Magnetic resonance angiography of the kidney.

Magnetic resonance angiography (MRA) of the kidneys has become a clinical standard for detecting renal artery stenosis. This test is performed by injecting a bolus of a gadolinium chelate and scanning with a three-dimensional volumetric data collection sensitized to the T1 shortening effects of gadolinium. In addition to displaying the renal arterial anatomy, atherosclerosis within the aorta and iliac arteries is commonly depicted. MRA is a time efficient and safe test when compared with conventional arteriography. Gadolinium-enhanced MRA has proven to have a high sensitivity for detecting stenoses in main and accessory renal arteries. Although false-negative studies are rare, overestimation of the degree of renal stenosis is problematic and may lead to false-positive diagnosis. To some extent this tendency to overestimate stenoses can be compensated for by performing phase contrast MRA, a type of MRA based on accumulated phase differences. As with conventional angiography, MRA is still only an anatomic test which provides little information about the functional significance of a stenosis. It is highly accurate in determining the number of renal arteries, the size of the kidneys, and the presence of any anatomic variants. Ultimately, MRA, needs to be combined with a functional test similar in concept to captopril renography. This test, termed MR renography together with MRA may replace the current multimodalitiy approach to the work-up of renovascular hypertension.

Vessel surface reconstruction with a tubular deformable model.

Three-dimensional (3-D) angiographic methods are gaining acceptance for evaluation of atherosclerotic disease. However, measurement of vessel stenosis from 3-D angiographic methods can be problematic due to limited image resolution and contrast. We present a method for reconstructing vessel surfaces from 3-D angiographic methods that allows for objective measurement of vessel stenosis. The method is a deformable model that employs a tubular coordinate system. Vertex merging is incorporated into the coordinate system to maintain even vertex spacing and to avoid problems of self-intersection of the surface. The deformable model was evaluated on clinical magnetic resonance (MR) images of the carotid (n = 6) and renal (n = 2) arteries, on an MR image of a physical vascular phantom and on a digital vascular phantom. Only one gross error occurred for all clinical images. All reconstructed surfaces had a realistic, smooth appearance. For all segments of the physical vascular phantom, vessel radii from the surface reconstruction had an error of less than 0.2 of the average voxel dimension. Variability of manual initialization of the deformable model had negligible effect on the measurement of the degree of stenosis of the digital vascular phantom.

Evaluation of Crohn's disease using half-fourier RARE and gadolinium-enhanced SGE sequences: initial results.

To assess the bowel changes in Crohn's disease, 11 consecutive patients underwent magnetic resonance imaging (MRI) study using T(2)-weighted half-Fourier rapid acquisition with relaxation enhancement (RARE) and gadolinium-enhanced standard and fat suppressed spoiled gradient echo (SGE) sequences. Comparison was made between MR findings of disease extent, severity, and complications and clinical data, endoscopic findings and/or surgical specimens in all patients. We found that the half-Fourier RARE images showed bowel wall thickening, dilatation of bowel and bowel obstruction well in all patients, however severity of bowel disease could not be determined as the signal intensity of diseased bowel was comparable to normal bowel in 10/11 patients. Gadolinium-enhanced fat suppressed SGE demonstrated variations of mural enhancement that correlated well with extent of disease severity in 10/11 patients. Complications such as intraperitoneal (i. p.) abscess (2 patients), gastric outlet obstruction (1 patient), bowel obstruction (2 patients), and fistula formation (3 patient), were accurately shown. We conclude that T(2)-weighted half-Fourier RARE and gadolinium-enhanced fat suppressed SGE sequences are complementary techniques that possess different imaging features that are of value for assessing bowel changes in Crohn's disease.

Adult intussusception: demonstration by current MR techniques.

We describe magnetic resonance findings in three patients with small bowel intussusception from different etiologies including idiopathic, adenomatous polyps, and hamartomatous polyps. Magnetic resonance findings showed a bowel-within-bowel appearance in two patients and a coiled-spring appearance in one patient. These findings were best shown on T2-weighted images, and clear definition was present on breathing independent T2-weighted images using half fourier acquisition snap shot turbo spin echo T2-weighted images.

Abdominal granulocytic sarcomas: demonstration by MRI.

The magnetic resonance imaging findings of histologically-proven renal and pancreatic granulocytic sarcomas are demonstrated in two patients. Granulocytic sarcomas were moderately hypointense on T1-weighted images, mildly hyperintense on T2-weighted images, and enhanced in a diminished fashion on early and late postgadolinium T1-weighted images.

