Jacqueline Hill

Molecular Imaging in Oncology: 18 F-Sodium Fluoride PET Imaging of Osseous Metastatic Disease

OBJECTIVE This literature review details the history, pharmacokinetics, and utility of (18)F-sodium fluoride (Na(18)F) PET/CT in detecting osseous metastases compared with the current standard of care, technetium-99m methylene diphosphonate ((99m)Tc-MDP) bone scintigraphy. Additional discussion highlights solutions to impediments for broader implementation of this modality and insight into the complementary roles of (18)F-FDG PET/CT and Na(18)F PET/CT in oncology imaging, including preliminary data for combined Na(18)F and FDG PET/CT. CONCLUSION Na(18)F PET/CT is the most comprehensive imaging modality for the evaluation of osseous metastatic disease. Although further data acquisition is necessary to expand cost-benefit analyses of this imaging agent, emerging data reinforce its diagnostic advantage, suggest methods to mitigate impediments to broader utilization of Na(18)F PET/CT, and introduce a potentially viable technique for single-session combined Na(18)F and FDG PET/CT staging of soft-tissue and osseous disease.

Prostate-Specific Antigen and Prostate-Specific Antigen Velocity as Threshold Indicators in 11C-Acetate PET/CTAC Scanning for Prostate Cancer Recurrence

Purpose The aim of this study was to identify which patient characteristics are associated with the highest likelihood of positive findings on 11C-acetate PET/computed tomography attenuation correction (CTAC) (PET/CTAC) scan when imaging for recurrent prostate cancer. Methods From 2007 to 2011, 250 11C-acetate PET/CTAC scans were performed at a single institution on patients with prostate cancer recurrence after surgery, brachytherapy, or external beam radiation. Of these patients, 120 met our inclusion criteria. Logistic regression analysis was used to examine the relationship between predictability of positive findings and patients’ characteristics, such as prostate-specific antigen (PSA) level at the time of scan, PSA kinetics, Gleason score, staging, and type of treatment before scan. Results In total, 68.3% of the 120 11C-acetate PET/CTAC scans were positive. The percentage of positive scans and PSA at the time of scanning and PSA velocity (PSAV) had positive correlations. The putative sensitivity and specificity were 86.6% and 65.8%, respectively, when a PSA level greater than 1.24 ng/mL was used as the threshold for scanning. The putative sensitivity and specificity were 74% and 75%, respectively, when a PSAV level greater than 1.32 ng/mL/y was used as the threshold. No significant associations were found between scan positivity and age, PSA doubling time, Gleason score, staging, or type of treatment before scanning. Conclusions This retrospective study suggests that threshold models of PSA greater than 1.24 ng/mL or PSAV greater than 1.32 ng/mL per year are independent predictors of positive findings in 11C-acetate PET/CTAC imaging of recurrent prostate cancer.

Outcomes of type II endoleaks after endovascular abdominal aortic aneurysm (AAA) repair: a single-center, retrospective study ☆ ☆☆

PURPOSE This study aims to determine incidence and outcomes of type II endoleaks (T2E) after endovascular abdominal aortic aneurysm repair (EVAR). METHODS A retrospective review of procedural angiograms, computed tomography angiography, and medical records of 202 patients who underwent EVAR with the Gore Excluder stent graft was performed to determine presence and outcomes of T2E. RESULTS Median follow-up time for 163 patients meeting inclusion criteria [136 males (83%)] was 24.7 months (range=0.5-85.2 months). T2E occurred in 66/163 patients (40.5%). Aneurysm sac size was unchanged in 32/66 patients (48.5%), decreased in 22/66 (33.3%), and increased in 12/66 (18.2%). No aneurysm ruptures, conversion to open repair, or aneurysm-related deaths occurred. CONCLUSION T2E are a common occurrence after EVAR, often with benign outcome. However, routine surveillance should be performed, particularly in patients with persistent endoleak or sac growth.

Rounding Radiologists: Clinical Collaboration Between Radiology Residents and Internal Medicine Teams

DESCRIPTION OF THE PROBLEM In the era of PACS, imaging has become more efficient and accessible. However, direct consultation and verbal communication between referring physicians and radiologists has dramatically decreased by as much as 82% [1]. As a result, opportunities to develop professional relationships with referring physicians have declined. Radiologists are in a unique position to assume a central role in the inpatient care setting by consulting with medical colleagues, discussing the meaning of imaging reports, and designing approaches to further guide diagnosis and management. Consulting services are gaining attention as an avenue to increase the value of radiologic services [2,3]. To this end, the ACR Imaging 3.0 initiative promotes establishing radiologists as valuable consultants in patient care [4]. Existing studies demonstrate the benefit of clinical-radiologic meetings by highlighting the clinical value of consultations [5-7]. However, no prior study has evaluated the effects on relationships between referring clinicians and radiologists by incorporating a radiologist into clinical rounds. Incorporation of radiology residents into clinical

