Three-dimensional bone-free computed tomographic angiography of aneurysms near the skull base using a new bone-removal application.

PURPOSE: Bone elimination is needed for computed tomography angiography (CTA) because bone structures obscure aneurysms located at the skull base. The purpose of our study was to evaluate the efficacy of three-dimensional (3D)-CTA using an application for bone elimination. MATERIALS AND METHODS: A total of 27 patients with 32 angiographically confirmed aneurysms near the skull base were investigated. The 3D maximum intensity projection (MIP) images were initially obtained using the application. Further postprocessing was performed to obtain the MIP and volume-rendered (VR) images. The quality of the initial MIP images by the application was analyzed. Visualization of aneurysms after further processing was also reviewed. RESULTS: The initial MIP images by the application showed almost bone-free images in 23 of the 27 patients. In 8 patients, the image of the internal carotid artery (ICA) was segmentally removed in the initial MIP images by the application. Further postprocessing was able to recover all loss of the ICA image in these eight patients. For visualizing aneurysms and their necks, VR images with the application were significantly superior to VR images without the application. CONCLUSION: The application for bone elimination allows fast, selective elimination of bony structures and can improve the interpretation of aneurysms near the skull base.

Accurate diagnosis of peripheral small cell lung cancer with computed tomography.

Small lesions are frequently detected in the lung with computed tomography (CT) in clinical practice. It is important to know the CT features of small-sized peripheral small cell lung cancer (SCLC) for early-stage diagnosis. We reviewed the CT findings of SCLC that presented as a solitary peripheral nodule without associated lymphadenopathy. This study included 12 patients (11 men and 1 woman; mean age, 68.5 years) with peripheral SCLC of diameters ranging from 9 - 28 mm (mean, 15.4 mm). We evaluated the findings with thin-section CT for each peripheral tumor; emphasis was laid on the predominant internal characteristics (whether the mass is solid), tumor-lung interface characteristics (whether the mass is well-defined with a smooth surface or with lobulation or spiculation), and surrounding structures (the presence or absence of perivascular thickening adjacent to the tumor). In all patients, most portions of the tumor consisted of a non-calcified solid mass. Contrast enhancement in varying degrees was observed in the tumors of all 8 patients, who were evaluated with enhanced CT. The tumor-lung interface characteristics observed on the CT images included a well-defined mass with a smooth surface (n = 5), a well-defined mass with lobulation (n = 3), and a mass with spiculation (n = 4). An irregular perivascular thickening adjacent to the tumor was observed in 4 patients. We conclude that peripheral SCLC without associated lymphadenopathy manifests as a non-calcified solid mass and is occasionally characterized by perivascular thickening.

Tumor-liver contrast and subjective tumor conspicuity of respiratory-triggered T2-weighted fast spin-echo sequence compared with T2*-weighted gradient recalled-echo sequence for ferucarbotran-enhanced magnetic resonance imaging of hepatic malignant tumors.

PURPOSE: To compare respiratory-triggered T2-weighted fast spin-echo (RTT2W-FSE) and gradient T2*-weighted recalled-echo (T2*W-GRE) images for visualization of malignant hepatic tumors using ferucarbotran-enhanced magnetic resonance (MR) imaging. MATERIALS AND METHODS: Ferucarbotran-enhanced RTT2W-FSE and breath-hold long-TE 2D-fast spoiled gradient recalled acquisition in the steady state (FSPGR) images as T2*W-GRE were used to evaluate 128 malignant hepatic tumors (77 metastases, 37 hepatocellular carcinomas, 14 other) in 62 patients. Tumor-to-liver contrast (TLC) was quantitatively compared using the paired Student's t-test, and the score of lesion conspicuity was qualitatively compared using Wilcoxon's signed rank test. RESULTS: The mean TLC of RTT2W-FSE was significantly higher than that of FSPGR (1.10 +/- 0.82 vs. 2.54 +/- 1.42) in all malignant tumors. The score of lesion conspicuity of RTT2W-FSE was significantly higher than that of FSPGR (4.84 +/- 0.52 vs. 4.52 +/- 0.99) in all malignant tumors. CONCLUSION: For ferucarbotran-enhanced MR imaging, compared to FSPGR images, RTT2W-FSE images provide greater TLC and subjective conspicuity for malignant tumors.

