Detection of EGFR T790M mutation using liquid biopsy for non-small cell lung cancer: Utility of droplet digital polymerase chain reaction vs. cobas real-time polymerase chain reaction.

BACKGROUND: Digital platforms for mutation detection yield higher sensitivity than non-digital platforms but lack universal positive cut-off values that correlate with the outcome of osimertinib treatment. This study determined compared droplet digital polymerase chain reaction (ddPCR) to the standard cobas assay for epithelial growth factor receptor (EGFR) T790M mutation detection in patients with non-small cell lung cancer. METHODS: Study patients had EGFR-mutant tumours with disease progression on first/second generation EGFR tyrosine kinase inhibitors, and osimertinib treatment after T790M mutation detection. T790M status was tested by cobas assay using liquid biopsy, and only by ddPCR if an EGFR mutation was identified but T790M was negative. Clinical efficacy of osimertinib was compared between patients with T790M detected by cobas vs. only by ddPCR. A positive cut-off value for ddPCR was determined by assessing efficacy with osimertinib. RESULTS: 61 patients had tumors with an acquired T790M mutation, 38 detected by cobas and an additional 23 only by ddPCR. The median progression-free survival (PFS) for the cobas- and ddPCR-positive groups was 9.5 and 7.8 months, respectively (p=0.43). For ddPCR, a fractional abundance (FA) of 0.1% was used as a cut-off value. The median PFS of patients with FA ≥0.1% and <0.1% was 8.3 and 4.6 months, respectively (p=0.08). FA ≥0.1% was independently associated with a longer PFS. CONCLUSION: Using ddPCR to follow up the cobas assay yielded more cases (38% of total) with a T790M mutation. A cut-off value of FA ≥0.1% identified patients who responded as well to osimertinib as those identified by cobas assay. This sequential approach should detect additional patients who might benefit from osimertinib treatment.

Differential expression of immune-regulatory proteins C5AR1, CLEC4A and NLRP3 on peripheral blood mononuclear cells in early-stage non-small cell lung cancer patients.

Changes in gene expression profiling of peripheral blood mononuclear cells (PBMC) appear to represent the host's response to the cancer cells via paracrine signaling. We speculated that protein expression on circulating T-lymphocytes represent T-lymphocyte trafficking before infiltration into the tumor microenvironment. The possibility of using protein expression on circulating T-lymphocytes as a biomarker to discriminate early-stage non-small cell lung cancer (NSCLC) was explored. Four independent PBMC gene expression microarray datasets (GSE12771, GSE13255, GSE20189 and GSE3934) were analyzed. We selected C5AR1, CLEC4A and NLRP3 based on their significant protein expression in tumor-infiltrating lymphocytes, but not in normal lymphoid tissue. A validation study using automated flow cytometry was conducted in 141 study participants including 76 treatment-naive early-stage non-small cell lung cancer patients (NSCLC), 12 individuals with non-malignant pulmonary diseases, and 53 healthy individuals. Median ratios of C5AR1, CLEC4A and NLRP3 specific antibody staining to CD3 positive cells in early-stage NSCLC patients compared to healthy controls were 0.014 [0-0.37] vs. 0.01 [0-0.07, p = 0.13], 0.03 [0-0.87] vs. 0.02 [0-0.13, p = 0.10] and 0.19 [0-0.60] vs. 0.09 [0.02-0.31, p < 0.0001], respectively. Median fluorescence intensity (MFI) of CD3+C5AR1+, CD3+CLEC4A+ and CD3+NLRP3+ expression in early-stage NSCLC patients compared to healthy volunteers was 185 [64.2-4801] vs. 107.5 [27-229, p < 0.0001], 91.2 [42.4-2355] vs. 71.25 [46.2-103, p = 0.0005], and 1585 [478-5224] vs. 758.5 [318-1976, p < 0.0001], respectively. NLRP3:CD3 ratio, CD3+C5AR1+, CD3+CLEC4A+ and CD3+NLRP3+ MFI were significantly higher in early-stage NSCLC than healthy volunteers with an area under the ROC curve of 0.69-0.76. The CD3+NLRP3+ MFI provided the most distinguishable expression at 71.5% sensitivity and 70% specificity. Furthermore, CD3+NLRP3+ MFI potentially discriminated between early-stage NSCLC from malignant-mimic inflammation and infection pulmonary disease. Further validation in various pulmonary inflammatory disease might be warranted. Our proof-of-principle findings strengthen the hypothesis that malignancies generate distinctive protein expression fingerprints on circulating T-lymphocytes.

