Magnetization Transfer Contrast on Gradient Echo MR Imaging of the Temporomandibular Joint

Thirty-nine temporomandibular joints (TMJ) from 20 patients with suspected internal derangements were imaged by a 1.5 T MR imager. The on-resonance binomial magnetization transfer contrast (MTC) pulse was applied to gradient echo images with a dual receiver coil (9 s/section). With the use of an opening device, a series of sequential images were obtained at increments of mouth opening and closing. The tissue signal intensities with (Ms) and without (Mo) MTC were measured and subjective image analysis was performed. Compared with the standard images, MTC technique provided selective signal suppression of disks. The average of Ms/Mo ratio of the disks (0.56) was lower than that of the retrodiskal pad (0.79) and of the effusion (0.89). With MTC technique, fluid conspicuity was superior to standard image. However, no significant superiority was found in disk definition subjectively.

Hepatic Cavernous Hemangioma in Patients at High Risk for Liver Cancer

Cavernous hemangioma of the liver occurring in patients at high risk for liver cancer has been reviewed. Twenty-four patients with hemangioma were encountered during the past 4 years. Five lesions over 3 cm in diameter were correctly diagnosed with enhanced CT alone. Definite CT findings were however obtained in only 6 out of 19 lesions smaller than 3 cm in diameter. Ultrasonography was the most sensitive method for picking up small liver tumors even when compared with angiography, but the findings were non-specific (an echogenic mass was noted in 14 of the 19 lesions). Magnetic resonance imaging (MRI) had almost the same sensitivity as ultrasound in detecting small hemangiomas, and a prolonged T2 was highly suggestive of the diagnosis (T2 over 80 ms in 8 of 11 lesions). The results suggest that combined use of non-invasive diagnostic modalities has sufficient reliability to make a diagnosis of cavernous hemangioma even in small hepatic lesions, in patients at high risk for liver cancer.

High-resolution MR imaging of the knee at 3 T

Purpose: To examine the practical feasibility of using a 3.0-T MR unit to obtain high-quality, high-resolution images of the knee joint.

Material and Methods: One human cadaveric and 5 porcine knees were imaged with the 3.0-T unit. Sets of T1-weighted spin echo images were obtained with in-plane resolution of 0.195 × 0.39 mm and an acquisition time of approximately 5 min. Two porcine knees were also imaged with the 1.0-T unit with an identical imaging protocol and the signal-to-noise (S/N) ratios were measured on images at 3 T and 1 T.

Results: The 3-T MR system provided detailed delineation of the knees. Deep layers of the medial collateral ligament and associated fine fibers beneath the medial and lateral collateral ligament were demarcated. We observed precise demonstration of the tibial attachment of the anterior cruciate ligament, irregularity of the meniscal free edge, and conjoint tendon formation together with the lateral collateral ligament and the biceps femoris tendon. Compared to the 1-T unit, the S/N ratio with the 3-T unit was increased by a factor of 1.39 to 1.72.

Conclusion: Due to the potential advantage of obtaining detailed images, the 3-T MR system suggests a practical utility for fine demonstration of the knee morphology.

Focal Fatty Masses of the Pancreas

Five patients with solitary fatty mass of the pancreas examined with CT and ultrasound (US) were evaluated. The areas of fat replacement were located in the pancreatic neck, body or tail. The size ranged from 4 to 30 mm in the longest diameter. The shape varied from roundish, to ovoid to semicircular, and the contour was universally well defined. The internal structure was homogeneous in 3 patients, but in one case there were thin septa and, in another, a slightly hyperdense part in the peripheral portion. All the masses except the smallest one were in part contact with pancreatic fat. CT showed fat with the same density as the peripancreatic fat and low HU units. The mass was hypoechoic in 2 cases and hyperechoic in one. The masses in the tail of the pancreas were not detected by US.