Reduced perfusion reserve in Leukoaraiosis demonstrated using acetazolamide challenge 123I-IMP SPECT.

OBJECTIVE: We examined the relationship between the perfusion reserve as measured by acetazolamide (ACZ)-challenge N-isopropyl-I-123-p-iodoamphetamine (IMP)-single-photon emission computed tomography (SPECT) and the degree of leukoaraiosis (LA) as estimated using magnetic resonance imaging. METHODS: In 51 patients receiving IMP-SPECT with the resting state and ACZ challenge, the unaffected cerebral hemispheres were included in the present study. Mean cerebral blood flow (CBF) in the resting state and ACZ reactivity were acquired. Absolute CBF value and ACZ reactivity were compared among patients with LA grades 0, 1, and 2. The relationship between mean age and LA grade was also assessed. RESULTS: No significant difference in the absolute CBF value in the resting state was observed among the 3 LA groups. Although vasoreactivity in LA grade 0 did not differ from that in grade 1, vasoreactivity in LA grade 2 was significantly lower (P < 0.05) than that in grades 0 or 1. CONCLUSIONS: The perfusion reserve is impaired in advanced LA.

Spontaneous regression of multiple lung metastases following regression of hepatocellular carcinoma after transcatheter arterial embolization. A case report.

Spontaneous regression of hepatocellular carcinoma (HCC) is a rare phenomenon. Some reports have described cases of spontaneous regression of HCC, but there have been few cases with spontaneous regression of only metastatic lesions from HCC. We report a case of a 70-year-old woman with multiple lung metastases from HCC that regressed spontaneously following regression of HCC after transcatheter arterial embolization (TAE). To our knowledge, this is the first reported case that multiple lung metastases regressed spontaneously following TAE for HCC. Numerous mechanisms for spontaneous regression of HCC have been suggested such as subintimal damage, blood transfusion, alcohol withdrawal, infection, hemorrhagic shock, hepatic artery occlusion and herbal medicine. Our case, however, had no connection with any such symptom and medication. Our case suggests that the mechanisms leading to spontaneous regression in remote organs may be associated with activation of host immune response involving cytokines.

CT features of pancreatic fistula after pancreaticoduodenectomy.

OBJECTIVE: Our objective was to establish the CT features that are indicative of pancreatic fistula after pancreaticoduodenectomy. CONCLUSION: A fluid collection seen on CT around the pancreaticojejunostomy site and in the pancreatic bed may be caused by pancreatic fistula in patients who have undergone pancreaticoduodenectomy. CT depiction of air bubbles in the fluid at these sites may strongly suggest the diagnosis of pancreatic fistula.

Visualization of anterior disc displacement in temporomandibular disorders on contrast-enhanced magnetic resonance imaging: comparison with T2-weighted, proton density-weighted, and precontrast T1-weighted imaging.

OBJECTIVE: To compare postcontrast T1-weighted imaging (T1WI+) with precontrast T1-weighted (T1WI-), T2-weighted (T2WI), and proton density-weighted imaging (ProWI) in depiction of the anterior disc displacement (ADD) in temporomandibular disorders (TMDs). STUDY DESIGN: A total of 120 joints with TMD were included in this study. Qualitatively, Receiver operating characteristic analysis was performed. Quantitatively, the ratio of the intensity in the retrodiscal tissue to intensity in the disc (intensity ratio) was measured. RESULTS: One reader achieved superior performance in visualization of ADD with T1WI+ than with the other sequences. The other reader showed superiority with T1WI+ rather than T2WI or T1WI-. The intensity ratio on T1WI+ was significantly higher than the intensity ratio on other sequences. On T1WI,+ the intensity ratio in the joints with ADD was significantly higher than that in the joints without ADD. CONCLUSION: Postcontrast T1-weighted imaging can improve the visualization of ADD in TMDs.

