Practical Considerations When Choosing Chemoembolization versus Radioembolization for Hepatocellular Carcinoma.

Transarterial chemoembolization (TACE) and transarterial radioembolization (TARE) are common liver-directed therapies (LDTs) for unresectable HCC. While both deliver intra-arterial treatment directly to the site of the tumor, they differ in mechanisms of action and side effects. Several studies have compared their side effect profile, time to progression, and overall survival data, but often these lack practical considerations when choosing which treatment modality to use. Many factors can impact operator's choice for treatment, and the choice depends on treatment availability, cost, insurance coverage, operator's comfort level, patient-specific factors, tumor location, tumor biology, and disease stage. This review discusses survival data, time to progression data, as well as more practical patient and tumor characteristics for personalized LDT with TACE or TARE.

Relationship of Seminal Megavesicles, Prostate Median Cysts, and Genotype in Autosomal Dominant Polycystic Kidney Disease.

BACKGROUND: Autosomal dominant polycystic kidney disease (ADPKD) can involve prostate and seminal vesicles but the potential interrelationship of these findings and associations with PKD gene mutation locus and type is unknown. PURPOSE: To determine the interrelationship of seminal megavesicles (seminal vesicles with lumen diameter > 10mm) and prostatic cysts in ADPKD and to determine whether there are associations with PKD gene mutations. STUDY TYPE: Retrospective, case control. POPULATION: Male ADPKD subjects (n = 92) with mutations in PKD1 (n = 71; 77%) or PKD2 (n = 21; 23%), and age/gender-matched controls without ADPKD (n = 92). FIELD STRENGTH/SEQUENCE: 1.5T, axial/coronal T2 -weighted MR images. ASSESSMENT: Reviewers blinded to genotype independently measured seminal vesicle lumen diameter and prevalence of cysts in prostate, kidney, and liver. STATISTICAL TESTS: Nonparametric tests for group comparisons and univariate and multivariable logistic regression analyses to identify associations of megavesicles and prostate median cysts with mutations and renal/hepatic cyst burden. RESULTS: Seminal megavesicles were found in 23 of 92 ADPKD (25%) subjects with PKD1 (22/71, 31%) or PKD2 (n = 1/21, 5%) mutations, but in only two control subjects (P < 0.0001). Prostate median cysts were found in 17/92 (18%) ADPKD subjects, compared with only 6/92 (7%) controls (P = 0.01), and were correlated with seminal vesicle diameters (ρ = 0.24, P = 0.02). Nonmedian prostate cyst prevalence was identical between ADPKD and controls (7/92, 8%). After adjusting for age, estimated glomerular filtration rate, and height-adjusted total kidney volume, ADPKD subjects with megavesicles were 10 times more likely to have a PKD1 than a PKD2 mutation. Among PKD1 subjects, seminal megavesicles occurred more frequently with nontruncating mutations with less severe kidney involvement. DATA CONCLUSION: ADPKD is associated with prostate median cysts near ejaculatory ducts. These cysts correlate with seminal megavesicles (dilated to >10 mm) which predict a 10-fold greater likelihood of PKD1 vs. PKD2 mutation. Cysts elsewhere in the prostate are not related to ADPKD. LEVEL OF EVIDENCE: 2 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2019;49:894-903.

Applications of PET/CT and PET/MR Imaging in Primary Bone Malignancies.

Primary bone malignancies are characterized with anatomic imaging. However, in recent years, there has been an increased interest in PET/computed tomography scanning and PET/MRI with fludeoxyglucose F 18 for evaluating and staging musculoskeletal neoplasms. These hybrid imaging modalities have shown promise largely owing to their high sensitivity, ability to perform more thorough staging, and ability to monitor treatment response. This article reviews the current role of PET/computed tomography scanning and PET/MRI in primary malignancies of bone, with an emphasis on imaging characteristics, clinical usefulness, and current limitations.

Bladder diverticuli following injection of onabotulinum toxin A in a patient with multiple sclerosis and autosomal dominant polycystic kidney disease.

Urinary incontinence due to neurogenic detrusor overactivity is common in patients with disorders of lower motor neurons controlling the bladder. Multiple sclerosis is a major cause of neurogenic detrusor overactivity, which negatively impacts quality of life. Bladder wall injection of onabotulinum toxin A can diminish spontaneous bladder contraction, urinary urgency, and urge incontinence. Herein we report a 61-year-old woman with multiple sclerosis and autosomal dominant polycystic kidney disease with bladder trabeculation developing after repeated injections of onabotulinum toxin A.

MRI of Foot Drop: How We Do It.