Comparison of early radiological predictors of outcome in patients with colorectal cancer with unresectable hepatic metastases treated with bevacizumab.

OBJECTIVE: The purpose was to validate the prognostic value of an early optimal morphological response on CT in patients treated with bevacizumab-containing chemotherapy for unresectable colorectal cancer liver metastases (CLM). It also evaluated the prognostic value of size-based criteria and the association of optimal morphological response with the receipt of bevacizumab. DESIGN: 141 patients treated first using bevacizumab and 142 patients from a randomised study evaluating the addition of bevacizumab to oxaliplatin-based chemotherapy were retrospectively analysed. Radiologists evaluated pretreatment and restaging CT scans using morphological response criteria. Responses were also assessed with size-based criteria: Response Evaluation Criteria in Solid Tumors (RECIST), early tumour shrinkage (ETS) and deepness of response (DpR). The ability of each criterion to predict progression-free survival (PFS), overall survival (OS) and postprogression survival (PPS) was determined using a univariate Cox proportional hazards model. RESULTS: In both populations, median PFS was significantly longer for patients achieving an optimal morphological response (10.4 vs 6.8 months, p=0.03; and 8.3 vs 4.9 months, p<00001, respectively). Neither RECIST nor ETS responses were associated with a prolonged PFS. Median OS was longer for those with an optimal morphological response but only at second restaging in the first population (n=141, 20.8 vs 12.3 months, p=0.002). DpR but not optimal morphological response was associated with PPS. In the randomised study, an optimal morphological response was 6.2 times more likely among patients receiving bevacizumab (p<0.0001). CONCLUSION: In patients with unresectable CLM, early morphological response may be a better predictor of PFS than size-based response. The addition of bevacizumab improves morphological response rate.

Technical challenges in 3 T magnetic resonance spectroscopic imaging of the prostate-A single-institution experience.

The magnetic resonance spectroscopic imaging (MRSI) is the only technique that is currently available in the clinical practice to provide the metabolic status of prostate tissue at the cellular level with a great potential to improve the clinical patient care. Increasing the field strength from 1.5 to 3 T can theoretically provide proportionately higher signal-to-noise ratio (SNR) and improve spectral separation between prostatic metabolite peaks. The technique, however, has been limited to a few academic institutions that are equipped with a team of experts primarily due to due to serious technical challenges in optimizing the spectral quality. High quality shimming is key to the successful MRSI acquisition. Without optimization of the increased field inhomogeneity and radiofrequency (RF) dielectric effect at 3 T, the spectral peak broadening and residual signal from the periprostatic fat tissue may render the overall spectra non-diagnostic. The purpose of this technical note is to present the practical steps of successful acquisition of 3 T MRSI and to address several important technical challenges in minimizing the effect of the increased magnetic field and RF field inhomogeneity in order to obtain highest possible spectral quality based on our initial experience in using 3 T MRSI prototype software.

Optimization of MR imaging for pretreatment evaluation of patients with endometrial and cervical cancer.

