共查询到20条相似文献,搜索用时 31 毫秒
1.
Plain and gadolinium-DTPA-enhanced MR imaging of hepatocellular carcinoma treated with transarterial chemoembolization 总被引:12,自引:0,他引:12
M. Castrucci S. Sironi F. De Cobelli M. Salvioni A. Del Maschio 《Abdominal imaging》1996,21(6):488-494
Background: To assess unenhanced and gadolinium-enhanced magnetic resonance (MR) imaging patterns of hepatocellular carcinoma (HCC) treated
with transarterial chemoembolization (TACE).
Methods: Thirty-two patients with 48 HCC lesions underwent MR imaging before and 15 days after TACE. Fifteen lesions were then surgically
resected. The remaining 33 lesions were not removed and were followed up with MR imaging at 3, 6, 12, and 18 months after
treatment. Spin echo (SE) T1- and T2-weighted and gadolinium-enhanced SE T1-weighted sequences were employed. Qualitative
evaluation of signal intensity pattern of the treated lesions was performed in all cases. Histological evaluation and selective
hepatic arteriography were considered the gold standard of the study for the 15 resected lesions and the 33 unresected lesions,
respectively.
Results: On follow-up enhanced T1-weighted images of the 15 resected lesions, seven showed no area of enhancement corresponding to
complete necrosis at histologic examination. The remaining eight resected lesions showed areas of enhancement; in six of these
cases, viable tumor tissue was found at histology; in the other two lesions, histologic examination revealed the presence
of complete tumor necrosis. In the group of resected lesions, T2-weighted images showed no pattern characteristic of necrosis.
In 24 of 33 unresected lesions, loss of enhancement on follow-up enhanced T1-weighted images was a characteristic finding,
which correlated to devascularization at arteriography. Of these 24 lesions, 17 were completely hypointense on follow-up T2-weighted
images; the remaining seven showed small foci of hyperintensity. The other nine unresected lesions showed enhanced portions
on follow-up enhanced T1-weighted images, which corresponded to hyperintense areas on T2-weighted images. These findings correlated
to persistence of hypervascular areas at arteriography.
Conclusion: Gadolinium-enhanced T1-weighted MR imaging is a reliable method for evaluating the outcome of TACE treatment and is more
accurate than unenhanced T2-weighted MR imaging.
Received: 2 June 1995/Accepted: 18 July 1995 相似文献
2.
Dysplastic nodules of the liver: imaging findings 总被引:2,自引:0,他引:2
Background: To verify characteristic features of hepatic dysplastic nodules at different imaging modalities.
Methods: Twenty-eight patients with 37 dysplastic nodules of the liver (0.8–3.0 cm) underwent sonography (28 patients), computed tomography
(CT; 24 patients), magnetic resonance (MR; 11 patients), and angiography (12 patients). Each nodule was analyzed for echogenicity,
attenuation, signal intensity, and vascularity.
Results: Echogenicity of nodules was high in 16 (43%), homogeneous in two (6%), and low in 19 (51%) of 37 nodules. Attenuation of
nodules was high in one (7%), homogeneous in four (26%), and low in 10 (67%) of 15 nodules on the arterial-phase CT images;
homogeneous in five (33%) and low in 10 (67%) of 15 nodules on the portal-phase CT images; and high in four (17%), homogeneous
in six (26%), and low in 13 (57%) of 23 nodules on the delayed-phase CT images. Signal intensity of nodules was high in 15
(94%) and homogeneous in one (6%) of 16 nodules on T1-weighted MR images and was homogeneous in seven (44%) and low in nine
(56%) of 16 nodules on T2-weighted MR images. Vascularity of nodules was avascular in 14 (88%) and slightly vascular in two
(12%) of 16 nodules.
Conclusions: Hepatic dysplastic nodules show diverse imaging characteristics with different imaging techniques; however, common imaging
findings of hepatic dysplastic nodules are low echo, low attenuation, and high, low, or homogeneous intensity on T1- and T2-weighted
MR, and avascularity.
