Kung-Chu Ho

Detection of lymph node metastasis in cervical and uterine cancers by diffusion‐weighted magnetic resonance imaging at 3T

To evaluate diffusion‐weighted imaging (DWI) for detection of pelvic lymph node metastasis in patients with cervical and uterine cancers.

Myometrial Invasion in Endometrial Cancer: Diagnostic Accuracy of Diffusion-weighted 3.0-T MR Imaging—Initial Experience

PURPOSE To assess the diagnostic accuracy of fused T2-weighted and high-b-value diffusion-weighted (DW) magnetic resonance (MR) images at 3 T for evaluation of myometrial invasion in patients with endometrial cancer. MATERIALS AND METHODS Institutional review board approval and informed consent were obtained. From May 2006 to October 2007, 48 consecutive patients aged 25-80 years (mean age, 57 years) who had endometrial cancer were prospectively enrolled for preoperative evaluation by using a 3-T MR unit. Two radiologists interpreted the depth of myometrial invasion on T2-weighted images, dynamic contrast material-enhanced MR images, and fused T2-weighted and DW MR images (b = 1000 sec/mm(2)). Statistical methods included kappa statistics for reader agreement, Pearson analysis for pathologic correlation, accuracy assessment, and receiver operating characteristic analysis for diagnostic performance comparison. Surgical pathologic findings were the reference standard. RESULTS Reader agreement was excellent for fused T2-weighted and DW images (weighted kappa, 0.79), with a significant pathologic correlation regarding the depth of myometrial invasion (r = 0.94, P < .0001). For assessing any myometrial involvement, addition of fused T2-weighted and DW imaging to dynamic contrast-enhanced or dynamic contrast-enhanced and T2-weighted imaging was significantly better compared with dynamic contrast-enhanced imaging alone (P < .001) or dynamic contrast-enhanced and T2-weighted (P = .001) imaging; T2-weighted imaging combined with fused T2-weighted and DW imaging also was better than dynamic contrast-enhanced and T2-weighted imaging (P = .001). Tumor apparent diffusion coefficients were 0.60-1.32 x 10(-3) mm(2)/sec (median, 0.75 x 10(-3) mm(2)/sec), with no significant correlation with the depth of myometrial invasion (P = .31, r = -0.15). CONCLUSION Fused T2-weighted and high-b-value DW images at 3 T can provide accurate information for preoperative evaluation of myometrial invasion.

Positron emission tomography in evaluating the feasibility of curative intent in cervical cancer patients with limited distant lymph node metastases

OBJECTIVE Clinical outcomes of cervical cancer patients with distant lymph node (LN) metastases are poor. [(18)F] fluorodeoxyglucose positron emission tomography (PET) or PET/computed tomography (CT) scans could potentially benefit treatment plan. METHODS Patients with cervical cancer whose CT/magnetic resonance imaging (MRI)-based imaging showed limited metastases to para-aortic lymph node (PALN), inguinal (ILN), and/or supraclavicular (SLN) were prospectively enrolled to evaluate whether PET or PET/CT influenced management. The clinical impact of PET or PET/CT was determined on a patient basis. RESULTS Between November 2001 and April 2007, 47 patients were enrolled for suspected metastasis to PALN with (n=8) or without other distant nodal involvement (n=31), ILN (n=6), or SLN metastasis (n=2). Additional PET or PET/CT had positive clinical impact in 21 (44.7%) of the 47 study patients, 23 had no impact, and three had negative impact. Positive impact included disclosing additional curable sites (n=8), down-staging (n=6), offering metabolic biopsy (n=4) or change to palliation (n=3). The 2-year overall survival (OS) of the study patients was 56.9% with median follow-up time of 47.0 months (range: 8-71 months) in surviving patients. The 2-year OS rates for PALN (based on histology or CT/MRI-PET consensus) and histology-proven SLN metastasis were 50.6% and 24.7%, respectively. Two (40.0%) of the five patients with histology-proven ILN metastases had no evidence of disease. CONCLUSIONS PET or PET/CT added benefit to primary treatment planning in cervical cancer with MRI-defined suspected distant nodal metastasis.

Identification of prognostic factors in patients with cervical cancer and supraclavicular lymph node recurrence.

