3.0-T MR-guided transgluteal in-bore-targeted prostate biopsy under local anesthesia in patients without rectal access: a single-institute experience and review of literature.

PURPOSE: To describe the technique and evaluate the performance of MRI-guided transgluteal in-bore-targeted biopsy of the prostate gland under local anesthesia in patients without rectal access. METHODS: Ten men (mean age, 69 (range 57-86) years) without rectal access underwent 13 MRI-guided transgluteal in-bore-targeted biopsy of the prostate gland under local anesthesia. All patients underwent mp-MRI at our institute prior to biopsy. Three patients had prior US-guided transperineal biopsy which was unsuccessful in one, negative in one, and yielded GG1 (GS6) PCa in one. Procedure time, complications, histopathology result, and subsequent management were recorded. RESULTS: Median interval between rectal surgery and presentation with elevated PSA was 12.5 years (interquartile range (IQR) 25-75, 8-36.5 years). Mean PSA was 11.9 (range, 4.8 -59.0) ng/ml and PSA density was 0.49 (0.05 -3.2) ng/ml/ml. Distribution of PI-RADS v2.0/2.1 scores of the targeted lesions were PI-RADS 5-3; PI-RADS 4-6; and PI-RADS 3-1. Mean lesion size was 1.5 cm (range, 1.0-3.6 cm). Median interval between MRI and biopsy was 5.5 months (IQR 25-75, 1.5-9 months). Mean procedure time was 47.4 min (range, 29-80 min) and the number of cores varied between 3 and 5. Of the 13 biopsies, 4 yielded clinically significant prostate cancer (csPca), with a Gleason score ≥ 7, 1 yielded insignificant prostate cancer (Gleason score = 6), 7 yielded benign prostatic tissue, and one was technically unsuccessful. 3/13 biopsies were repeat biopsies which detected csPCa in 2 out of the 3 patients. None of the patients had biopsy-related complication. Biopsy result changed management to radiation therapy with ADT in 2 patients with the rest on active surveillance. CONCLUSION: MRI-guided transgluteal in-bore-targeted biopsy of the prostate gland under local anesthesia is feasible in patients without rectal access.

Diagnostic Yield of Incremental Biopsy Cores and Second Lesion Sampling for In-Gantry MRI-Guided Prostate Biopsy.

BACKGROUND. In-gantry MRI-guided biopsy (MRGB) of the prostate has been shown to be more accurate than other targeted prostate biopsy methods. However, the optimal number of cores to obtain during in-gantry MRGB remains undetermined. OBJECTIVE. The purpose of this study was to assess the diagnostic yield of obtaining an incremental number of cores from the primary lesion and of second lesion sampling during in-gantry MRGB of the prostate. METHODS. This retrospective study included 128 men with 163 prostate lesions who underwent in-gantry MRGB between 2016 and 2019. The men had a total of 163 lesions sampled with two or more cores, 121 lesions sampled with three or more cores, and 52 lesions sampled with four or more cores. A total of 40 men underwent sampling of a second lesion. Upgrade on a given core was defined as a greater International Society of Urological Pathology (ISUP) grade group (GG) relative to the previously obtained cores. Clinically significant prostate cancer (csPCa) was defined as ISUP GG 2 or greater. RESULTS. The frequency of any upgrade was 12.9% (21/163) on core 2 versus 10.7% (13/121) on core 3 (p = .29 relative to core 2) and 1.9% (1/52) on core 4 (p = .03 relative to core 3). The frequency of upgrade to csPCa was 7.4% (12/163) on core 2 versus 4.1% (5/121) on core 3 (p = .13 relative to core 2) and 0% (0/52) on core 4 (p = .07 relative to core 3). The frequency of upgrade on core 2 was higher for anterior lesions (p < .001) and lesions with a higher PI-RADS score (p = .007); the frequency of upgrade on core 3 was higher for apical lesions (p = .01) and lesions with a higher PI-RADS score (p = .01). Sampling of a second lesion resulted in an upgrade in a single patient (2.5%; 1/40); both lesions were PI-RADS category 4 and showed csPCa. CONCLUSION. When performing in-gantry MRGB of the prostate, obtaining three cores from the primary lesion is warranted to optimize csPCa diagnosis. Obtaining a fourth core from the primary lesion or sampling a second lesion has very low yield in upgrading cancer diagnoses. CLINICAL IMPACT. To reduce patient discomfort and procedure times, operators may refrain from obtaining more than three cores or second lesion sampling.