Received: 13 May 1998/Accepted: 1 July 1998 相似文献
3.
Struma ovarii: MR appearances 总被引:1,自引:0,他引:1
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 相似文献
4.
Detection of lymph-node metastases in patients with gastric carcinoma: comparison of three MR imaging pulse sequences 总被引:9,自引:0,他引:9
Kato M Saji S Kanematsu M Fukada D Miya K Umemoto T Kunieda K Sugiyama Y Takao H Kawaguchi Y Takagi Y Kondo H Hoshi H 《Abdominal imaging》2000,25(1):25-29
Background: To compare the diagnostic accuracy of magnetic resonance (MR) images obtained with three different pulse sequences for lymph-node
metastases in patients with gastric cancer.
Methods: T1-weighted spin-echo (SE), breath-hold T2-weighted fast SE, and triphasic gadolinium-enhanced dynamic gradient-recall-echo
(GRE) MR images obtained in 16 patients with gastric carcinoma were retrospectively reviewed. Regional lymph nodes were assigned
to four different groups, and image review was conducted on a lymph-node group-by-group basis; 64 lymph-node groups were reviewed
by two radiologists. Relative sensitivity, specificity, and accuracy were determined based on the findings with definitive
surgery and follow-up imaging. Diagnostic accuracy was determined by means of receiver-operating-characteristic (ROC) analysis.
Results: Relative sensitivities for lymph-node metastases with T1-weighted SE, breath-hold T2-weighted fast SE, and dynamic GRE images
were 61%, 94%, and 59%, respectively. Relative sensitivity with breath-hold T2-weighted fast SE images was significantly greater
than that with T1-weighted SE (p < 0.05) and dynamic GRE (p < 0.05) images. Diagnostic accuracy determined by ROC analysis was marginally higher with breath-hold T2-weighted fast SE (area under
ROC curve [Az]= 0.87) than with T1-weighted SE (Az = 0.78, p= 0.08) and dynamic GRE (Az = 0.79, p= 0.12) images.
Conclusion: Breath-hold T2-weighted fast SE sequence is useful in the detection of regional lymph-node metastases in patients with gastric
carcinoma.
Received: 11 November 1998/Revision accepted: 7 April 1999 相似文献
5.
Struma ovarii: appearance on MR images 总被引:2,自引:0,他引:2
I. Joja T. Asakawa A. Mitsumori T. Nakagawa Y. Hiraki T. Kudo M. Ando N. Akamatsu 《Abdominal imaging》1998,23(6):652-656
Background: The purpose of this multi-institutional study was to examine the appearance of struma ovarii on magnetic resonance (MR) images.
Methods: MR images of 12 patients with histologically proven struma ovarii were retrospectively reviewed. All patients underwent T1-weighted
and T2-weighted imaging. Contrast-enhanced T1-weighted images with Gd-DTPA were available in 10 patients. The following determinations
were made: tumor morphology, signal intensities, contrast-enhancement effects of solid components with Gd-DTPA, and comparison
of MR images with resected specimens.
Results: All 12 patients had both cystic and solid components, with a multilobulated surface and thickened septa. Signal intensities
on T1-weighted images were mainly low, partly intermediate to high, or high, and those on T2-weighted images were mainly high,
with different signal intensities. Contrast-enhancement effects were marked or moderate. The contents that showed low signal
intensities on T1-weighted images and signal voids or low signal intensities on T2-weighted images were viscid gelatinous
materials.
Conclusions: A multicystic tumor with a solid component, a multilobulated surface, and signal intensities that indicate the presence of
viscid gelatinous materials appear to be a characteristic MR finding of struma ovarii.
Received: 10 April 1997/Accepted after revision: 7 July 1997 相似文献
6.
T. C. L. Soong R. C. Lee H. C. Cheng J. H. Chiang H. S. Tseng C. W. Lin M. M. H. Teng 《Abdominal imaging》1998,23(5):515-519
Background: To report the dynamic magnetic resonance (MR) imaging findings of hepatolithiasis.
