Monitoring tumor response to the vascular disrupting agent CKD-516 in a rabbit VX2 intramuscular tumor model using PET/MRI: Simultaneous evaluation of vascular and metabolic parameters.

OBJECTIVES: To determine whether the CKD-516 produces a significant change in vascular and metabolic parameters in PET/MRI. MATERIALS AND METHODS: With institutional Animal Care and Use Committee approval, 18 VX2 carcinoma tumors implanted in bilateral back muscles of 9 rabbits were evaluated. Serial PET/MRI were performed before, 4 hours after and 1-week after vascular disrupting agent, CKD-516 at a dose of 0.7 mg/kg (treated group, n = 10) or saline (control group, n = 8) administration. PET/MRI-derived parameters and their interval changes were compared between the treated and control group by using the linear mixed model. Each parameter within each group was also compared by using the linear mixed model. RESULTS: Changes of the volume transfer coefficient (Ktrans) and the initial area under the gadolinium concentration-time curve until 60 seconds (iAUC) in the treated group were significantly larger compared with those in the control group at 4-hour follow-up (mean, -39.91% vs. -6.04%, P = 0.018; and -49.71% vs. +6.23%, P = 0.013). Change of metabolic tumor volume (MTV) in the treated group was significantly smaller compared with that in the control group at 1-week follow-up (mean, +118.34% vs. +208.87%, P = 0.044). Serial measurements in the treated group revealed that Ktrans and iAUC decreased at 4-hour follow-up (P < 0.001) and partially recovered at 1-week follow-up (P = 0.001 and 0.024, respectively). MTV increased at a 4-hour follow-up (P = 0.038) and further increased at a 1-week follow-up (P < 0.001), while total lesion glycolysis (TLG) did not show a significant difference between the time points. SUVmax and SUVmean did not show significant interval changes between time points (P > 0.05). CONCLUSIONS: PET/MRI is able to monitor the changes of vascular and metabolic parameters at different time points simultaneously, and confirmed that vascular changes precede the metabolic changes by VDA, CKD-516.

Radiological characteristics and management of intramuscular myxoma of the temporal muscle: case report.

The patient was a 51-year-old male with a 3-year history of a slow-growing, asymptomatic, subcutaneous mass in the left temporal region. Magnetic resonance imaging revealed a well-defined extracranial lesion with heterogeneous enhancement and without invasion of the skull. A variety of soft tissue tumors were included in the differential diagnosis. The patient underwent total resection of the tumor, and a diagnosis of intramuscular myxoma was confirmed histologically. There was no evidence of recurrence at 6-month follow-up. The present case is the first characterization of the radiological appearance of intramuscular myxoma in the temporal muscle. I emphasize that increased awareness of this rare lesion and a careful clinical and radiological preoperative assessment are crucial in determining an appropriate treatment strategy for patients with a soft tissue tumor of the head.

Technical innovation in dynamic contrast-enhanced magnetic resonance imaging of musculoskeletal tumors: an MR angiographic sequence using a sparse k-space sampling strategy.

OBJECTIVE: We demonstrate the clinical use of an MR angiography sequence performed with sparse k-space sampling (MRA), as a method for dynamic contrast-enhanced (DCE)-MRI, and apply it to the assessment of sarcomas for treatment response. MATERIALS AND METHODS: Three subjects with sarcomas (2 with osteosarcoma, 1 with high-grade soft tissue sarcomas) underwent MRI after neoadjuvant therapy/prior to surgery, with conventional MRI (T1-weighted, fluid-sensitive, static post-contrast T1-weighted sequences) and DCE-MRI (MRA, time resolution = 7-10 s, TR/TE 2.4/0.9 ms, FOV 40 cm(2)). Images were reviewed by two observers in consensus who recorded image quality (1 = diagnostic, no significant artifacts, 2 = diagnostic, <25 % artifacts, 3 = nondiagnostic) and contrast enhancement characteristics by static MRI (presence/absence of contrast enhancement, percentage of enhancement) and DCE-MRI (presence/absence of arterial enhancement with time-intensity curves). Results were compared with histological response (defined as <5 % viable tumor [soft tissue sarcoma] or <10 % [bone sarcoma] following resection). RESULTS: Diagnostic quality for all conventional and DCE-MRI sequences was rated as 1. In 2 of the 3 sarcomas, there was good histological response (≤5 % viable tumor); in 1 there was poor response (50 % viable tumor). By static post-contrast T1-weighted sequences, there was enhancement in all sarcomas, regardless of response (up to >75 % with good response, >75 % with poor response). DCE-MRI findings were concordant with histological response (arterial enhancement with poor response, no arterial enhancement with good response). CONCLUSION: Unlike conventional DCE-MRI sequences, an MRA sequence with sparse k-space sampling is easily integrated into a routine musculoskeletal tumor MRI protocol, with high diagnostic quality. In this preliminary work, tumor enhancement characteristics by DCE-MRI were used to assess treatment response.

