False-negative Lesions Research Articles

Whole-Body Diffusion-Weighted MRI Compared With 18F-NaF PET/CT for Detection of Bone Metastases in Patients With High-Risk Prostate Carcinoma

The purpose of this study was to evaluate the accuracy of whole-body diffusion-weighted MRI (DWI) and (18)F-NaF PET/CT for detection of bone metastases in patients with high-risk prostate cancer. Both patient- and lesion-based analyses were performed on 49 consecutive patients (median age, 67 years; age range, 57-80 years) with recently diagnosed high-risk prostate cancer. All patients underwent bone scintigraphy, whole-body MRI including DWI and (18)F-NaF PET/CT before treatment. Bone scintigraphy, conventional MR images, and follow-up images were used as the standard of reference to evaluate (18)F-NaF PET/CT and DWI. On patient-based analysis, five patients had skeletal metastases on reference imaging that both DWI and (18)F-NaF PET/CT could verify, and (18)F-NaF PET/CT and DWI showed false-positive findings in four and one patient, respectively. With lesion-based analysis, (18)F-NaF PET/CT and DWI showed nine and five true-positive lesions, zero and four false-negative lesions, and seven and two false-positive lesions, respectively. Two patients with uncountable bone metastases were analyzed separately. In these patients, (18)F-NaF PET/CT showed more bone metastases than did DWI. We believe (18)F-NaF PET/CT is a sensitive modality for detection of bone metastases caused by prostate cancer. Whole-body DWI shows a higher specificity but lower sensitivity than (18)F-NaF PET/CT. Future studies with a larger patient cohort along with analyses of costs and clinical availability are needed before implementation of these methods can be considered.

Whole-Body Diffusion-Weighted Imaging: The Added Value to Whole-Body MRI at Initial Diagnosis of Lymphoma

The objective of our study was to evaluate the diagnostic performance of conventional whole-body MRI without and with diffusion-weighted imaging (DWI) in the detection of known (18)F-FDG-avid lymphomas. The conventional whole-body MRI protocol consisted of a T2-weighted sequence and a T2-weighted spectral attenuated inversion recovery (SPAIR) sequence with frequency-selective fat suppression. The second protocol used the same sequences as the first protocol but also included DWI. Seventeen patients with pathologically confirmed, newly diagnosed, untreated lymphoma were recruited. T2-weighted and T2-weighted SPAIR images were evaluated first, separate from the DW images, and then were evaluated with the DW images. We used (18)F-FDG PET/CT as the standard of reference. True-positive, false-positive, and false-negative values were evaluated on a per-lesion basis. Tumor staging based on T2-weighted and T2-weighted SPAIR imaging without DWI and then with DWI was compared using the Ann Arbor staging system. True-positive lesions were increased from 89% to 97%, false-positive lesions were increased from 3% to 6%, and false-negative lesions were decreased from 11% to 3% by the addition of DWI. Diagnostic sensitivity was significantly increased (p = 0.002) by adding DWI. Lesions detected on DWI but not on T2-weighted and T2-weighted SPAIR imaging were located in renal (n = 1), paraaortic (n = 6), and pelvic (n = 3) lymph nodes. On DWI, 47% of the lesions (n = 55) were more conspicuous than on T2-weighted and T2-weighted SPAIR imaging; most of these lesions (58%, n = 32) were from lymph nodes in the pelvic or abdominal regions and bone marrow. No difference was found between T2-weighted and T2-weighted SPAIR imaging without DWI and T2-weighted and T2-weighted SPAIR imaging with DWI in lymphoma staging, being consistent with PET/CT in 88% of the patients (n = 15). The addition of DWI to conventional whole-body MRI sequences enhanced lesion conspicuity and improved diagnostic accuracy for lymphomas. With technical optimization, whole-body MRI with DWI, as a nonionizing imaging modality, may potentially be useful as an alternative method to PET/CT in the management of malignant lymphoma.