Augmenting Amyloid PET Interpretations With Quantitative Information Improves Consistency of Early Amyloid Detection

Purpose Establishing reliable methods for interpreting elevated cerebral amyloid-&bgr; plaque on PET scans is increasingly important for radiologists, as availability of PET imaging in clinical practice increases. We examined a 3-step method to detect plaque in cognitively normal older adults, focusing on the additive value of quantitative information during the PET scan interpretation process. Methods Fifty-five 18F-florbetapir PET scans were evaluated by 3 experienced raters. Scans were first visually interpreted as having “elevated” or “nonelevated” plaque burden (“Visual Read”). Images were then processed using a standardized quantitative analysis software (MIMneuro) to generate whole brain and region of interest SUV ratios. This “Quantitative Read” was considered elevated if at least 2 of 6 regions of interest had an SUV ratio of more than 1.1. The final interpretation combined both visual and quantitative data together (“VisQ Read”). Cohen kappa values were assessed as a measure of interpretation agreement. Results Plaque was elevated in 25.5% to 29.1% of the 165 total Visual Reads. Interrater agreement was strong (kappa = 0.73–0.82) and consistent with reported values. Quantitative Reads were elevated in 45.5% of participants. Final VisQ Reads changed from initial Visual Reads in 16 interpretations (9.7%), with most changing from “nonelevated” Visual Reads to “elevated.” These changed interpretations demonstrated lower plaque quantification than those initially read as “elevated” that remained unchanged. Interrater variability improved for VisQ Reads with the addition of quantitative information (kappa = 0.88–0.96). Conclusions Inclusion of quantitative information increases consistency of PET scan interpretations for early detection of cerebral amyloid-&bgr; plaque accumulation.

Mammography Positioning Standards in the Digital Era: Is the Status Quo Acceptable?

OBJECTIVE The objective of our study was to evaluate positioning of full-field digital mammography (FFDM) and digital breast tomosynthesis (DBT) compared with film-screen (FS) mammography positioning standards. MATERIALS AND METHODS A retrospective study was conducted of consecutive patients who underwent screening FFDM in 2010-2012 and DBT in 2012-2013 at an academic institution. Examinations were performed by five experienced technologists who underwent updated standardized positioning training. Positioning criteria were assessed by consensus reads among three breast radiologists and compared with FS mammography data from a 1993 study by Bassett and colleagues. RESULTS One hundred seventy patients (n = 340 examinations) were analyzed, showing significant differences between FFDM and DBT examinations (p < 0.05) for medial or inferior skin folds (FFDM vs DBT: craniocaudal [CC] view, 16% [n = 56] vs 23% [n = 77]; mediolateral oblique [MLO] view, 35% [n = 118] vs 45% [n = 154]), inclusion of lateral glandular tissue on CC view (FFDM vs DBT, 73% [n = 247] vs 81% [n = 274]), and concave pectoralis muscle shape (FFDM vs DBT, 36% [n = 121] vs 28% [n = 95]). In comparison with Bassett et al. data, all positioning criteria for both FFDM and DBT examinations were significantly different (p < 0.05). The largest differences were found in visualization of the pectoralis muscle on CC views and the inframammary fold on MLO views, inclusion of posterior or lateral glandular tissue, and inclusion of skin folds, with DBT and FFDM more frequently exhibiting all criteria than originally reported Bassett et al. FINDINGS CONCLUSION DBT and FFDM mammograms more frequently include posterior or lateral tissue, the inframammary fold on MLO views, the pectoralis muscle on CC views, and skin folds than FS mammograms. Inclusion of more breast tissue with newer technologies suggests traditional positioning standards, in conjunction with updated standardized positioning training, are still applicable at the expense of including more skin folds.

Disseminated cat-scratch disease in an adult with selective IgA deficiency

A 51-year-old man with history of undiagnosed pulmonary nodules 4 years prior, presented with right-sided chest pain. Acute cardiac workup was negative, and a chest computed tomography examination demonstrated marked improvement in bilateral pulmonary nodules. A concordant abdominal computed tomography examination showed new subcentimeter hypodense lesions throughout the liver and spleen, mild progressive abdominopelvic lymphadenopathy, and new small lytic lesions of T11 and L4 vertebrae. A positron emission tomography examination demonstrated hypermetabolic activity of these abdominopelvic lesions suggesting metastatic disease. Extensive laboratory workup was negative, aside from IgA deficiency. Eventually, biopsy of a hepatic lesion was performed and compatible with Bartonella species. An elevated Bartonella IgG titer was noted, consistent with Bartonella Hensalae infection, or “cat-scratch disease.” Radiographic findings showed marked improvement after clinically appropriate antibiotic therapy.