High-resolution imaging of coronary calcifications by intense low-energy fluoroscopic X-ray obtained from synchrotron radiation

Purpose: To obtain an intense monochromatic low-energy X-ray from synchrotron radiation (SR) and apply it to detect coronary calcifications.

Methods and Results: The SR beam was reflected with a silicon crystal to be expanded (150 mm in height and 80 mm in width) and to be monochromatized at an energy level of 37 keV. The X-ray was intermittently irradiated to obtain dynamic imaging of 30 images/s. Images were recorded by a digital fluorography system. The low-energy X-ray from SR sharply visualized calcification of coronary arteries, while conventional X-ray could not visualize coronary calcification.

Conclusion: The intense monochromatic low-energy X-ray from SR is sensitive, has high-resolution for imaging coronary calcification and may serve as a screening method for coronary artery disease.

Low-dose dobutamine radionuclide ventriculography for prediction of myocardial viability: quantitative analysis of regional left ventricular function

BACKGROUND

It is important to distinguish viable myocardium from necrotic tissue in order to decide upon therapy in patients with ischemic heart disease.

HYPOTHESIS

We verified the hypothesis that quantitative analysis of regional left ventricular function using low-dose dobutamine radionuclide ventriculography (RNV) can sensitively predict myocardial viability and compared its usefulness with thallium-201 (201Tl) single-photon emission computed tomography (201Tl-SPECT).

METHODS

Radionuclide ventriculography at rest and during low-dose dobutamine infusion (5 micrograms/kg/min), 201Tl-SPECT, and coronary angiography were performed in 51 subjects with severe ischemia-related stenosis of coronary arteries and 3 subjects without coronary artery disease. 201Tl uptake was assessed as normal (control), low perfusion (LP), or defect. We compared the response of regional function to dobutamine with the regional 201Tl uptake. The accuracy of both methods for identifying viable myocardium was investigated in 17 patients who underwent successful coronary revascularization, with a resulting improvement in wall motion.

RESULTS

The increase in regional ejection fraction (delta r-EF) in response to dobutamine was significantly greater in the control (12 +/- 6%) and LP (16 +/- 11%) regions than in the defect (5 +/- 10%) regions. The increase in one-third regional ejection fraction (delta r-1/3EF) was also significantly higher in the control (14 +/- 7%) and LP (10 +/- 8%) regions than in the defect regions (5 +/- 6%). We defined myocardial viability as a delta r-EF > 5% or a delta r-1/3EF > 2%. The sensitivity and specificity of the delta r-EF for identification of myocardial viability were 91.4 and 55.5%, respectively. The sensitivity and specificity of the delta r-1/3EF were 91.4 and 66.6%, respectively; the corresponding values for 201Tl SPECT were 74.2 and 77.8%.

CONCLUSION

Low-dose dobutamine RNV with quantitative analysis of regional left ventricular function was more sensitive for identification of viable myocardium than 201Tl-SPECT.

Morphological changes in rat hindlimb muscle fibres during recovery from disuse atrophy

AIM

The present study attempted to use HE staining to clarify morphological changes in muscle fibres during recovery from disuse muscle atrophy.

METHODS

Disuse muscle atrophy was induced by suspending 7-week-old male Wistar rats by their tails for 5 weeks (hindlimb unloading or HU group). Histological changes in the soleus muscle (SOL) during the recovery process were examined and compared with those in control rats who were raised freely without unloading (C group).

RESULTS

Wet muscle mass and muscle cross-sectional area per fibre of SOL in the HU group were 52 +/- 5 and 22 +/- 5% of those in the C group, respectively. Muscle atrophy was largely attributable to decreases in the size of muscle fibres, rather than to muscle fibre damage or loss. Muscle mass in the HU group increased quickly after reloading, but recovery of cross-sectional area per fibre was slow, with mean area in the HU group measuring 69 +/- 10% of that in the C group even after 5 weeks of reloading. After 1, 2 and 5 weeks of reloading, incidences of muscle fibres displaying central nuclei (regenerated muscle fibres) were 7.4 +/- 2.4, 7.2 +/- 6.3 and 19.2 +/- 14.5%, respectively.