Ultrasound First for Removal of Nonpalpable Contraceptive Implants.

The Sound Judgment Series consists of invited articles highlighting the clinical value of using ultrasound first in specific clinical diagnoses where ultrasound has shown comparative or superior value. The series is meant to serve as an educational tool for medical and sonography students and clinical practitioners and may help integrate ultrasound into clinical practice.

MR Fingerprinting and ADC Mapping for Characterization of Lesions in the Transition Zone of the Prostate Gland.

BackgroundPreliminary studies have shown that MR fingerprinting-based relaxometry combined with apparent diffusion coefficient (ADC) mapping can be used to differentiate normal peripheral zone from prostate cancer and prostatitis. The utility of relaxometry and ADC mapping for the transition zone (TZ) is unknown.PurposeTo evaluate the utility of MR fingerprinting combined with ADC mapping for characterizing TZ lesions.Materials and MethodsTZ lesions that were suspicious for cancer in men who underwent MRI with T2-weighted imaging and ADC mapping (b values, 50-1400 sec/mm2), MR fingerprinting with steady-state free precession, and targeted biopsy (60 in-gantry and 15 cognitive targeting) between September 2014 and August 2018 in a single university hospital were retrospectively analyzed. Two radiologists blinded to Prostate Imaging Reporting and Data System (PI-RADS) scores and pathologic diagnosis drew regions of interest on cancer-suspicious lesions and contralateral visually normal TZs (NTZs) on MR fingerprinting and ADC maps. Linear mixed models compared two-reader means of T1, T2, and ADC. Generalized estimating equations logistic regression analysis was used to evaluate both MR fingerprinting and ADC in differentiating NTZ, cancers and noncancers, clinically significant (Gleason score ≥ 7) cancers from clinically insignificant lesions (noncancers and Gleason 6 cancers), and characterizing PI-RADS version 2 category 3 lesions.ResultsIn 67 men (mean age, 66 years ± 8 [standard deviation]) with 75 lesions, targeted biopsy revealed 37 cancers (six PI-RADS category 3 cancers and 31 PI-RADS category 4 or 5 cancers) and 38 noncancers (31 PI-RADS category 3 lesions and seven PI-RADS category 4 or 5 lesions). The T1, T2, and ADC of NTZ (1800 msec ± 150, 65 msec ± 22, and [1.13 ± 0.19] × 10-3 mm2/sec, respectively) were higher than those in cancers (1450 msec ± 110, 36 msec ± 11, and [0.57 ± 0.13] × 10-3 mm2/sec, respectively; P < .001 for all). The T1, T2, and ADC in cancers were lower than those in noncancers (1620 msec ± 120, 47 msec ± 16, and [0.82 ± 0.13] × 10-3 mm2/sec, respectively; P = .001 for T1 and ADC and P = .03 for T2). The area under the receiver operating characteristic curve (AUC) for T1 plus ADC was 0.94 for separation. T1 and ADC in clinically significant cancers (1440 msec ± 140 and [0.58 ± 0.14] × 10-3 mm2/sec, respectively) were lower than those in clinically insignificant lesions (1580 msec ± 120 and [0.75 ± 0.17] × 10-3 mm2/sec, respectively; P = .001 for all). The AUC for T1 plus ADC was 0.81 for separation. Within PI-RADS category 3 lesions, T1 and ADC of cancers (1430 msec ± 220 and [0.60 ± 0.17] × 10-3 mm2/sec, respectively) were lower than those of noncancers (1630 msec ± 120 and [0.81 ± 0.13] × 10-3 mm2/sec, respectively; P = .006 for T1 and P = .004 for ADC). The AUC for T1 was 0.79 for differentiating category 3 lesions.ConclusionMR fingerprinting-based relaxometry combined with apparent diffusion coefficient mapping may improve transition zone lesion characterization.© RSNA, 2019Online supplemental material is available for this article.

Contrast-Enhanced Ultrasound Guidance for Interventional Procedures.

Since its introduction, contrast-enhanced ultrasound (CEUS) has gained an important role in the diagnosis and management of abdominal and pelvic diseases. Contrast-enhanced ultrasound can improve lesion detection rates as well as success rates of interventional procedures when compared to conventional ultrasound alone. Additionally, CEUS enables the interventionalist to assess the dynamic enhancement of different tissues and lesions, without the adverse effects of contrast-enhanced computed tomography, such as exposure to ionizing radiation and nephrotoxicity from iodinated contrast material. This review article describes the various applications and advantages of the use of CEUS to enhance performance of ultrasound-guided interventions in the abdomen and pelvis.

