey. Mean confidence in understanding the radiology pathology learning objectives increased when the Rad-Path Anki deck was utilized, and students rated the flashcards favorably.

CONCLUSION

Students reported a high use of digital flashcards for studying topics in medical school. We identified a perceived need in students for a series of high-quality digital flashcards covering radiology topics. We created the first deck of AMSER Rad-Path flashcards which was well received by the medical students.