CONCLUSION

These findings suggest that recovery of muscle fibres atrophied by disuse involves not only growth of atrophied muscle fibres, but also regeneration of muscle fibres. Cross-sectional areas recovery of atrophied muscle fibres thus continues after increases of muscle mass.

Magnetic resonance imaging of the rotator cuff muscles after baseball pitching

AIM

The purposes of present study were to investigate quantitatively using functional MR imaging the effect of a series of throwing activities on rotator cuff muscles and to compare the effect of pitching with that of all-out shoulder external rotator exercise as the targeted external rotator muscle group (the infraspinatus and the teres minor).

METHODS

EXPERIMENTAL DESIGN

MRI measurements after 135 baseball pitches or all-out shoulder external rotator exercise (concentric mode) in each subject's nondominant shoulder.

PARTICIPANTS

6 amateur baseball pitchers.

MEASURES

serial T2-weighted images of rotator cuff muscles were obtained before pitching (or shoulder exercise) and immediately, 30, 60 min, 24, 48, 96 hrs after pitching (or shoulder exercise). T2 relaxation times (T2) at each measurement time were calculated for the rotator cuff muscles.

RESULTS

Both the supraspinatus and the external rotator muscle group showed significant T2 elevations until 96 hrs after pitching. The subscapularis also showed significantly increased T2 until postpitching 48 hrs. On the other hand, a significant T2 elevation continued until 60 min after shoulder exercise, but thereafter returned towards the value at rest over the next 24 hrs.

CONCLUSION

Long lasting T2 elevations in rotator cuff muscles would be associated with an increase in each intramuscular water content, and may be attributed to the muscle damage that resulted from eccentric contraction during pitching. This information should serve as a useful complement to shoulder injury prevention for baseball pitchers.

Early-enhancing Non-neoplastic Lesions on Gadolinium-enhanced MRI of the Liver

AIM

To assess the frequency, cause, and significance of early-enhancing, non-neoplastic (EN) lesions on gadolinium-enhanced magnetic resonance imaging (MRI) of the liver performed for the detection of malignant hepatic tumours.

MATERIALS AND METHODS

From September 1997 to September 2000, we reviewed the images of 125 patients, suspected of having hepatic tumours, in whom (1) gadolinium-enhanced triphasic dynamic gradient-recalled-echo (GRE) imaging in addition to unenhanced T1- and T2-weighted MRI was performed, (2) conventional angiography and combination computed tomography (CT) hepatic arteriography and CT during arterial portography were performed within 2 weeks of the MRI, and (3) definitive surgery within 2 weeks of the MRI or follow-up study by means of intravenously contrast-enhanced CT or MRI in 10 months or more was performed. Angiographic studies were correlated to determine the underlying causes of the EN lesions.

RESULTS

We found 78 EN lesions in 36 patients (29%), ranging in size from 4 and 50 mm (mean, 12.2 mm). From the MR reports, our radiologists had prospectively diagnosed EN lesions as probable malignant tumours in eight (10%), possible malignant tumours in 36 (46%), and probable non-neoplastic lesion in 34 (44%). EN lesions were found in 27 of 81 (33%) cirrhotic patients and in nine of 44 (20%) non-cirrhotic patients. Fifty-one EN lesions (65%) were located along the liver edge. The shape was circular in 42 (54%), oval in 14 (18%), irregular in 12 (15%), wedge-shaped in seven (9%), and fan-shaped in three (4%). Twenty EN lesions (26%) appeared slightly hyperintense on T2-weighted images. The causes were non-neoplastic arterio-portal shunting in 48 (62%), cystic venous drainage in four (5%), rib compression in four (5%), aberrant right gastric venous drainage in two (3%), and unknown in 20 (26%).