Evolving clinical applications of contrast-enhanced ultrasound (CEUS) in the abdominal aorta.

Ultrasound (US) represents the initial modality in the workup of abdominal aortic pathology based on the plethora of advantages including widespread availability, low cost, safety profile and repeatability. However, US has inherent limitations including limited spatial information of pathologic processes to neighboring structures, lower sensitivity to slow blood flow and aortic luminal irregularities. For evaluation of aortic pathology angiography has long been considered the gold standard. Non-invasive cross-sectional imaging techniques like computed tomography angiography (CTA) and magnetic resonance angiography (MRA) have gradually replaced interventional angiography for the evaluation of aorta, currently being regarded as the diagnostic imaging modalities of choice for diagnosis of virtually every aortic disease. Interventional angiography is currently primarily performed for treatment purposes of aortic pathology. The introduction of microbubbles as ultrasonographic contrast agents has rendered contrast-enhanced ultrasound (CEUS) an evolving valuable complementary technique with markedly increased diagnostic accuracy for certain aortic applications. CEUS is characterized by the potential to be performed in patients with impaired renal function. Due to its superior spatial and temporal resolution, ability for prolonged scanning and dynamic and real-time imaging, it provides clinically significant additional information compared to the standard Duplex US. The purpose of this paper is to discuss the currently available literature regarding abdominal aortic applications of CEUS, briefly elaborate on CEUS technique and safety and present cases in order to illustrate the added value in aortic pathologies. Conditions discussed include abdominal aortic aneurysm (AAA), aneurysm rupture, aneurysm surveillance after endovascular repair, dissection and aortitis.

Comparison of Local Injection of Fresh Frozen Plasma to Traditional Methods of Hemostasis in Minimally Invasive Procedures.

RATIONALE AND OBJECTIVES: To evaluate different techniques for reducing hemorrhagic complications in coagulopathic patients with elevated international normalized ratio having an image-guided percutaneous invasive procedure; techniques included systemic transfusion of fresh frozen plasma (FFP), local injection of FFP, percutaneous injection of gelatin sponge, and percutaneous placements of angiographic coils. MATERIALS AND METHODS: Retrospective review of 232 consecutive patients with known coagulopathy undergoing image-guided minimally invasive procedures were selected. Ninety-one patients had local FFP injected, 40 patients underwent local synthetic gelatin injection, 16 patients had percutaneous coil embolization, and 85 patients received systemic FFP. The number of bleeds, complications related to bleeds, and systemic complications were recorded. A 30 cc threshold was used to delineate significant bleeding. RESULTS: No patients experienced clinically significant or insignificant bleeding with local FFP injection (P value <.05). Other local hemostatic methods (Gelfoam, systemic FFP, and coil embolization) were associated with higher levels of bleeding (12.5%, 17.1%, 37.5%, respectively) and complications (7.5%, 31.4%, 37.5%, respectively). Systemic FFP infusion was associated with respiratory, infectious, and mortal complications. CONCLUSIONS: Local injection of blood products provides a safe and efficacious hemostatic agent to reduce the incidence of postprocedural bleeding. The technique is associated with lower rates of bleeding and systemic complications when compared to other local and systemic techniques. Further randomized prospective studies with a larger patient cohort need to be performed to corroborate these initial findings.

Real-time MRI-guided percutaneous sclerotherapy treatment of venous low-flow malformations in the head and neck.

Purpose This manuscript describes the technique of real-time MRI-guided sclerotherapy for low-flow venous malformations in the head and neck based on our institutional experience. Materials and methods Ethanolamine oleate is used as the sclerosant and is mixed with gadolinium for visualization during the procedure. The five procedural steps include: (I) an initial tri-plane T2-weighted sequence to visualize the lesion; (II) a T1 FSE or trueFISP sequence to assess needle placement and advancement within the lesion; (III) a tri-plane T1 FLASH sequence to monitor sclerosant injection; (IV) a T1 FSE or VIBE sequence to assess sclerosant coverage of the malformation before needle removal; (V) a post-procedural tri-plane T1 fat-saturated sequence to confirm sclerosant coverage of the lesion. Periprocedural medications typically include steroids, antibiotic prophylaxis, and non-steroidal anti-inflammatory medication. Patients are typically admitted for overnight observation. Conclusion Real-time MRI-guided sclerotherapy for low-flow venous malformations in the head and neck is effective and safe.