Usefulness of transcatheter arterial embolization prior to excision of hypervascular musculoskeletal tumors.

The objective of this study was to evaluate the usefulness of transcatheter arterial embolization prior to surgical excision of musculoskeletal tumors. We reviewed the records of nine patients (3 females and 6 males) who received arterial embolization prior to excision of musculoskeletal tumors in our hospital from December 2009 to April 2010. We evaluated tumor region, size, histopathology, feeding artery, embolic material, and blood loss during surgery. We compared the actual amount of intraoperative bleeding with arterial embolization to estimated amounts of bleeding without embolization predicted by three orthopedic surgeons. Arterial embolization was performed on the same day or within 5 days before surgery. Operations were performed as planned in all patients without serious complications. The amount of intraoperative bleeding was 35-4200 mL and there was significantly less bleeding with arterial embolization compared with the estimated amounts (p<0.01). Our results show that arterial embolization prior to resection of hypervascular musculoskeletal tumors reduces the amount of bleeding during surgery and contributes to patient safety.

Modified model of VX2 tumor overexpressing vascular endothelial growth factor.

PURPOSE: To determine whether upregulated expression of vascular endothelial growth factor (VEGF) in VX2 cells can increase vessel density (VD) and reduce tumor necrosis. MATERIALS AND METHODS: The VX2 cell line was transfected with expression vectors containing cDNA for rabbit VEGF. Stable clones producing rabbit VEGF (VEGF-VX2) were selected. VEGF-VX2 cells (n = 5 rabbits) or nontransfected VX2 cells (controls; n = 5 rabbits) were implanted into leg muscle of 10 rabbits. The animals were sacrificed at day 21. Tumor volume, percentage of necrosis, VD, and VEGF concentration in tumor protein extract were quantified. RESULTS: Overexpression of VEGF by VX2 cells augmented tumor implantation efficiency 100% and favored cyst formation. The tumor volume was significantly larger for VEGF-VX2 transfected tumors versus controls (P = .0143). Overexpression of VEGF in VX2 cells significantly increased the VD of the tumors (P = .0138). The percentage of necrosis was reduced in VEGF-VX2 tumors versus controls (19.5% vs 38.5 %; P = .002). VEGF concentration in VEGF-VX2 tumors was significantly higher than in control tumors (P = .041) and was correlated with tumor volume (ρ = .883, P = .012). CONCLUSIONS: The overexpression of VEGF increased tumor growth and vascularization, favored cyst formation, and reduced tumor necrosis. This new phenotype of the VX2 tumor may offer some advantages over classic models of VX2 tumor for evaluating anticancer therapies.

Intramuscular cavernous hemangioma in the left soleus muscle: successful surgical treatment.

We describe here the case of a 16-year-old boy successfully treated at our hospital for intramuscular cavernous hemangioma in the left soleus muscle. The patient was diagnosed using magnetic resonance imaging and open biopsy after attempted/failed surgery at another institution. We performed lower leg phlebography in order to identify all the feeding and draining veins of the cavernous hemangioma. Our surgical approach of ligation of the feeding and draining veins of the intramuscular cavernous hemangioma with subsequent thrombosis of the hemangioma proved successful, resulting in cure with no operative or postoperative complications, a minimal hospital stay and a good functional and cosmetic outcome.

Interstitial fluid pressure and vascularity of intradermal and intramuscular human tumor xenografts.

