Hepatic parenchymal enhancement in the cirrhotic liver: evaluation by triple-phase dynamic MRI

Background: To evaluate the changes of liver parenchymal enhancement in the cirrhotic liver by means of triple-phase dynamic magnetic resonance (MR) imaging. Methods: Triple-phase multisection dynamic MR imaging was performed in 32 patients with liver cirrhosis. The control group consisted of 19 patients without liver cirrhosis. After precontrast images were obtained, arterial phase images were acquired 20 s after the start of intravenous bolus administration of 0.10 mmol/kg of gadopentetate dimeglumine. Portal and delayed phase images were then acquired 1 and 3 min, respectively, after the injection of contrast material. On each phase image, the signal-to-noise ratio (S/N) from the liver parenchyma was measured by operator-defined regions of interest (ROIs). The contrast-enhanced ratio (CER) on each phase was then obtained according to the following formula: [S/N(arterial or portal or delayed phase image) − S/N(precontrast image)]÷ S/N(precontrast image). The portal perfusion index (PPI) also was obtained according to the following formula: [S/N(portal phase image − S/N(arterial phase image)]÷ S/N(arterial phase image). The results were expressed as mean ± SD. Results: The CERs of arterial, portal, and delayed phase images in patients with and without liver cirrhosis were 0.256 ± 0.211, 0.640 ± 0.384, and 0.554 ± 0.318 and 0.132 ± 0.094, 0.404 ± 0.204, and 0.324 ± 0.144, respectively. The CERs were highest in the portal phase and lowest in the arterial phase in patients with and without liver cirrhosis. The CER of the cirrhotic liver was significantly higher than that of the normal liver in every phase (p < 0.05). PPIs with and without liver cirrhosis were 2.90 ± 4.03 and 3.86 ± 3.89, respectively. The PPI with liver cirrhosis was significantly lower than that without liver cirrhosis (p < 0.05). Conclusion: The enhancement of cirrhotic liver parenchyma is greater than that of the normal liver parenchyma at every phase of triple-phase dynamic MR imaging. Received: 17 August 2000/Revision accepted: 7 March 2001     

Struma ovarii: MR appearances

Background: Analysis of unenhanced and contrast-enhanced magnetic resonance (MR) images of struma ovarii, a rare benign neoplasm of the ovary, is the aim of this study. Methods: T2-weighted and Gd-DTPA-enhanced T1-weighted MR images of five histologically proven struma ovarii were evaluated retrospectively. Results: In all patients, unenhanced and contrast-enhanced T1-weighted MR images showed complex cystic masses composed of multiple cysts and a solid component, indicating the presence of large and small thyroid follicles. In four patients, the cyst fluid was hypointense on T1-weighted images and hyperintense on T2-weighted images. In one patient, the fluid was hyperintense on T1-weighted images and hypointense on T2-weighted images due to hemorrhage. Conclusion: A complex mass composed of multiple cysts and a solid component, indicating the presence of large and small thyroid follicles, appeared to be a characteristic MR finding of struma ovarii. Received: 11 December 1995/Accepted: 15 December 1995     

Adult celiac disease: MRI findings

The purpose of our report is to describe a spectrum of findings of celiac disease at MR enterography. MR enterography is a non-invasive, feasible, and reproducible imaging technique for the evaluation of small bowel. Findings on MR enterography, similar to those of conventional barium studies, may suggest a diagnosis of celiac disease.     

Focal nodular hyperplasia of the liver: serial MRI with Gd-DOTA,superparamagnetic iron oxide,and Gd-EOB-DTPA

Background: To demonstrate the improved specificity of liver MRI in diagnosis of focal nodular hyperplasia (FNH) using liver specific contrast agents. Methods: In a patient after resected adenosarcoma of the uterus a focal nodular hyperplasia was followed. Serial MRI of the liver was performed using first Gd-DOTA, followed by superparamagnetic iron oxide (SPIO) as well as Gd-EOB-DTPA. Results: During the follow-up of FNH specificity of liver MRI improved using liver specific contrast agents. The central scar as well as the pseudocapsule showed different typical contrast uptake using all three methods. Conclusion: Serial MRI of the liver with Gd-DOTA, SPIO and Gd-EOB-DTPA can exclude a malignant liver lesion. Liver biopsy of FNH can be avoided with increased specificity of MRI for FNH. Received: 15 December 1995/Accepted: 17 January 1996     

