Hero K. Hussain

Comparison of levator ani muscle defects and function in women with and without pelvic organ prolapse.

BACKGROUND: To compare levator ani defects and pelvic floor function among women with prolapse and controls. METHODS: Levator ani structure and function were measured in a case–control study with group matching for age, race, and hysterectomy status among 151 women with prolapse (cases) and 135 controls with normal support (controls) determined by pelvic organ prolapse quantification examination. Magnetic resonance imaging was used to determine whether there were “major” (more than half missing), “minor” (less than half of the muscle missing), or no defects in the levator ani muscles. Vaginal closure force at rest and during maximal pelvic muscle contraction was measured with an instrumented vaginal speculum. RESULTS: Cases were more likely to have major levator ani defects than controls (55% compared with 16%), with an adjusted odds ratio of 7.3 (95% confidence interval 3.9–13.6, P<.001) but equally likely to have minor defects (16% compared with 22%). Of women who reported delivery by forceps, 53% had major defects compared with 28% for the nonforceps women, adjusted odds ratio 3.4 (95% confidence interval 1.95–5.78). Women with prolapse generated less vaginal closure force during pelvic muscle contraction than controls (2.0 Newtons compared with 3.2 Newtons P<.001), whereas those with defects generated less force than women without defects (2.0 Newtons compared with 3.1 Newtons, P<.001). The genital hiatus was 50% longer in cases than controls (4.7±1.4 cm compared with 3.1±1.0 cm, P<.001). CONCLUSION: Women with prolapse more often have defects in the levator ani and generate less vaginal closure force during a maximal contraction than controls. LEVEL OF EVIDENCE: II

MR Imaging of Hepatocellular Carcinoma in the Cirrhotic Liver: Challenges and Controversies

The incidence of hepatocellular carcinoma (HCC) is expected to increase in the next 2 decades, largely due to hepatitis C infection and secondary cirrhosis. HCC is being detected at an earlier stage owing to the implementation of screening programs. Biopsy is no longer required prior to treatment, and diagnosis of HCC is heavily dependent on imaging characteristics. The most recent recommendations by the American Association for the Study of Liver Diseases (AASLD) state that a diagnosis of HCC can be made if a mass larger than 2 cm shows typical features of HCC (hypervascularity in the arterial phase and washout in the venous phase) at contrast material-enhanced computed tomography or magnetic resonance (MR) imaging or if a mass measuring 1-2 cm shows these features at both modalities. There is an ever-increasing demand on radiologists to detect smaller tumors, when curative therapies are most effective. However, the major difficulty in imaging cirrhosis is the characterization of hypervascular nodules smaller than 2 cm, which often have nonspecific imaging characteristics. The authors present a review of the MR imaging and pathologic features of regenerative nodules and dysplastic nodules and focus on HCC in the cirrhotic liver, with particular reference to small tumors and lesions that may mimic HCC. The authors also review the sensitivity of MR imaging for the detection of these tumors and discuss the staging of HCC and the treatment options in the context of the guidelines of the AASLD and the imaging criteria required by the United Network for Organ Sharing for transplantation. MR findings following ablation and chemoembolization are also reviewed.

New OPTN/UNOS Policy for Liver Transplant Allocation: Standardization of Liver Imaging, Diagnosis, Classification, and Reporting of Hepatocellular Carcinoma

A new liver allocation policy featuring improved imaging criteria for hepatocellular carcinoma exceptions has been developed and approved by the Organ Procurement and Transplantation Network–United Network for Organ Sharing, in late 2011; radiologists in accredited transplantation centers in the United States are now challenged to implement the policy.

Primovist, Eovist: What to expect?