Diffusion changes in a tumor and peritumoral tissue after stereotactic irradiation for brain tumors: possible prediction of treatment response.

OBJECTIVE: Changes in apparent diffusion coefficient (ADC) in a tumor and peritumoral tissue after stereotactic irradiation (STI) were evaluated, and then the therapeutic efficacy of ADC measurement was assessed. METHODS: In 20 tumors, diffusion-weighted imaging within 1 week before and 2-4 weeks after STI was performed. The normalized ADC (nADC) was measured. The nADCs in the tumor and peritumoral region before STI were compared with those after STI and the change in tumor nADC compared with the change in tumor size. RESULTS: The nADC of the tumors was significantly higher 2-4 weeks after STI compared with that before STI. The nADC of the peritumoral regions 2-4 weeks after STI did not differ significantly from that before STI. A significant difference in the nADC at 2-4 weeks after STI was observed between the responder and nonresponder groups. CONCLUSIONS: Changes in nADC as measured by diffusion-weighted imaging can predict response to STI.

Comparison of the MR findings on indirect MR arthrography in patients with rotator cuff tears with and without symptoms.

PURPOSE: To compare indirect magnetic resonance (MR) arthrography findings in patients with rotator cuff tears with and without symptoms. MATERIALS AND METHODS: Indirect MR arthrography results of 15 asymptomatic and 23 symptomatic rotator cuff tears were retrospectively reviewed, comparing the type and size of tears and amount of subacrominal-subdeltoid bursal fluid. RESULTS: There were 14 partial-thickness tears and one full-thickness tear in the asymptomatic group, with 4 small and 11 medium tears. In the symptomatic group, there were 16 partial-thickness and 7 full-thickness tears, with 14 small, 5 medium, and 4 large tears. In the asymptomatic group, the amount of subacrominal-subdeltoid bursal fluid was grade 0, 6 patients; grade 1, 6 patients; grade 2, 2 patients; and grade 3, 1 patient. In the symptomatic group, the amount of subacrominal-subdeltoid bursal fluid was grade 0, 4 patients; grade 1, 3 patients; grade 2, 8 patients; and grade 3, 8 patients. We found no statistically significant difference between symptomatic and asymptomatic tears in the kind and size of tears, and in the amount of subacrominal-subdeltoid bursal fluid. CONCLUSION: We found no difference in the MR findings between symptomatic and asymptomatic rotator cuff tears.

Visualization of lymphatic basin from the tumor using magnetic resonance lymphography with superparamagnetic iron oxide in patients with thoracic esophageal cancer.

OBJECTIVE: To evaluate magnetic resonance (MR) lymphography with submucosal injection of superparamagnetic iron oxide (SPIO) for imaging lymphatic pathways from thoracic esophageal cancer. METHODS: In 24 patients with esophageal cancer, SPIO was injected into the submucosal layer of the peritumoral region endoscopically and MR lymphography was conducted. In study 1, fast spoiled gradient-recalled acquisition using a steady-state (FSPGR) sequence was performed from the neck to the upper abdomen before and at 20, 40, and 60 minutes after injection in 10 patients. In study 2, FSPGR and spin echo T1-weighted images were obtained after injection in 14 patients. Areas scanned were the neck to the upper mediastinum and the upper abdomen. RESULTS: In study 1, at 20 minutes after injection, the signal of each lymph node appeared attenuated when compared with precontrast images. The signal-to-noise ratio in lymph nodes exhibiting influx of SPIO was significantly lower than that found on precontrast images (P < 0.0005). In study 2, influx to the neck lymph nodes was detected in 8 patients (64.3%), whereas influx to the upper abdominal lymph nodes was detected in 13 (92.9%). CONCLUSIONS: Magnetic resonance lymphography with SPIO could visualize the lymphatic pathways draining from the injection site and the location of lymph nodes exhibiting influx of SPIO in patients with thoracic esophageal cancer.