MR imaging of metastatic pancreatic VIPoma.

The MR findings in a 32-year-old man with pancreatic VIPoma and liver metastases are described. A 2-cm mass was present in the region of the tail of the pancreas that was best shown on T1-weighted fat-suppressed images as a low-signal intensity mass. Multiple liver metastases were present that showed intense peripheral ring enhancement on immediate post gadolinium spoiled gradient echo images.

MRI of normal and abnormal duodenum using Half-Fourier Single-Shot RARE and gadolinium-enhanced spoiled gradient echo sequences.

The objective of this research was two-fold: First, to describe the normal and abnormal MR appearances of the duodenum using combined Half-Fourier Acquisition Single Shot RARE (HASTE) and gadolinium-enhanced standard and fat suppressed spoiled gradient echo (SGE) sequences. The second objective was to assess the ability of these combined sequences to detect and characterize duodenal diseases. MR examinations were performed on fifty consecutive patients with no clinical history of duodenal diseases, who were 1) imaged with HASTE and gadolinium-enhanced standard and fat suppressed SGE sequences and 2) referred to MR examination for reasons other than duodenal diseases, and were reviewed retrospectively to determine the normal MR appearances of the duodenum. A second population of patients with abnormal duodenum who were imaged with the same MR sequences were included in the second part of this study. This population was composed of 20 consecutive patients with subsequently proven duodenal abnormalities, including: malrotation (2), diverticula (4), intussusception (1), sprue (1), polyps (2), neurofibroma (1), lymphoma (1), Zollinger Ellison syndrome (1), metastatic disease (1), Crohn's disease (1), and wall thickening and duodenitis (5). Normal measurements of the duodenum are described. Abnormalities of wall thickness and duodenal masses required combined HASTE and gadolinium-enhanced SGE images to evaluate well. Abnormalities of the bowel lumen (e.g., diverticula and intussusception), and developmental variants (e.g., malrotation), were sufficiently visualized on HASTE images alone. Bowel inflammation was best shown on gadolinium-enhanced fat suppressed SGE images. HASTE and gadolinium-enhanced fat suppressed SGE sequences are complementary techniques for the demonstration of normal and abnormal duodenum. The combined use of both sequences allows evaluation of different aspects of bowel diseases; abnormalities of position, lumen, and contents are well shown on HASTE, while inflammation is best shown on gadolinium enhanced fat suppressed SGE, and wall thickening and masses are best evaluated with the combined use of both techniques.

Metastatic gastric leiomyoblastoma: a case report.

Gastric leiomyoblastoma is a rare entity. In this report, we describe the magnetic resonance (MR) appearance of a recurrent gastric leiomyoblastoma 14 years after initial presentation. This tumor was heterogeneous and moderately low signal intensity on T1-weighted images and heterogeneous and moderately high signal intensity on T2-weighted images. The tumor also contained foci of low signal intensity on the post gadolinium images, consistent with areas of necrosis. The mass enhanced mildly and increased in enhancement on the delayed images, consistent with a hypovascular mass. Multiple liver metastases were noted. Magnetic resonance findings were confirmed with surgical specimens.

Polyposis syndromes of the gastrointestinal tract: MR findings.

We describe the magnetic resonance (MR) findings in patients with gastrointestinal polyposis syndromes using breath-hold T1-weighted sequences, both standard and with fat suppression, prior to and following gadolinium administration, and breathing-independent single-shot half-Fourier RARE T2-weighted sequences. Six patients with gastrointestinal polyposis syndromes underwent MR examination to investigate for the presence of metastatic disease. The appearances of the gastrointestinal polyps on noncontrast T1-weighted spoiled gradient-echo (SGE), T2-weighted (half-Fourier RARE) images, and early and late gadolinium-enhanced SGE images were determined. Other gastrointestinal findings and extragastrointestinal disease were also evaluated. Patients with the following gastrointestinal polyposis syndromes were included: familial polyposis (n = 3), Peutz-Jeghers syndrome (n = 1), Gardner's syndrome (n = 1), and neurofibromatosis (n = 1). Polypoid lesions in all patients exhibited signal intensity comparable to bowel on noncontrast images and enhanced similar to bowel on early and late gadolinium-enhanced images. Polyps larger than 2 cm, observed in one patient with familial polyposis and the patient with Gardner's disease, showed mild heterogeneity on late gadolinium-enhanced fat-suppressed images. Multiple colonic polyps ranging from 5 mm to 3 cm in diameter were observed in patients with familial adenomatous polyposis. A solitary 1.5 cm polyp associated with entero-enteric intussusception was observed in the patient with Peutz-Jeghers syndrome. Gastric polyps ranging from 5 mm to 6 cm were observed in the stomach of the patient with Gardner's syndrome. Duodenal and jejunal neurofibromas ranging from 1 to 2 cm in diameter were present in the patient with neurofibromatosis. Extra gastrointestinal findings included an adrenal adenoma (1 patient), a pheochromocytoma (1 patient), and liver metastases (2 patients). Gastrointestinal polyps in patients with polyposis syndromes may be visualized on MR images employing breath-hold T1-weighted and breathing-independent snapshot T2-weighted techniques. Appreciation of polyp enhancement on post-gadolinium images is an important finding, which should help distinguish polyps from bowel contents.

