Intrahepatic portosystemic venous shunts: spectrum of CT findings in external and internal subtypes

PURPOSE

The purpose of this work was to survey the spectrum of CT findings in intrahepatic portosystemic venous shunts (IPSVSs).

METHOD

One thousand consecutive liver CT scans examined with an enhanced helical technique were retrospectively reviewed on workstation to find IPSVSs.

RESULTS

IPSVSs were noted in 37 patients and divided into two subtypes according to the location of the communicating systemic vein, either outside (external type, n = 34) or within (n = 4) the liver (one patient had both internal and external types). All the external-type shunts were noted in cases with portal hypertension (n = 34). Most shunts (n = 30) ran through segment 4 and/or 3 and came out near the falciform ligament, but five shunts were noted in segment 2 communicating either with the systemic vein (n = 3) or probably with an enlarged left gastric vein (n = 2). Solitary portohepatic venous shunts (internal type) were noted in three cases with (n = 2) or without (n = 1) aneurysmal dilatation and many portohepatic venous shunts in another patient.

CONCLUSION

IPSVSs of the external type were far common than those of the internal type, always associated with increased pressure of the portal system and in specific sites probably lacking the hepatic capsule.

High temporal resolution dynamic contrast MRI in a high risk group for placenta accreta

Antenatal diagnosis of placenta accreta with MR is not easy even now because T2-weighted images (T2WI) cannot differentiate chorionic villi from decidua basalis. We performed dynamic contrast MRI to study whether trophoblastic villi could be separately demonstrated from the decidua basalis, and whether the contrast resolution between the placenta and myometrium could improve compared to T2WI. Six pregnant women with prior cesarean section were examined at 34-38 gestational weeks. Sagittal T2-weighted images with fast spin echo sequences and dynamic contrast studies with fast field echo sequence every 10-14 s after contrast injection were performed. We analyzed the enhancing pattern of the placenta and compared the contrast between placenta and myometrium. We reviewed medical records to identify complications during the placental delivery and the complications of their newborns. In the early phase after contrast enhancement, multiple foci of the strong lobular enhancement were observed in all cases. Other parts of placenta were slowly but strongly enhanced following them. We speculated that the former corresponded to intervillous space and the latter decidua basalis. The contrast between placenta and myometrium tended to be distinct near the inner cervical os on both T2WI and dynamic contrast study. On the other hand, it was indistinct in the upper part of the uterine body on T2WI despite it was clearly demonstrated on dynamic contrast study. The placentae were delivered without any complication in all cases. Although two neonates showed fetal distress, none of the infant remained any sequelae at the time of the discharge. The other four were well although one of them complicated with meconium staining. As dynamic contrast MRI can differentiate chorionic villi and decidua basalis, and can provide excellent contrast between placenta and myometrium at anywhere within the uterus, it may be a promising technique for antepartum diagnosis of the placenta accreta.

Influence of postsurgical residual tumor volume on local control in radiotherapy for maxillary sinus cancer

BACKGROUND

The aim was to study the influence of postsurgical gross residual tumor volume on local control of maxillary sinus cancer treated with radiotherapy combined with debulking surgery.

METHODS

Forty-three patients who underwent combined surgery and radiotherapy (50-72 Gy, median 60 Gy) for squamous cell carcinoma of the maxillary sinus were reviewed. Gross residual tumor volume (GRTV) after surgery was measured on computed tomograms obtained during the radiotherapy planning. Patients were classified according to GRTV as follows: group AA, GRTV = 0 (microscopic residual, n = 2); group A, GRTV < 10 cm3 (n = 24); group B, 10-40 cm3 (n = 9); and group C, > or = 40 cm3 (n = 8). The relationship between local control and GRTV was analyzed using univariate and multivariate analysis.