Comparison of 201Tl-chloride SPECT with 99mtc-MIBI SPECT in the depiction of malignant head and neck tumors.

OBJECTIVE: Comparison of 201Tl chloride SPECT (TI-SPECT) with 99mTc-MIBI SPECT (MIBI-SPECT) in the depiction of malignant head and neck tumors was prospectively studied. METHODS: Forty-one patients with various tumors of the head and neck were included in this prospective study. Histologically, 36 patients had squamous cell carcinomas, 3 undifferentiated carcinomas, 1 transitional cell carcinoma, and 1 MALT lymphoma. All patients underwent a simultaneous dual-isotope SPECT of the head and neck with 201Tl and 99mTc-MIBI. Dual-isotope SPECT for early (n=41) and delayed acquisition (n=21) was performed. Qualitatively, 3 observers evaluated both TI-SPECT and MIBI-SPECT individually. The interpretation criteria were graded as grade 1 (no abnormal increased uptake) to 5 (definitely increased uptake of a degree equal to or greater than that of normal salivary gland). Statistical analysis of the comparison of Tl-SPECT and MIBI-SPECT was performed. The interobserver difference was evaluated using the kappa-coefficient. Quantitatively, T/N ratio (the ratio of the counts in the tumor divided by that in the normal nuchal muscles) and retention index were compared between TI-SPECT and MIBI-SPECT. RESULTS: On both the early and delayed images, the grades of uptake of the tumor in TI-SPECT were significantly higher than those in MIBI-SPECT by three observers. The grade of Tl-uptake of the tumor on the delayed images was 5 for all observers (kappa-coefficient=1); however, the kappa-coefficient varied from 0.39 to 0.84 in early T1-SPECT, and in early and delayed MIBI-SPECT. Statistical differences in T/N ratio were noted between early TI-SPECT (2.87 +/- 1.19) and MIBI-SPECT (2.48 +/- 1.06), and between delayed Tl-SPECT (2.11 +/- 0.70) and MIBI-SPECT (1.20 +/- 0.48). The retention index or Tl-SPECT (0.81 +/- 0.24) was significantly higher than that of MIBI-SPECT (0.52 +/- 0.15). CONCLUSIONS: The present study qualitatively and quantitatively showed that 201Tl had higher accumulation in the tumor than 99mTc-MIBI in both early and delayed images.

123I-metaiodobenzylguanidine single-photon emission computerized tomography in brain tumors - a preliminary study.

OBJECTIVE: (123)I-metaiodobenzylguanidine (MIBG) has been developed as a functional analog of the neurotransmitter norepinephrine. The success of MIBG as an imaging agent for neural crest tumors is derived from its chemical similarities to norepinephrine. The present study aimed to explore a potential of (123)I-MIBG to differentiate embryonal tumors from other types of brain tumors. METHODS: Sixteen patients with brain tumors including three medulloblastomas, one neuroblastoma, six gliomas, and six meningiomas were examined with single-photon emission computerized tomography (SPECT) using (123)I-MIBG. The (123)I-MIBG uptake of tumors was defined as the ratios of tumor/nontumor (early and delayed T/NT) on SPECT images scanned 30 min and 6 h after intravenous injection of the tracer, respectively. Retention index was calculated as (delayed T/NT - early T/NT)/early T/NT. RESULTS: The T/NT ratios on the early images for embryonal tumors (medulloblastomas and neuroblastoma), gliomas, and meningiomas were 3.2+/-1.7 (mean+/-SD), 1.4+/-0.3, and 1.6+/-0.5, respectively. The early uptake was significantly higher in the embryonal tumors than in gliomas (P<0.05). Delayed T/NT ratios for embryonal tumors were increased compared to the early T/NT ratios, while in contrast delayed T/NT ratios for the other tumors remained low (1.2-1.7). The high retention indices of the embryonal tumors indicate specific uptake of (123)I-MIBG in the tumors. CONCLUSION: Early high accumulation and high retention on delayed imaging may indicate a possibility of (123)I-MIBG SPECT in differentiating embryonal brain tumors from gliomas and meningiomas.

