Vikas Agarwal

Indications for PET/CT in the Head and Neck

PET/CT has revolutionized the evaluation of patients with head and neck cancer by allowing more accurate staging, more focused treatment modalities, earlier detection of recurrent disease, and identification of incurable disease. In some clinical scenarios, PET/CT is clearly useful, while in others the cost may not be warranted. In this chapter, the authors review the literature on the use of PET/CT in head and neck cancers (in particular squamous cell carcinoma) and provide an evidence-based approach to the use of PET/CT for staging, treatment planning, monitoring of treatment response, and surveillance of treated patients with squamous cell carcinoma. They also briefly address the use of PET/CT for thyroid cancer, lymphoma, and melanoma. At the end of each section, key points are summarized in a box for quick reference.

Associations Between Serum Biomarkers and Pain and Pain‐Related Function in Older Adults with Low Back Pain: A Pilot Study

To examine the relationship between serum biomarkers and self‐reported pain intensity and pain‐related function, in addition to the contribution of magnetic resonance imaging (MRI) findings of lumbar spine degenerative changes, in older adults with chronic low back pain.

Competitiveness of the Match for Interventional Radiology and Neuroradiology Fellowships

PURPOSE Overall resident interest in certain subspecialties changes with time. We sought to investigate the latest 6-year trend in interventional radiology (IR) and neuroradiology fellowship applications and how it has affected competitiveness in obtaining a position. METHODS We analyzed statistics published by the National Resident Matching Program in Results and Data: Specialties Matching Service from 2008 to 2013. From these data, we calculated the positions per IR applicant (PPIRA) and positions per neuroradiology applicant (PPNRA) for each year. RESULTS The number of positions per applicant is one way to assess specialty competitiveness on a supply-and-demand basis. A lower PPIRA or PPNRA indicates a more competitive year. PPIRA has decreased every year, from 1.71 to the present 0.84, and contributed to 52 applicants being unmatched in 2013, up from 9 in 2008. Accordingly, the number of unfilled positions has decreased from 86 in 2008 to 8 in 2013. PPNRA waxed and waned from 2008 to 2010 but stabilized at around 1.15 thereafter. The number of unfilled positions has never dropped below 46. The number of unmatched applicants was consistently in the teens, except in 2011, when it increased to 23. CONCLUSIONS Interest in IR fellowship has increased significantly over the past 6 years, whereas interest in neuroradiology fellowships has plateaued. IR fellowships have become increasingly competitive, leading to many unmatched residents.

Multicenter clinical and imaging evaluation of targeted radiofrequency ablation (t-RFA) and cement augmentation of neoplastic vertebral lesions

Background Treatment of spinal metastatic lesions by radiofrequency ablation (RFA) before cementation can potentially help in local tumor control and pain relief. This is often limited by access and tumor location. This study reports multicenter clinical and imaging outcomes following targeted RFA (t-RFA) and cement augmentation in neoplastic lesions of the spine. Material and methods A retrospective multicenter study of 49 patients with 72 painful vertebral lesions, evaluated for clinical and imaging outcomes following RFA and cement augmentation of spinal metastatic lesions, was undertaken. Visual Analogue Pain score (VAS) and Oswestry Disability Index (ODI) were obtained before and 2–4 weeks after treatment. Pre- and post-procedure imaging examinations including MRI and positron emission tomography (PET) were also evaluated. Results Mean ablation time was 3.7±2.5 min (range 0.92–15). Mean VAS scores decreased from 7.9±2.5 pre-procedure to 3.5±2.6 post-procedure (p<0.0001). Mean ODI scores improved from 34.9±18.3 to 21.6±13.8 post-procedure (p<0.0001). Post-contrast MRI resulted in a predictable pattern of decreased tumor volume and an enhancing rim. Metabolically active lesions in pre-procedure PET scans (n=10 levels) showed decreased fluorodeoxyglucose activity after ablation. Conclusions t-RFA followed by vertebral augmentation in malignant vertebral lesions resulted in significant pain reduction and functional status improvement, with no major complications. t-RFA permitted access to vertebral lesions and real-time accurate monitoring of the ablation zone temperature. Post-procedure MRI and PET examinations correlated with a favorable tumor response and helped to monitor tumor growth and the timing of adjuvant therapy.

Correlation of pain with objective quantification of magnetic resonance images in older adults with chronic low back pain.

Study Design. Cross sectional study. Objective. The goal of this study is to identify relationships between objectively measured and subjectively scored parameters and reported pain. Summary of Background Data. Studies have demonstrated the unreliability of magnetic resonance imaging (MRI)–based parameters to identify pathological pain generators of chronic low back pain, but they were based on visual inspection and subjective assessment of lumbar disc features. Advancements in computer image analysis provide objective measurements of lumbar disc features. Methods. Two radiologists evaluated 39 axial and sagittal T1- and T2-weighted MR images of patients with chronic axial low back pain (age, >65 yr) and graded 4 subjective lumbar disc parameters (T2 signal intensity, nucleus shape, Modic changes, and osteophyte formation) whose sum is the cumulative MRI score. Objective parameter, MRI index, was calculated as the product of the measured lumbar disc area and total disc MRI signal intensity. Discs were sorted from least to the most degenerated relative to each parameter. Pearson correlation coefficient and multiple linear regression analysis were performed between the reported pain score and each parameter. Results. The most and least degenerated discs in each patient, as assessed by MRI index, had the highest negative and positive correlation coefficient and regression weight contribution, respectively. All subjective parameters had low correlation coefficients and regression goodness of fit. Conclusion. Although limited by small sample size, the objective parameter, MRI index, can be a potential imaging biomarker used to identify possible pain generators. This study presents a potential new application of MR imaging in identifying pain generators of patients with chronic low back pain. Level of Evidence: N/A