Stomach diseases: MR evaluation using combined t2-weighted single-shot echo train spin-echo and gadolinium-enhanced spoiled gradient-echo sequences.

The aim of this study was to describe the magnetic resonance (MR) appearances of diseases of the stomach using combined T1-weighted spoiled gradient-echo, T2-weighted single-shot echo train spin-echo and gadolinium-enhanced spoiled gradient-echo sequences. All patients with gastric diseases who underwent combined T2-weighted single-shot echo train spin-echo and gadolinium-enhanced conventional and fat-suppressed spoiled gradient-echo imaging between October 1, 1996 and March 1, 1999, and who had histological or other imaging proof of disease, were included in this study. This patient population was comprised of 40 patients with subsequently proven gastric abnormalities, including malignant tumors (25) or benign disease (15). The MRI sequences included T1-weighted, T2-weighted, and early and late gadolinium-enhanced spoiled gradient-echo (SGE) images. Evaluation was made of the following parameters: a) the ability to detect the disease process on MRI, by comparing the original prospective MR reports with the records of the pathology department; b) the MR appearance of a variety of gastric diseases; and c) the sequences that most clearly demonstrated abnormalities by retrospective review of the MR studies. MR images demonstrated 22 of 25 malignant tumors. Evaluation of the extent of the tumor was correctly shown in 22 of 25 tumors. Small-volume tumor (one patient with gastric adenocarcinoma, and one patient with lymphoma) and coexistent infiltrative adenocarcinoma and gastritis (one patient) rendered demonstration of tumor poor on MR images in three patients. Tumors were mildly hypointense on T1-weighted images and mildly hyperintense on T2-weighted images. Tumors enhanced in a heterogeneous fashion compared with background stomach wall, but they ranged from hypointense to hyperintense on early and late post-gadolinium SGE images. Regarding benign diseases, the changes of gastritis were evident in three of four cases. Gastritis appeared as increased mucosal enhancement that ranged from moderate to intense on early and late post-gadolinium SGE images. Imaging findings of the various entities are described in greater detail in the text. MR findings in a variety of neoplastic and non-neoplastic diseases of the stomach are described. Neoplastic diseases were consistently observed in most cases; however, small tumors and tumors coexistent with inflammatory changes were poorly evaluated. The changes of gastritis were demonstrated as increased enhancement of the gastric wall. J. Magn. Reson. Imaging 10:950-960, 1999.

Normal placenta: gadolinium-enhanced dynamic MR imaging.

PURPOSE: To establish the appearance of the normal placenta on dynamic, gadolinium-enhanced magnetic resonance (MR) images. MATERIALS AND METHODS: Eleven patients underwent MR imaging for suspected uterine (four patients) or placental (seven patients) abnormalities (but not placental insufficiency or intrauterine growth retardation). Unenhanced or gadolinium-enhanced, T1-weighted, fat suppressed, spoiled gradient-recalled-echo MR images and T2-weighted, half-Fourier, single-shot, spin-echo-train MR images were obtained. Two investigators retrospectively evaluated the images to determine the rate, pattern, and degree of placental contrast material enhancement with myometrial enhancement as a reference. RESULTS: The diagnoses were normal placenta (six patients), abnormal placental position (four patients), and subchorionic hematoma (one patient). The placenta rapidly and intensely enhanced on images acquired immediately after contrast material administration and preceded substantial enhancement of the myometrium. Immediately postcontrast images showed closely packed 2-3-cm lobules of placental enhancement in third-trimester pregnancies and heterogeneous placental enhancement in second-trimester pregnancies. In all cases, placental enhancement became more homogeneous over time. The placenta could be readily distinguished from the myometrium. All neonates were healthy with no evidence of intrauterine growth retardation. CONCLUSION: Normal placental enhancement is intense on immediately postcontrast images and precedes substantial myometrial enhancement. Third-trimester placentas exhibit a lobular pattern of enhancement, while second-trimester placentas exhibit heterogeneous enhancement.

