Whole-body MRI for staging prostate cancer: a narrative review.

OBJECTIVE: To present a narrative review regarding the diagnostic accuracy of whole-body magnetic resonance imaging (WBMRI) in staging patients with high-risk prostate cancer (HRPCa) and compare it to established imaging modalities. METHODS: A narrative review was carried out using PubMed using the following keywords: 'whole body', 'magnetic resonance imaging', 'MRI', 'prostate cancer', 'risk stratification', and 'staging'. Articles that evaluated WBMRI as the imaging modality to stage patients with HRPCa were included, while studies that solely assessed for biochemical recurrence or metastatic disease progression were excluded. RESULTS: In the evaluation of lymphatic metastases, WBMRI has demonstrated a comparable, if not improved, sensitivity and specificity compared to conventional imaging of computed tomography (CT). Furthermore, WBMRI demonstrates improved sensitivity and specificity in detecting bone metastases compared to bone scintigraphy (BS). However, with advent of prostate-specific membrane antigen (PSMA) radioligands for positron emission tomography (PET), the diagnostic performance of WBMRI to detect metastatic disease appears inferior. CONCLUSIONS: The diagnostic capabilities of WBMRI exceed that of conventional imaging of CT and BS in detecting metastatic disease in patients with HRPCa. However, WBMRI does not perform as well as PSMA PET/CT. Further study on cost comparisons between WBMRI and PSMA PET/CT are needed, as well as evaluations of combined PSMA PET/MRI are needed.

A Feasibility Study on Deep Learning Reconstruction to Improve Image Quality With PROPELLER Acquisition in the Setting of T2-Weighted Gynecologic Pelvic Magnetic Resonance Imaging.

OBJECTIVES: Evaluate deep learning (DL) to improve the image quality of the PROPELLER (Periodically Rotated Overlapping Parallel Lines with Enhanced Reconstruction technique) for 3 T magnetic resonance imaging of the female pelvis. METHODS: Three radiologists prospectively and independently compared non-DL and DL PROPELLER sequences from 20 patients with a history of gynecologic malignancy. Sequences with different noise reduction factors (DL 25%, DL 50%, and DL 75%) were blindly reviewed and scored based on artifacts, noise, relative sharpness, and overall image quality. The generalized estimating equation method was used to assess the effect of methods on the Likert scales. Quantitatively, the contrast-to-noise ratio and signal-to-noise ratio (SNR) of the iliac muscle were calculated, and pairwise comparisons were performed based on a linear mixed model. P values were adjusted using the Dunnett method. Interobserver agreement was assessed using the κ statistic. P value was considered statistically significant at less than 0.05. RESULTS: Qualitatively, DL 50 and DL 75 were ranked as the best sequences in 86% of cases. Images generated by the DL method were significantly better than non-DL images ( P < 0.0001). Iliacus muscle SNR on DL 50 and DL 75 was significantly better than non-DL images ( P < 0.0001). There was no difference in contrast-to-noise ratio between the DL and non-DL techniques in the iliac muscle. There was a high percent agreement (97.1%) in terms of DL sequences' superior image quality (97.1%) and sharpness (100%) relative to non-DL images. CONCLUSION: The utilization of DL reconstruction improves the image quality of PROPELLER sequences with improved SNR quantitatively.

Defining Diagnostic Criteria for Prostatic Ductal Adenocarcinoma at Multiparametric MRI.