Endometrial and cervical cancer are the most common gynecologic malignancies in the world. Accurate staging of cervical and endometrial cancer is essential to determine the correct treatment approach. The current International Federation of Gynecology and Obstetrics (FIGO) staging system does not include modern imaging modalities. However, magnetic resonance (MR) imaging has proved to be the most accurate noninvasive modality for staging endometrial and cervical carcinomas and often helps with risk stratification and making treatment decisions. Multiparametric MR imaging is increasingly being used to evaluate the female pelvis, an approach that combines anatomic T2-weighted imaging with functional imaging (ie, dynamic contrast material-enhanced and diffusion-weighted imaging). MR imaging helps guide treatment decisions by depicting the depth of myometrial invasion and cervical stromal involvement in patients with endometrial cancer and tumor size and parametrial invasion in those with cervical cancer. However, its accuracy for local staging depends on technique and image quality, namely thin-section high-resolution multiplanar T2-weighted imaging with simple modifications, such as double oblique T2-weighting supplemented by diffusion weighting and contrast enhancement.

Differentiating pericardial recesses from mediastinal adenopathy: potential pitfalls in oncological imaging.

In oncological imaging, staging with computed tomography (CT) is widely used to determine treatment. Misinterpretation of fluid in pericardial recesses as mediastinal adenopathy can lead to inaccurate clinical staging and inappropriate management. In this review, we describe normal pericardial anatomy and illustrate imaging features to differentiate fluid in pericardial sinuses and recesses from mediastinal adenopathy.

Fungal infection mimicking pulmonary malignancy: clinical and radiological characteristics.

OBJECTIVE: The purpose of this study was to evaluate the clinical and radiological features of patients with fungal infection mimicking thoracic malignancy and to establish a diagnostic approach for both clinicians and radiologists to avoid misdiagnosis. METHODS: In this retrospective study, we reviewed clinical and computed tomography (CT) findings from 27 patients who presented with suspicion of thoracic malignancy who were ultimately diagnosed with fungal disease. RESULTS: Patients' median age was 55.7 (range 31-78) years. The most common clinical findings were cough (48.1 %), expectoration (33.3 %), chest pain (25.9 %), weakness (25.9 %), weight loss (18.5 %), and hemoptysis, dyspnea, and fever (7.4 % each). The median lesion size was 35.5 (range 10-85) mm. CT findings included a solid nodule (51.9 %), solid mass (37 %), or both (11.1 %). Nodule and mass margins were lobulated in 9 (33.3 %) patients, ill-defined in 5 (18.5 %), spiculated in 4 (14.8 %), and smooth in 4 (14.8 %) patients. Additional findings included consolidation in 4 (14.8 %) patients, cavitation in 3 (11.1 %), pleural effusion in 2 (7.4 %), and lymphadenopathy in 11 (40.7 %) patients. In all patients, specific diagnoses were made and confirmed by histopathology; final diagnoses were histoplasmosis (25.9 %), coccidiomycosis (22.2 %), cryptococcosis (22.2 %), aspergillosis (14.8 %), North American blastomycosis (7.4 %), mucormycosis (3.75 %), and paracoccidioidomycosis (3.75 %). CONCLUSIONS: Fungal infection can present with clinical and radiological features that are indistinguishable from thoracic malignancy, such as lung nodules or masses. Because the management and outcomes of fungal infection and malignancy are entirely distinct, the establishment of a specific diagnosis is critical to provide appropriate therapy.

MR imaging of prostate cancer in radiation oncology: what radiologists need to know.

Radiation therapy (RT) is one of the principal treatment modalities for localized or locally advanced prostate cancer. The two major forms of RT for prostate cancer are external-beam RT (EBRT) with a photon or proton beam and brachytherapy. With modern conformal techniques for EBRT (three-dimensional conformal RT, intensity-modulated RT, and image-guided RT) and advanced computer-based planning systems for brachytherapy, the dose can be more precisely delivered to the prostate while reducing unnecessary radiation to normal tissue. The dominant intraprostatic tumor can be targeted with a higher dose, so-called dose painting. Magnetic resonance (MR) imaging plays a pivotal role in pretreatment assessment of prostate cancer. Multiparametric MR imaging, a combination of anatomic and functional MR imaging techniques (diffusion-weighted imaging, dynamic contrast material-enhanced imaging, and MR spectroscopy), significantly improves the accuracy of tumor localization and local staging. For pretreatment planning, anatomic MR imaging provides highly accurate local staging information, particularly about extraprostatic extension and seminal vesicle invasion. The dominant intraprostatic tumor and local recurrence in the prostatectomy bed can be better localized with multiparametric MR imaging for dose painting. MR imaging allows excellent delineation of the contours of the prostate and surrounding structures. It can also be used in early posttreatment evaluation after brachytherapy.