[Three-dimensional surface anatomical scanning with 3D-FSPGR: anatomical conformity with surgical findings].

Three-dimensional imaging with MRI is a useful method for neurosurgical simulations. As in our previous study, we have constructed three-dimensional surface anatomical scanning (3D-SAS) from the data of contrast enhanced 3D fast spoiled gradient recalled acquisition in the steady state (3D-FSPGR) sequence. Using this technique, it is possible to generate 3D images from the data of only one acquisition, without using the fusion function. In our previous study, we did not compare the 3D images with the operative views at surgery. In the present study, two radiologists and one neurosurgeon assessed the 3D images in comparison with the operative views. There were problems in some cases, including unclear cortical sulci owing to brain swelling, lack of depiction of the cortical veins owing to meningeal enhancement, inadequate distinction between pial veins and meningeal veins, and so forth. However, in the majority of cases, 3D-SAS with 3D-FSPGR was able to demonstrate good anatomical conformity with the operative views, indicating the clinical usefulness of this technique.

Comparison of technetium Tc 99m hexamethylpropyleneamine oxime single-photon emission tomograph with stump pressure during the balloon occlusion test of the internal carotid artery.

BACKGROUND AND PURPOSE: Measuring blood pressure (stump pressure) in the distal internal carotid artery during occlusion of the internal carotid artery is reportedly a reliable safety index with which to predict ischemia following permanent occlusion of the internal carotid artery. We compared the stump pressure during occlusion of the internal carotid artery with single-photon emission CT (SPECT) using technetium Tc 99m hexamethylpropyleneamine oxime (HMPAO). METHODS: Twenty-seven patients underwent the balloon occlusion test. After occlusion of the internal carotid artery was performed by a balloon catheter, technetium Tc 99m HMPAO was injected, and then the balloon remained inflated for 15 minutes. The stump pressure was continuously monitored for those 15 minutes. After the balloon catheter was deflated and removed, SPECT was performed. Sixty-four symmetric pairs of regions of interest were set on both sides of the cerebral hemisphere. The radioactivity count ratio (L/n ratio) of the occluded side to the contralateral normal side was calculated. We defined hypoperfusion as an area with an L/n ratio <0.8. The minimum mean stump pressure (minMSP) during the balloon occlusion test and the pressure ratio of the minMSP to the mean systemic pressure were compared with the hypoperfusion area on SPECT. RESULTS: The number of regions of interest with hypoperfusion was significantly (P < .001) greater in patients with a minMSP <40 mm Hg (mean [+/-SD] = 31.5 +/- 13.7) than in patients with a minMSP > or =40 mm Hg (5.1 +/- 4.0). The number of regions of interest with hypoperfusion was also significantly (P < .001) greater in patients with a pressure ratio <0.5 (26.7 +/- 15.8) than in patients with a pressure ratio > or =0.5 (4.5 +/- 3.5). CONCLUSION: The minMSP during the balloon test occlusion reflects the extent of the hypoperfused area measured by SPECT using technetium Tc 99m HMPAO.

Evaluating benign and malignant musculoskeletal lesions with radionuclide angiography and SPECT using Tc-99m MIBI.

PURPOSE: The purpose of this study was to evaluate the use of radionuclide angiography and single photon emission computed tomography (SPECT) using Tc-99m hexakis-2-methoxyisobutylisonitrile (Tc-99m MIBI) for analyzing musculoskeletal lesions. MATERIALS AND METHODS: Radionuclide angiography and SPECT using Tc-99m MIBI were performed in 36 patients with various soft tissue and bone pathologies (18 benign and 18 malignant lesions). The ratio of the counts of the lesion to that of the contralateral normal area was calculated from the region of interest drawn on the MIBI scan. The MIBI-uptake ratio was calculated using SPECT and the MIBI-perfusion index was calculated using radionuclide angiography. RESULTS: The MIBI-uptake ratio in malignant lesions (4.80 +/- 4.43) was significantly higher (P < 0.05) than that in benign lesions (1.83+/-2.48). The sensitivity, specificity, accuracy, positive predictive value, and negative predictive value of the MIBI-uptake ratio for malignant lesions were 72%, 83%, 78%, 81%, and 75%, respectively. The MIBI-perfusion index in malignant lesions (17.68 +/- 21.19) was significantly higher (P < 0.05) than that in benign lesions (2.25 +/- 2.56). The sensitivity, specificity, accuracy, positive predictive value, and negative predictive value of the MIBI-perfusion index for malignant lesions were 87%, 75%, 81%, 77%, and 86%, respectively. CONCLUSIONS: The MIBI-uptake ratio and MIBI-perfusion index using Tc-99m MIBI can yield important additional information with which to differentiate musculoskeletal lesions.

