Assessment of Aggressiveness of Breast Cancer Using Simultaneous 18F-FDG-PET and DCE-MRI: Preliminary Observation.

PURPOSE: This study aims to investigate the feasibility of using simultaneous breast MRI and PET to assess the synergy of MR pharmacokinetic and fluorine-18 fluorodeoxyglucose (F-FDG) uptake data to characterize tumor aggressiveness in terms of metastatic burden and Ki67 status. METHODS: Twelve consecutive patients underwent breast and whole-body PET/MRI. During the MR scan, PET events were simultaneously accumulated. MR contrast kinetic model parametric maps were computed using the extended Tofts model, including the volume transfer constant between blood plasma and the interstitial space (K), the transfer constant from the interstitial space to the blood plasma (kep), and the plasmatic volume fraction (Vp). RESULTS: Patients with systemic metastases had a significantly lower kep compared to those with local disease (0.45 vs. 0.99 min, P = 0.011). Metastatic burden correlated positively with K and standardized uptake value (SUV), and negatively with kep. Ki67 positive tumors had a significantly greater K compared to Ki67 negative tumors (0.29 vs. 0.45 min, P = 0.03). A negative correlation was found between metabolic tumor volume and transfer constant (K or Kep). CONCLUSION: These preliminary results suggest that MR pharmacokinetic parameters and FDG-PET may aid in the assessment of tumor aggressiveness and metastatic potential. Future studies are warranted with a larger cohort to further assess the role of pharmacokinetic modeling in simultaneous PET/MRI imaging.

Polyacrylamide gel breast augmentation: report of two cases and review of the literature.

Polyacrylamide gel (PAAG) injection remains an uncommon method of breast augmentation. Providers must recognize the clinical and radiological manifestations to optimize management. The clinical and radiological findings of PAAG injection may mimic malignancy and silicone breast augmentation. We described two patients with prior PAAG breast augmentation with physical exam and imaging findings concerning for malignancy. We reviewed the literature on PAAG breast augmentation and compare PAAG to silicone breast augmentation. The management of such patients is discussed.

Frequency of recommendations for additional imaging in diagnostic ultrasound examinations: Evaluation of radiologist, technologist, and other examination-related factors.

OBJECTIVE: Our aim in this study was to evaluate the effect of the radiologist, technologist, and other examination-related factors on the frequency of recommendations for additional imaging (RAI) during sonographic (US) interpretation. METHODS: We retrospectively reviewed 719 US reports from a single academic medical center for the presence of RAI. All studies had been interpreted by one of three abdominal radiologists. Examinations were performed at an outpatient radiology facility with no onsite radiologist (n = 299) or at an inpatient emergency department or hospital-based outpatient setting that had an onsite radiologist (n = 420). Possible associations between the frequency of RAI and the presence of an onsite radiologist, location of the examination, body part or region imaged, patient age, technologist performing the exam, and radiologist reading the exam were evaluated. RESULTS: There were significant differences between each pair of radiologists in terms of overall frequency of RAI (p < 0.001) (radiologist 1: 12.0% [22/184]; radiologist 2: 21.6% [78/361]; and radiologist 3: 45.5% [79/174]). In addition, there were statistically significant differences in the frequency of RAI among studies scanned by the 10 different US technologists (13.6%-40.0%, p = 0.03). However, other factors such as patient age, patient sex, US unit, patient location, and radiologist location were not associated with the frequency of RAI (p = 0.15-0.93). CONCLUSIONS: The individual radiologist and technologist influenced the frequency of RAI for US examinations, whereas other examination-related factors did not. The observed substantial variability in RAI between radiologists and technologists warrants further study, with consideration of strategies to optimize RAI within US reports.

Update on imaging of the postsurgical breast.

Oncologic, reconstructive, and cosmetic breast surgery has evolved in the last 20 years. Familiarity with cutting-edge surgical techniques and their imaging characteristics is essential for radiologic interpretation and may help avert false-positive imaging findings. Novel surgical techniques include skin- and nipple-sparing mastectomies, autologous free flaps, autologous fat grafting, and nipple-areola-complex breast reconstruction. These techniques are illustrated and compared with conventional surgical techniques, including modified radical mastectomy and autologous pedicled flaps. The role of magnetic resonance (MR) imaging in surgical planning, evaluation for complications, and postsurgical cancer detection is described. Breast reconstruction and augmentation using silicone gel-filled implants is discussed in light of the Food and Drug Administration's recommendation for MR imaging screening for "silent" implant rupture 3 years after implantation and every 2 years thereafter. Recent developments in skin incision techniques for reduction mammoplasty are presented. The effects of postsurgical changes on the detection of breast cancer are discussed by type of surgery.

Indeterminate liver and renal lesions: comparison of computed tomography and magnetic resonance imaging in providing a definitive diagnosis and impact on recommendations for additional imaging.

PURPOSE: The purpose of this study was to compare computed tomography (CT) and magnetic resonance imaging (MRI) in terms of likelihood of providing a definitive diagnosis (DD) and a recommendation for additional imaging (RAI), when performed to evaluate indeterminate liver and renal lesions detected on ultrasound as well as in terms of impact on imaging costs. METHODS: This retrospective study was Health Insurance Portability an Accountability Act (HIPAA)-compliant and institutional review board-approved, with waiver of informed consent. We identified consecutive indeterminate liver and renal lesions detected on ultrasound that underwent contrast-enhanced CT or MRI for further characterization. Reports from follow-up studies were reviewed for whether the impression provided DD and RAI. Frequency of DD and RAI was compared between CT and MRI using the Fisher exact test. On the basis of the observed frequency of DD, anticipated imaging costs were compared in a hypothetical sample of 100 patients with indeterminate lesions between first obtaining multiphase CT for all lesions and a subsequent MRI for those lesions indeterminate on CT versus directly obtaining a multiphase MRI for all lesions. RESULTS: A total of 143 renal lesions were included, of which 77 and 66 underwent CT and MRI, respectively. Magnetic resonance imaging was significantly more likely than CT to provide DD (95.5% vs 77.9%; P = 0.003) and significantly less likely to provide RAI (1.5% vs 10.4%; P = 0.038). A total of 221 liver lesions were included, of which 76 and 145 underwent CT and MRI, respectively. Magnetic resonance imaging was significantly more likely than CT to provide DD (95.2% vs 71.1%; P < 0.001) and significantly less likely to provide RAI (0% vs 10.5%; P < 0.001). Across the entire study cohort, there were 13 instances of MRI recommended after an indeterminate CT and 1 case of CT recommended after an indeterminate MRI. A DD was provided in 8 of 9 instances in which MRI was performed after an indeterminate CT. However, anticipated imaging costs were higher when directly obtaining MRI for all indeterminate lesions, compared with initially obtaining multiphase CT, for both kidney ($64,739 vs $49,759) and liver ($64,739 vs. $56,975) lesions, respectively. CONCLUSIONS: For indeterminate liver and renal lesions detected on ultrasound, MRI is more likely to provide DD and less likely to provide RAI in comparison with CT, although these differences did not result in lower anticipated imaging costs.