Optimal morphologic response to preoperative chemotherapy: an alternate outcome end point before resection of hepatic colorectal metastases.

PURPOSE: The purposes of this study were to confirm the prognostic value of an optimal morphologic response to preoperative chemotherapy in patients undergoing chemotherapy with or without bevacizumab before resection of colorectal liver metastases (CLM) and to identify predictors of the optimal morphologic response. PATIENTS AND METHODS: The study included 209 patients who underwent resection of CLM after preoperative chemotherapy with oxaliplatin- or irinotecan-based regimens with or without bevacizumab. Radiologic responses were classified as optimal or suboptimal according to the morphologic response criteria. Overall survival (OS) was determined, and prognostic factors associated with an optimal response were identified in multivariate analysis. RESULTS: An optimal morphologic response was observed in 47% of patients treated with bevacizumab and 12% of patients treated without bevacizumab (P < .001). The 3- and 5-year OS rates were higher in the optimal response group (82% and 74%, respectively) compared with the suboptimal response group (60% and 45%, respectively; P < .001). On multivariate analysis, suboptimal morphologic response was an independent predictor of worse OS (hazard ratio, 2.09; P = .007). Receipt of bevacizumab (odds ratio, 6.71; P < .001) and largest metastasis before chemotherapy of ≤ 3 cm (odds ratio, 2.12; P = .025) were significantly associated with optimal morphologic response. The morphologic response showed no specific correlation with conventional size-based RECIST criteria, and it was superior to RECIST in predicting major pathologic response. CONCLUSION: Independent of preoperative chemotherapy regimen, optimal morphologic response is sufficiently correlated with OS to be considered a surrogate therapeutic end point for patients with CLM.

Efficacy of first-line doxorubicin and ifosfamide in myxoid liposarcoma.

BACKGROUND: Myxoid liposarcoma (MLS) is a soft tissue sarcoma with adipocytic differentiation characterized by a unique chromosome rearrangement, t(12;16)(q13;p11). The exact efficacy of chemotherapy in MLS has not been clearly established. PATIENTS AND METHODS: We retrospectively analyzed the records of 37 histologically confirmed MLS patients who were treated at the University of Texas MD Anderson Cancer Center from January 2000 to December 2009 with doxorubicin 75-90 mg/m2 over 72 hours combined with ifosfamide 10 gm/m2 in the first-line setting. Response was assessed using RECIST and Choi criteria. The Kaplan-Meier method and log-rank test was used to estimate clinical outcomes. RESULTS: The median follow-up period was 50.1 months. The overall response rates were 43.2% using RECIST and 86.5% using the Choi criteria. The 5-year disease-free survival rate was 90% for patients with resectable tumors. Median time to progression and overall survival time for the advanced-disease group were 23 and 31.1 months, respectively. CONCLUSION: Our study demonstrates that doxorubicin-ifosfamide combination therapy has a role in the treatment of MLS. The Choi criteria may be more sensitive in evaluating response to chemotherapy in MLS.

Use of maximum slope images generated from dynamic contrast-enhanced MRI to detect locally recurrent prostate carcinoma after prostatectomy: a practical approach.