RESULTS

The 2-year local control rate for all patients was 62%. The differences in local control rates between groups AA, A and B were not significant (P > 0.05), but the rate was significantly lower in group C than in the other groups (69% at 2 years vs 31% at 1 year, P < 0.001). Multivariate analysis showed that GRTV (P = 0.002) and histological differentiation (poorly differentiated histology was favorable, P = 0.035) were independent prognostic factors and that intra-arterial chemotherapy and administered total dose were not. Local control in groups A and B significantly depended on the total dose of radiotherapy, with 2-year control rates of patients receiving 50 Gy (n = 6) and > or = 60 Gy (n = 27) of 17% vs 79%, respectively (P < 0.001).

CONCLUSIONS

Our data suggest that adequate, not complete, debulking associated with a total radiotherapy dose of > or = 60 Gy can provide satisfactory local control for patients with squamous cell carcinoma of the maxillary sinus.

Utility of serum CA 19-9 monitoring in preoperative radiotherapy for pancreatic cancer

BACKGROUND/AIMS

Pancreatic cancer is extremely refractory even to aggressive treatments including surgery, resulting in early metastasis and/or local recurrence. We investigated changes in serum tumor marker CA 19-9 levels during preoperative radiotherapy in conjunction with initial treatment failure.

METHODOLOGY

Twenty-three patients presenting with localized disease and an increased serum CA 19-9 level, who were slated to undergo pancreatectomy and/or intraoperative radiotherapy following preoperative radiotherapy were reviewed. CA 19-9 response, the ratio of post-radiotherapy level before laparotomy to pre-radiotherapy level, was analyzed in relation to disease-control time and survival.

RESULTS

Eleven patients revealed metastasis at restaging or laparotomy; 12 patients (52%) completed aggressive treatments. Initial failure was identified at the liver (52%), peritoneum (52%), or local site (26%) with a median disease-control time of 91 days; 7 patients showed combined failure. All but 1 patient died of cancer with a median survival time of 264 days. CA 19-9 response (range: 0-1185%) did not correlate with disease-control time or survival; 8 progressive-disease patients (> 140% response), however, showed significantly shorter disease-control time than 15 nonprogressive-disease patients (< or = 140% response).

CONCLUSIONS

CA 19-9 monitoring is useful in preoperative radiotherapy for identifying patients who will not benefit by succeeding aggressive treatments by predicting early metastasis.

Preliminary experiment of fluorescent X-ray computed tomography to detect dual agents for biological study

The simultaneous observation of various information, such as blood flow, tissue metabolism and distribution of receptors, is quite important in order to understand the functional state of biomedical objects. The simultaneous detectability of contrast agents by fluorescent X-ray computed tomography (FXCT) with synchrotron radiation is examined in this study. The system consisted of a silicon (111) double-crystal monochromator, an X-ray slit system, a scanning table, a PIN diode, a highly purified germanium detector and an X-ray charge-coupled device (CCD) camera. The monochromatic X-ray beam energy was adjusted to 37.0 keV and collimated into a pencil beam of 1 x 1 mm. The fluorescent spectra of the K alpha lines for iodine and xenon were detected simultaneously. FXCT could image the distribution of both iodine and xenon agents in a phantom clearly and the contrast ratio was significantly better than that of transmission X-ray computed tomography images.

MR imaging of the flexed knee: comparison to the extended knee in delineation of meniscal lesions

The aim of this study was to obtain MR images in the flexed-knee position and to compare the diagnostic value to the extended position in delineation of the menisci. With a mobile knee brace and a flexible surface coil, the knee joint was either fully extended or bent to a semi-flexed position (average 45 degrees of flexion) within a 1.5-T superconducting magnet. Sets of sagittal MR images were obtained for both the extended- and flexed-knee positions. Using the arthroscopic results as gold standards, 97 menisci were evaluated. Two observers interpreted each MR image of the extended and flexed positions independently without knowledge of the arthroscopic results. Flexed-knee MR images revealed 22 of the 27 arthroscopically proven torn menisci and 69 of the 70 intact menisci, for a sensitivity of 81.5%, a specificity of 98.6%, and an accuracy of 93.8%. Extended-knee MR images indicated a sensitivity of 81.5%, a specificity of 92.9%, and an accuracy of 89.7%. No statistically significant difference was found between the two positions. To enhance MR visualization of all the knee components, we recommend examining the knee in a flexed position within the magnet.