Efficacy and safety of hepatic artery infusion catheter placement without fixation in the right gastroepiploic artery.

PURPOSE: To evaluate the feasibility of placing the tip of an infusion catheter in the right gastroepiploic artery via the femoral route and whether coil placement in the gastroduodenal artery and around the infusion catheter tip should be performed to avoid gastroduodenal toxicity and catheter dislocation. MATERIALS AND METHODS: Seventy-eight patients (25 women and 53 men; age, 38-79 years; mean, 63 years) underwent implantation of a 5-F chemotherapeutic infusion catheter via the femoral artery, positioned so that the tip was in the right gastroepiploic artery and a side hole was in the common hepatic artery. Patients were randomly divided into two groups: group A included patients with coil placement in the gastroduodenal artery and around the infusion catheter tip and group B included patients without coil placement. RESULTS: Catheter placement via the femoral route was successful in 70 of 78 patients (90%). Mean catheter indwell durations were 250 days (range, 0-962 days) in group A (n = 35) and 230 days (range, 0-834 days) in group B (n = 43; P = .9). Complications relating to long-term catheter duration in the right gastroepiploic artery did not occur in any patient. Two patients in each group had abdominal pain during infusion chemotherapy. Endoscopy revealed acute gastric mucosal lesions. Dislocation of the catheter tip during treatment occurred in one patient in each group. CONCLUSION: Catheter placement in the right gastroepiploic artery is safe and feasible except in patients with a long and caudally oriented celiac trunk. Coil embolization of the gastroduodenal artery and around the catheter tip is unnecessary.

Dynamic contrast-enhanced magnetic resonance imaging in radiotherapeutic efficacy in the head and neck tumors.

PURPOSE: The purpose to this study is to identify correlations between pathology and dynamic contrast-enhanced magnetic resonance imaging (MRI) and to assess the utility of this technique in the evaluation of radiation response for head and neck cancer. MATERIALS AND METHODS: MRI was prospectively performed after radiotherapy in 27 patients with various head and neck tumors. After bolus injection of contrast material, a dynamic study was performed using a spoiled gradient-recalled imaging sequence. The maximum slope of increase (MSI) on the time-intensity curve was displayed as a color-coded image. The ratio of MSI (MSIR) was obtained for tumor and normal muscles. Pathological specimens were obtained after MRI in all cases. Histological grading of irradiation changes was classified into 5 grades (0-4). Correlations between MSIR and histological grade were examined. RESULTS: Histologically, 18 tumors were classified as grade 2 (presence of viable tumor cells), 4 were grade 3 (nonviable tumor cells), and 5 were grade 4 (no tumor cells). Although the mean +/- SD of MSIR in patients with histological grade 2 or 3 was 7.4 +/- 7.9, MSIR in patients with grade 4 was 1.8 +/- 0.73, representing a significant difference ( P < .05). Every patient with grade 4 displayed an MSIR of 2.5 or less, although 5 of 22 patients with grade 2 or 3 had an MSIR of 2.5 or less. CONCLUSIONS: MSI quantitatively reflects response to radiotherapy for head and neck cancer. Color-coded MSI display is feasible for depicting permeability changes after radiotherapy.

Craniocervical junction venous anatomy around the suboccipital cavernous sinus: evaluation by MR imaging.

