Anish Ghodadra

Abscopal Effects and Yttrium-90 Radioembolization

We present the case of an 80-year-old male with squamous cell carcinoma with bilobar hepatic metastases who underwent targeted Yttrium-90 radioembolization of the right hepatic lobe lesion. Subsequently, there was complete regression of the nontargeted, left hepatic lobe lesion. This may represent the first ever reported abscopal effect in radioembolization. The abscopal effect refers to the phenomenon of tumor response in nontargeted sites after targeted radiotherapy. In this article, we briefly review the immune-mediated mechanisms responsible for the abscopal effect.

Principal Component Analysis of Diffusion Tensor Images to Determine White Matter Injury Patterns Underlying Postconcussive Headache.

BACKGROUND AND PURPOSE: Principal component analysis, a data-reduction algorithm, generates a set of principal components that are independent, linear combinations of the original dataset. Our study sought to use principal component analysis of fractional anisotropy maps to identify white matter injury patterns that correlate with posttraumatic headache after mild traumatic brain injury. MATERIALS AND METHODS: Diffusion tensor imaging and neurocognitive testing with the Immediate Post-Concussion Assessment and Cognitive Test were performed in 40 patients with mild traumatic brain injury and 24 without posttraumatic headache. Principal component analysis of coregistered fractional anisotropy maps was performed. Regression analysis of the major principal components was used to identify those correlated with posttraumatic headache. Finally, each principal component that correlated with posttraumatic headache was screened against other postconcussive symptoms and demographic factors. RESULTS: Principal component 4 (mean, 7.1 ± 10.3) correlated with the presence of posttraumatic headache in mild traumatic brain injury (odds ratio per SD, 2.32; 95% CI, 1.29–4.67; P = .01). Decreasing principal component 4 corresponded with decreased fractional anisotropy in the midsplenium and increased fractional anisotropy in the genu of the corpus callosum. Principal component 4 identified patients with posttraumatic headache with an area under the receiver operating characteristic curve of 0.73 and uniquely correlated with posttraumatic headache and no other postconcussive symptom or demographic factors. CONCLUSIONS: Principal component analysis can be an effective data-mining method to identify white matter injury patterns on DTI that correlate with clinically relevant symptoms in mild traumatic brain injury. A pattern of reduced fractional anisotropy in the splenium and increased fractional anisotropy in the genu of the corpus callosum identified by principal component analysis can help identify patients at risk for posttraumatic headache after mild traumatic brain injury.

Reducing Radiation Dose in Pediatric Diagnostic Fluoroscopy

PURPOSE To assess radiation dose in common pediatric diagnostic fluoroscopy procedures and determine the efficacy of dose tracking and dose reduction training to reduce radiation use. METHODS Fluoroscopy time and radiation dose area product (DAP) were recorded for upper GIs (UGI), voiding cystourethrograms (VCUGs), and barium enemas (BEs) during a six-month period. The results were presented to radiologists followed by a 1-hour training session on radiation dose reduction methods. Data were recorded for an additional six months. DAP was normalized to fluoroscopy time, and Wilcoxon testing was used to assess for differences between groups. RESULTS Data from 1,479 cases (945 pretraining and 530 post-training) from 9 radiologists were collected. No statistically significant difference was found in patient age, proportion of examination types, or fluoroscopy time between the pre- and post-training groups (P ≥ .1), with the exception of a small decrease in median fluoroscopy time for VCUGs (1.0 vs 0.9 minutes, P = .04). For all examination types, a statistically significant decrease was found in the median normalized DAP (P < .05) between pre- and post-training groups. The median (quartiles) for pretraining and post-training normalized DAPs (μGy·m(2) per minute) were 14.36 (5.00, 38.95) and 6.67 (2.67, 17.09) for UGIs; 13.00 (5.34, 32.71) and 7.16 (2.73, 19.85) for VCUGs; and 33.14 (9.80, 85.26) and 17.55 (7.96, 46.31) for BEs. CONCLUSIONS Radiation dose tracking with feedback, paired with dose reduction training, can reduce radiation dose during diagnostic pediatric fluoroscopic procedures by nearly 50%.