OBJECTIVE Patients with cervical cancer and supraclavicular lymph nodes (SLN) recurrence have a poor but heterogeneous prognosis. The aim of this study was to identify potential prognostic factors - including FDG-PET results - that may affect survival and treatment outcomes in patients with this group of patients. METHODS Between January 2001 and December 2008, we identified a total of 31 consecutive patients with cervical cancer who had evidence of SLN recurrence. All participants underwent FDG-PET. Survival was measured from the date of documented SLN recurrence. The latency period was defined as the length of time from the date of first diagnosis to the date of SLN recurrence. RESULTS The median follow-up time was 22.8 months (range: 4.7-105.1). The 3- and 5-year survival rates were 41% and 27.3%, respectively. Patients with intermediate SUV values (between 4.3 and 8) had a significantly better prognosis than subjects with both high (>8) or low (<4.3) SUV values (p=0.004). Latency period <2 years, SCC-Ag levels ≥ 4ng/mL, recurrence extend beyond SLN, and SUV of <4.3 >8 were significant adverse prognostic factors by multivariate analysis. The 3-year overall survival (OS) rate of patients carrying 0-1 adverse prognostic factors was 90% (low-risk group), while 3-year OS rates for intermediate-risk group (2 factors) and high-risk group (3-4 factors) were 30% and 0%, respectively (p=0.001). CONCLUSION Our results justify the use of PET (accurate extent of relapse and SUV) as a prognostic tool in patients with cervical cancer and SLN recurrence.

Node/Aorta and Node/Liver SUV Ratios from 18F-FDG PET/CT May Improve the Detection of Occult Mediastinal Lymph Node Metastases in Patients with Non-Small Cell Lung Carcinoma

RATIONALE AND OBJECTIVES Research suggests that the semiquantitative determination of nodal (18)F-fluorodeoxyglucose (FDG) uptake on positron emission tomography (PET)/computed tomography (CT) may be useful for the assessment of mediastinal metastases in patients with non-small-cell lung carcinoma (NSCLC). The aim of this study was to evaluate the diagnostic ability of using different standardized uptake value (SUV) parameters in the detection of ipsilateral mediastinal (N2) disease. MATERIALS AND METHODS A total of 102 patients newly diagnosed with non-small-cell lung carcinoma who underwent (18)F-FDG PET/CT before surgery and had not received prior therapy were retrospectively included. All patients underwent surgical resection of the primary tumor and mediastinal lymph node dissection. On a station-based analysis, different SUV parameters (eg, mediastinal lymph node SUV, node/aorta SUV ratio, and node/liver SUV ratio) were evaluated using the histopathologic results as the reference standard. The optimal cutoff value for each SUV parameter was determined with receiver-operating characteristic curve analysis. RESULTS The areas under the receiver-operating characteristic curves were 0.674, 0.693, and 0.715 for node SUV, node/aorta SUV ratio, and node/liver SUV ratio, respectively (P < .05). With cutoff values of 3.15, 1.37, and 1.02 for node SUV, node/aorta SUV ratio, and node/liver SUV ratio, respectively, the sensitivity of (18)F-FDG PET/CT for N2 staging was 57.1%, 85.7%, and 71.4%, and specificity was 74.2%, 50.5%, and 61.9%. CONCLUSIONS Compared to node SUV alone, the use of node/aorta and node/liver SUV ratios resulted in improved detection of N2 metastases. The two SUV parameters may potentially improve the diagnostic accuracy of (18)F-FDG PET/CT for the diagnosis of N2 disease in patients with non-small-cell lung carcinoma.

Single-scan rest/stress imaging with 99mTc-Sestamibi and cadmium zinc telluride-based SPECT for hyperemic flow quantification: A feasibility study evaluated with cardiac magnetic resonance imaging