MRI evaluation of acute renal trauma.

We describe the MR findings in a patient with acute renal injury after blunt abdominal trauma associated with perinephric hematoma and urinoma. Both CT and MR findings are described. Active urine extravasation into a perinephric urinoma is demonstrated by serial post-contrast imaging with CT and MRI showing progressively increased attenuation/signal intensity fluid in communication with the collecting system, commencing 2 minutes after contrast administration.

MR imaging of the small bowel using the HASTE sequence.

OBJECTIVE: To establish the normal MR appearance of small bowel on half-Fourier acquisition single-shot turbo spin-echo (HASTE) sequence and to determine the ability of HASTE to reveal small-bowel disease. MATERIALS AND METHODS: HASTE images in 50 patients without small-bowel disease were reviewed retrospectively to determine the normal MR appearance of small bowel. All patients fasted for at least 6 hr. The images of 18 patients with proven small-bowel abnormalities that were obtained with the HASTE sequence were also reviewed retrospectively by one observer unaware of the findings. The ability to characterize small-bowel diseases using the HASTE sequence was assessed. RESULTS: In the 50 patients with normal small bowel, no fluid was seen in the jejunum and ileum loops in four (8%). Fluid was present in less than 25% of small-bowel loops in 20 patients (40%), 25-50% of small-bowel loops in 20 patients (40%), and 50-75% of small-bowel loops in six patients (12%). Equal amounts of fluid were present in the jejunum and ileum in 30 patients (60%). More fluid was seen in the jejunum than the ileum in 16 patients (32%) and the reverse was true in four patients (8%). The mean diameter of the jejunum was 2.1 cm (SD = 0.34 cm) and of the ileum, 1.9 cm (SD = 0.41 cm). The thickness of the small-bowel wall and valvulae conniventes averaged 2 mm. Findings of dilatation of the bowel lumen and increased thickness of the bowel wall and valvulae conniventes were identified in 18 patients with small-bowel abnormalities. CONCLUSION: The normal and abnormal small bowel can be assessed using the HASTE sequence.

Colon diseases: MR evaluation using combined T2-weighted single-shot echo train spin-echo and gadolinium-enhanced spoiled gradient-echo sequences.

This study demonstrates the appearance of large bowel diseases on magnetic resonance (MR) images using breath-hold T2-weighted half-Fourier acquisition snapshot turbo spin-echo (HASTE), breath-hold T1-weighted spoiled gradient-echo (SGE), and breath-hold gadolinium-enhanced T1-weighted SGE with and without fat-suppression sequences. The study represents a collective experience using a generalized combined abdominal-pelvic imaging protocol. Of 29 patients, 27 had surgical, endoscopic, microbiological, and/or histopathological correlation, and 2 had a diagnosis based on characteristic imaging findings. Fifteen patients had neoplastic disease including colon adenocarcinoma (n = 11), rectosigmoid carcinoid (n = 1), familial adenomatous polyposis (n = 2), and cecal lipoma (n = 1). Fourteen patients had non-neoplastic disease including diverticulosis (n = 6), ischemic colitis (n = 2), pseudomembranous colitis (n = 2), acute appendicitis with periappendiceal abscess (n = 2), Mycobacterium avium intracellulare (MAI) colitis (n = 1), and Crohn's proctocolitis (n = 1). In all 15 patients with neoplastic diseases, MR imaging depicted the primary lesions and demonstrated local extent. Mass lesions were best shown on T2-weighted HASTE and gadolinium-enhanced fat-suppressed SGE images. Of 14 patients with non-neoplastic diseases, inflammatory changes were best shown on gadolinium-enhanced fat-suppressed T1-weighted SGE images in all cases. MR imaging with fast scanning breath-hold techniques and intravenous gadolinium enhancement provided good depiction and characterization of large bowel diseases.

Perilesional enhancement of hepatic metastases: correlation between MR imaging and histopathologic findings-initial observations.