CT-Fluoroscopic Cervical Transforaminal Epidural Steroid Injections: Extraforaminal Needle Tip Position Decreases Risk of Intravascular Injection

BACKGROUND AND PURPOSE: Cervical transforaminal epidural steroid injections are commonly performed for temporary pain relief or diagnostic presurgical planning in patients with cervical radiculopathy. Intravascular injection of steroids during the procedure can potentially result in cord infarct, stroke, and even death. CT-fluoroscopy allows excellent anatomic resolution and precise needle positioning. This study sought to determine the safest needle tip position during CT-guided cervical transforaminal epidural steroid injection as determined by the incidence of intravascular injection. MATERIALS AND METHODS: We retrospectively evaluated procedural imaging for consecutive single-site CT-fluoroscopic cervical transforaminal epidural steroid injection performed during a 13-month period. Intravascular injections were identified and classified by volume, procedure phase, vessel type, and needle tip position relative to the targeted neural foramen. ANOVA, Wilcoxon, or Pearson χ2 testing was used to assess differences among groups as appropriate. RESULTS: Intravascular injections occurred in 49/201 (24%) procedures. Of the intravascular injections, 13/49 (27%) were large, 10/49 (20%) were small, and 26/49 (53%) were trace volume. Sixteen of 49 (33%) intravascular injections occurred with a trial contrast dose; 27/49 (55%), with a steroid/analgesic cocktail; and 6/49 (12%), with both. Twenty-seven of 49 (55%) intravascular injections were likely venous, 22/49 (45%) were indeterminate, and none were likely arterial. The intravascular injection rate was significantly lower (P < .001) for the extraforaminal needle position (8/82, 10%) compared with junctional (27/88, 31%) and foraminal (14/31, 45%) needle tip positions. CONCLUSIONS: An extraforaminal needle position for CT-guided cervical transforaminal epidural steroid injection decreases the risk of intravascular injection and therefore may be safer than other needle tip positions.

Extraforaminal needle tip position reduces risk of intravascular injection in CT-fluoroscopic lumbar transforaminal epidural steroid injections

BACKGROUND Lumbar transforaminal epidural steroid injection is a common and effective tool for managing lumbar radicular pain, although accidental intravascular injection can rarely result in paralysis. The purpose of this study is to determine the safest needle tip position for computed tomography (CT)-guided lumbar transforaminal epidural steroid injections as determined by incidence of intravascular injection. METHODS Three radiologists, in consensus, reviewed procedural imaging for consecutive CT-fluoroscopic lumbar transforaminal epidural steroid injections performed during a 16-month period. Intravascular injections were identified and categorized by needle tip position, vessel type injected, intravascular injection volume and procedural phase containing the intravascular injection. Pearson chi-square and logistic regression testing were used to assess differences between groups, as appropriate. RESULTS Intravascular injections occurred in 9% (52/606) of injections. The intravascular injection rate was significantly lower (P<0.001) for extraforaminal needle position (0%, 0/109) compared to junctional (8%, 27/319) and foraminal (14%, 25/178) needle tip positions. Of the intravascular injections, 4% (2/52) were likely arterial, 35% (18/52) were likely venous, and 62% (32/52) were indeterminate for vessel type injected. 46% (24/52) of intravascular injections were large volume, 33% (17/52) were small volume, and 21% (11/52) were trace volume. 56% (29/52) of intravascular injections occurred with the contrast trial dose, 29% (15/52) with the steroid/analgesic cocktail, and 15% (8/52) with both. CONCLUSIONS An extraforaminal needle position for CT-fluoroscopic lumbar transforaminal epidural steroid injections decreases the risk of intravascular injection and therefore may be safer than other needle tip positions.

Sestamibi SPECT/CT versus SPECT only for preoperative localization in primary hyperparathyroidism: a single institution 8-year analysis