Various pathologic conditions extending from the lumbar and pelvic regions to the lower leg may manifest as foot drop, or weakness of ankle dorsiflexion. Potential causes of foot drop include L5 radiculopathy, lumbosacral plexopathy, sciatic neuropathy, and peroneal neuropathy. Although the first-line test in lesion localization is most commonly electrodiagnostic testing, MR neurography has emerged as a useful tool to verify lesion site, to accurately characterize the cause of the neuropathy, and to guide patient treatment. MR neurography, when tailored and focused, can help overcome potential pitfalls in clinical and electrodiagnostic evaluation and is commonly performed in the authors' practice. MR neurography studies are protocoled in advance after careful review of clinical notes and electrodiagnostic findings and often after discussion with the referring clinician. Radiologists who interpret MR neurography studies should have a sound understanding not only of peripheral nerve anatomy and common pathologic conditions, but also of the clinical and electrodiagnostic evaluation performed in patients with foot drop. In this way, the radiologist can actively guide the referring clinician in ordering the most appropriate imaging examination, efficiently reaching the correct diagnosis, and deciding appropriate treatment.

Dentate Nucleus Signal Intensity Decrease on T1-weighted MR Images after Switching from Gadopentetate Dimeglumine to Gadobutrol.

Purpose To determine if the increased dentate nucleus signal intensity following six or more doses of a linear gadolinium-based contrast agent (GBCA) (gadopentetate dimeglumine) changes at follow-up examinations performed with a macrocyclic GBCA (gadobutrol). Materials and Methods This retrospective study included 13 patients with increased dentate nucleus signal intensity following at least six (range, 6-18) gadopentetate dimeglumine administrations who then underwent at least 12 months of follow-up imaging with multiple (range, 3-29) gadobutrol-enhanced magnetic resonance (MR) examinations. Dentate nucleus-to-pons and dentate nucleus-to-cerebellar peduncle signal intensity ratios were measured by two radiologists blinded to all patient information, and changes were analyzed by using the paired t test and linear regression. Results The mean dentate nucleus-to-pons and dentate nucleus-to-cerebellar peduncle signal intensity ratios increased after gadopentetate dimeglumine administration, from 0.98 ± 0.03 to 1.10 ± 0.03 (P < .0001) and from 0.98 ± 0.030 to 1.09 ± 0.02 (P < .0001), respectively. With gadobutrol, the mean dentate nucleus-to-pons and dentate nucleus-to-cerebellar peduncle signal intensity ratios decreased to 1.03 ± 0.03 and 1.02 ± 0.04, respectively (P < .0001). With use of a mixed effects model linear regression allowing for each patient to have a different y intercept, mean dentate nucleus-to-pons and dentate nucleus-to-cerebellar peduncle signal intensity ratios decreased with follow-up time (dentate nucleus-to-pons: slope = -0.2% per month [95% confidence interval: -0.0024, -0.0015], R2 = 0.58, P < .0001 for nonzero slope; dentate nucleus-to-cerebellar peduncle: slope = -0.2% per month [95% confidence interval: -0.0024, -0.0015], R2 = 0.61, P < .0001 for nonzero slope). Conclusion Dentate signal intensity increased with at least six gadopentetate dimeglumine-enhanced MR examinations and decreased after switching from a linear (gadopentetate dimeglumine) to a macrocyclic (gadobutrol) GBCA. © RSNA, 2018 Online supplemental material is available for this article.

Immediate Allergic Reactions to Gadolinium-based Contrast Agents: A Systematic Review and Meta-Analysis.

Purpose To perform a systematic review and meta-analysis to determine if there are differences in rates of immediate allergic events between classes of gadolinium-based contrast agents (GBCAs). Materials and Methods PubMed and Google Scholar databases were searched for studies in which rates of immediate adverse events to GBCAs were reported. The American College of Radiology classification system was used to characterize allergic-like events as mild, moderate, or severe, and the total number of administrations of each GBCA was recorded. Where necessary, authors of studies were contacted to clarify data and eliminate physiologic reactions. Relative risks of GBCA types were estimated by using the Mantel-Haenszel type method. Results Nine studies in which immediate reactions to GBCA were recorded from a total of 716 978 administrations of GBCA met the criteria for inclusion and exclusion. The overall rate of patients who had immediate allergic-like reactions was 9.2 per 10 000 administrations and the overall rate of severe immediate allergic-like reactions was 0.52 per 10 000 administrations.. The nonionic linear chelate gadodiamide had the lowest rate of reactions, at 1.5 (95% confidence interval [CI]: 0.74, 2.4) per 10 000 administrations, which was significantly less than that of linear ionic GBCAs at 8.3 (95% CI: 7.5, 9.2) per 10 000 administrations (relative risk, 0.19 [95% CI: 0.099, 0.36]; P < .00001) and less than that for nonionic macrocyclic GBCAs at 16 (95% CI: 14, 19) per 10 000 administrations (relative risk, 0.12 [95% CI: 0.05, 0.31]; P < .001). GBCAs known to be associated with protein binding had a higher rate of reactions, at 17 (95% CI: 15, 20) per 10 000 administrations compared with the same chelate classification without protein binding, at 5.2 (95% CI: 4.5, 6.0) per 10 000 administrations (relative risk, 3.1 [95% CI: 2.4, 3.8]; P < .0001). Conclusion These data show the lowest rate of immediate allergic adverse events with use of the nonionic linear GBCA gadodiamide in comparison with those of ionic linear or nonionic macrocyclic GBCAs. A higher rate of immediate allergic adverse events was associated with ionicity, protein binding, and macrocyclic structure. © RSNA, 2017 An earlier incorrect version of this article appeared online. This article was corrected on August 31, 2017.