OBJECTIVE: The purpose of this article is to present the value of high-temporal-resolution and high-spatial-resolution dynamic contrast-enhanced MRI (DCE-MRI) combined with the postprocessed slope images generated from the fastest rate of enhancement of each voxel for detecting local recurrence of prostate carcinoma after radical prostatectomy. METHODS AND MATERIALS: Of 125 patients, 47 patients with and without local recurrence confirmed by biopsy or clinical follow-up were identified. All patients underwent DCE-MRI with a spatial resolution of 3 mm and mean temporal resolution of 11.3 seconds (range, 8.4-14.0 seconds). RESULTS: In patients with local recurrence, the mean (± SD) prostate-specific antigen level and tumor size were 1.9 ± 1.8 mg/dL and 10.8 ± 5.7 mm, respectively, at the time of MRI. Thirty-six of 37 patients (97%) with biopsy or clinically confirmed local recurrence had positive MRI findings. Eight of 10 patients (80%) with negative recurrence had negative MRI findings. Of the 36 patients, 16 (44%) had time-intensity curves of rapid increase-rapid washout and 18 (50%) had rapid increase-plateau or slow washout. The recurrent tumor reached the peak enhancement within one phase following the peak enhancement of the common femoral artery. In patients with a negative MRI result, the mean PSA level was 0.2 ± 0.1 mg/dL. CONCLUSION: DCE-MRI using high temporal and spatial resolution is highly accurate in detecting subcentimeter local recurrences within the postprostatectomy bed. Combined with visual inspection of original source images (using the common femoral artery as a reference), the slope image is a simple and practical way of identifying locally recurrent prostate carcinoma.

CT findings of response and recurrence, independent of change in tumor size, in colorectal liver metastasis treated with bevacizumab.

OBJECTIVE: The purpose of this article is to provide a practical review of newly established morphologic tumor response criteria for hepatic colorectal metastasis treated with bevacizumab-containing chemotherapy and a description of the patterns of early recurrence. We also discuss the respective value of these criteria and the Response Evaluation Criteria in Solid Tumors (RECIST). CONCLUSION: RECIST alone are not sufficient to assess response after bevacizumab-containing chemotherapy for hepatic colorectal metastasis. The combined use of RECIST and morphologic criteria is mandatory for optimal evaluation in this population.

Activity of temozolomide and bevacizumab in the treatment of locally advanced, recurrent, and metastatic hemangiopericytoma and malignant solitary fibrous tumor.

BACKGROUND: Hemangiopericytomas and malignant solitary fibrous tumors (HPC/SFT) are rare, closely related sarcomas with unpredictable behavior that respond infrequently to chemotherapy. An optimal systemic treatment strategy for advanced HPC/SFT has not yet been identified. METHODS: We retrospectively analyzed the records of 14 patients with histopathologically confirmed HPC/SFT who were treated at The University of Texas MD Anderson Cancer Center between May 2005 and June 2007. All patients were treated with temozolomide 150 mg/m(2) orally on days 1-7 and days 15-21 and bevacizumab 5 mg/kg intravenously on days 8 and 22, repeated at 28-day intervals. Computed tomography assessment of tumor size and density (Choi criteria) was used to determine the best response to therapy. The Kaplan-Meier method was used to estimate progression-free survival. RESULTS: The median follow-up period was 34 months. Eleven patients (79%) achieved a Choi partial response, with a median time to response of 2.5 months. Two patients (14%) had stable disease as the best response, and 1 patient (7%) had Choi progressive disease as the best response. The estimated median progression-free survival was 9.7 months, with a 6-month progression-free rate of 78.6%. The most frequently observed toxic effect was myelosuppression. CONCLUSION: Combination therapy with temozolomide and bevacizumab is a generally well-tolerated and clinically beneficial regimen for HPC/SFT patients. Additional investigation in a controlled, prospective trial is warranted.

Planning and follow-up after ablation of hepatic tumors: imaging evaluation.