CONCLUSION

Over half the number of EN lesions were caused by non-neoplastic arterio-portal shunting, occasionally showing slight hyperintensity on T2-weighted images. On MR images the non-neoplastic nature of the EN lesion was often ascertained. Radiologists should not overcall EN lesions as malignant as the patients involved would be inappropriately considered inoperable. In problematic cases, further investigation with angiographic CT or follow-up imaging studies should be performed.

The effects of various therapeutic measures on shoulder range of motion and cross-sectional areas of rotator cuff muscles after baseball pitching

AIM

The purpose of this study was to investigate the effects of various therapeutic measures on the shoulder range of motion (ROM) and muscle cross-sectional area (mCSA) of rotator cuff muscles after baseball pitching.

METHODS

EXPERIMENTAL DESIGN

a mode of therapeutic measures was classified in 4 groups; the control (CON), ice treatment (IT), light shoulder exercise (LSE) and ice treatment with LSE (ILSE) groups. Each therapeutic measure was performed after pitching.

PARTICIPANTS

7 healthy, skilled baseball pitchers.

MEASURES

ROM and mCSA were measured before pitching, immediately after pitching, at the time of the therapeutic measure, and 24 hours after pitching. Shoulder ROM at 90 inverted exclamation mark of abduction included internal rotation (IROM), maximum internal rotation (IMROM), external rotation (EROM) and maximum external rotation (EMROM).

RESULTS

In all groups, both IROM and IMROM were significantly decreased after pitching compared with the pre-exercise values and conversely both EROM and EMROM were significantly increased. The mCSA of all rotator cuff muscles were increased significantly after pitching. For IMROM, ILSE showed a significant recovery at the post-therapeutic measure compared with the others and at 24 hours after pitching compared with IT, respectively. For IROM, both LSE and ILSE showed significant recovery compared with CON at the post-therapeutic measure. For the mCSA of external muscles, ILSE showed a greater decrease at the post-therapeutic measure than the others, and at 24 hours after pitching than CON.

CONCLUSION

This study suggested the possibility that ILSE was more effective to recover ROM and decrease mCSA than the other methods.

The effects of various therapeutic measures on shoulder strength and muscle soreness after baseball pitching

AIM

This study was intended as an investigation of the effects of various therapeutic measures on the shoulder strength and muscle soreness after baseball pitching.

METHODS

EXPERIMENTAL DESIGN

participants threw 98 pitches in a simulated single game. The mode of the therapeutic measures after pitching were classified into 4 groups; the control group (CON), the ice treatment group (IT), the light shoulder exercise group (LSE) and the ice treatment with LSE group (ILSE). Each therapeutic measure was applied to the dominant shoulder immediately after pitching.

PARTICIPANTS

7 healthy, skilled baseball pitchers.

MEASURES

both shoulder strength and muscle soreness were measured before pitching, immediately after pitching (Post-P), at the time of the therapeutic measure (Post-TM), and 24 hours after pitching (Post-24 h).

RESULTS

All 4 groups showed shoulder strength losses in shoulder abduction, internal/external rotation with no shoulder abduction or with the shoulder abducted to 90 degrees immediately after pitching. ILSE had greater recovery from Post-P values at Post-TM or Post-24 h than the other methods in all 5 shoulder strengths. On the other hand, the soreness in shoulder internal rotation was increased significantly from Post-P and continued by Post-24 h. Both IT and ILSE had beneficial effects on reducing the shoulder muscle soreness at Post-TM or Post-24 h.

CONCLUSION

The findings of this study suggested that ILSE was the optimal therapeutic measure against decreased shoulder strength or increased shoulder muscle soreness resulting from the repetitive baseball pitching.