Gadolinium ethoxybenzyl dimeglumine (Gd-EOB-DTPA, Primovist in Europe and Eovist in the USA) is a liver-specific magnetic resonance imaging contrast agent that has up to 50% hepatobiliary excretion in the normal liver. After intravenous injection, Gd-EOB-DTPA distributes into the vascular and extravascular spaces during the arterial, portal venous and late dynamic phases, and progressively into the hepatocytes and bile ducts during the hepatobiliary phase. The hepatocyte uptake of Gd-EOB-DTPA mainly occurs via the organic anion transporter polypeptides OATP1B1 and B3 located at the sinusoidal membrane and biliary excretion via the multidrug resistance-associated proteins MRP2 at the canalicular membrane. Because of these characteristics, Gd-EOB-DTPA behaves similarly to non-specific gadolinium chelates during the dynamic phases, and adds substantial information during the hepatobiliary phase, improving the detection and characterization of focal liver lesions and diffuse liver disease. This information is particularly relevant for the detection of metastases, and for the detection and characterization of nodular lesions in liver cirrhosis, including early hepatocellular carcinomas. Finally, GD-EOB-DTPA-enhanced magnetic resonance imaging may provide quantitative assessment regarding liver perfusion and hepatocyte function in diffuse liver diseases. The full potential of GD-EOB-DTPA-enhanced magnetic resonance imaging has to be established further. It is already clear that GD-EOB-DTPA-enhanced magnetic resonance imaging provides anatomic and functional information in the setting of focal and diffuse liver disease that is unattainable with magnetic resonance imaging enhanced with non-specific contrast agents.

Improving the prediction of hepatocellular carcinoma in cirrhotic patients with an arterially-enhancing liver mass

In the United States, cirrhotic patients with known or suspected hepatocellular carcinoma (HCC) are prioritized for liver transplantation. Noninvasive criteria for the diagnosis of HCC rely on arterial enhancement of a mass. The aim of this study was to determine whether clinical, laboratory, and / or radiologic data can improve the prediction of HCC in cirrhotic patients with an arterially‐enhancing mass. Between May 2002 and June 2003, dynamic gadolinium‐enhanced magnetic resonance imaging (MRI) of consecutive patients with liver cirrhosis and a solid mass were reviewed by 2 radiologists blinded to the clinical diagnosis. Clinical, laboratory, and radiologic data were recorded for all patients. A total of 94 patients with cirrhosis and an arterially‐enhancing liver mass were studied, 66 (70%) of whom had HCC. Alpha‐fetoprotein (AFP) >20 ng/mL (P = .029), tumor size >2 cm (P = .0018), and delayed hypointensity (P = .0001) were independent predictors of HCC. Delayed hypointensity of an arterially‐enhancing mass had a sensitivity of 89% and a specificity of 96% for HCC. The presence of delayed hypointensity was the only independent predictor of HCC among patients with arterially‐enhancing lesions <2 cm (odds ratio, 6.3; 95% confidence interval [CI], 1.8‐13), with a sensitivity of 80% and a specificity of 95%. In conclusion, delayed hypointensity of an arterially‐enhancing mass was the strongest independent predictor of HCC, regardless of the size of the lesion. If additional studies confirm our results, the noninvasive criteria utilized to make a diagnosis of HCC should be revised. (Liver Transpl 2005;11:281–289.)

Comparison of Acute Transient Dyspnea after Intravenous Administration of Gadoxetate Disodium and Gadobenate Dimeglumine: Effect on Arterial Phase Image Quality