PURPOSE: High interstitial fluid pressure (IFP) in tumors has been shown to be associated with poor prognosis. Mechanisms underlying the intertumor heterogeneity in IFP were investigated in this study. METHODS AND MATERIALS: A-07 melanoma xenografts were transplanted intradermally or intramuscularly in BALB/c nu/nu mice. IFP was measured in the center of the tumors with a Millar catheter. Tumor blood perfusion and extracellular volume fraction were assessed by dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI). The necrotic fraction, vascular density, and vessel diameters of the tumors were determined by image analysis of histological preparations. RESULTS: Significant intertumor heterogeneity in IFP, blood perfusion, and microvascular morphology was observed whether the tumors were transplanted intradermally or intramuscularly. High IFP was mainly a consequence of high resistance to blood flow caused by low vessel diameters in either transplantation site. IFP decreased with increasing blood perfusion in intradermal tumors and increased with increasing blood perfusion in intramuscular tumors, mainly because the morphology of the tumor microvasculature differed systematically between the two tumor models. CONCLUSION: The potential of DCE-MRI as a noninvasive method for assessing the IFP of tumors may be limited because any relationship between IFP and blood perfusion may differ with the tumor growth site.

Bevacizumab-induced tumor vessel remodeling in rhabdomyosarcoma xenografts increases the effectiveness of adjuvant ionizing radiation.

PURPOSE: Inhibition of vascular endothelial growth factor (VEGF) may effect transient "normalization" of tumor vasculature by pruning immature vessels, resulting in improved tumor perfusion and oxygenation. This may improve the efficacy of adjuvant ionizing radiation (IR). We tested this hypothesis using bevacizumab, an anti-VEGF antibody, in rhabdomyosarcoma (RMS) xenografts. METHODS: Mice bearing orthotopic alveolar RMS xenografts were treated with a single dose of bevacizumab, IR, or a combination of the two on different schedules. Tumors were then evaluated for changes in microvessel density, vessel maturity, vessel permeability, intratumoral oxygenation, as well as altered growth. RESULTS: After bevacizumab treatment, a significant decrease in tumor microvessel density and a significant increase in tumor vessel maturity, defined as the ratio of pericytes to endothelial cells, were observed, suggesting pruning of immature vessels lacking pericytes. Tumor vessel permeability was also significantly decreased and intratumoral oxygen tension increased 2 and 5 days after bevacizumab owing to a transient improvement in tumor perfusion. Treatment with IR 2 or 5 days after bevacizumab resulted in the greatest antitumor activity. CONCLUSION: Our findings support the hypothesis that VEGF inhibition with bevacizumab transiently normalizes the dysfunctional vasculature of RMS xenografts, improving tumor oxygenation and increasing tumor sensitivity to adjuvant IR.

[3D-CTA and 4D-CE-MRA for dynamic monitoring tumor angiogenesis in a rabbit VX2 tumor].

OBJECTIVE: To study possibility of dynamic monitoring tumor angiogenesis in vivo by 3D-CTA on a 64-row multidetector CT and 4D-CE-MRA on a 3T MR scanner; compare the advantages and faults of these two methods; and analyze the relationship between tumor angiogenesis and tumor growth. METHODS: This study had been approved by the institutional animal care and use committee. Thirty New Zealand white rabbits with implanted VX2 tumors in the right thigh muscle were randomly divided into five groups according to survive time (n = 6). The rabbits were scanned by a 64-row multidetector CT and a 3T MR at 4, 7, 10, 13, 16 days after tumor implantation respectively, and then sacrificed to extract the tumor. The tumors' long diameters, short diameters and volume measurements derived from CT and MR imaging were compared with pathological data. The minimum tumor diameter and the number of new tumor blood vessels detectable by 3D-CTA and 4D-CE-MRA were also compared. The morphologic process of tumor angiogenesis was monitored and described. RESULTS: (1) The volume of tumors measured by CT imaging, MR imaging and pathological data had no significant difference (P > 0.05). (2) The minimum diameter of tumor vessels displayed on 3D-CTA and 4D-CE-MRA images was 0.68 mm +/- 0.07 mm and 0.85 mm +/- 0.12 mm respectively. The minimum diameter of tumor vessels displayed on 3D-CTA imaging was significantly smaller than 4D-CE-MRA imaging (t = -6.5075, P = 0.005). (3) The number of tumor vessels on 3D-CTA imaging and 4D-CE-MRA imaging had no significant difference at 4, 7, 10 days after tumor implantation. The number of tumor vessels on 3D-CTA images were significantly more than that on 4D-CE-MRA images at 13, 16 days after tumor implantation (all P < 0.01). (4) The morphologic process of tumor angiogenesis was demonstrated as sprouting from pre-existing blood vessel, forming lots of new vessels around tumor, and forming the immature vessels web with lots of tortuous, dilated, irregular vessels penetrating into the tumor at last. CONCLUSIONS: Volume CT and high magnet field MR can monitor tumor growth in vivo. 3D-CTA and 4D-CE-MRA can dynamicly monitor morphological changes of tumor angiogenesis in vivo. Of the two methods, 3D-CTA has better spatial resolution, but 4D-CE-MRA allows better temporal resolution of tumor angiogenesis monitoring.