Background. Primary hyperparathyroidism is caused by single gland disease in 85% of cases and by multiglandular disease in 15%. Our aim was to discover if the addition of computed tomography acquisition/fusion on a hybrid scanner to traditional dual‐phase single‐photon emission tomography improves localization accuracy. Methods. A prospective database was queried for the perioperative data of patients with sporadic primary hyperparathyroidism who had initial exploration from 2006–2014 with ≥6 month follow‐up to define anatomy. Prior to 2010, patients had single‐photon emission tomography (n = 633); after 2010, they had single‐photon emission tomography/computed tomography (n = 755). Results. In 1,388 patients, the rates of single gland disease (P = .8), bilateral exploration (P = .4), and negative imaging (145 patients, P = .33) were equal between imaging cohorts. In 1,186 patients with single gland disease, the positive predictive value of single‐photon emission tomography/computed tomography was somewhat greater (90% vs 85%) and the accuracy of single‐photon emission tomography/computed tomography was superior (83% vs 77%, P = .02). In the 202 patients with multiglandular disease, 20% had negative imaging results with no difference by type (single‐photon emission tomography/computed tomography 17%, single‐photon emission tomography 23%, P = .3), but single‐photon emission tomography/computed tomography was more accurate (36%) than single‐photon emission tomography (22%, P = .04) in predicting multiglandular disease. Conclusion. In a large cohort study of patients with sporadic primary hyperparathyroidism undergoing parathyroidectomy, positive single‐photon emission tomography/computed tomography results provided more reliable operative guidance than single‐photon emission tomography for both single gland disease and multiglandular disease.

Normal Glenoid Relationships Used for Unilateral Quantification of Glenoid Bone Loss in Glenohumeral Instability

Objectives: Current methods used to quantify glenoid bone loss following anterior shoulder instability rely on bilateral shoulder imaging to obtain normal linear and surface area parameters of the uninjured glenoid fossa. This method is based on the assumption that there is little side-side variability in these anatomical relationships. Previous reports have demonstrated differences in the morphology of the glenoid fossa based on the anterior glenoid notch. The purpose of this study was to determine the normal dimensions of height, width, surface area, and shape of the human glenoid fossa as function of glenoid notch, and to determine if side-to-side differences exist for these parameters. Due to notch variation, we hypothesize that the inferior glenoid fossa is better represented as an ellipse versus a perfect circle as previously described. We also hypothesize that side-to-side differences exist in glenoid surface area. Methods: The authors studied 58 human scapulae pairs between 18 and 35 years of age from the Hamann-Todd Osteological Collection. Age, sex, race, body height and weight were known for each specimen. Paired specimens were sorted into groups of 5 according to race, sex, and notch type. All specimens were digitized using a 3-D laser scanner, with a stated accuracy of 0.005 inches. Height, width, surface area, and notch angle measurements were calculated using software written in the MATLAB platform. A best fit ellipse was applied to the inferior glenoid based on the glenoid circumference below the notch. Differences in surface area of paired glenoids were assessed using a matched pairs T-test. Multiple stepwise linear regression models were created to select predictors of glenoid surface area. Lastly, the intra-rater and inter-rater reliability of the notch classification as reported by Merrill et al. was assessed among 13 raters. Results: The mean height (s.d.) of the glenoid fossae was 35.0 ± 2.8 mm. Inferior width was 24.8 ± 2.5 mm. The best-fit ellipse of the inferior glenoid had a mean eccentricity of 0.425 ± 0.099. The right glenoid, when compared to its left counterpart, had greater overall surface area (x̄right= 679.6 mm2, x̄left= 657.2 mm2, P< 0.0001*) and inferior surface area (x̄right= 548.2 mm2, x̄left= 533.1 mm2, P< 0.0076*). Patient height, sex, and glenoid height correlated with total and inferior glenoid surface area with r2= 0.902 and 0.779, respectively (P< 0.0001*). Analysis of intra-observer reliability showed a consistency of 0.56 (95% CI= 0.26- 0.77), while the inter-observer reliability kappa coefficient was 0.43 (95% CI= 0.41- 0.45). Conclusion: By considering unilateral anatomic relationships of the glenoid fossa, we were able to determine alternative methods of evaluating glenoid bone loss. Glenoid notch angle had moderate reliability and was not considered clinically useful to stratify glenoid morphology. Based on non-zero eccentricity values of the best-fit ellipse, the inferior glenoid fossa did not represent a perfect circle. In addition, side-to-side differences were found between glenoid surface area measurements. The latter two findings contradict assumptions made by current techniques used in clinical practice to calculate bone loss and raise concern as to their validity. Using easily obtainable patient (height and sex) and glenoid (height) parameters, glenoid surface area can be predicted by means of regression modeling, permitting unilateral measurements of glenoid bone loss to be made in clinical practice.