Evaluation of the vestibular aqueduct in vestibulocochlear disorders by magnetic resonance imaging

The visibility of the vestibular aqueduct (VA) was examined using magnetic resonance imaging (MRI) in 95 patients: 15 patients with Meniere's disease, 4 with vestibular Meniere's disease, 4 with cochlear Meniere's disease and 72 patients with other vestibular and/or cochlear disorders. In order to visualize the VA, the T2-weighted image (T2WI) and the proton-density weighted image (PDWI) were obtained in the sagittal plane with a head coil. The visibility of the VA was classified into 4 grades, i.e. grade 0 (not visible), grade 1 (partially visible with PDWI), grade 2 (partially visible with T2WI) and grade 3 (clearly visible with T2WI). The visibility of the VA was significantly lower bilaterally in Meniere's disease, vestibular Meniere's disease, cochlear Meniere's disease and idiopathic bilateral sensorineural hearing loss (IBSNHL) than in the other diseases. The differences among Meniere's disease, vestibular Meniere's disease and cochlear Meniere's disease were not significant. The significance of decreased visibility in IBSNHL is unknown so far. The VA studies using MRI strongly suggest that the pathogenesis of Meniere's disease, vestibular Meniere's disease, cochlear Meniere's disease and IBSNHL is, at least in part, related to the findings of the VA.

Biopsy of lung nodules with use of I-I device under intermittent CT fluoroscopic guidance: preliminary clinical study

PURPOSE

To investigate the efficacy of computed tomography (CT) fluoroscopy and a new needle holder (the I-I device) in lung nodule biopsy.

MATERIALS AND METHODS

The I-I device is made of acrylate resin and was used to keep the entire needle in the tomographic plane. This study consisted of biopsies of 79 lung nodules in 77 patients. The final diagnoses were malignant in 54 patients, benign in 23, and unconfirmed in two. The biopsy procedure time from the beginning of the CT fluoroscopy procedure to the removal of the needle was measured for 24 needle passes. The radiation dose on the physician's hand was measured in five cases with use of a thermoluminescence ring.

RESULTS

Fifty-one malignant and 20 benign lesions were correctly diagnosed with histologic specimens (90%). In 58 of 77 patients (75%), the biopsy procedures were completed within a single breath-hold. Pneumothorax occurred in 20 of 77 patients (26%) and chest tube insertion was required in five. The incidence of pneumothorax was significantly lower in patients who held their breath during biopsy procedures compared with those who did not (P < .0001; chi2 test). The biopsy procedure time ranged from 15 to 39 seconds (mean: 28.2 sec). The mean radiation dose on the physician's hand was 2 mSv/case.

CONCLUSION

The diagnostic accuracy of biopsy with use of the I-I device under CT fluoroscopic guidance is comparable with that of the conventional method; however, a combination of CT fluoroscopy and the I-I device enables rapid biopsy procedures.

Recurrent hepatocellular carcinoma versus radiation-induced hepatic injury: differential diagnosis with MR imaging

The objective of this study was to assess the value of MR imaging in the differentiation between a recurrent hepatocellular carcinoma (HCC) and a radiation-induced hepatic injury. Nine male patients with suspected recurrence after radiotherapy for HCC underwent T(2)-, T(1)-weighted imaging and Gd-DTPA enhanced dynamic studies. T(2) relaxation times, signal intensity ratios in T(1)-weighted images (WI) and the relative enhancement of the dynamic study were calculated. Recurrent tumors and the irradiated area showed similar image characteristics: hypointense in T(1)-WI and hyperintense in T(2)-WI. T(2) values and signal intensity ratios in the T(1)-WI were not significantly different. In the gadolinium-enhanced dynamic study, a recurrent HCC showed early enhancement, followed by a rapid washout. However, the irradiated liver parenchyma showed hyperintensity from an early phase, and contrast enhancement tended to be more prominent and prolonged at the end of the dynamic studies. The characteristic findings of the dynamic MR study enable us to distinguish between a recurrent HCC and a radiation-induced hepatic injury.