[A case of metastasis to the diaphragm from ascending colon cancer].

We reported a case of metastatic tumor to the diaphragm discovered by rising CEA after operation of ascending colon cancer. A 72-year-old female underwent right hemicolectomy on January 2005. After discharge, she received adjuvant chemotherapy by S-1, but a rise of CEA was shown. Based on exploratory findings, laparotomy was done with the diagnosis of metastasis to the liver(S7). A tumor was present in the right diaphragm, and contacted the liver(S7). Partial resection of the right diaphragm was performed. The removed specimen revealed the same histological findings of the last operated ascending colon. Metastasis to the diaphragm is very rare, especially a solitary one as in this case. Etiologically speaking, the tumor cells might be absorbed or have strayed into peritoneal stomata of the diaphragm.

Visualization of treatment response in tumors by use of dynamic contrast-enhanced magnetic resonance imaging.

Our goal in this study was to present a method for generating functional parametric maps of hemodynamic parameters in tumors and a visualization method for assessing treatment response by use of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI). A total of 13 patients with musculoskeletal tumors were included in this study. First, tumor blood flow (F(T)) maps were generated from DCE-MRI data by use of deconvolution analysis, and K(1), k(2), and f were obtained from a two-compartment model, where K(1) and k(2) denote the rate constant for the transfer of contrast agent from blood to tissue and from tissue to blood, respectively, and f is the fraction of the blood volume. Images were generated by application of the linear least squares method pixel by pixel. Furthermore, the images of the distribution volume (V(d)) and permeability-surface area product (PS) were obtained from the relations V(d) = K(1)/k(2) and PS = -F(T) x ln(1 - K(1)/(F(T)), respectively. Second, two-dimensional (2D) plots were generated with V(d) and K(1) placed on the x- and y-axes, and three-dimensional (3D) plots were generated by the addition of PS on the z-axis. In the case of good responders whose biopsied specimens revealed tumor necrosis greater than 90%, both 2D and 3D plots gradually approached the origin after an increasing number of treatments. On the other hand, in the case of non-responders whose biopsied specimens showed little chemotherapeutic effect, large changes were not observed in either plot. In conclusion, our method will be promising for evaluating the treatment response in tumors visually.

Evaluation of tumor blood flow in musculoskeletal lesions: dynamic contrast-enhanced MR imaging and its possibility when monitoring the response to preoperative chemotherapy-work in progress.

PURPOSE: The objective of this study was to calculate tumor blood flow (TBF) in musculoskeletal lesions and to evaluate the usefulness of this parameter in differentiating malignant from benign lesions and monitoring the treatment response to preoperative chemotherapy. MATERIALS AND METHODS: Altogether, 33 patients with musculoskeletal lesions underwent a total of 50 dynamic magnetic resonance imaging (MRI) examinations, including 28 on 9 patients undergoing preoperative chemotherapy. TBF was calculated using deconvolution analysis. Steepest slope (SS) was determined from the time-intensity curve during the first pass of contrast medium. RESULTS: TBF ranged from 2.7 to 178.6 mL/100 mL/min in benign lesions and from 15.4 to 296.3 mL/100 mL/min in malignant lesions. SS ranged from 0.5%/s to 31.8%/s for benign lesions and from 3.1%/s to 64.8%/sec for malignant lesions. TBF and SS did not differ significantly between benign and malignant lesions. Among the nine patients who underwent preoperative chemotherapy, TBF after chemotherapy was lower in good responders (11.7, 11.0, 7.9 mL/100 mL/min) (n = 3, tumor necrosis > or =90%) than in poor responders (23.4-141.5 mL/100 mL/min) (n = 6, tumor necrosis <90%). CONCLUSION: TBF and SS cannot reliably differentiate malignant from benign lesions. However, they have potential utility in evaluating the preoperative treatment response in patients with malignant musculoskeletal tumors.

Measurement of tumor blood flow using dynamic contrast-enhanced magnetic resonance imaging and deconvolution analysis: a preliminary study in musculoskeletal tumors.