Fan-shaped hepatic parenchymal damage after ethanol injection therapy for hepatocellular carcinoma: MRI appearances

Background: T1- and T2-weighted magnetic resonance (MR) images frequently show fan-shaped areas of hypo- or hyperintensity in the hepatic parenchyma adjacent to a treated hepatocellular carcinoma after percutaneous ethanol injection (PEI) therapy. These areas correspond to abnormal contrast enhancement on serial dynamic MR images. The purpose of the present study was to describe the location, appearance, and frequency of these abnormalities because it is important to understand these entities for the correct assessment of therapeutic efficacy. Methods: MR imaging including a multisection dynamic study was performed in 20 consecutive patients with hepatocellular carcinoma treated with PEI therapy. We retrospectively evaluated the presence of fan-shaped hypointensities adjacent to treated tumors in the liver parenchyma on T1-weighted images and hyperintensities on T2-weighted images and corresponding fan-shaped contrast enhancement on both arterial-dominant and delayed-phase dynamic MR images. We review the location, appearance, and frequency of these findings, and we discuss the possible causes on the basis of pathologic examinations. Results: Seven (35%) of the 20 patients showed fan-shaped hyperintense areas adjacent to the treated tumors on T2-weighted images. These areas showed isointensity in five patients and hypointensity in two patients on T1-weighted images. Of these seven patients, one (14%) underwent the MR imaging within 1 month after the completion of PEI therapy, and six (86%) had it 2–9 months after the completion of PEI therapy (mean = 6 months). In all seven patients, fan-shaped hyperperfusion abnormalities corresponding to these areas of hyperintensity on T2-weighted images were seen on both arterial-dominant and delayed-phase dynamic MR images. Pathologically, the coagulative necrosis of the hepatocytes with sinusoidal dilatation and the restoration by the development of fibrous tissue were seen in these fan-shaped areas. Conclusion: The fan-shaped areas of abnormal intensity on T1- and T2-weighted images and contrast enhancement on dynamic MR images seem to be attributable to pathologic changes in the normal liver parenchyma induced by the toxic reaction of ethanol. Awareness of the occurrence of such abnormalities in the peripheral liver parenchyma adjacent to the treated tumor is important for the correct assessment of therapeutic efficacy. RID="ID="<e5>Correspondence to:</e5> T. Fujita Received: 24 June 1997/Accepted after revision: 22 October 1997     

Sinusoidal spread of liver metastases from renal cell carcinoma: simulation of diffuse liver disease on MR imaging

Rarely, hepatic metastases can simulate hepatic infiltrative diseases. We present a case of a patient with advanced metastatic renal cell carcinoma who developed hepatomegaly and clinical signs of hepatocellular injury. On magnetic resonance imaging, the injury simulated a diffuse process, e.g., acute fulminant viral or chemical hepatitis or drug toxicity. Despite its high resolution, magnetic resonance imaging might not depict focal lesions in patients with extensive metastases. In correlation with clinical history, malignant disease should be considered when diffusely abnormal hepatic signal intensity is noted. Received: 2 April 2001/Revision accepted: 21 April 2001     

Virtual cystoscopy of the bladder based on CT and MRI data

Carcinoma of the bladder can be a serious and complex condition that is not always easy to diagnose with radiologic methods. Numerous investigations are available to establish the diagnosis and demonstrate extravesical manifestations. This article updates the role of virtual cystoscopy based on computed tomographic (CT) data at different dose levels and magnetic resonance imaging (MRI) data in the diagnosis of the carcinoma of the bladder. The appearances of normal bladder and polypoid bladder carcinoma are shown. Factors for improvement of both virtual procedures are presented and pitfalls are discussed. New developments in CT, MRI, and postprocessing procedures are discussed. The value of virtual cystoscopy in sizing, localizing, and staging of bladder carcinoma is described and compared with cystoscopy, axial CT, and MRI.     