Methods: Dynamic MR images (fast spoiled gradient echo sequence with intravenous injection of gadopentate dimeglumine) and computed
tomography, cholangiography, or angiography of nine patients with hepatolithiasis are analyzed.
Results: All affected hepatic segments showed atrophic changes and contained dilated intrahepatic ducts. These segments showed either
iso- or hypointensity on T1-weighted imaging and hyperintensity on T2-weighted imaging. Preferential enhancement was noted
throughout all phases of the dynamic study and persisted to delayed T1-weighted imaging in seven patients. In the last two
patients, severe atrophic changes made evaluating signal intensity differences and enhancement patterns difficult.
Conclusion: In addition to intrahepatic stones and biliary dilatation, segmental atrophy, signal intensity differences, and preferential
and persistent enhancement are important MR findings of hepatolithiasis.
Received: 18 June 1997/Accepted: 23 July 1997 相似文献
7.
Small hepatocellular carcinoma: differentiation from adenomatous hyperplasia with color Doppler US and dynamic Gd-DTPA-enhanced MR imaging 总被引:4,自引:0,他引:4
Background: To investigate the usefulness of color Doppler ultrasound (US) and dynamic Gd-DTPA-enhanced magnetic resonance (MR) imaging
in the differentiation of small hepatocellular carcinoma (HCC) and adenomatous hyperplasia (AH).
Methods: Thirty-eight small (3 cm or less) nodular lesions (in 38 cirrhotic patients) with US features consistent with HCC underwent
evaluation with color Doppler US and MR imaging. Breath-hold T1-weighted rapid acquisition spin echo MR sequence after bolus
injection of 0.1 mmol/kg gadopentetate dimeglumine was used to evaluate dynamic enhancement. US-guided tissue-core percutaneous
biopsy established the diagnosis: HCC in 28 cases and AH in 10.
Results: Color signals with pulsatile or continuous Doppler spectrum were demonstrated in 19 of 28 HCCs (68%) but in none of the AHs.
Although there was considerable overlap in signal intensity between HCC and AH on both unenhanced T1- and T2-weighted images,
early enhancement on breath-hold T1-weighted images obtained 40 s after starting contrast administration was observed in 22
of 28 HCCs (79%) but in none of the AHs. In 26 of 28 HCCs (93%), pulsatile or continuous flow at color Doppler US, early enhancement
at dynamic MR imaging, or both were observed.
Conclusion: Findings with color Doppler US and dynamic Gd-DTPA-enhanced MR imaging enable a reliable distinction between small HCC and
AH.
Received: 8 August 1994/Accepted after revision: 27 January 1995 相似文献
8.
Focal nodular hyperplasia of the liver: detection and characterization with plain and dynamic-enhanced MRI 总被引:2,自引:0,他引:2
Mortelé KJ Praet M Van Vlierberghe H de Hemptinne B Zou K Ros PR 《Abdominal imaging》2002,27(6):0700-0707
Background: We compared nonenhanced and dynamic gadolinium (Gd)–enhanced magnetic resonance imaging (MRI) appearances of hepatic focal
nodular hyperplasia (FNH) as depicted with breath-hold MR sequences and assessed the detectability of the individual MR sequences
used. Methods: We retrospectively reviewed 48 consecutive patients with FNH. All patients underwent nonenhanced (T1 fast low-angle shot
[FLASH] and T2 half-Fourier acquisition [HASTE]) and dynamic Gd-enhanced (T1 FLASH) MRI between December 1997 and March 2000.