Background Prostatic ductal adenocarcinoma (DAC) is an aggressive histologic variant of prostate cancer that often warrants multimodal therapy and poses a significant diagnostic challenge clinically and at imaging. Purpose To develop multiparametric MRI criteria to define DAC and to assess their diagnostic performance in differentiating DAC from prostatic acinar adenocarcinoma (PAC). Materials and Methods Men with histologically proven DAC who had multiparametric MRI before radical prostatectomy were retrospectively identified from January 2011 through November 2018. MRI features were predefined using a subset of nine DACs and then compared for men with peripheral-zone DACs 1 cm or greater in size and men with matched biopsy-confirmed International Society of Urological Pathology grade group 4-5 PAC, by four independent radiologists blinded to the pathologic diagnosis. Diagnostic performance was determined by consensus read. Patient and tumor characteristics were compared by using the Fisher test, t-tests, and Mann-Whitney U test. Agreement (Cohen κ) and sensitivity analyses were also performed. Results There were 59 men with DAC (median age, 63 years [interquartile range, 56, 67 years]) and 59 men with PAC (median age, 64 years [interquartile range, 59, 69 years]). Predefined MRI features, including intermediate T2 signal, well-defined margin, lobulation, and hypointense rim, were detected in a higher proportion of DACs than PACs (76% [45 of 59] vs 5% [three of 59]; P < .001). On consensus reading, the presence of three or more features demonstrated 76% sensitivity, 94% specificity, 94% positive predictive value [PPV], and 80% negative predictive value [NPV] for all DACs and 100% sensitivity, 95% specificity, 81% PPV, and 100% NPV for pure DACs. The DACs and PACs showed no difference in contrast enhancement (100% vs 100%; P >.99, median T2 signal intensity (254 vs 230; P = .99), or apparent diffusion coefficient (median, 677 10-6 mm2/sec vs 685 10-6 mm2/sec; P = .73). Conclusion The presence of intermediate T2 signal, well-defined margin, lobulation, and/or hypointense rim, together with restricted diffusion and contrast enhancement at multiparametric MRI of the prostate, suggests prostatic ductal adenocarcinoma rather than prostatic acinar adenocarcinoma. © RSNA, 2022 Online supplemental material is available for this article.

Diagnostic value of 3.0 T versus 1.5 T MRI in staging prostate cancer: systematic review and meta-analysis.

Purpose: To compare the diagnostic performance of 3.0 T and 1.5 T MRI in the staging of prostate cancer. Material and methods: English-language studies on the diagnostic accuracy of 3.0 T and 1.5 T MRI in prostate cancer staging published through May 2020 were searched for in relevant databases. The focus was on studies in which both 3.0 T and 1.5 T MRI were performed in the study population, to reduce interstudy heterogeneity. Pooled sensitivity, specificity, diagnostic odds ratio (DOR), and area under the receiver operating characteristic curve were determined for 3.0 T and for 1.5 T along with 95% confidence intervals (CIs). Results: Out of 8 studies identified, 4 met the inclusion criteria. 3.0 T (n = 160) had a pooled sensitivity of 69.5% (95% CI: 56.4-80.1%) and a pooled specificity of 48.8% (95% CI: 6.0-93.4%), while 1.5 T (n = 139) had a pooled sensitivity of 70.6% (95% CI: 55.0-82.5%; p = 0.91) and a pooled specificity of 41.7% (95% CI: 6.2-88.6%; p = 0.88). The pooled DOR for 3.0 T was 3 (95% CI: 0-26.0%), while the pooled DOR for 1.5 T was 2 (95% CI: 0-18.0%), which was not a significant difference (p = 0.89). Conclusions: 3.0 T has slightly better diagnostic performance than 1.5 T MRI in prostate cancer staging (3 vs. 2), although without statistical significance. Our findings suggest the need for larger, randomized trials directly comparing 3.0 T and 1.5 T MRI in prostate cancer.

Pitfalls in liver MRI: Technical approach to avoiding misdiagnosis and improving image quality.

The following is an illustrative review of common pitfalls in liver MRI that may challenge interpretation. This article reviews common technical and diagnostic challenges encountered when interpreting dynamic multiphasic T1 -weighted imaging, hepatobiliary phase imaging, and diffusion-weighted imaging of the liver. Additionally, each section includes suggestions for avoiding diagnostic and technical errors. Level of Evidence: 5 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2019;49:41-58.

Automated Volumetric Assessment of Hepatocellular Carcinoma Response to Sorafenib: A Pilot Study.