Patterns of lymph node positivity on 11C-acetate PET imaging in correlation to the RTOG pelvic radiation field for prostate cancer

PURPOSE 11C-acetate positron emission tomography (PET) imaging allows for the detection of occult metastatic disease that may otherwise go undetected with standard imaging for prostate cancer (PCa). The aim of this study was to evaluate lymph node coverage of the standard Radiation Therapy Oncology Group (RTOG) whole pelvic radiation therapy (WPRT) field in patients found to have node-positive PCa determined by 11C-acetate PET imaging. METHODS AND MATERIALS A retrospective analysis was conducted on 125 PCa patients who underwent 11C-acetate PET scans at our institution between 2007 and 2014. Patients were included if they had evidence of nodal disease without distant metastatic cancer. Individual lymph nodes were characterized by location, size, and relationship to the RTOG WPRT field. RESULTS A total of 55 11C-acetate PET scans (from 54 men) met criteria for inclusion in the study. Median age at diagnosis was 61 years. Median prostate-specific antigen values at diagnosis and at the time of the scan were 9.2 and 8.1 ng/mL, respectively. A total of 159 positive lymph nodes were identified, 78% of which were smaller than 1 cm. The most frequently involved lymphatic regions were the external iliacs (38.4%), para-aortics (19.5%), and common iliacs (16.3%). Additionally, 10.1% of positive nodes were identified as nodes of Cloquet. Of the positive nodes, 51.6% were determined to reside outside of the radiation field and, of those, the most common sites were para-aortic (36.9%), proximal common iliac (17.8%), distal external iliac (17.8%), and nodes of Cloquet (17.8%). CONCLUSIONS Based on 11C-acetate PET imaging in patients with PCa, the standard RTOG WPRT field may miss more than one-half of all positive lymph nodes. Clinicians should be aware of the potential for insufficient nodal coverage when using the standard RTOG WPRT field in patients with node-positive PCa. 11C-acetate PET imaging may be useful in defining target volumes for these patients.

Radiologic and Pathologic Features Associated With Upgrade of Atypical Ductal Hyperplasia at Surgical Excision

RATIONALE AND OBJECTIVES To evaluate radiologic and pathologic features associated with upgrade of atypical ductal hyperplasia (ADH) to ductal carcinoma in situ or invasive breast cancer at surgical excision, in order to identify patients who may consider alternatives to excision. MATERIALS AND METHODS This retrospective analysis examined patients who underwent surgical excision of biopsy-proven ADH at our institution. Imaging and pathology from biopsy were reviewed to determine radiologic (lesion size, radiologic abnormality, biopsy type, needle gauge, number of cores, percent of lesion removed) and pathologic features (histologic calcifications, presence of necrosis, micropapillary features, extent of ADH) associated with ADH upgrade. RESULTS One hundred twenty four cases of percutaneous biopsy-proven ADH with subsequent excision were included. The overall upgrade rate was 17.7% (n = 22), with 17 cases to ductal carcinoma in situ and five to invasive cancer. Radiologic features associated with a lower upgrade rate were smaller lesion size (p = 0.032) and larger percent of lesion removed at biopsy (p = 0.047). Larger needle gauge at biopsy (p = 0.070), absence of necrosis (p = 0.051) and focal ADH (<3 foci, p = 0.12) were nearly associated with a lower rate of upgrade and were included for the purpose of multi parameter analyses. CONCLUSION For women with ADH identified on percutaneous biopsy, the risk of upgrade may in part be determined by lesion size, percent of lesion removed at biopsy, presence of necrosis, and extent of ADH. Using a combination of these radiographic and pathologic features to stratify patients with biopsy-proven ADH may help identify women who could be considered for alternative treatment options.

Preventing Intravenous Contrast Extravasation in CT: A Simple Solution

Contrast-enhanced CT (CECT) is one of the most frequently used imaging examinations because of its fast acquisition time and wide accessibility [1]. However, administration of intravenous (IV) contrast for CECT has an innate risk. Contrast extravasation incidence in CECT ranges from 0.25% to 0.90% [2-5]. Extravasation, defined as material leakage through a vessel wall into perivascular tissues, has multiple etiologies, including leak at the venipuncture site due to cannula malposition, loss of vascular wall integrity because of increased pressure, vessel fragility associated with age or disease processes, or sequela from IV administration of cytotoxic agents [6,7]. Tissue injury that occurs from extravasation is due to the iodinated compound’s intrinsic osmotic activity. Biochemically, this causes an osmotic shift, resulting in direct cellular toxicity, even in small volumes (<10 mL) [8]. Extravasation complications, most commonly focal pain and swelling around injection site, usually resolve with conservative management, such as elevation and direct application of warm or cold compresses [6]. Although rare, serious injury can