Introduction We aimed to evaluate whether the hyperemic myocardial blood flow (MBF) can be estimated using cadmium zinc telluride (CZT)-based single-photon emission computed tomography (SPECT) cameras with a single, rapid rest/stress dynamic scan. Dynamic contrast-enhanced (DCE) cardiac magnetic resonance imaging (MRI) was used as a reference modality for flow measurement. Materials and methods The proposed protocol included both the rest and stress acquisitions within a 24-min scan. Patients were first injected with 99mTc-Sestamibi at the resting state. Sixty minutes after the first injection, the subject was positioned via scintigraphy, after which the list-mode data acquisition was initiated and continued for 24 minutes. Five minutes after data acquisition was initiated, a stressed state was induced via dipyridamole infusion, after which a second dose of 99mTc-Sestamibi was injected. Dynamic SPECT images were reconstructed for all subjects, who also underwent T1-weighted cardiac DCE-MRI performed on days other than those of the SPECT studies. MBF values were estimated for the rest and stress MRI studies, and for the stress portion of the SPECT study. The SPECT-measured hyperemic MBF was compared with the MR-measured hyperemic MBF and coronary flow reserve (CFR), based on the regions of interest. Results A total of 30 subjects were included in this study. The hyperemic MBF estimated from SPECT showed a strong correlation with the MR-measured hyperemic MBF (r2 = 0.76) and a modest correlation with the MR-measured CFR (r2 = 0.56). Using MR-measured CFR <1.3 as a cutoff for coronary stenosis, we found that the SPECT-measured hyperemic MBF served as a useful clinical index with 94% sensitivity, 90% specificity, and 93% accuracy. Conclusions Hyperemic MBF can be measured with a rapid, single-scan rest/stress study with CZT-based SPECT cameras.

Presurgical Identification of Uterine Smooth Muscle Malignancies through the Characteristic FDG Uptake Pattern on PET Scans

The unidentified presence of uterine smooth muscle malignancies poses a tremendous risk in women planning surgery for presumed benign leiomyomas. We sought to investigate whether preoperative FDG PET may be useful to identify leiomyosarcomas (LMS) and smooth muscle tumors of uncertain malignant potential (STUMP). Methods. We investigated patients with rapidly growing uterine masses which were suspected of being malignant on ultrasound or MRI. Among the 21 patients who underwent FDG PET, we identified 7 LMS, 1 STUMP, and 13 leiomyomas. PET-derived parameters and FDG uptake patterns were analyzed retrospectively. Results. The SUVmax values of LMS/STUMP (range: 3.7–11.8) were significantly higher than those observed in leiomyomas (range: 2.0–9.4; P=0.003) despite a significant overlap. The metabolic tumor/necrosis ratio was significantly higher in LMS/STUMP than in leiomyomas (P < 0.001), with no significant intergroup overlaps. All LMS/STUMP revealed a characteristic pattern of FDG uptake, identifying a specific “hollow ball” sign (corresponding to areas of coagulative tumor necrosis). In contrast, this sign was invariably absent in patients with leiomyomas. Conclusion. The characteristic FDG uptake pattern instead of SUV on PET images allows identifying LMS/STUMP in patients with rapidly growing uterine masses, avoiding the deleterious consequences of regular surgery for presumed benign leiomyomas.

Detecting Triple-Vessel Disease with Cadmium Zinc Telluride-Based Single-Photon Emission Computed Tomography Using the Intensity Signal-to-Noise Ratio between Rest and Stress Studies

The purpose of this study was to investigate if a novel parameter, the stress-to-rest ratio of the signal-to-noise ratio (RSNR) obtained with a cadmium zinc telluride (CZT) SPECT scanner, could be used to distinguish triple-vessel disease (TVD) patients. Methods. One hundred and two patients with suspected coronary artery disease were retrospectively involved. Each subject underwent a Tl-201 SPECT scan and subsequent coronary angiography. Subjects were separated into TVD (n = 41) and control (n = 61) groups based on coronary angiography results using 50% as the stenosis cutoff. The RSNR was calculated by dividing the stress signal-to-noise ratio (SNR) by the rest SNR. Summed scores were calculated using quantitative perfusion SPECT (QPS) for all subjects. Results. The RSNR in the TVD group was found to be significantly lower than that in the control group (0.83 ± 0.15 and 1.06 ± 0.17, resp.; P < 0.01). Receiver-operating characteristic (ROC) analysis showed that RSNR can detect TVD more accurately than the summed difference score with higher sensitivity (85% versus 68%), higher specificity (90% versus 72%), and higher accuracy (88% versus 71%). Conclusion. The RSNR may serve as a useful index to assist the diagnosis of TVD when a fully automatic quantification method is used in CZT-based SPECT studies.