Arterioportal shunts in cirrhotic patients: evaluation of the difference between tumorous and nontumorous arterioportal shunts on MR imaging with superparamagnetic iron oxide

OBJECTIVE

The study objective was to distinguish between the features of tumorous and nontumorous arterioportal shunts on superparamagnetic iron oxide-enhanced MR imaging in patients with cirrhosis.

SUBJECTS AND METHODS

Ten arterioportal shunts in eight patients, including four tumorous and six nontumorous arterioportal shunts, were evaluated on T2-weighted turbo spin-echo and T2(*)-weighted gradient-echo sequences before and after administration of superparamagnetic iron oxide. Qualitatively, the relative signal intensity of the arterioportal shunt compared with that of the surrounding liver parenchyma was categorized into three grades: high, slightly high, and not detected. Quantitatively, signal-to-noise ratio, contrast-to-noise ratio, lesion-to-liver contrast, and percentage enhancement were calculated and compared between tumorous and nontumorous arterioportal shunts by a nonparametric statistical test (Mann-Whitney test).

RESULTS

Qualitatively, all four tumorous arterioportal shunts appeared as areas of slightly high or high intensity without and with superparamagnetic iron oxide on T2-weighted turbo spin-echo images and changed from isointensity to high intensity after the administration of superparamagnetic iron oxide on T2(*)-weighted gradient-echo images. All nontumorous arterioportal shunts except one could not be recognized without or with superparamagnetic iron oxide on either sequence. Quantitatively, with superparamagnetic iron oxide the contrast-to-noise ratio and the lesion-to-liver contrast of the tumorous arterioportal shunts were significantly higher than those of the nontumorous arterioportal shunts.

CONCLUSION

Tumorous arterioportal shunts are seen as areas of reduced signal loss, whereas most nontumorous arterioportal shunts are seen as areas of normal signal loss, like the normal liver parenchyma. The difference is more marked on T2(*)-weighted gradient-echo images than on T2-weighted turbo spin-echo images.

MRI of gynaecological solid masses

Differential diagnosis of gynaecological masses is sometimes difficult, as there are so many histological types. However, magnetic resonance characteristics of some gynaecological tumours have been reported past several years. On the basis of the recent literature, we have made a decision tree for differential diagnosis of solid gynaecological tumours, in which there are some important divergences. Bilateral disease and invasive growth are malignant signs in most cases. Specific findings for different tumour types include: fibrovascular septa in dysgerminomas; preserving ovarian follicles in round cell tumours; pseudolobular patterns in young patients in sclerosing stromal tumours; and extremely hypointense masses on T2WI in Brenner tumours. Distinguishing between sex-cord stromal tumours, Brenner tumours and metastatic tumours may be hard, however, especially in middle age, because they all tend to show well-demarcated, hypointense masses on T2WI. Disproportionately clear zonal anatomy of the uterus, enlarged uterus and thickened endometrium, which are indirect findings of oestrogen-producing tumours, are useful diagnostic findings in children and postmenopausals.

[T1-weighted vs. short-TE-long-TR images: usefulness for knee MR examinations of ligament and meniscal lesions]

The purpose of this study was to compare short-TE-long-TR images with T1-weighted images in knee MR examinations. Sagittal MR images of the knee were obtained in 31 patients with knee pain. T1-weighted images were obtained by the spin-echo technique (TR/TE = 350/15), and short-TE-long-TR images by fast spin-echo (TR/TE = 1300/15) with an echo-train length of 5. Contrast-to-noise-ratios (CNRs) of the anterior cruciate ligament and synovial space, meniscus and articular cartilage, and meniscal lesion and normal meniscus were compared between short-TE-long-TR images and T1-weighted images. On each of the three examinations, short-TE-long-TR images provided significantly higher CNRs than T1-weighted images. It was concluded that short-TE-long-TR images can be a useful alternative to T1-weighted images in evaluating the anterior cruciate ligament and meniscal lesions.