CTs or MRIs are essential for preablative therapy planning of hepatic tumors to identify accurate size, number, and location of tumors. Tumors larger than 5 cm and located near the major branches of the portal vein and hepatic vein have a higher potential for incomplete ablation. Postablative imaging studies are needed to determine if the entire tumors are included in the treatment zone to minimize the risk of local tumor recurrences. Complications of ablative therapy can be identified on post-treatment imaging studies.

Pathways of extrapelvic spread of pelvic disease: imaging findings.

The complex extraperitoneal anatomy of the pelvis includes various outlets for the transit of organs and neurovascular structures to the rest of the body. These outlets include the greater sciatic foramen, lesser sciatic foramen, inguinal canal, femoral triangle, obturator canal, anal and genitourinary hiatuses of the pelvic floor, prevesical space, and iliopsoas compartment. All of these structures serve as conduits for the dissemination of malignant and benign inflammatory diseases from the pelvic cavity and into the soft-tissue structures of the abdominal wall, buttocks, and upper thigh. Knowledge of the pelvic anatomy is crucial to understand these patterns of disease spread. Cross-sectional imaging provides important anatomic information and depicts the extent of disease and its involvement of surrounding extrapelvic structures, information that is important for planning surgery and radiation therapy.

Extramural venous invasion by gastrointestinal malignancies: CT appearances.

The purpose of this article is to describe and demonstrate the appearances of extramural vascular invasion on computed tomography in gastrointestinal malignancies as one of the pathways of disease spread. In this article, we demonstrate the imaging features with pathologically proven examples, along with a brief description of relevant vascular anatomy. We shall also discuss the clinical significance and prognostic implications of extramural vascular invasion in gastrointestinal malignancies.

Tumor thickness at the tumor-normal interface: a novel pathologic indicator of chemotherapy response in hepatic colorectal metastases.

BACKGROUND: Progress in the treatment of hepatic colorectal metastases (HCRM) demands pathologic indicators of therapy response. We observed that a majority of residual tumor cells are seen at the tumor-normal interface (TNI) in resected HCRM specimens and hypothesized that tumor thickness at the TNI correlates with radiologic and pathologic response and recurrence-free survival (RFS). DESIGN: This study included 103 patients with HCRM resected after preoperative chemotherapy with or without bevacizumab. Imaging response was assessed by response evaluation criteria in solid tumors (RECIST) and recently described CT morphology criteria by Chun et al. The pathologic response was categorized as complete (no tumor cells), major (<50% residual tumor cells), or minor (> or =50% residual tumor cells). The maximum thickness of uninterrupted layers of tumor cells was measured perpendicular to the TNI by 2 pathologists independently, followed by consensus review for discrepant cases. For specimens containing >1 tumor, the average tumor thickness at the TNI was used. RESULTS: Sixty-five patients received oxaliplatin-based chemotherapy, 38 received irinotecan-based chemotherapy, and 75 received concurrent bevacizumab. A complete pathologic response was seen in 9 patients, a major response in 44, and a minor response in 50. Median tumor thickness at the TNI was 2.8 mm (interquartile range, 0.5 to 6 mm). Tumor thickness correlated better with radiologic response as determined by Chun et al (P<0.0001) than by RECIST criteria (Spearman r=0.35, P<0.001). Tumor thickness correlated with pathologic response (Spearman r=0.80, P<0.0001). Greater thickness predicted shorter recurrence-free survival, and this correlation remained in multivariate analysis (P=0.015). Tumor thickness was smaller in patients treated with bevacizumab than in patients not given bevacizumab (P=0.03). CONCLUSIONS: Tumor thickness measured at the TNI is potentially a new prognostic factor for therapy response and survival outcome in patients with resected HCRM.

Association of computed tomography morphologic criteria with pathologic response and survival in patients treated with bevacizumab for colorectal liver metastases.