PURPOSE: To correlate perilesional enhancement on gadolinium-enhanced magnetic resonance (MR) images with histopathologic findings in patients with hepatic metastases. MATERIALS AND METHODS: In seven patients with histopathologically proved hepatic metastases, MR images obtained before and early and late after the administration of gadopentetate dimeglumine were retrospectively evaluated for perilesional enhancement. The thickness of hepatic parenchyma with intense perilesional enhancement was calculated. The thickness of the histologic tumor border (the zone separating the outermost border of the tumor nodule from the surrounding hepatic parenchyma) also was measured. RESULTS: In three patients, early gadolinium-enhanced images showed prominent perilesional enhancement, which correlated with a thick tumor border containing peritumoral desmoplastic reaction, peritumoral inflammation, and vascular proliferation at histopathologic examination. In one patient, mild perilesional enhancement was shown. At histopathologic examination, the lesion periphery showed moderate peritumoral changes. In the remaining three patients, no perilesional enhancement was observed, and at histopathologic examination there was a thin tumor border that contained minimal to mild perilesional changes. The thickness of hepatic parenchyma with intense perilesional enhancement on early gadolinium-enhanced images showed a strong positive correlation with tumor border thickness at histopathologic examination (r = 0.99). CONCLUSION: Intense perilesional enhancement of metastases on early gadolinium-enhanced MR images correlates with histopathologic hepatic parenchymal changes, which include peritumoral desmoplastic reaction, inflammatory cell infiltration, and vascular proliferation.

Liver metastases: comparison of current MR techniques and spiral CT during arterial portography for detection in 20 surgically staged cases.

PURPOSE: To compare spiral computed tomography during arterial portography (CTAP) with current magnetic resonance (MR) imaging, including hepatic arterial-dominant phase, gadolinium-enhanced, spoiled gradient-echo imaging, for the prospective detection of liver metastases in 20 patients who subsequently underwent surgery to confirm findings. MATERIALS AND METHODS: Twenty patients underwent spiral CTAP and MR imaging within 1 week. Spiral CTAP and MR images were interpreted separately in blinded fashion. All patients subsequently had intraoperative confirmation. Sensitivity, specificity, and positive and negative predictive values were determined for lesion detection and segmental distribution. RESULTS: CTAP and MR images demonstrated, respectively, 54 and 60 true-positive lesions, six and one false-positive lesions, 15 and 22 true-negative (i.e., benign) lesions, and eight and two false-negative lesions. CTAP and MR images demonstrated, respectively, 57 and 62 true-positive segmental involvements, six and one false-positive segmental involvements, 89 and 95 true-negative segmental involvements, and eight and two false-negative segmental involvements. No significant difference in lesion detection was observed. CONCLUSION: Spiral CTAP and MR imaging were approximately equivalent for lesion detection in patients who were evaluated preoperatively for resection of liver metastases. The lower cost and fewer problems with artifacts may suggest that MR imaging is the preferred modality for preoperative assessment of patients for surgical treatment of liver metastases.

Incidental detection of acute myocardial infarction during routine performance of three-dimensional dynamic MR angiographic study with dynamic injection of gadolinium.

We report on the MR appearance of acute myocardial infarction in a 61-year-old man with Ehlers-Danlos syndrome using motion-independent, T2-weighted echo train spin echo and immediate post-gadolinium three-dimensional gradient echo imaging performed as an MRI angiographic study of the aortic arch. The region of acute infarction was of high signal intensity on the T2-weighted images and demonstrated greatly diminished enhancement on the immediate post-gadolinium three-dimensional gradient echo images. MRI findings showed good correlation with autopsy specimens obtained within 24 hours of the MRI study.

Intraperitoneal abscesses: diagnostic accuracy of and appearances at MR imaging.