OBJECTIVE: To measure tumor blood flow (TBF) using dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI). METHODS: A DCE-MRI was performed using inversion recovery-preparation fast-field echo sequences. Dynamic data were obtained every 3.2 seconds for 2 minutes, immediately after gadolinium injection. In 14 patients with malignant musculoskeletal tumors, TBF maps were generated pixel-by-pixel by deconvolution analysis. For preclinical studies, muscle blood flow in 5 volunteers and signal intensities of different gadolinium concentrations were measured. RESULTS: There was a good linear relationship between signal intensities and gadolinium concentrations (r = 0.989, P < 0.001, at gadolinium concentrations

Combination of extremity computed tomography angiography and abdominal imaging in patients with musculoskeletal tumors.

PURPOSE: To introduce a comprehensive computed tomography (CT) protocol for the evaluation of patients with musculoskeletal tumors by combining extremity CT angiography and abdomen CT in a dynamic multidetector CT study. METHODS: Single contrast bolus was used for each study in 4 patients with musculoskeletal tumors involving the lower extremities. Extremity CT angiography and abdominal CT were acquired sequentially by 4-channel multidetector CT. Technical parameters for extremity CT angiography were as follows: detector collimation, 4 mm x 1 mm; pitch, 1.75; slice thickness, 1.25 mm; reconstruction interval, 1 mm; coverage, 42 cm; and table speed, 14 mm/s. Thick and thin maximum intensity projections, volume renderings, and multiplanar reformats with or without bone subtraction were used to display vascular supply of the extremity mass and adjacent vascular structures. RESULTS: Satisfactory images of the extremity arterial system and abdomen were obtained in all patients. The mean delay time for CT angiography was 25 seconds. Extremity CT angiography demonstrated feeding arteries of a fibular giant cell tumor and a large lymphomatous mass. The same protocol was used for the evaluation of a distal tibial osteosarcoma and a fibular chondrosarcoma. In 2 patients, early venous return was noted, indicating vascularity of the tumors. In all patients, the relation of osseus masses to adjacent vascular structures was visualized as well as the bony anatomy. CONCLUSION: Extremity CT angiography and abdominal staging CT can be combined in a single dynamic multidetector CT protocol in patients with musculoskeletal tumors, resulting in a reduction of costs, acquisition time, and contrast dose as well as an improvement in patient management. The same protocol can also be used in trauma patients.

New model for analysis of dynamic contrast-enhanced MRI data distinguishes metastatic from nonmetastatic transplanted rodent prostate tumors.

Dynamic contrast-enhanced MRI (DCEMRI) data were acquired from metastatic and nonmetastatic tumors in rodents to follow the uptake and washout of a low-molecular-weight contrast agent (Gd-DTPA) and a contrast agent with higher molecular weight (P792). The concentration vs. time curves calculated for the tumor rims and centers were analyzed using the two-compartment model (TCM) and a newly developed empirical mathematical model (EMM). The EMM provided improved fits to the experimental data compared to the TCM. Parameters derived from the empirical model showed that the contrast agent washout rate was significantly slower in metastatic tumors than in nonmetastatic tumors for both Gd-DTPA (P < 0.03) and P792 (P < 0.04). The effects of the tumor on blood flow in "normal" tissue immediately adjacent to the tumors were evident: Gd-DTPA uptake and washout rates were much lower in muscle near the tumor (P < 0.05) than normal muscle farther from the tumor. The results suggest that accurate fits of DCEMRI data provide kinetic parameters that distinguish between metastatic and relatively benign cancers. In addition, a comparison of the dynamics of Gd-DTPA and P792 provides information regarding the microenvironment of tumors.

Carbon dioxide reactivity of computed tomography functional parameters in rabbit VX2 soft tissue tumour.

Tumour blood flow is one of the important factors limiting the efficacy of radiation therapy (hypoxic radioresistance), chemotherapy (drug delivery) and thermal therapy (heat dissipation) in treating cancer. The modification of tumour blood flow has been an area of intense investigation. In the current study, the arterial carbon dioxide tension (PaCO2) was changed in order to investigate the tumour vascular response to carbon dioxide. Functional maps of blood flow, blood volume and mean transit time were generated at four PaCO2 levels in VX2 tumour in the rabbit thigh and normal soft tissue. The PaCO2 levels investigated were normocapnia (PaCO2 = 40.9 +/- 1.2 mmHg), hypocapnia (27.2 +/- 2.3 and 33.5 +/- 2.3 mmHg) and hypercapnia (54.9 +/- 4.4 mmHg). The carbon dioxide reactivity of the global tumour blood flow and mean transit time showed significant differences between normocapnia and the two levels of hypocapnia, but not between normocapnia and hypercapnia. The average fractional change of blood flow from normocapnia for the two levels of hypocapnia was -0.41 +/- 0.06 and -0.29 +/- 0.08, respectively (P < 0.05). In the case of mean transit time the fractional change was +0.39 +/- 0.30 and +0.23 +/- 0.24, respectively (P < 0.05). The fractional change of blood volume from normocapnia, however, was not significantly different at any capnic level, as was the case with respect to each of the functional parameters in normal tissue. The ability to reduce blood flow and increase mean transit time through hypocapnia has significant implications in thermal therapy, since heat dissipation is a major factor in limiting the effectiveness of treatment.