PURPOSE: This pilot study evaluates the feasibility of automated volumetric quantification of hepatocellular carcinoma (HCC) as an imaging biomarker to assess treatment response for sorafenib. METHODS: In this institutional review board-approved, Health Insurance Portability and Accountability Act-compliant retrospective study, a training database of manually labeled background liver, enhancing and nonenhancing tumor tissue was established using pretherapy and first posttherapy multiphasic computed tomography images from a registry of 13 HCC patients. For each patient, Hounsfield density and geometry-based feature images were generated from registered multiphasic computed tomography data sets and used as the input for a random forest-based classifier of enhancing and nonenhancing tumor tissue. Leave-one-out cross-validation of the dice similarity measure was applied to quantify the classifier accuracy. A Cox regression model was used to confirm volume changes as predictors of time to progression (TTP) of target lesions for both manual and automatic methods. RESULTS: When compared with manual labels, an overall classification accuracy of dice similarity coefficient of 0.71 for pretherapy and 0.66 posttherapy enhancing tumor labels and 0.45 for pretherapy and 0.59 for posttherapy nonenhancing tumor labels was observed. Automated methods for quantifying volumetric changes in the enhancing lesion agreed with manual methods and were observed as a significant predictor of TTP. CONCLUSIONS: Automated volumetric analysis was determined to be feasible for monitoring HCC response to treatment. The information extracted using automated volumetrics is likely to reproduce labor-intensive manual data and provide a good predictor for TTP. Further work will extend these studies to additional treatment modalities and larger patient populations.

A phase II study of tipifarnib and gemcitabine in metastatic breast cancer.

Background Tipifarnib is an orally active, competitive inhibitor of farnesyltransferase which has shown encouraging signs of activity either alone or when combined with other agents. Clinical studies of tipifarnib in combination with anti-estrogen therapy have yielded disappointing results. In contrast, tipifarnib appears to be synergistic in combination with anthracycline based chemotherapy. Here we report the results of the first prospective phase II trial evaluating the efficacy of the novel combination of tipifarnib and gemcitabine in the treatment of metastatic breast cancer. Patients and Methods 30 postmenopausal women with metastatic breast cancer were treated on a 21-day cycle with tipifarnib 300 mg PO twice daily from days 1 through 14. Gemcitabine was administered intravenously at a dose of 1000 mg/m2 on days 1 and 8. Patients were treated until disease progression or unacceptable toxicity. Results There was one complete response and four partial responses yielding an objective response rate of 16.7%. Median progression-free survival and overall survival was 2.5 months (95% confidence interval: 1.6-5.7 months) and 13.1 months (95% confidence interval: 9.1-20.6 months), respectively. 40% of patients experienced grade 4 neutropenia in this study. Conclusion The combination of tipifarnib and gemcitabine is not well tolerated with high rates of myelosuppression and is not more effective than gemcitabine monotherapy in the treatment of metastatic breast cancer.

Spectrum of Pitfalls, Pseudolesions, and Misdiagnoses in Noncirrhotic Liver.

OBJECTIVE: The purpose of this article is to illustrate the various pitfalls, mimics, and atypical features that can lead to inaccurate diagnosis of focal lesions in a noncirrhotic liver. The content includes relevant pathogenesis and background as well as specific clues that can be used to reach an accurate diagnosis. CONCLUSION: When assessing focal hepatic lesions, it is important to avoid pitfalls and misdiagnoses that can alter the management plan. Helpful strategies for avoiding pitfalls include paying close attention to the clinical history of the patient, carefully evaluating all of the available imaging studies, and being aware of the various radiologic mimics.

Evaluation of the added value of imaging the pelvis in patients with hepatocellular cancer.