Apparent Diffusion Coefficient (ADC) of the vitreous humor and Susceptibility Weighted Imaging (SWI) of the retina in abused children with retinal hemorrhages

This study speculated that the apparent diffusion coefficient (ADC) of the vitreous humor might be altered in the setting of abusive head trauma (AHT) with retinal hemorrhages (RH). Fourty-four subjects were analyzed (n=20 AHT cases; n=24 controls). There was no statistically significant difference in normalized ADC values between the cases and controls (-0.14 and -0.08 respectively, p=0.46), but analysis of RH by susceptibility weighted imaging (SWI) compared to dilated funduscopic exam demonstrated statistically significant correlation (p=0.003 and 0.012). Our results suggest that SWI serves as a more sensitive diagnostic tool for detection of ocular injury in AHT than ADC.

Lumbar Transforaminal Epidural Steroid Injections: Incidental Extraspinal Findings on Planning Imaging

OBJECTIVE Planning imaging performed during CT-guided procedures may occasionally contain important incidental findings. The purpose of this study was to identify and characterize by clinical relevance the extraspinal findings detected on planning imaging for CT-guided lumbar transforaminal epidural steroid injections (TFESIs). MATERIALS AND METHODS Four radiologists retrospectively evaluated the planning scout views and CT studies for 488 consecutive CT-guided lumbar TFESIs performed in 400 patients over a 1-year period. Incidental extraspinal findings were identified and used to characterize patients by the need for follow-up using the CT Colonography Reporting and Data System (C-RADS), a classification scheme originally developed to characterize incidental findings on CT colonography. Patients with C-RADS E4 findings have potentially important findings that should be communicated to the referring physician; patients with C-RADS E3 findings have findings that are likely unimportant, but workup may be indicated. All previously unknown C-RADS E3 and E4 findings discovered in the course of this research were reported to referring physicians for appropriate patient follow-up. RESULTS Ten of 400 (2.5%) patients were classified as C-RADS E4; the most common C-RADS E4 finding was vascular aneurysm or stenosis (4/400, 1.0%). Thirteen of 400 (3.3%) patients were classified as C-RADS E3; the most common C-RADS E3 finding was hepatomegaly (4/400, 1.0%). Of 22 patients with C-RADS E3 and E4 findings unknown to clinicians, the finding for only one (4.5%) was communicated to clinicians at the time of the procedure. CONCLUSION Clinically important incidental extraspinal findings were identified in 5.8% of patients on the planning imaging performed for CT-guided lumbar TFESIs. Communication of clinically important findings was poor (4.5%).

A method for registration of full-limb radiographs to knee MRI.

Knee osteoarthritis (OA) is a major source of morbidity in the aging population with a prevalence of over 16 % in people older than 45 [1]. Previous studies have correlated lower extremity alignment with disease progression [2]. This is defined by the mechanical axis, which is the vector running from the center of the hip joint to the center of the talar dome and can be measured on weight-bearing full limb radiographs [2]. Varus alignment, when the mechanical axis passes medial to the central point between the tibial spines, has been linked to progression of structural damage in the medial compartment of the knee, while valgus alignment, when the mechanical axis passes lateral to the central point between the tibial spines, has been linked to progression of lateral compartment disease [3, 4]. Thus, evaluation of a patient’s lower extremity alignment is important in the assessment of knee OA and treatment planning. Another principal imaging modality in knee OA, magnetic resonance (MR) imaging, has become increasingly utilized for the assessment of joint damage [5, 6]. To improve our understanding of the pathogenesis of knee OA, it would be useful to directly compare the location of damage in relation to the mechanical axis in the knee joint. However, it is not possible to localize the mechanical axis on a clinical knee MRI as the hip and ankle joints are not included in the imaging field of view (FOV). In addition, most MR imaging is not performed with the patient bearing weight, and full-limb magnetic resonance imaging is not often performed. Approximations of these alignment angles can be measured using limited FOV radiographs as well as the portion of the knee visualized on knee MRI. However, studies using radiographs limited to the knees showed that these measurements have limited correlation with the true mechanical axis [7]. To determine the location of the mechanical axis relative to damage identified on knee MRI, we present a method of registering full-limb radiographs to coronal knee MR images. We also present as an example, implementation of this method for quantification of the spatial relationship between the mechanical axis and areas of bone marrow edema-like signal on knee MR images.