Malignant fibrous histocytoma of the inferior vena cava: appearances on contrast-enhanced spiral CT and MRI

Primary malignant tumors of the inferior vena cava are infrequent. We report a very rare case of primary malignant fibrous histiocytoma of the inferior vena cava and describe the contrast-enhanced spiral computed tomographic and magnetic resonance imaging findings. Received: 16 March 1995/Accepted: 23 April 1995     

Cholangiocarcinoma presenting as lung mass with hemoptysis

A case of peripheral cholangiocarcinoma with the presentation of chronic hemoptysis and lung mass without evident jaundice is reported. Exophytic spread of hepatobiliary disease through the diaphragm through perihepatic ligaments is described as the possible route of invasion of the tumor. Received: 16 January 1998/Revision accepted: 17 June 1998     

Women's imaging fellowships: development and future

Fellowships, which consist of training in predominantly breast imaging and in gynecologic and obstetric sonography, have steadily increased in number since 1992. There are currently 10 such fellowships, and the majority of these are called ``women's imaging fellowships.' All 19 fellows (100%) trained between 1992 and 1996 have immediately gained employment upon completion of the training, compared with the 86% employment rate of radiology fellows in general. Indications are that women's imaging fellowships will continue to provide subspecialists in radiology oriented to the imaging requests of obstetrician-gynecologists and other physicians who take care of women. Received: 0/0/0/Accepted: 0/0/0     

Endorectal surface coil MR imaging as a staging technique for rectal carcinoma: a comparison study to rectal endosonography

Background: Preoperative staging of rectal cancer is critical for guiding therapy and prescribing the most appropriate treatment option. The purpose of this investigation was to compare the accuracy of endorectal surface coil magnetic resonance imaging (ERSCMRI) with endosonography (EUS) in staging rectal lesions. Methods: Fourteen patients with rectal carcinoma, initially detected by barium enema or sigmoidoscopy underwent ERSCMRI and EUS. Subsequent resection of the lesions was performed, and the staging accuracies of these two modalities are compared. Results: MR T-staging agreement with pathologic T-staging was similar to that of EUS, but MR enabled more accurate identification of nodal involvement. Conclusion: ERSCMRI produced greater overall accuracy in staging for rectal carcinoma than did EUS. Received: 10 September 1998/Revision accepted: 10 February 1999     

Insulinoma: correlation of short-TI inversion-recovery (STIR) imaging and histopathologic findings

We studied the value of short-TI inversion-recovery (STIR) imaging for the localization of pancreatic insulinoma. Four patients (three women and one man aged 35–65 years) with surgically proven insulinoma were included in this study. All patients were examined by MR imaging with spin echo (SE) and STIR sequences. The STIR images were compared with the histopathologic findings in each case. In two patients, the tumors were markedly hyperintense on STIR images, and a 5-mm insulinoma was depicted only by this imaging method in one of the two. In the other two patients, 10-mm insulinomas were only slightly hyperintense on STIR images. The latter tumors had a higher content of collagen fibers than the former, indicating that the amount of collagen influences the signal intensity of insulinoma. Despite some limitations, STIR imaging is a useful noninvasive method for the localization of pancreatic insulinoma. Received: 11 October 1994/Accepted after revision: 10 April 1995     

Hepatic angiomyolipoma: radiologic and histopathologic correlation

We present two cases of hepatic angiomyolipoma. Histologic analysis showed that mature adipose tissue occupied 79.0% of the area on the largest cut surface in the first case and 40.2% in the second case. We suggest that the difference in the ratio of adipose tissue volume to its distribution is reflected on diagnostic images. Received: 8 February 2001/Revision accepted: 4 April 2001     

Primary malignant lymphoma in the porta hepatis: a case report

A case of primary lymphoma in the porta hepatis is presented here. Cholangiography, angiography, ultrasonography and computed tomography suggested the presence of a mass in the porta hepatis, but all these failed to demonstrate the tumor clearly. Magnetic resonance imaging was very useful in defining the characteristics of the tumor and in delineating its extent, though it was not specifically diagnostic. Received: 28 March 1995/Accepted: 4 May 1995     

Value of endorectal coil versus body coil MRI for diagnosis of recurrent pelvic malignancies