BACKGROUND AND AIM: The study aims to evaluate added value of the pelvic portion of the computed tomography (CT) and magnetic resonance imaging (MRI) examination in patients with a primary diagnosis of hepatocellular cancer (HCC). METHODS: The study reviewed the medical records of 478 patients with 881 examinations of the abdomen and pelvis who underwent treatment at our institution between March 2015 and March 2016. These patients were reviewed for presence of pathology in the pelvis, which were classified into two categories as new or old (already known on prior imaging). RESULTS: Of 478 patients, 230 underwent MRI examination of the abdomen and pelvis, and the other 248 underwent CT scans of these regions. There were no findings on the CT or MRI of the pelvis in 80.5% of patients (n = 385), including 81.5% of those who had CT and 79.6% of those who had MRI. Ninety-three patients had findings in the pelvis, the most common of which were bone metastases (31 patients), ascites (27 patients), implants (seven patients), and bladder wall thickening (five patients). In only 7.9% of patients, the findings were related to metastatic disease. In 5.4% of all imaging studies revealed a new finding in the pelvis. CONCLUSION: Imaging of the pelvis (CT or MRI) does not seem to provide additional information in the majority of cases with HCC. The results suggest that the follow-up evaluation of patients with HCC may not include a pelvis exam.

Evaluation of Abdominal Computed Tomography Image Quality Using a New Version of Vendor-Specific Model-Based Iterative Reconstruction.

PURPOSE: To qualitatively and quantitatively compare abdominal computed tomography (CT) images reconstructed with a new version of model-based iterative reconstruction (Veo 3.0; GE Healthcare) to those created with Veo 2.0. MATERIALS AND METHODS: This retrospective study was approved by our institutional review board and was Health Insurance Portability and Accountability Act compliant. The raw data from 29 consecutive patients who had undergone CT abdomen scanning was used to reconstruct 4 sets of 3.75-mm axial images: Veo 2.0, Veo 3.0 standard, Veo 3.0 5% resolution preference (RP), and Veo 3.0 20% RP. A slice thickness optimization of 3.75 mm and texture feature was selected for Veo 3.0 reconstructions.The images were reviewed by 3 independent readers in a blinded, randomized fashion using a 5-point Likert scale and 5-point comparative scale.Multiple 2-dimensional circular regions of interest were defined for noise and contrast-to-noise ratio measurements. Line profiles were drawn across the 7 lp/cm bar pattern of the CatPhan 600 phantom for spatial resolution evaluation. RESULTS: The Veo 3.0 standard image set was scored better than Veo 2.0 in terms of artifacts (mean difference, 0.43; 95% confidence interval [95% CI], 0.25-0.6; P < 0.0001), overall image quality (mean difference, 0.87; 95% CI, 0.62-1.13; P < 0.0001) and qualitative resolution (mean difference, 0.9; 95% CI, 0.69-1.1; P < 0.0001). Although the Veo 3.0 standard and RP05 presets were preferred across most categories, the Veo 3.0 RP20 series ranked best for bone detail. Image noise and spatial resolution increased along a spectrum with Veo 2.0 the lowest and RP20 the highest. CONCLUSION: Veo 3.0 enhances imaging evaluation relative to Veo 2.0; readers preferred Veo 3.0 image appearance despite the associated mild increases in image noise. These results provide suggested parameters to be used clinically and as a basis for future evaluations, such as focal lesion detection, in the oncology setting.

Evaluation of Magnetic Resonance (MR) Biomarkers for Assessment of Response With Response Evaluation Criteria in Solid Tumors: Comparison of the Measurements of Neuroendocrine Tumor Liver Metastases (NETLM) With Various MR Sequences and at Multiple Phases of Contrast Administration.