Ovarian carcinoma in patients with endometriosis: MR imaging findings

OBJECTIVE

Various types of malignancy can develop in patients with endometriosis. Enhancing mural nodules have been reported as an imaging characteristic of malignant transformations. We evaluated contrast-enhanced MR imaging to determine the optimum sequence to reveal mural nodules and other characteristics of malignant transformations.

MATERIALS AND METHODS

We examined 10 patients with pathologically proven ovarian adenocarcinoma in endometriosis and 10 patients (the control group) with ovarian endometrioma suggestive of malignant transformation on the basis of sonographic findings. We analyzed the size and nature of the endometriomas in each patient. We compared four types of contrast-enhanced MR imaging to determine which sequence best revealed mural nodules.

RESULTS

In the malignant and control groups, 80% of the cysts with findings suggestive of malignant transformation showed unilateral disease or larger endometrial cysts on the suggestive side than on the contralateral side. High signal intensity on T1-weighted images and low signal intensity on T2-weighted images relative to the myometrium were observed only in two of 10 malignant endometrial cysts and in all control cysts. All malignant endometriomas had small mural nodules with low signal intensity on T1-weighted contrast-enhanced images. Only three benign endometriomas had mural nodules and none of them enhanced. The enhancement of mural nodules was easily seen on dynamic subtraction imaging.

CONCLUSION

On the basis of our findings, endometrial cysts with malignant transformation rarely show low signal intensity on T2-weighted images and usually have enhancing mural nodules. Because the enhancement of mural nodules is often difficult to evaluate on conventional T1-weighted images, dynamic subtraction imaging can be valuable.

Reevaluation of spiral CT cholangiography: basic considerations and reliability for detecting choledocholithiasis in 80 patients

PURPOSE

The purpose of this work was to reevaluate the characteristics and diagnostic accuracy of spiral CT cholangiography (CTC) for detecting biliary calculi.

METHOD

Spiral CTC was performed in 133 patients with suspected biliary or pancreatic diseases. All source images were reviewed by two radiologists who were unaware of final diagnoses. Attenuation values of bile were correlated with biochemical data and visualization of anatomic detail. The statistical measures in detecting the presence of choledocholithiasis were calculated in 80 patients with confirmed diagnoses.

RESULTS

Statistically significant correlations were found between the degree of biliary enhancement and both serum bilirubin and alkaline phosphatase levels. Of the 80 patients, 18 (23%) had choledocholithiasis and 62 did not. Observers diagnosed them with a sensitivity of 89% and a specificity of 98%. A mild adverse reaction to contrast material was observed in three (2.3%) patients.

CONCLUSION

Spiral CTC is a reliable, noninvasive, and accessible technique for detecting choledocholithiasis.

Superparamagnetic iron oxide-enhanced MR imaging for early and late radiation-induced hepatic injuries

Superparamagnetic iron oxide (SPIO)-enhanced MRI was performed in twenty-one patients undergoing proton-beam radiotherapy for hepatocellular carcinomas. Patients were divided into two groups: early and late phase hepatic injuries. Each group was investigated 3 to 9 weeks and 4 to 65 months after the start of irradiation, respectively. T(1)-weighted, T(2)-weighted, and T(2)*-weighted images were obtained before and after SPIO administration. In all postcontrast sequences in the early phase, irradiated livers demonstrated relatively higher intensity than nonirradiated livers and the radiation-to-liver contrast-to-noise ratio (C/N) was improved. Postcontrast T(2)*-weighted images showed the highest C/N. In the late phase, the irradiated areas showed high intensity on T(2)-weighted images and low intensity on T(1)-weighted images without SPIO, while high intensity on T(1)-weighted images with SPIO. The C/N increased with SPIO in all sequences and postcontrast T(2)-weighted images showed the highest C/N in the late phase. SPIO-enhanced MRI is useful to evaluate this entity both in the early and late phase of clinical studies.