Comparison of MRI segmentation techniques for measuring liver cyst volumes in autosomal dominant polycystic kidney disease.

PURPOSE: To compare MRI segmentation methods for measuring liver cyst volumes in autosomal dominant polycystic kidney disease (ADPKD). METHODS: Liver cyst volumes in 42 ADPKD patients were measured using region growing, thresholding and cyst diameter techniques. Manual segmentation was the reference standard. RESULTS: Root mean square deviation was 113, 155, and 500 for cyst diameter, thresholding and region growing respectively. Thresholding error for cyst volumes below 500ml was 550% vs 17% for cyst volumes above 500ml (p<0.001). CONCLUSION: For measuring volume of a small number of cysts, cyst diameter and manual segmentation methods are recommended. For severe disease with numerous, large hepatic cysts, thresholding is an acceptable alternative.

Complex liver cysts in Autosomal Dominant Polycystic Kidney Disease.

PURPOSE: To determine prevalence of complex liver cysts in Autosomal Dominant Polycystic Kidney Disease (ADPKD). METHODS: Abdominal MRI in 186 ADPKD subjects were evaluated by two independent observers to determine prevalence of complex liver cysts. RESULTS: 23 (12%) of subjects, had at least 1 complex cyst. Only 8 (4%) were reported to have a complex cyst prospectively, representing an under-reporting rate of 65%. Median total cyst volume was 66-times greater for subjects with complex cysts compared to subjects without (p<0.0001). CONCLUSION: Complex hepatic cysts were observed in 12% of ADPKD cases, occurring more frequently in livers with extensive cystic involvement.

Obesity and urologic complications after renal transplantation.

Although obesity has been associated with improved survival on dialysis, its short-and long-term effects on renal transplantation outcomes remain unclear. Herein, we evaluate the short-term and intermediate long-term effects of obesity on first-time renal transplant patients. A retrospective analysis was performed on 180 consecutive renal transplant recipients from living unrelated donors during 2006-2008 in a major transplantation center in Tehran, Iran. Among these, 34 (18%) patients were found to be obese (body mass index ≥30 kg/m 2 ). Obese patients were more likely to develop post-transplant renal artery stenosis (RAS) (17.6% vs. 2.8%, P <0.001), hematoma (47.9% vs. 17.6, P = 0.009), surgical wound complications (64.7% vs. 9.6%, P <0.001) and renal vein thrombosis (2% vs. 0%, P <0.001). However, the incidence of delayed graft function, lymphocele, urologic complications of ureterovesical junction stenosis or urinary leakage, surgical complications of excessive bleeding or renal artery thrombosis and duration of hospitalization were similar between the two groups. The two-year patient and graft survival were also statistically not different. Renal transplantation in obese recipients is associated with a higher incidence of post-transplant RAS, hematoma, surgical wound complications and renal vein thrombosis, but similar two-year patient and graft survival.

High-resolution magnetic resonance neurography in upper extremity neuropathy.

The most common sites of nerve entrapment are in the upper extremity, commonly diagnosed based on clinical findings and electrophysiologic studies. Cross-sectional imaging modalities, such as ultrasonography and magnetic resonance (MR) imaging, have been used to enhance diagnostic accuracy and provide anatomic mapping of abnormalities. MR neurography offers multiplanar high-resolution imaging of upper extremity nerves as well as adjacent soft tissues, and provides an objective assessment of the neuromuscular anatomy and related abnormalities. This article reviews the normal 3-T MR neurographic appearance of the upper extremity nerves, and abnormal findings related to injury, entrapment, and other pathologic conditions.