PURPOSE To determine whether acute transient dyspnea and/or arterial phase image degradation occurs more or less often after intravenous administration of gadoxetate disodium than with intravenous administration of gadobenate dimeglumine. MATERIALS AND METHODS Institutional review board approval and patient consent were obtained for this prospective observational study. One hundred ninety-eight gadolinium-based contrast media administrations (99 with gadoxetate disodium [10 mL, n = 97; 8 mL, n = 1; 16 mL, n = 1] and 99 with gadobenate dimeglumine [0.1 mmol per kilogram of body weight, maximum dose, 20 mL]) for hepatobiliary indications were assessed in 192 patients. Subjective patient complaints were assessed. Objective respiratory motion degradation on T1-weighted precontrast and dynamic postcontrast (arterial, venous, or late dynamic or extracellular) magnetic resonance (MR) imaging datasets were independently assessed in a randomized, blinded fashion by five readers using a five-point scale, with mean scores of 4 or greater indicating severe motion. Comparisons between agents were made by using χ(2) or Fisher exact test, where appropriate. RESULTS Significantly more patient complaints of acute transient dyspnea occurred after gadoxetate disodium administration than gadobenate dimeglumine (14% [14 of 99] vs 5% [five of 99], P = .05). There were significantly more severely degraded arterial phase data sets for gadoxetate disodium than for gadobenate dimeglumine for both the general population (17% [17 of 99] vs 2% [two of 99], P = .0007) and the subpopulation with cirrhosis (19% [14 of 72] vs 3% [one of 37], P = .02). This effect did not extend to venous (1% [one of 99] vs 2% [two of 99], P > .99 [overall population]) or late dynamic or extracellular (2% [two of 99] vs 0% [zero of 99], P = .5 [overall population]) phases. No patient required treatment for self-limited dyspnea. CONCLUSION Intravenous gadoxetate disodium can result in acute self-limiting dyspnea that can have a deleterious effect on arterial phase MR image quality and occurs significantly more often than with intravenous gadobenate dimeglumine.

Nephrogenic Systemic Fibrosis: A Report of 29 Cases

OBJECTIVE The purpose of this study was to determine the incidence of nephrogenic systemic fibrosis and its relation to renal failure and the administration of gadolinium-based contrast material at an academic medical center. MATERIALS AND METHODS A dermatopathology database was searched to identify patients in whom nephrogenic systemic fibrosis was diagnosed. The medical records of these patients were reviewed. Renal function concurrent with any administration of gadolinium-based contrast material was assessed, as was patient outcome. A database of patients undergoing long-term dialysis was reviewed separately to determine how many had received gadolinium and the frequency of nephrogenic systemic fibrosis among these patients. RESULTS Twenty-nine patients were found to have had nephrogenic systemic fibrosis between November 15, 1999, and December 31, 2006. It was known that gadolinium-based contrast material had been administered to 25 of these patients before diagnosis. All 29 patients had compromised renal function (27 had chronic renal failure, and two had acute renal failure). Determination of the temporal relation between gadolinium-based contrast administration and symptom onset often was difficult. Only eight patients had severe morbidity. Nephrogenic systemic fibrosis developed in 12 (2.9%) of 414 patients undergoing long-term dialysis who received gadolinium-based contrast material. CONCLUSION We confirm the strong association between nephrogenic systemic fibrosis and gadolinium-based contrast administration. Although the use of high doses of gadolinium and the occurrence of chronic renal failure have been implicated in other reports, several of our patients received standard doses of gadolinium, and two had transient acute renal failure before diagnosis. Most patients had mild or moderate symptoms. Nephrogenic systemic fibrosis developed in 2.9% of patients undergoing long-term dialysis who received gadolinium-based contrast material but in none of the long-term dialysis patients who did not receive gadolinium-based contrast material.

Magnetization Transfer Helps Detect Intestinal Fibrosis in an Animal Model of Crohn Disease

PURPOSE To determine the utility of magnetization transfer (MT) in the identification and quantification of intestinal fibrosis in a rat model of Crohn disease. MATERIALS AND METHODS The university committee on the use and care of animals approved this study (UCUCA 08592). Lewis rats injected subserosally with peptidoglycan-polysaccharide (PG-PS) develop bowel inflammation 1 day after laparotomy (early phase) and fibrosis starting 14 days after laparotomy (late phase). The authors performed 2.0-T magnetic resonance (MR) imaging in 25 rats injected with PG-PS and 13 injected with human serum albumin (HSA) (control animals). Imaging was performed before laparotomy and on a weekly basis thereafter for up to 28 days. The MT ratio in the bowel wall was calculated. Resected cecal tissue was scored for inflammation and fibrosis. Tissue fibrosis was determined with colorimetric analysis of trichrome-stained specimens. Collagen content was measured with Western blot analysis. Statistical analyses were performed with the Student t test for continuous bivariate comparisons, the Pearson correlation for continuous variables, and the Spearman correlation for ordinal variables. RESULTS All rats developed early inflammation, which subsided over time. Rats injected with PG-PS developed increased fibrosis in the late phase, whereas control rats did not. The mean MT ratio of rats injected with PG-PS with late-phase fibrosis was higher than that in rats with early phase inflammation (P = .017). In addition, the MT ratio of rats injected with PG-PS with late-phase fibrosis was higher than that of control animals that did not develop fibrosis in the late phase (P = .0001). The MT ratio of control animals remained unchanged over time as inflammation subsided. The MT ratio in rats injected with PG-PS showed correlation with tissue fibrosis (ρ = 0.63). The MT ratio showed correlation with tissue collagen (R = 0.74). The positive and negative predictive values of the MT ratio in the prediction of fibrosis were 92% (12 of 13 rats) and 83% (five of six rats), respectively. CONCLUSION These results indicate that MT is sensitive to bowel wall fibrosis as occurs in Crohn strictures.