The present study evaluated the venous anatomy of the craniocervical junction, focusing on the suboccipital cavernous sinus (SCS), a vertebral venous plexus surrounding the horizontal portion of the vertebral artery at the skull base. MR imaging was reviewed to clarify the venous anatomy of the SCS in 33 patients. Multiplanar reconstruction MR images were obtained using contrast-enhanced three-dimensional fast spoiled gradient-recalled acquisition in the steady state (3-D fast SPGR) with fat suppression. Connections with the SCS were evaluated for the following venous structures: anterior condylar vein (ACV); posterior condylar vein (PCV); lateral condylar vein (LCV); vertebral artery venous plexus (VAVP); and anterior internal vertebral venous plexus (AVVP). The SCS connected with the ACV superomedially, with the VAVP inferolaterally, and with the AVVP medially. The LCV connected with the external orifice of the ACV and superoanterior aspect of the SCS. The PCV connected with the posteromedial aspect of the jugular bulb and superoposterior aspect of the SCS. The findings of craniocervical junction venography performed in eight patients corresponded with those on MR imaging, other than with regard to the PCV. Contrast-enhanced 3-D fast SPGR allows visualization of the detailed anatomy of these venous structures, and this technique facilitates interventions and description of pathologies occurring in this area.

Thallium-201 SPECT in the evaluation of early effects on brain tumors treated with stereotactic irradiation.

PURPOSE: To determine whether thallium-201 SPECT can predict response to stereotactic irradiation (STI) earlier than magnetic resonance imaging (MRI), the change in tumor size measured by MRI was compared with the change in tumor activity measured by Tl-201 SPECT before and after STI. MATERIALS AND METHODS: Twenty-one tumors in 16 patients with intracranial tumors were treated by STI. Tl-201 SPECT was performed within 1 week before the beginning of STI and within 1 week after the end of STI in all patients. All patients underwent MRI within 1 week before the beginning of STI, and 14 patients (19 tumors) underwent MRI within 1 week after the end of STI. Follow-up MRI was performed 1 to 2 months after the end of STI in 14 patients (16 tumors). The activity of Tl-201 in the tumor divided by that of the uninvolved symmetric area was defined as the Tl-index. The change in tumor size immediately and 1 to 2 months after STI was compared with the change in Tl-index immediately after STI. RESULTS: No significant relationship between the ratio of tumor size immediately after STI and the ratio of Tl-index immediately after STI was found. A significant correlation (r = 0.69, P <0.05) between the ratio of tumor size 1 to 2 months after STI and the ratio of Tl-index immediately after STI was found. CONCLUSIONS: This study suggests that Tl-201 SPECT immediately after STI can predict treatment response 1 to 2 months after STI, and that Tl-201 SPECT can be an early indicator of treatment response.

Hepatic infarction following selective hepatic artery embolization with microcoils for iatrogenic biliary hemorrhage.

Purpose: The aim of this study was to explore the relation of collateral filling to ischemic or infarcted liver following selective embolization of hepatic artery with microcoils in patients with iatrogenic hemobilia. Methods: We performed retrospective analysis of clinical outcomes and post-embolization angiograms in eight patients (mean age of 66 years) studied over the last 7 years. Hemobilia occurred after percutaneous biliary drainage (n = 5) and percutaneous hepatic biopsy (n = 3). Causes of bleeding were pseudoaneurysm (n = 6), arterial laceration (n = 1), and direct hepatic artery-to-biliary duct fistula (n = 1). We placed microcoils in the subsegmental (n = 4) or segmental branch (n = 2), or both branches (n = 2), distal and proximal to the bleeding point. Results: We obtained complete hemostasis in all patients (100%). Four patients had no hepatic infarction after embolization. Normal filling of the distal part of the embolized branch through collaterals was seen on post-embolization films. Four patients with no collateral filling experienced liver infarction in the area corresponding to embolized branch. One patient with severe portal stenosis died of hepatic failure. Conclusion: Hepatic infarction is related to lack of immediate collateral flow.