Cytological evaluation by fine needle aspiration biopsy of incidental focal increased fluorodeoxyglucose uptake in thyroid on positron emission tomography scan.

BACKGROUND: With the increased use of whole body fluorodeoxyglucose positron emission tomography (PET) scan for staging/restaging or primary diagnosis of neoplasia, thyroid incidentalomas have become more common. The limited reports of PET-positive thyroid incidentalomas showed incidence of malignancy ranging from 14 to 66%, and there is discrepancy in terms of the diagnostic significance of the standard uptake value (SUV) value. METHODS: This is a retrospective study of 20 PET incidentalomas which had cytological evaluation from October 2009 to February 2015 at a tertiary care university medical center, M:F = 8:12. RESULTS: Of the 20 cases, 14 (70%) had a cytological diagnosis of atypia or suspicious for neoplasia. Eleven of those (55%) underwent surgical resection with final diagnosis of PTC in 8 cases, follicular carcinoma in one case (5%), follicular adenoma in one case (5%), and Hurthle cell adenoma in one case (5%). There was good correlation between cytological and histological diagnosis. For two cases with cytological diagnosis of suspicious for follicular neoplasm, no further histological diagnosis was obtained. One patient had direct cytological diagnosis of PTC also did not undergo surgical resection/diagnosis due to the advanced primary pancreatic adenocarcinoma. The remaining 6 (30%) cases had a cytological diagnosis of benign follicular nodule. Furthermore, no significant difference between malignant SUV and benign SUV was observed. CONCLUSIONS: Malignancy was identified in 50% of the PET-positive incidentalomas in our series. PTC constitutes the major malignant diagnosis. No diagnostic value of SUV was observed to differentiate malignant from benign lesions. Diagn. Cytopathol. 2017;45:501-506. © 2017 Wiley Periodicals, Inc.

The Radiologist Is in, but Was it Worth the Wait? Radiology Resident Note Quality in an Outpatient Interventional Radiology Clinic.

Preprocedural evaluation of patients in an interventional radiology (IR) clinic is a complex synthesis of physical examination and imaging findings, and as IR transitions to an independent clinical specialty, such evaluations will become an increasingly critical component of a successful IR practice and quality patient care. Prior research suggests that preprocedural evaluations increased patient's perceived quality of care and may improve procedural technical success rates. Appropriate documentation of a preprocedural evaluation in the medical record is also paramount for an interventional radiologist to add value and function as an effective member of a larger IR service and multidisciplinary health care team. The purpose of this study is to examine the quality of radiology resident notes for patients seen in an outpatient IR clinic at a single academic medical center before and after the adoption of clinic note template with reminders to include platelet count, international normalized ratio, glomerular filtration rate, and plan for periprocedural coagulation status. Before adoption of the template, platelet count, international normalized ratio, glomerular filtration rate and an appropriate plan for periprocedural coagulation status were documented in 72%, 82%, 42%, and 33% of patients, respectively. After adoption of the template, appropriate documentation of platelet count, international normalized ratio, and glomerular filtration rate increased to 96%, and appropriate plan for periprocedural coagulation status was documented in 83% of patients. Patient evaluation and clinical documentation skills may not be adequately practiced during radiology residency, and tools such as templates may help increase documentation quality by radiology residents.

Real-time MRI-guided percutaneous sclerotherapy of low-flow head and neck lymphatic malformations in the pediatric population - a stepwise approach.

Real-time MRI-guided percutaneous sclerotherapy is a novel and evolving treatment for congenital lymphatic malformations in the head and neck. We elaborate on the specific steps necessary to perform an MRI-guided percutaneous sclerotherapy of lymphatic malformations including pre-procedure patient work-up and preparation, stepwise intraprocedural interventional techniques and post-procedure management. Based on our institutional experience, MRI-guided sclerotherapy with a doxycycline-gadolinium-based mixture as a sclerosant for lymphatic malformations of the head and neck region in children is well tolerated and effective.

Contrast enhanced ultrasound guided biopsies of liver lesions not visualized on standard B-mode ultrasound-preliminary experience.