Traumatic Brain Injury

Traumatic brain injury (TBI) is a serious public health problem worldwide. In adults, motor vehicle accidents are a frequent cause with the elderly population more susceptible to accidental falls. The numbers of cases continue to increase each year and it is predicted that TBI will soon become the third leading cause of death and disability worldwide. This chapter discusses the classification of TBI, the various imaging modalities available for evaluation of TBI and the most common pathologies encountered in patients with TBI.

Lumbar discal cyst in an elite athlete

Our patient, a 22-year-old starting wide receiver for an NCAA Division I football team, presented with low back pain and sciatica. A lumbar-spine MRI without contrast demonstrated findings suspicious for discal cyst. The patient was referred for surgery, and the lesion was resected. The rarity of discal cyst makes it difficult to diagnose because most radiologists are not aware of the entity. An organized approach to diagnosis can facilitate appropriate management.

Diagnostic accuracy of emergency CT angiography for presumed tandem internal carotid artery occlusion before acute endovascular therapy

Background Extracranial internal carotid artery (ICA) occlusion can be overestimated on emergent single phase CT angiography (CTA) of stroke patients with isolated intracranial ICA occlusion. We aimed to measure the ability of identifying the extracranial site of presumed tandem ICA occlusions on pre-procedural CTA relative to catheter angiography during acute endovascular stroke therapy. Methods Retrospective study of patients with intracranial ICA occlusion, with or without extracranial ICA occlusion, who underwent single phase CTA before acute endovascular treatment. Two neuroradiologists reviewed CTA images for the presence or absence of extracranial ICA occlusion, blinded to the catheter angiography results. The sensitivity, specificity, and predictive values of presumed extracranial ICA occlusions on CTA were calculated in reference to catheter angiography. Results 91 stroke patients with acute intracranial ICA occlusion met the inclusion criteria for the study. 24% of patients (22/91) had tandem ICA occlusion confirmed on catheter angiography. Single phase CTA had a sensitivity of 95.5% (95% CI 77.2 to 99.9%) and a specificity of 69.6% (95% CI 57.3 to 80.1%) for concomitant extracranial ICA occlusion (false positive rate 30.4%). The positive and negative predictive values of single phase CTA for extracranial ICA occlusion in the presence of a distal ICA occlusion were 50% (95% CI 34.2 to 65.8%) and 98% (95% CI 89.1 to 100%), respectively. Conclusions Emergency single phase CTA is highly sensitive but has reduced specificity to identify extracranial ICA occlusion in patients with intracranial ICA occlusion, which may confound planning for acute endovascular stroke therapy and cause over exclusion of patients with isolated ICA terminus occlusion from clinical trials.

Do Residency Selection Factors Predict Radiology Resident Performance

RATIONALE AND OBJECTIVES The purpose of our study is to determine what information in medical student residency applications predicts radiology residency success as defined by objective clinical performance data. MATERIALS AND METHODS We performed a retrospective cohort study of residents who entered our institutions residency program through the National Resident Matching Program as postgraduate year 2 residents and completed the program over the past 2 years. Medical school grades, selection to Alpha Omega Alpha (AOA) Honor Society, United States Medical Licensing Examination (USMLE) scores, publication in peer-reviewed journals, and whether the applicant was from a peer institution were the variables examined. Clinical performance was determined by calculating each residents cumulative major discordance rate for on-call cases the resident read and gave a preliminary interpretation. A major discordance was defined as a difference between the preliminary resident and the final attending interpretations that could immediately impact the care of the patient. A multivariate logistic regression was performed to determine significant variables. RESULTS Twenty-seven residents provided preliminary reports on call for 67,145 studies. The mean major discordance rate was 1.08% (range 0.34%-2.54%). Higher USMLE Step 1 scores, publication before residency, and election to AOA Honor Society were all statistically significant predictors of lower major discordance rates (P values 0.01, 0.01,  and <0.001, respectively). CONCLUSIONS Overall resident performance was excellent. There are predictors that help select the better performing residents, namely higher USMLE Step 1 scores, one to two publications during medical school, and election to AOA in the junior year of medical school.

Spontaneous regression of a large calcified thoracic disk extrusion

Although spontaneous regression of herniated disk material has been reported in the lumbar and cervical spine, reports of complete spontaneous regression of calcified thoracic disk herniations are exceedingly rare. In symptomatic patients, surgery is typically the treatment of choice; however, conservative therapy with surveillance may allow time for spontaneous resolution and potentially avoid high-risk surgery. We report a 40-year-old woman with complete spontaneous resolution of a large calcified thoracic disk extrusion with conservative management over an 8-month period.