Use of small pelvic field instead of whole pelvic field in postoperative radiotherapy for node-negative, high-risk stages I and II cervical squamous cell carcinoma

We investigated whether a small pelvic (SP) field that covers primarily the pericervical regions in postoperative radiotherapy for cervical squamous cell carcinoma is adequate for a subgroup of node-negative patients. Of 84 patients with stage I-II disease treated with postoperative radiotherapy due to pathologic risk factors, 42 node-negative patients received SP-field radiotherapy, whereas remaining 42 node-positive patients were treated with a conventional whole pelvic (WP) field that also covered pelvic lymph nodes, both with 50.0-50.4 Gy/25-28 fractions. The pathologic risk factors included positive nodes, deep stromal invasion (>/=2 /3 thickness), parametrial extension, and positive or close surgical margin. Recurrence was identified for 20 patients: three in the SP group and 17 in the WP group. Intrapelvic recurrence accounted for all three recurrences in the SP group and for four in the WP group; 5-year pelvic-control rate did not differ significantly between the SP (93%) and WP (90%) groups. Extrapelvic recurrence (n = 11) was identified exclusively in the WP group. Patterns of recurrence indicate that use of an SP field instead of a WP field may be adequate in postoperative radiotherapy for a subgroup of node-negative, high-risk patients.

Use of small pelvic field instead of whole pelvic field in postoperative radiotherapy for node-negative, high-risk stages I and II cervical squamous cell carcinoma

We investigated whether a small pelvic (SP) field that covers primarily the pericervical regions in postoperative radiotherapy for cervical squamous cell carcinoma is adequate for a subgroup of node-negative patients. Of 84 patients with stage I–II disease treated with postoperative radiotherapy due to pathologic risk factors, 42 node-negative patients received SP-field radiotherapy, whereas remaining 42 node-positive patients were treated with a conventional whole pelvic (WP) field that also covered pelvic lymph nodes, both with 50.0–50.4 Gy/25–28 fractions. The pathologic risk factors included positive nodes, deep stromal invasion (≥2 /3 thickness), parametrial extension, and positive or close surgical margin. Recurrence was identified for 20 patients: three in the SP group and 17 in the WP group. Intrapelvic recurrence accounted for all three recurrences in the SP group and for four in the WP group; 5-year pelvic-control rate did not differ significantly between the SP (93%) and WP (90%) groups. Extrapelvic recurrence (n = 11) was identified exclusively in the WP group. Patterns of recurrence indicate that use of an SP field instead of a WP field may be adequate in postoperative radiotherapy for a subgroup of node-negative, high-risk patients.

Intraductal papillary-mucinous tumor and mucinous cystic neoplasm: CT and MR findings

Cystic lesions of the pancreas are increasingly detected by imaging at daily clinical practice. Among them mucinous cystic tumor and intradcutal papillary-mucinous tumor of the pancreas are clinically important since they are latently or overtly malignant and still have potentially good prognosis after resection. In this review article we describe history, clinicopathology and differential diagnosis of two entities, and findings and role of CT and MR imaging as well as MR cholangiopancreatography in the diagnosis and evaluation of intraductal papillary-mucinous tumor.

Chronological change of brain abscess in (1)H magnetic resonance spectroscopy

We studied chronological magnetic resonance spectral changes in brain abscesses before and after medical and/or surgical treatment. We examined five patients with MRI imaging and (1)H magnetic resonance spectroscopy (MRS) on two or more occasions, using two volume-of-interest patterns, and saw chronological changes related to the evolution of the abscess. A spectrum specific for brain abscess was found in three of the five cases, while two showed a single lactate peak in the first study. In two cases, phenylalanine or alanine appeared in the second study. We observed the disappearance of the specific spectra and a single lactate peak following surgery. Only one patient showed different spectra in different volume of interest.

Distal migration of duodenal tumors: simple prolapse or intussusception?

BACKGROUND

To define radiographically simple prolapse or intussusception in cases of distal migration of duodenal tumors.

METHODS

In one pyloric and four duodenal tumors showing distal migration, the findings of gastrointestinal contrast examinations were retrospectively evaluated in relation to CT and operative findings.