BACKGROUND: To assess the technical success of contrast enhanced ultrasound (CEUS) guided biopsies of liver lesions poorly visualized on B-mode ultrasound. METHODS: Patients were selected during the procedure based on the real-time clinical scenario of unsatisfactory B-mode ultrasound lesion visualization and all patients would have otherwise undergone CT guided liver lesion biopsy. A total of 26 patients underwent CEUS guided biopsy and were included in this retrospective analysis. The review of the patients' files included demographic information, lesion characteristics on imaging, procedural details and pathology outcome. Technical success was defined as concordance between the radiological findings, pathology report and clinical follow-up-demonstrating lack of need for re-biopsy or re-biopsy with identical pathological results. Patients with less than 2 months follow-up were excluded from the study. RESULTS: CEUS guided liver biopsy was successful in 23 out of 26 patients (88.5%). The average procedure time was 30.7±12.3 minutes and the average lesion size was 2.2±1.7 cm. The majority of lesions (80.8%) were hypoenhancing on the delayed phase of CEUS. The mean number of samples taken from each lesion per procedure was 3.2 (±1.7). CONCLUSIONS: CEUS guidance biopsies of focal liver lesions (FLL) that were difficult to visualize on B-mode ultrasound demonstrated high success rate and may be an evolving image guidance modality in selected patients to avoid CT guided procedures.

Utility of Doppler ultrasonography for predicting improvement of platelet count after transjugular intrahepatic portosystemic shunt.

OBJECTIVE: Portal pressure gradient (PPG) after transjugular intrahepatic portosystemic shunt (TIPS) <12 mmHg has been reported as the only factor predictive of increase in platelet count. As flow velocities measured on Doppler ultrasound are related to pressure gradient based on the Bernoulli equation, we used this parameter to predict increased platelet count after TIPS placement. METHODS: A total of 161 consecutive patients who underwent TIPS placement entered this retrospective study. The platelet count was measured before, one week after and one month after TIPS placement. Clinically significant thrombocytopenia was defined as platelet count ≤100 000. Pre- and post-TIPS PPGs were measured. The velocity of blood flow in the proximal, mid and distal TIPS stent was measured using Doppler ultrasound, and the difference in the highest and lowest measured velocity was entitled flow velocity gradient (FVG), which was considered normal when ≤100 cm/s. RESULTS: In 121 patients with pre-TIPS thrombocytopenia, the mean platelet count one week and one month after TIPS placement increased 25.7 x 103 and 35.0 x 103 in 90 patients with PPG≤12 mmHg (P=0.028 and P=0.015), while there was no significant change in platelet count in patients with a PPG >12 mmHg (P=0.098 and P=0.075). Platelets increased significantly when FVG≤ 100 cm/s (n=95) vs FVG >100 cm/s (n=26) one week (37.0x103 vs 11.0x103; P = 0.005 vs 0.07) and one month after TIPS placement (17.0x103 vs 5.2x103; P = 0.01 vs 0.21). CONCLUSION: FVG >100 cm/s is not associated with increase in post-TIPS platelet count. On the other hand, findings suggestive of proper TIPS function (FVG ≤100 cm/s and PPG≤ 12 mmHg) predict a significant increase in post-TIPS platelet count.

Percutaneous CT-Guided Cryoablation of the Salivary Glands in a Porcine Model.

PURPOSE: To evaluate the imaging, histologic changes and safety of computed tomography (CT)-guided cryoablation of the parotid glands in a porcine model. MATERIALS AND METHODS: Unilateral CT-guided parotid gland cryoablation was performed in 5 juvenile miniature pigs. The ablated parotid glands underwent 2 cycles of 10-minute freeze and 5-minute thaw using three 17-g cryoprobes. The animals were monitored daily for complications including pain, frostbite, infection, and sialocele or fistula formation. Follow-up CT was performed at 6 weeks postcryoablation. Pathologic evaluation was performed on 2 of the ablated parotid glands. RESULTS: All cryoablations in 5 right parotid glands, with 3 sites in each gland, were technically successful. No symptoms suggestive of facial nerve damage were observed during 6-week follow-up. One pig developed an infected sialocele, which was treated with percutaneous drainage and oral antibiotic therapy. No CT evidence of sialocele or other abnormality was identified at the 6-week follow-up in all pigs. Histologic evaluation was performed on 2 of the parotid gland specimens, 1 with the treated sialocele, and 1 of the remaining pigs without sialocele. Both glands demonstrated postprocedural intraglandular lymph nodes and reactive changes without evidence of sialocele or abscess on histopathology. CONCLUSIONS: Cryoablation of parotid glands was technically feasible in a porcine model. Only 1 pig developed sialocele, which was successfully treated. Further research is warranted to determine the potential use of salivary gland cryoablation to treat patients with drooling.