PURPOSE: To prospectively investigate the diagnostic accuracy of and appearances at magnetic resonance (MR) imaging of patients clinically suspected to have intraperitoneal abscesses. MATERIALS AND METHODS: Sixty-seven consecutive patients underwent MR imaging for suspected intraperitoneal abscesses. MR images were prospectively interpreted for intraperitoneal abscesses; the results were correlated with surgical, histopathologic, and laboratory findings. RESULTS: MR imaging revealed 25 fluid collections consistent with intraperitoneal abscesses in 22 of 67 patients (33%). Of these collections, 22 were intraperitoneal abscesses; one, a giant sigmoid diverticulum; and two, sterile fluid collections. The latter two patients had been receiving antibiotic therapy. MR imaging allowed exclusion of intraperitoneal abscesses in 45 patients (67%). All collections demonstrated decreased signal intensity on T1-weighted images; on T2-weighted images, 13 collections demonstrated homogeneously increased signal intensity and 12 demonstrated heterogeneously increased signal intensity. The abscesses were best demonstrated on gadolinium-enhanced T1-weighted fat-suppressed images as well-defined fluid collections with peripheral rim enhancement. Sensitivity was 100%; specificity, 94% (95% confidence interval = 83%, 99%); positive predictive value, 88% (95% confidence interval = 69%, 97%); negative predictive value, 100%; and accuracy, 96% (95% confidence interval = 88%, 99%). CONCLUSION: MR imaging has high diagnostic accuracy in evaluation of acute intraperitoneal abscesses.

Biliary hamartomas: solitary and multiple lesions shown on current MR techniques including gadolinium enhancement.

The purpose of this study was to describe the magnetic resonance (MR) imaging features of biliary hamartomas on T1- and T2-weighted and gadolinium-enhanced sequences, and to correlate these findings with histopathology. MR imaging findings in four patients with pathologically proved biliary hamartomas are described. In all patients, MR imaging sequences, including T1- and T2-weighted and early and late gadolinium-enhanced images, were retrospectively evaluated for the size, morphology, signal intensity, and enhancement pattern of the lesions. Correlation was made between the MR imaging findings and histopathology. Biliary hamartomas ranged in diameter from 0.5 to 1.5 cm. Lesions were solitary in one patient and numerous in three patients. In all patients, the lesions were low signal on T1-weighted images and high signal and well-defined on T2-weighted images and demonstrated thin rim enhancement on early post-gadolinium images that persisted on late post-gadolinium images. No appreciable central enhancement of the lesions was observed. At histopathology, the lesions were composed of cystic spaces and fibrous stroma. Lesions showed compressed liver parenchyma surrounding the lesions (three cases) and inflammatory cell infiltrate (one case), which correlated with the rim enhancement on the gadolinium-enhanced MR images. Most of the biliary hamartomas in our small series were less than 1 cm in diameter and of high signal intensity on T2-weighted images, and had a thin rim of enhancement on early and late post-gadolinium images. The imaging features were explainable by the underlying histopathology. In patients with known malignancy, caution should be exercised not to misinterpret these lesions as metastases due to the presence of thin rim enhancement. J. Magn. Reson Imaging 1999;10:196-201, 1999.

Chronic hepatitis: correlation of early patchy and late linear enhancement patterns on gadolinium-enhanced MR images with histopathology initial experience.

The purposes of our study were to describe the early and late enhancement patterns of the liver on gadolinium-enhanced dynamic magnetic resonance (MR) images in patients with chronic hepatitis and to correlate these findings with histopathology. Patients were entered into the study based on the presence of chronic hepatitis, imaging evaluation with MR imaging (MRI), including early and late postgadolinium images, and histopathologic correlation. Early and late dynamic postgadolinium MR images of 29 consecutive patients with a pathologically proven diagnosis of chronic hepatitis were retrospectively evaluated for the presence of three types of enhancement, i.e., homogeneous, linear, and patchy. Correlation was made between the enhancement patterns on MR images and blinded retrospective interpretation of the histopathologic specimens, which were obtained within 3 months of the MR examination. Of the 29 patients, 16 (55.2%) patients showed patchy enhancement on the early gadolinium-enhanced MR images. In 11 (68.8%) of these 16 patients, histopathology demonstrated numerous macrophages, variable hepatocyte necrosis, and increased steatosis. The remaining 13 (44.8%) patients showed homogeneous enhancement on the early gadolinium-enhanced MR images. In 11 (84.6%) of these 13 patients, histopathology demonstrated few or no macrophages, little or no hepatocellular necrosis, and little or no steatosis. The correlation between patchy enhancement and acute liver inflammation was significant (P = 0.005). On the late gadolinium-enhanced MR images, 20 (69.0%) of 29 patients showed prominent linear enhancement. In 19 (95.0%) of these 20 patients, histopathology revealed hepatic fibrosis. We concluded that in patients with chronic hepatitis, the presence of early patchy enhancement indicates either concurrent or recent hepatocellular damage, whereas the presence of late linear enhancement indicates the presence of fibrosis, with a high degree of correlation with histopathologic findings.