PURPOSE: Our aim was to compare the interobserver and intraobserver variability for the measurement of the size of liver metastases in patients with carcinoid tumors with various magnetic resonance (MR) series. MATERIALS AND METHODS: In this retrospective institutional review board-approved study, 30 patients with liver metastases from a carcinoid primary had a complete MR examination of the abdomen at 1.5 T with gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid (Gd-EOB-DTPA). The complete MR examination included T1 (in-phase [IP]/out-of-phase [OOP], T2, diffusion-weighted imaging, pre-Gd-EOB-DTPA and post-Gd-EOB-DTPA 3D gradient echo (4 phases plus 20-minute hepatobiliary phase [HBP] Gd]). Four readers reviewed each series independently. The measurement for each lesion was compared to HBP-Gd images. The sensitivity for detection of each lesion was compared to HBP-Gd. Variance component analysis was used to estimate variance due to patient, lesion within patient, and reader by sequence. Linear mixed model was used to compare lesion size between sequences. RESULTS: The HBP-Gd had the smallest interreader variability. There was no significant difference between series with respect to interreader variability. Lesion sizes measured in diffusion-weighted imaging was significantly higher. T2-weighted imaging was the closest to HBP-Gd. Lesion sizes measured with the other sequences were significantly smaller. There was significant difference in sensitivity of lesion detection of some series when compared to HBP-Gd. CONCLUSION: The HBP-Gd series had the smallest interreader variability and is the recommended series to measure lesion size for evaluation of response to treatment.

CAIPIRINHA-VIBE and GRAPPA-VIBE for liver MRI at 1.5 T: a comparative in vivo patient study.

OBJECTIVE: Three-dimensional T1-weighted (T1W) gradient recall echo volumetric interpolated breath-hold examination (VIBE) using generalized autocalibrating partially parallel acquisitions (GRAPPA) is one of the key sequences in liver magnetic resonance imaging (MRI) and is used for precontrast, dynamic postcontrast, and delayed postcontrast imaging. The purpose of this study is to compare image quality and liver lesion detection (LLD) on a shorter-duration T1W VIBE sequence using the controlled aliasing in parallel imaging results in higher acceleration (CAIPIRINHA) technique with the conventional T1W GRAPPA-VIBE sequence during a single liver MRI session on a 1.5-T Seimens scanner. METHODS: Twenty consecutive patients (9 women and 11 men; age range, 36-85 years) were included in this prospective study. All patients underwent a complete liver MRI on a 1.5-T magnet (Aera; Siemens Medical Systems, Erlangen, Germany) that consisted of a T1W (in/out-of-phase), T2W, DWI, and precontrast and postcontrast multiphasic images (late arterial, 50 seconds, 120 seconds, and 300 seconds) with GRAPPA-VIBE. The CAIPI-VIBE images were acquired for precontrast and at 300 seconds (5 minutes) postcontrast phases (6.9 seconds per phase) in addition to GRAPPA-VIBE (21 seconds per phase). The shorter time for the CAIPI-VIBE was selected to allow postprocessing of image acquisition in the setting of multi-late arterial phase (single breath hold) postcontrast images. Five radiologists independently analyzed image quality with predefined scores for liver edge sharpness, artifacts, fat saturation deficiency, visualization of the portal veins and hepatic veins, and LLD (size, <0.5-3.8 cm). Score 0 was suboptimal (inadequate), 1 was acceptable for diagnosis, and 2 was optimal (excellent). Kappa statistics were used to assess agreement among readers. Generalized linear mixed model with generalized estimation equation method was used to estimate and compare the LLD failure rates. RESULTS: No statistically significant difference was seen in the degree of reader variability between CAIPI-VIBE and GRAPPA-VIBE for all evaluated categories using multirater κ statistics. For the precontrast and 5-minutepostcontrast phase sequences, greater than 95% of images were considered to be of acceptable quality in all image quality categories for both sequences. Forty-one lesions were evaluated in 17 patients with total of 204 observations (n = 204) by 5 readers. For 5-minute postcontrast images, the LLD rate of CAIPI-VIBE (80%) was lower than GRAPPA-VIBE (84%) (P = 0.03) for small lesions (0.5-1.7 cm). There was no significant difference in lesion detection on precontrast images. CONCLUSIONS: At 1.5 T, the CAIPI-VIBE may be helpful in reducing scan time and demonstrates similar image quality compared with the traditional GRAPPA-VIBE. The CAIPI-VIBE has shorter breath-hold time requirement and thus can be an acceptable alternative for the precontrast and 5-minute postcontrast GRAPPA-VIBE in patients with breath-hold difficulties.