RESULTS

All lesions were intraluminal growing and well demarcated, and they included two carcinoids, a papillary adenoma, a Brunner's gland adenoma, and a hyperplastic polyp. All lesions were accompanied by long mucosal stalks, and, in three, folding deformity of the proximal jejunum was observed. CT showed no target signs except for one with gastroduodenal intussusception. Intussusception was not verified surgically in any cases.

CONCLUSION

Distal migration of duodenal tumors can occur as the result of mucosal elongation and slipping. Duodenojejunal intussusception is not necessarily associated with that phenomenon.

CT fluoroscopy-guided intervention: marked reduction of scattered radiation dose to the physician's hand by use of a lead plate and an improved I-I device

PURPOSE

To estimate the effects of a lead plate, three types of needle holders, tube current, and slice thickness on decreasing the radiation dose to the physician's hand during interventional procedures with computed tomographic (CT) fluoroscopic guidance. The needle holders (I-I devices), which were developed by the authors, maintained the distance between the physician's hand and the CT plane at 7 cm, 10 cm, and 15 cm, respectively.

MATERIALS AND METHODS

The dose rate (mSv/tube current/CT fluoroscopy time) was measured in 55 cases, which were divided into six groups. In group A (n = 14), the current was 135 kV, there was a 5-mm slice thickness, and a 7-cm I-I device was used without the lead plate. Group B (n = 11) entailed a 120-kV current, a 5-mm slice thickness, and a 7-cm I-I device without the lead plate. Group C (n = 8) entailed a 120-kV current, 5-mm slice thickness, and 7-cm I-I device with the lead plate. Group D (n = 9) entailed a 120-kV current, 5-mm slice thickness, and 10-cm I-I device with the lead plate. Group E (n = 7) entailed a 120-kV current, 5-mm slice thickness, and 15-cm I-I device with the lead plate. Group F (n = 6) entailed a 120-kV current, 1-mm slice thickness and 10-cm I-I device with the lead plate. To compare the effects of tube voltage, lead plate use, slice collimation, and I-I devices, differences were compared between groups A and B, B and C, D and F, and among groups C, D, and E.

RESULTS

The dose rates of groups A, B, C, D, E, and F were 126.3, 75.2, 17.8, 13.9, 2.8, and 4.1 mSv/mA/sec x 100,000, respectively. There were significant differences in dose rates between groups A and B (t-test, P =.037), B and C (Student t-test, P =.002), D and F (Mann-Whitney test, P =.011), and among groups C, D, and E (Kruskal-Wallis test, P =.016).

CONCLUSION

The lead plate, the improved I-I devices, use of a 120 kV (vs 135 kV) current, and 1-mm (vs 5 mm) collimation were all useful in decreasing the dose rate.

Exfoliative tumor clearance following radiotherapy estimated by comparing radioresponse between primary esophageal cancer and its lymph node metastasis

BACKGROUND/AIMS

We estimated the capacity for exfoliative mechanical clearance which could occur in shrinkage of esophageal tumors following radiotherapy; both mechanical clearance and phagocytotic biological clearance of another clearance mechanism could participate in primary diseases located on outer tissue surfaces, whereas only biological clearance can participate in lymph node metastases surrounded by normal tissues which prevent mechanical clearance.

METHODOLOGY

Twenty-one patients with primary esophageal cancer and lymph node metastasis both treated by radiotherapy with the same dose were reviewed. The extent of tumor shrinkage was estimated by measuring the size on computed tomography scans before and after radiotherapy. The capacity for biological clearance plus mechanical clearance (primary disease) or biological clearance alone (lymph node metastasis) was defined as the slope of a tumor shrinkage curve. The capacity for mechanical clearance was estimated by intra-patient subtraction.

RESULTS

Extent of tumor shrinkage was consistently greater in primary disease than in lymph node metastasis for each patient, showing significant correlation in extent of shrinkage between them. The capacity was smaller for mechanical clearance than for biological clearance as a whole, showing no correlation between them.