Background: To compare endorectal coil magnetic resonance imaging (MRI) with body coil MRI in detecting local recurrence of gynecologic tumors and prostate and rectal cancers. Methods: Forty-six patients with suspected recurrent pelvic malignancies (13 gynecologic, 15 prostatic, and 18 anorectal primaries) were enrolled in the study. Axial T1- and T2-weighted body coil images and T2- and contrast-enhanced T1-weighted axial endorectal coil images were obtained on a 1.5 T system. Results of the MR examinations were compared with histogical findings and follow-up examinations with respect to the diagnostic accuracy and diagnostic confidence for assessment or exclusion of local recurrence. Results: Recurrent disease was histologically confirmed in eight patients with primary gynecologic malignancies, seven with suspected prostatic recurrence, and seven with suspected anorectal recurrence. Overall, accuracy of body coil MRI was 67% for gynecologic tumors, 36% for prostatic recurrences, and 59% for rectal recurrences. T2- and contrast-enhanced T1-weighted endorectal sequences yielded similar results, with an accuracy of 73% for depiction of gynecologic recurrence, 77% for prostatic recurrence, and 77% for rectal recurrence. The difference in accuracy between body coil and endorectal coil examinations was statistically significant (p < 0.05) only for prostatic cancer. Diagnostic confidence was, however, significantly improved (p < 0.05) in all tumors (T2-weighted endorectal coil examination was superior to T2-weighted body coil images in 71% of cases). Conclusion: Although the results of endorectal coil MRI are only slightly superior to those of body coil MRI for the detection of recurrent gynecologic and anorectal tumors, diagnosis can be made with greater diagnostic confidence in many cases. For detection of prostatic recurrence, endorectal MRI is highly recommended. Received: 27 April 1995/Accepted: 17 June 1995     

Ultrasound appearances of intra- and extrahepatic biliary ascariasis

Background: To determine the range of ultrasonographic (US) appearances of Ascaris lumbricoides roundworms in the biliary system, their distribution in the intra- and extrahepatic parts of the system, and associated features. Methods: All cases of biliary ascariasis during a 10-year period were reviewed. There were 42 cases in which diagnosis was based on established US criteria, and 2 cases diagnosed surgically in which US had been negative. These 44 cases occurred in 36 patients. Results: In the US-diagnosed cases, worms were present in intrahepatic ducts in 32 cases, in the main duct in 37, and in the gallbladder in eight. In six cases, the liver was lifted off the main portal vein by a bundle of worms obliterating the lumen of the main bile duct. Worms packing and dilating intrahepatic ducts produced pseudotumorous appearances in the liver in four cases and bundlelike appearances in three. Worms were also seen in the pancreatic duct in two cases. Stones in intrahepatic ducts were present in 12 patients. Conclusion: Biliary ascariasis should be searched for inside and outside the liver. The appearances of bundles and boluses are different from those of single worms. Intra- and extrahepatic biliary stones may be present. Received: 7/30/96/Accepted: 9/4/96     

Cirrhosis: spectrum of findings on unenhanced and dynamic gadolinium-enhanced MR imaging

The appearance of the cirrhotic liver on computed tomography can be difficult to evaluate and can frustrate the radiologist distinguishing benign from malignant lesions. Hepatic edema, fibrosis, atrophy, and vascular abnormalities are common in the cirrhotic liver and produce derangements in morphology, attenuation, and perfusion, limiting the accurate characterization of hepatic masses. With the development of fast magnetic resonance (MR) sequences and dynamic postgadolinium-enhanced imaging, most hepatic lesions with uncertain etiology on computed tomography can be accurately characterized on MR imaging. We describe MR imaging techniques useful for imaging cirrhosis and its complications. We also illustrate the spectrum of findings in the cirrhotic liver on dynamic gadolinium-enhanced MR imaging, including reticular and confluent fibrosis, fatty infiltration, hemochromatosis, regenerating nodules, dysplastic nodules, hepatocellular carcinoma, and sequela of portal hypertension. Received: 16 November 2000/Revision accepted: 7 February 2001     

Vaginal arteriovenous malformation: MR imaging

Vaginal arteriovenous malformations (AVMs), although rare, can lead to life-threatening complications. We report the first case of a vaginal AVM whose diagnosis and follow-up were performed by magnetic resonance imaging (MRI). MRI findings of the AVM are the blood flow-related features within the tumor, such as the phase-shift artifact, paradoxical enhancement, and flow voids. Received: 10 October 1995/Accepted: 16 October 1995     

Renal metastasis from choriocarcinoma: MRI appearance

Choriocarcinoma is the most malignant tumor of gestational trophoblastic neoplasia. It grows rapidly and metastasizes to the lung, liver, and, less frequently, to the brain. Renal involvement is rare. Magnetic resonance imaging (MRI) is a useful modality to image the affected tissues; it contributes to the evaluation and management of the disease. One case of renal choriocarcinoma with MRI evaluation is reported. Received: 24 February 1997/Accepted: 14 April 1997