Imaging features of fibrolamellar hepatocellular carcinoma.

OBJECTIVE: Fibrolamellar hepatocellular carcinoma (HCC) is a rare primary liver tumor, which significantly differs from conventional HCC. This article reviews the molecular cytogenetics, pathology, imaging features, and management of this relatively rare tumor. CONCLUSION: Fibrolamellar HCC predominantly occurs in young patients without underlying hepatitis or cirrhosis. Serum α-fetoproteins are not elevated in most cases, and hence imaging plays an important role in diagnosis, staging, and surveillance.

TNM/Okuda/Barcelona/UNOS/CLIP International Multidisciplinary Classification of Hepatocellular Carcinoma: concepts, perspectives, and radiologic implications.

Hepatocellular carcinoma (HCC) is a major health problem worldwide. Moreover, the liver cancer field is evolving rapidly, with early diagnosis, new therapies, and a better understanding of HCC's biology and development. Accurate staging is important for determining prognosis and selecting the most appropriate treatment for each patient. Surgical intervention remains the most effective treatment for HCC and is the only potentially curative modality. However, in HCC patients, overall survival is also independently affected by underlying liver disease and cirrhosis, which in turn affect the applicability and efficacy of treatment. Although several staging classification and prognostic scoring systems have been proposed for determining the stage and prognosis of HCC, no consensus exists on the best classification method. The most common staging classification systems include tumor-node-metastasis stage, Okuda staging, Cancer of the Liver Italian Program score, Barcelona Clinic Liver Cancer staging classification, the French, the Chinese University Prognostic Index, Japanese Integrated Scoring, and the Tokyo score. Radiologists should be aware of the different staging classification systems for HCC and familiar with the system relevant to their respective referring clinicians, as it will provide pertinent radiological evaluation for multidisciplinary management.

Phase I trial of single-photon emission computed tomography-guided liver-directed radiotherapy for patients with low functional liver volume.

BACKGROUND: Traditional constraints specify that 700 cc of liver should be spared a hepatotoxic dose when delivering liver-directed radiotherapy to reduce the risk of inducing liver failure. We investigated the role of single-photon emission computed tomography (SPECT) to identify and preferentially avoid functional liver during liver-directed radiation treatment planning in patients with preserved liver function but limited functional liver volume after receiving prior hepatotoxic chemotherapy or surgical resection. METHODS: This phase I trial with a 3 + 3 design evaluated the safety of liver-directed radiotherapy using escalating functional liver radiation dose constraints in patients with liver metastases. Dose-limiting toxicities were assessed 6-8 weeks and 6 months after completing radiotherapy. RESULTS: All 12 patients had colorectal liver metastases and received prior hepatotoxic chemotherapy; 8 patients underwent prior liver resection. Median computed tomography anatomical nontumor liver volume was 1584 cc (range = 764-2699 cc). Median SPECT functional liver volume was 1117 cc (range = 570-1928 cc). Median nontarget computed tomography and SPECT liver volumes below the volumetric dose constraint were 997 cc (range = 544-1576 cc) and 684 cc (range = 429-1244 cc), respectively. The prescription dose was 67.5-75 Gy in 15 fractions or 75-100 Gy in 25 fractions. No dose-limiting toxicities were observed during follow-up. One-year in-field control was 57%. One-year overall survival was 73%. CONCLUSION: Liver-directed radiotherapy can be safely delivered to high doses when incorporating functional SPECT into the radiation treatment planning process, which may enable sparing of lower volumes of liver than traditionally accepted in patients with preserved liver function. TRIAL REGISTRATION: NCT02626312.