Is Ultrasound Fusion a Reasonable Replacement for Computed Tomography in Guiding Abdominal Interventions?

OBJECTIVES: To compare the diagnostic yield, complication rate, and procedure length of ultrasound fusion-guided liver biopsy to the diagnostic yield, complication rate, and procedure length of computed tomography (CT)-guided liver biopsy; to measure the average ionizing radiation dose that patients are exposed to during a typical CT-guided liver biopsy procedure; and to present relevant and interesting cases of ultrasound fusion-guided abdominal interventions to describe the efficacious use of the technology. METHODS: A retrospective analysis of 63 patients who had image-guided liver biopsies performed at our institution was completed. Patient records were divided into 2 groups according to the type of image guidance used during the procedure (ultrasound fusion versus CT), and data were compared by the χ(2) test, Student t test, and Mann-Whitney U test. RESULTS: The diagnostic yields and complication rates were not statistically significantly different between the modalities. The average procedure durations were significantly different: ultrasound fusion-guided biopsy, 31.63 minutes; compared to CT-guided biopsy, 61.67 minutes (P = .003). CONCLUSIONS: Diagnostic yields and complication rates were comparable for ultrasound fusion and CT. However, the average procedure duration for an ultrasound fusion-guided liver biopsy was approximately half that of CT-guided liver biopsy, likely increasing both cost-effectiveness and patient satisfaction.

The Radiologist Will See You Now: Patients' Perceptions of an Outpatient Interventional Clinic.

Patient satisfaction is becoming an increasingly important part of America's healthcare system. Patient satisfaction is now a metric assessed for value-based incentive payments by the Center for Medicare and Medicaid Services, and the healthcare market is becoming increasingly consumer-driven as patients are provided with more options regarding where they receive care as well as improved access to medical information. Radiologists, while less involved with direct patient care than other medical specialties, are not immune to the changing medical landscape and need to adapt to a progressively value- and patient-oriented healthcare system. At our institution, first-year radiology residents take an active role in our outpatient interventional radiology clinic by performing clinical histories and physical exams in a dedicated radiology clinic examination rooms. Stressing the various opportunities for patient interaction and the potential benefits of patient- centered radiology in the evolving healthcare system may increase its perceived value among both radiology residents as well as practicing radiologists. ​Directly engaging patients may be unfamiliar territory for the practicing radiologist and an unexpected prospect for current residents, but available data suggests that patients do value direct interaction with radiologists during the course of their care.

National Trends of Local Ablative Therapy Among Young Patients With Small Renal Masses in the United States.

OBJECTIVE: To assess national trends in the usage of local ablative therapy for small renal masses (SRMs) in a cohort of young patients. Ablation of SRMs has been shown to offer cancer control with limited follow-up. Although ablation is considered effective for patients with limited life expectancy, its use among younger patients may be considered controversial. METHODS: We used the National Cancer Data Base to identify patients between the ages of 40 and 65 years who were diagnosed with SRMs from 2004 to 2011. The primary outcome was the use of local ablative therapy. Multivariable logistic regression analysis was used to identify patient and hospital factors associated with ablation therapies in this cohort. RESULTS: During the study period, we identified 49,441 patients with SRMs, of which 2789 (5.6%) were treated with ablative therapies. The proportion of patients undergoing ablation gradually rose from 2.2% in 2004 to 6.2% in 2011 (P < .001). On multivariable analysis, patients were more likely to receive local ablation at academic hospitals (odds ratio [OR]: 1.5; P < .001) compared with community hospitals, or primarily insured by Medicaid (OR: 1.4; P < .001) or Medicare (OR: 1.3; P < .001) compared with private insurance. CONCLUSION: The use of local ablative therapies is gradually rising but has so far been limited to a small fraction of young patients with SRMs. Patients treated at high-volume, academic hospitals or insured with Medicaid or Medicare were treated to a greater degree with ablation. These results have important implications for the adoption of ablation and the need for long-term surveillance.

Free-breathing liver perfusion imaging using 3-dimensional through-time spiral generalized autocalibrating partially parallel acquisition acceleration.