CONTEXT: The standard criteria used to evaluate tumor response, the Response Evaluation Criteria in Solid Tumors (RECIST), were developed to assess tumor shrinkage after cytotoxic chemotherapy and may be limited in assessing response to biologic agents, which have a cytostatic mechanism of action. OBJECTIVE: To validate novel tumor response criteria based on morphologic changes observed on computed tomography (CT) in patients with colorectal liver metastases treated with bevacizumab-containing chemotherapy regimens. DESIGN, SETTING, AND PATIENTS: A total of 234 colorectal liver metastases were analyzed from 50 patients who underwent hepatic resection after preoperative chemotherapy that included bevacizumab at a comprehensive US cancer center from 2004 to 2007; date of last follow-up was March 2008. All patients underwent routine contrast-enhanced CT at the start and end of preoperative therapy. Three blinded, independent radiologists evaluated images for morphologic response, based on metastases changing from heterogeneous masses with ill-defined margins into homogeneous hypoattenuating lesions with sharp borders. These criteria were validated with a separate cohort of 82 patients with unresectable colorectal liver metastases treated with bevacizumab-containing chemotherapy. MAIN OUTCOME MEASURES: Response determined using morphologic criteria and RECIST was correlated with pathologic response in resected liver specimens and with patient survival. RESULTS: Interobserver agreement for scoring morphologic changes was good among 3 radiologists (kappa, 0.68-0.78; 95% confidence interval [CI], 0.51-0.93). In resected tumor specimens, the median (interquartile range [IQR]) percentages of residual tumor cells for optimal morphologic response was 20% (10%-30%); for incomplete response, 50% (30%-60%); and no response, 70% (60%-70%; P < .001). With RECIST, the median (IQR) percentages of residual tumor cells were for partial response 30% (10%-60%); for stable disease, 50% (20%-70%); and for progressive disease, 70% (65%-70%; P = .04). Among patients who underwent hepatic resection, median overall survival was not yet reached with optimal morphologic response and 25 months (95% CI, 20.2-29.8 months) with incomplete or no morphologic response (P = .03). In the validation cohort, patients with optimal morphologic response had median overall survival of 31 months (95% CI, 26.8-35.2 months) compared with 19 months (95% CI, 14.6-23.4 months) with incomplete or no morphologic response (P = .009). RECIST did not correlate with survival in either the surgical or validation cohort. CONCLUSION: Among patients with colorectal liver metastases treated with bevacizumab-containing chemotherapy, CT-based morphologic criteria had a statistically significant association with pathologic response and overall survival.

Imaging of gastrointestinal stromal tumors and assessment of benefit from systemic therapy.

While gastrointestinal stromal tumors have been increasingly recognized with the prolonged survival and highly effective new targeted treatments, the role of imaging has become important not only for diagnosing and staging the tumors, but also for monitoring the effects of treatment and surveillance. Computed tomography is the imaging modality of choice for these purposes. Fluorine-18 fluorodeoxyglucose positron emission tomography is primarily used in problem solving when there are inconsistencies between CT and clinical findings or inconclusive CT images. The roles of MRI and ultrasound are also described.

Normal measurements of extraocular muscle using computed tomography.

OBJECTIVE: Establish criteria for the diameters of normal extraocular muscles using computerized tomography in a Thai population. MATERIAL AND METHOD: Diameters of extraocular muscles (medial, lateral, superior complex, and inferior rectus) were calculated for 200 patients on coronal direction of screening paranasal sinuses. The effects of age and sex were also analyzed. RESULT: Normal ranges for the diameters (mean +/- 2 SDs) of extraocular muscles were 3.7 +/- 0.9 mm for medial rectus, 3.6 +/- 1.2 mm for lateral rectus, 4.0 +/- 1.4 mm for inferior rectus and 3.8 +/- 1.4 mm for the superior group. The mean diameter of the extraocular muscles in male patients was not significantly larger than in female patients (p > 0.05). There was also no statistically significant correlation between age, diameter of each extramuscular muscle and the sum of all four muscles. CONCLUSION: The present result may help radiologists and ophthalmologists to accurately assess enlargement of the extraocular muscles, particularly in Oriental populations.