MR imaging of hepatocellular carcinoma

MR imaging is useful in the diagnosis and early detection of HCC. Characteristic findings for overt HCC, a pseudocapsule and an intratumoral mosaic pattern, are better demonstrated on MR imaging than by other imaging modalities such as ultrasound and CT scanning. Signal intensity on T2-weighted images is useful in evaluating the grade of malignancy of hepatocytic nodular lesions. Hyperintensity on T1-weighted MR imaging is almost always seen in precancerous hepatocellular lesions and in about one third of overt HCC tumors, whereas other hepatic tumors show hypointensity on T1-weighted MR imaging. In evaluating tumor vascularity, gadolinium-enhanced dynamic MR imaging is an essential and powerful tool.

Blood vessels: depiction at phase-contrast X-ray imaging without contrast agents in the mouse and rat-feasibility study

The ability of phase-contrast x-ray imaging to depict blood vessels without contrast agents was tested by observing livers of a mouse and a rat with synchrotron x rays. Livers were excised by tying arteries and veins to prevent blood from flowing out of the liver. An x-ray interferometer was used to obtain x-ray phase contrast. With the technique of phase-shifting x-ray interferometry, the image mapping x-ray phase shift caused by a liver was measured. The x-ray phase shift caused by blood was substantially different from that caused by other soft tissues; consequently, trees of blood vessels were revealed on the image. Vessels with diameter smaller than 0.1 mm were recognized. This result allows new possibilities for investigation of the vascular system.

[Rapid production of gelatin sponge particles for transcatheter arterial embolization: pumping method]

We devised a simple "pumping" method to make gelatin sponge particles for transcatheter arterial embolization. As the frequency of pumping increased, the number of particles 0.2-1.6 mm in diameter increased, whereas no particles of more than 3.2 mm in diameter were present after 20 pumpings. After passing through the microcatheter, particles of less than 0.2 mm in diameter were relatively increased by about 10 points in both the pumping and cutting methods. It was histologically demonstrated that the size of embolized arteries corresponded well to the size of particles. These results suggest that our "pumping" method offers sufficient quality for transcatheter arterial embolization.

Highly enhanced hepatic masses seen on CT during arterial portography: early hepatocellular carcinoma and adenomatous hyperplasia

BACKGROUND

To describe computed tomographic (CT) features of highly enhanced hepatic masses as seen on CT during arterial portography (CTAP) and to survey the varieties of hepatic lesions associated with such findings.

METHODS

CTAP files for 400 patients were reviewed, on the basis of which six patients with highly enhanced hepatic masses were selected. These six patients also subsequently underwent CT during hepatic arteriography (CTHA) on the same day. All the patients had chronic liver damage, which was cirrhotic in five cases. Five had a current diagnosis and one had a history of hepatocellular carcinoma (HCC).

RESULTS

Solitary highly enhanced masses were observed on CTAP in three patients, three masses were seen in one patient and multiple (10-12) masses in the other two patients. All the CTAP-enhanced masses except one were round in shape and homogeneous in attenuation. The size of the mass ranged from 6 to 25 mm in diameter. In all except two nodules in one patient, the masses were hypoattenuated on CTHA. On histopathological examination of five nodules in three patients, the nodular lesions were consistent with so-called early HCC (well-differentiated HCC of Edmondson I) in four nodules and adenomatous hyperplasia in the other nodule.

CONCLUSIONS

Highly enhanced hepatic masses relative to the surrounding liver parenchyma have been sporadically noted on CTAP, especially in patients with liver cirrhosis. When present, such nodules are typically hypoattenuated on CTHA and histological features are consistent with early HCC and adenomatous hyperplasia.