Individual MR sequences were analyzed separately for number of lesions, signal intensity features, dynamic enhancement pattern,
and the presence and enhancement profile of a central scar. Ninety-five percent confidence intervals of absolute discrepancy
were calculated to define differences in lesion detection. Results: Seventy-seven lesions were found in 48 patients. Nonenhanced FLASH imaging depicted 59 (76.6%) lesions in 45 patients. HASTE
images showed 55 (71.4%) lesions in 44 patients. On T1- and T2-weighted images, lesions appeared predominantly hypointense
(69.5%) and hyperintense (72.7%), respectively. Arterial and portal venous dominant phase Gd-enhanced MRI demonstrated all
77 lesions (100%), most of which showed hypervascular (94.8%), homogeneous (97.4%), and incomplete (except the central scar:
58.4%) enhancement in the arterial phase. Portal venous phase images showed lesion isointensity (50.6%) or moderate hyperintensity
(46.8%) with complete enhancement (central scar: 94.8%). A central scar was detected on nonenhanced T1-weighted images (hypointense:
100%), T2-weighted images (hyperintense: 100%), arterial phase (hypointense: 59.7%) and portal venous phase (hyperintense:
71.4%) Gd-enhanced images in 78%, 69.1%, 77.9%, and 75.3% of tumors, respectively. Conclusion: Arterial and portal venous phase Gd-enhanced T1-weighted sequences are superior to nonenhanced images in the detection of
FNH. Typical MRI appearances include hypointensity on T1-weighted and hyperintensity on nonenhanced T2-weighted images. Most
commonly, FNH shows a homogeneous (without scar) and strong enhancement during the arterial phase, with lesion isointensity
or slight hyperintensity during the portal venous phase.
Received: 15 May 2001/Revision accepted: 22 August 2001 相似文献
9.
Background: To elucidate the imaging characteristics of well-differentiated hepatocellular carcinomas (HCCs) on ultrasonography (US),
computed tomography (CT), and magnetic resonance (MR) imaging.
Methods: Ultrasonograms, CTs, and MR images of 18 histopathologically proven well-differentiated HCCs in 15 patients were reviewed.
The findings of these images were correlated with histopathologic findings.
Results: On US, seven tumors were depicted as a hyperechoic area and eight as a hypoechoic area. Three tumors were not visualized.
On precontrast CT, four tumors were depicted as a low-density area, but 14 were not visualized. On conventional contrast-enhanced
CT, 12 tumors were depicted as a low-density area but six were not visualized. On T1-weighted MR images, 10 tumors had high
signal intensity and two had low signal intensity. Six tumors were not visualized. On T2-weighted MR images, five tumors had
high signal intensity and two had low signal intensity. Eleven tumors were not visualized. Tumors with fatty change and/or
clear cell formation were frequently hyperechoic on US and hyperintense on T1-weighted MR images.
Conclusions: Well-differentiated HCCs show different findings on US, CT, and MR imaging. Therefore, reliable diagnosis of well-differentiated
HCCs by these imaging techniques may be difficult.
Received: 29 April 1998/Revision accepted: 15 July 1998 相似文献
10.
Background: Double contrast magnetic resonance (MR) imaging using superparamagnetic iron oxide (SPIO) and gadolinium (Gd) is performed to detect and characterize focal liver lesions. However, this technique is a costly and lengthy process. The purpose of this study was to determine the usefulness of SPIO-enhanced MR imaging including SPIO-enhanced T1-weighted imaging in diagnosing focal liver lesions.
Methods: Eighty-four focal liver lesions were examined with a 1.5-T MR unit. Transverse precontrast T1- and T2-weighted images and SPIO (ferumoxides)-enhanced T1- and T2-weighted images were obtained, followed by Gd-enhanced T1-weighted imaging. The Gd set (i.e., precontrast T1- and T2-weighted and delayed-phase gadolinium-enhanced T1-weighted images) and ferumoxides set (i.e., precontrast T1- and ferumoxides-enhanced T1- and T2-weighted images) were reviewed by two independent readers.
Results: More lesions were detected from the ferumoxides set than from the Gd set. Ferumoxides-enhanced T1-weighted imaging showed enhancement patterns of the lesions similar to those of delayed-phase Gd-enhanced T1-weighted imaging. The diagnoses of hepatic metastasis and cyst by the ferumoxides set were similar to those by the Gd set. However, a dynamic study may be inevitable for the diagnosis of hepatocellular carcinoma and hemangioma.
Conclusion: The ferumoxides set was useful for the detection of focal hepatic lesions. Ferumoxides-enhanced T1-weighted imaging may replace delayed-phase gadolinium-enhanced T1-weighted imaging in the diagnosis of hepatic metastasis and cysts. 相似文献
11.