Multimodality annotated hepatocellular carcinoma data set including pre- and post-TACE with imaging segmentation.

Hepatocellular carcinoma (HCC) is the most common primary liver neoplasm, and its incidence has doubled over the past two decades owing to increasing risk factors. Despite surveillance, most HCC cases are diagnosed at advanced stages and can only be treated using transarterial chemo-embolization (TACE) or systemic therapy. TACE failure may occur with incidence reaching up to 60% of cases, leaving patients with a financial and emotional burden. Radiomics has emerged as a new tool capable of predicting tumor response to TACE from pre-procedural computed tomography (CT) studies. This data report defines the HCC-TACE data collection of confirmed HCC patients who underwent TACE and have pre- and post-procedure CT imaging studies and available treatment outcomes (time-to-progression and overall survival). Clinically curated segmentation of pre-procedural CT studies was done for the purpose of algorithm training for prediction and automatic liver tumor segmentation.

Portal vein embolization: cross-sectional imaging of normal features and complications.

OBJECTIVE: The purpose of this article is to describe the role of cross-sectional imaging before portal vein embolization, the normal imaging findings after the procedure, and the imaging findings of postprocedural complications. CONCLUSION: With the increasing emphasis on aggressive resection of hepatic malignancies, portal vein embolization has evolved into a leading technique. Radiologists need to be familiar with the normal imaging findings after this procedure and with the imaging findings of postprocedural complications.

Quality initiatives: planning, setting up, and carrying out radiology process improvement projects.

In the coming decades, those who provide radiologic imaging services will be increasingly challenged by the economic, demographic, and political forces affecting healthcare to improve their efficiency, enhance the value of their services, and achieve greater customer satisfaction. It is essential that radiologists master and consistently apply basic process improvement skills that have allowed professionals in many other fields to thrive in a competitive environment. The authors provide a step-by-step overview of process improvement from the perspective of a radiologic imaging practice by describing their experience in conducting a process improvement project: to increase the daily volume of body magnetic resonance imaging examinations performed at their institution. The first step in any process improvement project is to identify and prioritize opportunities for improvement in the work process. Next, an effective project team must be formed that includes representatives of all participants in the process. An achievable aim must be formulated, appropriate measures selected, and baseline data collected to determine the effects of subsequent efforts to achieve the aim. Each aspect of the process in question is then analyzed by using appropriate tools (eg, flowcharts, fishbone diagrams, Pareto diagrams) to identify opportunities for beneficial change. Plans for change are then established and implemented with regular measurements and review followed by necessary adjustments in course. These so-called PDSA (planning, doing, studying, and acting) cycles are repeated until the aim is achieved or modified and the project closed.

Errors and Misinterpretations in Imaging of Chronic Liver Diseases.

MRI is an important problem-solving tool for accurate characterization of liver lesions. Chronic liver disease alters the typical imaging characteristics and complicates liver imaging. Awareness of imaging pitfalls and technical artifacts and ways to mitigate them allows for more accurate and timely diagnosis.

What's New in Hepatic Steatosis.

Hepatic steatosis can lead to liver cancer, cirrhosis, and portal hypertension. There are two main types, non-alcoholic fatty liver disease (NAFLD) and alcoholic liver disease. The detection and quantification of hepatic steatosis with lifestyle changes can slow the evolution from NAFLD to steatohepatitis. Currently, the gold standard for the quantification of fat in the liver is biopsy, has some limitations. Hepatic steatosis is frequently detected during cross sectional imaging. Ultrasound (US), Computed Tomography (CT), and Magnetic Resonance Imaging (MRI) provide noninvasive assessment of liver parenchyma and can detect fat infiltration in the liver. However, the non-invasive quantification of hepatic steatosis by imaging has been challenging. Recent MRI techniques show great promise in the detection and quantification of liver fat. The aim of this article is to review the utilization of non-invasive imaging modalities for the detection and quantification of hepatic steatosis, to evaluate their advantages and limitations.