New types of X-ray computed tomography (CT) with synchrotron radiation: fluorescent X-ray CT and phase-contrast X-ray CT using interferometer

New types of X-ray computed tomography (CT), fluorescent X-ray CT and phase-contrast X-ray CT are being developed for biomedical research. While fluorescent scanning X-ray CT (FXCT) can detect specific contrast elements, or endogenous iodine, at very low content (less than 400 pg iodine of tissue in a volume of 8 x 10(-6) ml), the phase-contrast X-ray CT (PCCT) is a highly sensitive imaging technique to differentiate between different biological tissue types (based on their specific gravity variation) without the use of a contrast agent. Therefore, we can expect functional diagnosis with FXCT, and high contrast, high resolution biological imaging with PCCT. In this paper, a human thyroid gland imaged by FXCT, and a metastatic human cancerous lesion depicted using PCCT are presented. The latter method used a newly manufactured, large, monolithic, X-ray interferometer, which is described in this paper in detail.

Diffuse and marked breast uptake of both 123I-BMIPP and 99mTc-TF by myocardial scintigraphy

Unexpected breast uptake was observed in a 32-year-old woman referred for evaluation of hypertrophic cardiomyopathy. Diffuse and marked bilateral breast uptake of 123I-BMIPP and 99mTc-TF was shown by both planar and SPECT imaging during the first study, and the uptake of both radionuclides had decreased significantly eleven months later. At the time of the first radionuclide examination, she was occasionally breast feeding her 2-year-old child and had small amounts of milk production. At the follow up examination, the frequency of breast feeding was significantly reduced and she produced only small amounts of milk. Therefore, the uptake of 123I-BMIPP and 99mTc-TF may have been caused by lactation.

Phase-contrast X-ray imaging with a large monolithic X-ray interferometer

To increase the field of view for large objects in phase-contrast X-ray imaging, a large monolithic X-ray interferometer has been fabricated using an available silicon ingot of diameter 10 cm. A performance study of this interferometer has been carried out using a synchrotron X-ray source. The view size of the interference pattern obtained with this interferometer was 25 mm wide and 15 mm high and its visibility was 79%. Various structures of a sliced human hepatocellular carcinoma were identified as necrosis, hemorrhagic necrosis, normal liver tissue and blood vessel. The performance of this interferometer was sufficient for phase-contrast X-ray imaging.

Changes in the liver parenchyma after proton beam radiotherapy: evaluation with MR imaging

The objective of this study was to describe magnetic resonance (MR) findings with a 1.5T imager for hepatic parenchymal changes after proton beam radiotherapy. Thirty-two patients who received proton radiotherapy with doses of 50-87 Gy underwent MR imaging 1-75 months (mean 22 months) after the start of irradiation. Axial T(2), T(1)-weighted imaging, and a dynamic study after a gadolinium injection were performed. The irradiated areas showed hypointense in T(1)-weighted images, hyperintense in T(2)-weighted images, and intense and prolonged enhancement on the dynamic study (maximum relative enhancement 441.8%+/-263.3 vs. surrounding liver 145.6%+/-67.7, p<0.0001). T(2) values of the irradiated areas were 50.6 to 65.8 msec greater than in the surrounding liver (p<0.005). The values increased with time, being significantly greater 13 months or longer after the beginning of the therapy than after a period of less than 3 months (p<0.05). Pathologic examinations (n = 3) indicated that the irradiated areas were composed of collapsed lobules with hepatic small vein occlusions, and rich extracellular matrices which retained extracellular fluid. MR imaging can demonstrate hepatic parenchymal changes after proton beam radiotherapy, and show the changes are irreversible.

Early radiation effects on the liver demonstrated on superparamegnetic iron oxide-enhanced T1-weighted MRI

Early radiation-induced liver injury during radiotherapy detected by a particulate reticuloendothelial MR contrast agent (superparamagnetic iron oxide; SPIO) is described in a patient with cholangiocarcinoma. The irradiated hepatic parenchyma appeared as a heterogeneous, less decreased signal intensity area than the nonirradiated area on MR images after SPIO administration. Resultant differences in signal intensity were better visualized on SPIO-enhanced T1-weighted images than SPIO-enhanced T2-weighted images, although SPIO-enhanced T2*-weighted fast field echo imaging was the most sensitive.