Background: We compared T2-weighted and heavily T2-weighted breath-hold turbo spin-echo (TSE) sequences with T2-weighted non-breath-hold
TSE sequence to evaluate hepatic hemangiomas on magnetic resonance (MR) with a phased-array multicoil.
Methods: Twenty-two patients with 27 hemangiomas were studied at 1.0-T scanner by using T2-weighted and heavily T2-weighted breath-hold
TSE sequences (18 s each) and non-breath-hold T2-weighted TSE sequences with use of a phased-array multicoil. Images were
quantitatively analyzed for tumor-to-liver signal-difference-to-noise ratios (SD/Ns) and tumor-to-liver signal intensity ratios
(T/Ls) and qualitatively analyzed for tumor conspicuity and motion-induced image artifacts.
Results: Quantitatively, T2-weighted breath-hold TSE images showed the highest SD/Ns among the three sequences, although the differences
from the heavily T2-weighted breath-hold TSE sequence and the T2-weighted non-breath-hold TSE sequence were not statistically
significant (p= 0.61 and 0.06, respectively). Heavily T2-weighted breath-hold TSE images showed the highest T/Ls among the three sequences.
The differences from the T2-weighted breath-hold TSE sequence and the T2-weighted non-breath-hold TSE sequence were statistically
significant (p < 0.001). Qualitatively, breath-hold TSE images were superior to non-breath-hold TSE images in terms of tumor conspicuity
(p < 0.01) and motion artifacts (p < 0.01).
Conclusion: T2-weighted breath-hold TSE sequence is superior to T2-weighted non-breath-hold TSE sequence in the evaluation of hepatic
hemangiomas on MR with a phased-array multicoil.
Received: 7 April 1997/Accepted: 28 May 1997 相似文献
12.
MR imaging of cervical carcinoma: comparison among T2-weighted,dynamic, and postcontrast T1-weighted images with histopathological correlation 总被引:4,自引:0,他引:4
K. Tsuda T. Murakami H. Kurachi H. Ogawa H. Oi A. Miyake Y. Narumi H. Nakamura 《Abdominal imaging》1997,22(1):103-107
Background: To identify the reasons for misdiagnosis of the degree of stromal invasion by uterine cervical cancer with various magnetic
resonance sequences.
Methods: T2-weighted, dynamic, and postcontrast T1-weighted images were obtained in the sagittal plane in 20 patients with uterine
cervical cancer. After evaluating these sequences for the degree of stromal invasion, histologic specimens were directly correlated
with these images.
Results: The degree of stromal invasion was correctly diagnosed in 15 of the 20 cases on T2-weighted images, in 12 on dynamic images,
and in eight on postcontrast T1-weighted images. All misdiagnoses were due to overestimation. Histologically, peritumoral
stroma showed inflammation or edema in two patients, whereas no histological abnormality was found in the other patients.
A hyperintense rim, i.e., a peritumoral enhanced ring-shaped structure, was observed on the enhanced images of five patients.
The hyperintense rim corresponded to the periphery of the tumor in three patients and to the cervical stroma in two patients.
Conclusion: T2-weighted images permitted the most accurate evaluation of stromal invasion by uterine tumors. Overdiagnosis may be due
to an abnormal intensity of the cervical stroma, which was observed more frequently on dynamic and postcontrast T1-weighted
images than on T2-weighted images.
Received: 10 November 1995/Accepted after revision: 13 March 1996 相似文献
13.
R. A. Huch Böni C. Meyenberger J. Pok Lundquist F. Trinkler U. Lütolf G. P. Krestin 《Abdominal imaging》1996,21(4):345-352
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 相似文献
14.