Lack of Tumor Seeding of Hepatocellular Carcinoma After Percutaneous Needle Biopsy Using Coaxial Cutting Needle Technique

OBJECTIVE The objective of our study was to determine the incidence of tumor seeding after biopsy of hepatocellular carcinoma (HCC) using a coaxial cutting needle technique. Seeding along the needle track is a dreaded complication of percutaneous biopsy in patients with HCC, particularly in potential liver transplant recipients. Reported seeding rates range from 0.6% to 5.1% using various biopsy techniques. To our knowledge, the rate of seeding using a coaxial cutting needle technique has not been reported. MATERIALS AND METHODS Retrospective review identified 128 patients with imaging-guided percutaneous liver biopsies positive for HCC. A coaxial cutting needle technique was uniformly used with a 17-gauge introducer and 18-gauge biopsy needle. Radiology and clinical reports were reviewed, and findings at clinical and imaging follow-up were assessed. RESULTS During the 6-year study period, 1,012 liver mass biopsies were performed, with 128 positive for HCC (100 men and 28 women; average age, 58.4 years). One hundred one patients had more than 30 days of clinical or imaging follow-up (or both) after biopsy (mean, 410 days; range, 33-1,989 days) and constituted the study population. The remaining 27 were excluded because of inadequate follow-up. No suspected or confirmed tumor seeding on imaging, physical examination, or laparotomy was identified. CONCLUSION We found no tumor seeding after percutaneous biopsy of HCC using a coaxial cutting needle technique. This rate, 0%, is lower than those reported with other techniques. The use of a needle introducer that remains in position during multiple cutting needle passes protects normal tissue along the track and may reduce seeding. This has particular importance for patients with stage I-II HCC, for whom liver transplantation may be curative.

MR Imaging and CT of the Biliary Tract

Magnetic resonance (MR) imaging and computed tomography (CT) can be useful in the diagnosis of biliary disease, with both modalities allowing detailed evaluation of the biliary tract. Careful interrogation of the images is critical, regardless of modality. The identification of dilated bile ducts necessitates evaluation for strictures or filling defects, which is best performed with thin-section imaging. Smooth, concentric short-segment strictures favor a benign cause, whereas abrupt, eccentric long-segment strictures favor a malignancy. At MR imaging, extrabiliary entities such as crossing vessels or metallic clip artifact may mimic strictures and should not be mistaken for disease. A stone is the most common biliary filling defect and may occur in the absence of dilated ducts. Stones commonly have a lamellated, geometric shape and are found in a dependent portion of the duct. Identification of bile duct wall thickening raises concern for cholangitis or malignancy. Improved diagnosis of biliary disease can be achieved with a knowledge of the benefits and limitations of modern MR and CT cholangiographic techniques, including the use of biliary-excreted contrast material and of various postprocessing techniques. Familiarity with the radiologic appearances of the duct lumen, wall, and surrounding structures is also important for accurate image interpretation. The rapidly evolving technology for both MR imaging and CT of the biliary tract will continue to present radiologists with opportunities as well as challenges.