OBJECTIVES: The goal of this study was to develop free-breathing high-spatiotemporal resolution dynamic contrast-enhanced liver magnetic resonance imaging using non-Cartesian parallel imaging acceleration, and quantitative liver perfusion mapping. MATERIALS AND METHODS: This study was approved by the local institutional review board and written informed consent was obtained from all participants. Ten healthy subjects and 5 patients were scanned on a Siemens 3-T Skyra scanner. A stack-of-spirals trajectory was undersampled in-plane with a reduction factor of 6 and reconstructed using 3-dimensional (3D) through-time non-Cartesian generalized autocalibrating partially parallel acquisition. High-resolution 3D images were acquired with a true temporal resolution of 1.6 to 1.9 seconds while the subjects were breathing freely. A dual-input single-compartment model was used to retrieve liver perfusion parameters from dynamic contrast-enhanced magnetic resonance imaging data, which were coregistered using an algorithm designed to reduce the effects of dynamic contrast changes on registration. Image quality evaluation was performed on spiral images and conventional images from 5 healthy subjects. RESULTS: Images with a spatial resolution of 1.9 × 1.9 × 3 mm3 were obtained with whole-liver coverage. With an imaging speed of better than 2 s/vol, free-breathing scans were achieved and dynamic changes in enhancement were captured. The overall image quality of free-breathing spiral images was slightly lower than that of conventional long breath-hold Cartesian images, but it provided clinically acceptable or better image quality. The free-breathing 3D images were registered with almost no residual motion in liver tissue. After the registration, quantitative whole-liver 3D perfusion maps were obtained and the perfusion parameters are all in good agreement with the literature. CONCLUSIONS: This high-spatiotemporal resolution free-breathing 3D liver imaging technique allows voxelwise quantification of liver perfusion.

Device localization and dynamic scan plane selection using a wireless magnetic resonance imaging detector array.

PURPOSE: A prototype wireless guidance device using single sideband amplitude modulation (SSB) is presented for a 1.5T magnetic resonance imaging system. METHODS: The device contained three fiducial markers each mounted to an independent receiver coil equipped with wireless SSB technology. Acquiring orthogonal projections of these markers determined the position and orientation of the device, which was used to define the scan plane for a subsequent image acquisition. Device localization and scan plane update required approximately 30 ms, so it could be interleaved with high temporal resolution imaging. Since the wireless device is used for localization and does not require full imaging capability, the design of the SSB wireless system was simplified by allowing an asynchronous clock between the transmitter and receiver. RESULTS: When coupled to a high readout bandwidth, the error caused by the lack of a shared frequency reference was quantified to be less than one pixel (0.78 mm) in the projection acquisitions. Image guidance with the prototype was demonstrated with a phantom where a needle was successfully guided to a target and contrast was delivered. CONCLUSION: The feasibility of active tracking with a wireless detector array is demonstrated. Wireless arrays could be incorporated into devices to assist in image-guided procedures.

Clinical evaluation of CAIPIRINHA: comparison against a GRAPPA standard.

PURPOSE: To evaluate image quality when using a CAIPIRINHA sampling pattern in comparison to a standard GRAPPA sampling pattern in patients undergoing a routine three-dimensional (3D) breathheld liver exam. CAIPIRINHA uses an optimized phase encoding sampling strategy to alter aliasing artifacts in 3D acquisitions to improve parallel imaging reconstruction. MATERIALS AND METHODS: Twenty patient volunteers were scanned using a 3D VIBE acquisition with an acceleration factor of four using a CAIPIRINHA and standard GRAPPA sampling pattern. CAIPIRINHA and GRAPPA images were evaluated by three radiologists in a two alternative forced choice test, and the Wilcoxon signed rank test was performed. RESULTS: The CAIPIRINHA sampling pattern was preferred in an average of 68% of the comparisons, and the Wilcoxon signed rank test showed a significant improvement in CAIPIRINHA images (P = 0.014). This analysis indicates that in the given sample set, CAIPIRINHA preference over the GRAPPA standard was statistically significant. CONCLUSION: This work shows that for an acceleration factor of four, a CAIPIRINHA accelerated VIBE acquisition provides significantly improved image quality in comparison to the current GRAPPA standard. This allows a further reduction in imaging time for similar spatial resolutions, which can reduce long breathhold requirements in abdominal imaging, and may be particularly helpful in patients who cannot provide requisite breathholds with current protocols.