Background: We describe the computed tomographic (CT) and magnetic resonance imaging (MRI) findings of hepatic metastases caused by soft tissue angiosarcomas to clarify the relation between radiologic appearances and clinicopathologic features.Methods: CT and MR examinations of 13 patients with hepatic metastases of soft tissue angiosarcoma were retrospectively analyzed.Results: Contrast-enhanced CT images showed multiple hypoattenuating lesions relative to the adjacent liver parenchyma. Lesions contained peripheral areas of enhancement in eight patients (62%). Tumors showed cystic attenuation with fluid–fluid levels, which were suggestive of hemorrhage in five patients (38%). In one patient (8%) with cystic attenuation and fluid–fluid levels, lesions also contained marked enhanced nodular portions located centrally or peripherally. On T1-weighted MR images, all four liver tumors appeared heterogeneous and hypointense relative to adjacent liver parenchyma. Fluid–fluid levels were identified on T2-weighted MR images in five patients (38%). After an intravenous bolus of gadolinium-based contrast material was administered, slight peripheral enhancement was seen in three patients (75%).Conclusion: The common CT findings of metastatic angiosarcoma in our series were multiple hypoattenuating lesions often associated with nodular enhancement and cystic lesions with hemorrhagic change. 相似文献
15.
We report the magnetic resonance findings of an unusual hemangioma in the lesser omentum. A well-circumscribed, large mass
was identified between the stomach and the left lobe of the liver, with compression of adjacent liver parenchyma. The mass
showed low signal intensity (SI) on T1-weighted images, high SI on T2-weighted images with multiple septa, and slightly decreased
SI on out-of-phase T1-weighted images. After gadolinium contrast administration, septa within the mass showed minimal enhancement
on 30-s T1-weighted images and mild enhancement on 5-min T1-weighted images. The mass was histopathologically diagnosed as
a cavernous hemangioma comprised of multiple vascular spaces, fibrotic tissue, and adipocytes.
Received: 1 December 1999/Accepted: 12 January 2000 相似文献
16.
Cervical carcinoma: efficacy of thin-section oblique axial T2-weighted images for evaluating parametrial invasion 总被引:5,自引:0,他引:5
M. Shiraiwa I. Joja T. Asakawa K. Okuno O. Shibutani N. Akamatsu T. Kudo Y. Hiraki 《Abdominal imaging》1999,24(5):514-519
Background: To investigate the efficacy of thin-section oblique axial T2-weighted images in the assessment of parametrial invasion by
cervical carcinoma.
Methods: One hundred parametria of 50 patients with cervical carcinoma were evaluated with pathologic correlation. We compared the
sensitivity, specificity, and diagnostic accuracy in the assessment of parametrial invasion by cervical carcinoma between
axial T2-weighted images and thin-section oblique axial T2-weighted images.
Results: Thin-section oblique axial T2-weighted images provided accurate cross sections of the cervix with excellent detail and detected
parametrial invasion more accurately than did axial T2-weighted images showing cross sections of the trunk. Although the sensitivity,
specificity, and accuracy for parametrial invasion were 46.4%, 91.7%, and 79.0%, respectively, on axial T2-weighted images,
the corresponding values were 67.9%, 97.2%, and 89.0%, respectively, on thin-section oblique axial T2-weighted images. There
were statistically significant differences in the sensitivity (p = 0.014), specificity (p = 0.046), and accuracy (p = 0.002) in detecting parametrial invasion between these two types of images.
Conclusions: Thin-section oblique axial T2-weighted images are useful for the assessment of parametrial invasion by cervical carcinoma.
Received: 11 September 1998/Accepted: 2 December 1998 相似文献
17.
Hepatic parenchymal enhancement in the cirrhotic liver: evaluation by triple-phase dynamic MRI 总被引:7,自引:0,他引:7
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 相似文献
18.
Dynamic enhancement of upper abdominal organs in normal volunteers with MRI and effects of contrast dose reduction 总被引:3,自引:0,他引:3
Background: To quantify enhancement parameters of the upper abdominal organs over time during magnetic resonance (MR) examinations and
to evaluate the effect of a dose reduction of contrast medium on these parameters.
Methods: Ten volunteers underwent two separate dynamic enhanced MR examinations with 0.1 and 0.075 mmol/kg of contrast medium, respectively.