CONCLUSIONS

Mechanical clearance is highly likely to participate extra in the shrinkage of tumors located on outer tissue surfaces; therefore, these tumors will normally respond more highly than parenchymal tumors.

[Preliminary trial of three-dimensional water-excitation magnetization transfer contrast MR imaging of articular cartilage]

MR images of articular cartilage were evaluated with a three-dimensional (3D) water-excitation sequence (repetition time/echo time/flip angle = 28 msec/14 msec/20 degrees) with and without on-resonance magnetization transfer contrast (MTC) pulse in-vitro and in-vivo. 3D water-excitation images with MTC pulse showed a significantly higher contrast-to-noise ratio between normal saline or joint effusion and articular cartilage than images without MTC pulse. In 2 patients with osteoarthritis of the knee, joint effusion showed higher signal intensity than cartilage (arthrogram-like effect) on 3D water-excitation MTC images. The contrast between joint effusion and articular cartilage on 3D water-excitation MTC images was similar to that on fat-suppressed 2D protondensity-weighted fast spin echo images. In conclusion, 3D water-excitation MTC imaging is a promising method by which to evaluate articular cartilage in osteoarthritis and cartilage defect with thin sections and a reasonable scan time.

Prostatic abscess in young males: a rare complication of Crohn's disease

We report a rare case of prostatic abscess with Crohn's disease in a 21-year-old male. Computed tomography showed a typical prostatic abscess. Moreover, filling of the abscess cavities with contrast medium was demonstrated after micturition, which represented the rupturing of the abscess into the urethra. Crohn's disease should be included in the differential diagnosis of prostatic abscesses even in young males.

Preliminary estimation of minimum target dose in intracavitary radiotherapy for cervical cancer

PURPOSE

In intracavitary radiotherapy (ICRT) for cervical cancer, minimum target dose (Dmin) will pertain to local disease control more directly than will reference point A dose (D(A)). However, ICRT has been performed traditionally without specifying Dmin since the target volume was not identified. We have estimated Dmin retrospectively by identifying tumors using magnetic resonance (MR) images.

MATERIALS AND METHODS

Pre- and posttreatment MR images of 31 patients treated with high-dose-rate ICRT were used. ICRT was performed once weekly at 6.0 Gy DA, and involved 2-5 insertions for each patient, 119 insertions in total. Dmin was calculated arbitrarily simply at the point A level using the tumor width (W(A)) to compare with D(A). W(A) at each insertion was estimated by regression analysis with pre- and posttreatment W(A).

RESULTS

Dmin for each insertion varied from 3.0 to 46.0 Gy, a 16-fold difference. The ratio of total Dmin to total DA for each patient varied from 0.5 to 6.5. Intrapatient Dmin difference between the initial insertion and final insertion varied from 1.1 to 3.4.

CONCLUSION

Preliminary estimation revealed that Dmin varies widely under generic dose prescription. Thorough Dmin specification will be realized when ICRT-applicator insertion is performed under MR imaging.

[MR imaging of posterior cruciate ligament injuries]

Posterior cruciate ligament(PCL) injuries are less frequent than anterior cruciate ligament(ACL) injuries, but are presumably more common than once thought. Thirty-nine patients with PCL injuries identified on MR images were studied. The criteria for PCL injury were complete tear, partial tear, and avulsion fracture. The approximate site of a partial tear was categorized as proximal, midsubstance, distal, or combination. Fourteen patients(35.9%) had complete tears of the PCL, 21 patients(53.8%) had partial tears, and four patients(10.3%) had avulsion fractures. A total of 12 patients (30.7%) had isolated PCL injuries, while the remaining 27 patients demonstrated evidence of other coexistent knee injuries, such as meniscal tears and ligamentous injuries. Of coexistent knee injuries, meniscal tears(18 patients, 46.2%) were most often seen.

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.