99mTc-tetrofosmin scintigraphy in musculoskeletal tumours: the relationship between P-glycoprotein expression and tetrofosmin uptake in malignant lesions.

The aims of this study were to assess the role of (99m)Tc-tetrofosmin scintigraphy in the diagnosis of malignant vs. benign musculoskeletal tumours and to determine the relationship between P-glycoprotein expression and tetrofosmin uptake in malignant lesions. Forty-six patients (32 malignant, 14 benign) with various musculoskeletal lesions were studied. Each patient underwent (99m)Tc-methylene diphosphonate three-phase bone scanning initially. At least 2 days later, dynamic and static (99m)Tc-tetrofosmin scans were obtained. The tetrofosmin scans were evaluated by visual and quantitative analysis. The count ratio of the lesion to the contralateral normal area (uptake ratio, UR) was calculated from the region of interest drawn on the tetrofosmin scan. The lesions were then resected by open biopsy to obtain a histopathological diagnosis. P-glycoprotein levels were determined immunohistochemically in 22 of 32 malignant lesions. A significant difference between the mean UR values of benign and malignant lesions was found (1.36 +/- 0.47 vs. 3.35 +/- 2.08, P = 0.000). Visual analysis showed an accuracy of 85%, and the accuracy of the quantitative analysis was 87% with the threshold level of UR as 1.76. When perfusion findings were added to the evaluation criteria, the accuracies of visual and quantitative analysis were increased to 87% and 89%, respectively. The relationship between the levels of P-glycoprotein and the UR values of tetrofosmin was not statistically significant (r = -0.235, P = 0.2). In addition, the mean UR value of the patients with P-glycoprotein expression was not statistically different from that of the patients without P-glycoprotein expression (3.01 +/- 1.48 vs. 4.27 +/- 2.90, P = 0.297). In conclusion, visually significant tetrofosmin uptake and increased perfusion in a musculoskeletal lesion strongly suggest that the lesion is malignant (positive predictive value, 96%). P-glycoprotein expression was not found to be a major factor interfering with 30 min tetrofosmin uptake in a malignant musculoskeletal lesion. However, the relatively high false-negative rate among negative results (28%) limits the value of (99m)Tc-tetrofosmin scintigraphy as a single diagnostic tool in differentiating between benign and malignant musculoskeletal tumours.

Blood flow in and around the masseter muscle: normal and pathologic features demonstrated by color Doppler sonography.

OBJECTIVE: The purpose of this study was to clarify the normal findings of arteries in and around the masseter muscle and to present their pathologic changes with the use of color Doppler sonography. STUDY DESIGN: The vascular appearances were examined for the 4 main arteries feeding the masseter muscle in healthy volunteers (n = 38) and patients with inflammation (n = 5) and intramuscular hemangioma (n = 3). The features of these arteries were investigated together with the flow diameter, flow velocities, and arterial resistances. The symmetry indices were also calculated to assess the pathologic changes. RESULTS: The detection rates of the branch from the transverse facial artery, the masseter artery, and the branch from the maxillary or external carotid artery were 98.7%, 21.1%, and 84.2% in healthy volunteers, respectively. The facial artery that feeds the muscle from the inferior part represented 2 patterns according to anatomic variant: the masseteric branch (22.4%) and the main trunk itself (77.6%). The means of the flow diameter, maximum and minimum velocities, resistive index, and pulsatility index in healthy subjects were 1.8 mm, 24.6 cm/s, 5.1 cm/s, 0.80, and 2.51, respectively. In most of the patients with symptoms, the symmetry indices of all measurement values increased in comparison with those of healthy volunteers. CONCLUSION: Color Doppler sonography is useful in describing the arteries in and around the masseter muscle and has the potential of being used to depict the pathologic changes.