Breath-hold gradient-echo T1-weighted images were acquired every second for 118 s followed by delayed images. The percentages
of enhancement, the time to maximum enhancement, and the area under the time-versus-enhancement curve were calculated for
each organ.
Results: The mean times to maximum percentage of enhancement were less than 25 s for the pancreas, kidneys, and spleen and 50 s for
the liver. The mean values of maximum percentage of enhancement for the standard/reduced doses were 72%/62% (pancreas), 165%/155%
(kidneys), 114%/87% (spleen), and 67%/53% (liver). This difference was significant when liver enhancement was considered (p= 0.02). In addition, when the areas under the time-versus-enhancement curves were compared, the difference between the standard
dose and reduced dose was significant for all organs tested (p < 0.05).
Conclusions: Dynamic scanning of the upper abdomen should start early after contrast injection. Injection parameters should be standardized
to capture arterial and venous enhancements in liver examinations. A 25% dose reduction did not significantly affect peak
enhancement (except for the liver) but did significantly reduce overall enhancement.
Received: 8 September 1998/Revision accepted: 13 January 1999 相似文献
19.
Background: To evaluate the relationship between magnetic resonance (MR) imaging grading of iron deposition and serial serum ferritin
concentration in patients with chronic viral liver diseases.
Methods: In 80 patients with viral hepatitis and cirrhosis, MR images including T2*-weighted gradient echo images (echo time ≥ 6.5
ms) were reviewed. The grades of parenchymal iron deposition and iron-containing nodules in the liver and spleen and the liver-to-muscle
and spleen-to-muscle signal intensity ratios were compared with the most recent, the mean, the lowest, and the highest values
from all available serum ferritin levels.
Results: The serum ferritin concentration was significantly correlated with the grades of iron deposition in liver and spleen and
with the grades of iron-containing nodules seen on MR images (p < 0.05). Liver-to-muscle signal intensity ratio was weakly correlated with the ferritin concentrations. Among categories of ferritin
concentration, correlation with MR grades was highest for mean ferritin concentration (r = 0.487, p < 0.001).
Conclusion: MR imaging grades of hepatic iron and siderotic nodules correlate with serum ferritin, especially with the mean levels.
Received: 9 May 2000/Accepted: 28 June 2000 相似文献
20.
M. Kanematsu H. Hoshi T. Yamada T. Murakami T. Kim M. Kato R. Yokoyama H. Nakamura 《Abdominal imaging》1999,24(1):47-55
Purpose: The purpose of this study was to assess the imaging findings of pathologically-proved small hepatic nodules 2 cm in size
or smaller detected with ultrasonography in cirrhotic patients with suspected hepatocellular carcinoma (HCC).
Materials and Methods: We evaluated sonographically detected 32 small hepatic nodules which were pathologically confirmed in 23 consecutive cirrhotic
patients who were suspected of having HCC. Twenty-six lesions were confirmed with ultrasonographically-guided aspiration needle-core
biopsy, and six with definitive surgery. Ultrasonographic examination records were retrospectively reviewed. CT, and MR images
obtained with various imaging techniques were retrospectively reviewed by two radiologists in a blind fashion.
Results: The 32 hepatic nodules were comprised of seven focal fatty changes, two large regenerative nodules, three low-grade dysplastic
nodules, five high-grade dysplastic nodules, and fifteen HCCs. Ultrasonography showed various echogenicity for the hepatic
nodules. The signal-intensity characteristics with T1-weighted spin-echo, in-phase gradient-recalled-echo, and dynamic MR
imagings may be useful in distinguishing HCC from nonHCC nodules.
Conclusions: Nearly half of small hepatic nodules detected with ultrasonography were nonHCC nodules. Ultrasonographic findings may not
be reliable in characterizing small hepatic nodules in cirrhosis. CT and MR imaging obtained with the various techniques are
still insensitive to these hepatic nodules.
RID="ID="<e5>Correspondence to:</e5> M. Kanematsu
Received: 25 August 1997/Revision accepted: 19 November 1997 相似文献