Dual-source virtual non-contrast CT of the head: a preliminary study

：Objective To investigateimage quality and clinical value of dual-source dual energy virtual non-contrast (VNC) CTof the head. Methods Sixty-two patients suspected of cerebrovascular diseases underwentconventional non-contrast (CNC) CT and dual energy CTA examination of the head withdual-source CT. Virtual non-contrast images were reconstructed using dual energy software.The CT values of gray matter, white matter, cerebrospinal fluid, hyperdense hemorrhagiclesion and hypodense ischemic lesion were compared between CNC and VNC images. Afour-score scale was used to assess image quality subjectively. Image noise, radiationdosage and detection rate were compared between CNC and VNC images. Paired t test,Wilcoxon signed ranks test and Chi-square test (McNemar test and Kappa test) were used.Results The CT value on CNC and VNC images, were (43. 3 ± 1.5) and (33. 2 ± 1.3) HU forgray matter (t = 46.98, P ＜ 0. 01), (32. 9 ± 1.3) and(28.8 ± 1.6) HU for white matter(t = 16. 28, P ＜0.01), (9.0 ± 1.4) and (5.3± 1.9) HU for cerebrospinal fluid (t=12.41, P＜0.01),(62.8 ±10.0) and (51.3± 11.5) HU for hyperdense lesion (Z = -4.37, P ＜ 0.01), (20.7 ±4.7) and (18.0 ±6. 9) HU for hypodense lesion (t = 3. 84, P＜ 0. 01), respectively. VNC images[(1.63 ±0.34)HU]had more noise than CNC images[(0.99±0.18) HU](Z= -6.41, P＜0.01). VNC [(0. 53 ± 0. 08)mSv]had less effective dose than CNC[(1.37 ± 0. 23) mSy](Z= - 6. 45, P ＜ 0. 01).In subjective assessment, VNC images had more noise (2. 7 ±0. 5 for VNC and 3.9 ± 0. 3 for CNC,Z = -6. 84, P ＜ 0. 01) and skull base-related artifacts (2. 4 ± 0. 9 for VNC and 3.7 ± 0. 5 forCNC,Z = -6. 15, P ＜0. 01) than CNC images. The gray/white mattercontrast (1.3 ± 0. 5 for VNC and 3.3 ±0. 6 for CNC, Z = - 7. 01, P ＜ 0. 01), hyperdense lesion display (3.0 ± 0. 4 for VNC and 4. 0 ±0. 0 for CNC,Z = -4. 52, P ＜ 0. 01) and hypodense lesiondisplay (3.2 ± 0. 8 for VNC and 3.9 ± 0. 3 for CNC,Z= -3. 12, P ＜0.01) on VNC images were lower than those on CNC images. In per-patient analysis,29 cases ofhyperdense lesion (hemorrhage) were found on VNC images without misdiagnosis. Thesensitivity, specificity, positive predictive value and negative predictive value were all100. 0% (29/29,33/33, 29/29, 33/33). VNC images had the same detection rate of hyperdenselesions as CNC images (P ＞0. 05, Kappa = 1. 000) atper-patient level. Twenty-two patients with hypodense ischemic lesions were found on VNCimages with one false positive case and two false negative cases. Thesensitivity,specificity, positive predictive value and negative predictive value were91.3% (21/23), 97.4%(38/39), 95.5% (21/22) and 95.0% (38/40) respectively. No statisticaldifference was found in detecting hypodense lesions between VNC and CNC images (χ2 =0. 00, P ＞ 0. 05, Kappa = 0. 895). Inper-lesion analysis, 53 hemorrhage lesions were found on VNC images with false negativeresults of four lesions and no false positive result. The sensitivity, specificity,positive predictive value and negative predictive value were 93.0% (53/57), 100. 0%(38/38), 100. 0% (53/53) and 90. 5% (38/42)respectively. There was no significantdifference in detection rate of hyperdense lesion between VNC and CNC images (χ2 =2.25, P ＞0. 05, Kappa =0. 914). Thirty-eight hypodense lesions were found onVNC images with 2 false positive lesions and 13 false negative lesions. The sensitivity,specificity, positive predictive value and negative predictive value were 73.5% (36/49),96.4% (53/55), 94. 7% (36/38)and 80. 3% (53/66) respectively. The detection rate ofhypodense lesion on VNC images was lower than that on CNC images (χ2 =6. 67 ,P ＜ 0.01,Kappa = 0. 707). Conclusion Compared with CNC images,head VNC images have reduced imagequality and radiation dosage. VNC images can replace CNC images potentially in detectingintracranial hemorrhage and provide information for ischemic cerebrovascular diseases tosome extent. Key words: Tomography,X-ray computed; Head; Cerebrovascular trauma

Abstract P6-01-05: Long-Term Diagnostic Accuracy of Fine-Needle Aspiration Cytology Performed in a One Stop Clinic for the Diagnosis of Suspect Nodular Breast Lesions

Abstract Background: Fine-needle aspiration cytology (FNAC) has been used extensively in the diagnosis of breast lesions, but false-negative rates are a matter of concern. Immediate onsite evaluation of breast lesions, combining FNAC results with clinical and radiological data allows improving its diagnostic accuracy. The objective of this study was to evaluate the diagnostic accuracy of a large series of FNAC of breast lesions during the first 3-year period of a dedicated one-stop clinic, by comparing the FNAC results with the corresponding definitive histological examination outcome or the results of the radiological follow-up at 18 months. Method: Data of all consecutive patients (pts) whose lesions were prospectively characterized by ultrasonography (US) and diagnosed by FNAC in the one stop clinic of the Institute Gustave Roussy between May 2004 and March 2007. Histological verification by core-needle biopsy or surgery was systematically performed for lesions classified malignant or suspicious by cytopathology, and for benign lesions, when no perfect concordance between clinico-radiologic features and FNAC results (such as benign FNAC but BI-RAD 5) was found. For non-operated patients, follow-up consisted on biannual US and/or mammography; the results at 18 months were considered. Pts characteristics, radiological findings, cytopathological and histological results were extracted from the hospital computerized prospectively registered medical records. Complete sensitivity (number of carcinomas that were malignant or suspicious by cytopathology) and full specificity (benign lesions at cytology of the total number of benign lesions) were calculated by comparing the cytopathological results to the histological or the long-term follow-up status. Results: A total of 1822 nodular breast lesions (mean size: 20 mm, BI-RAD ACR 1/2/3/4/5/unknown: 10/96/471/459/777/9) in 1739 pts (mean age: 56 years) were studied. FNAC was US-guided in 1115 lesions (61 %). Lesions were classified by FNAC as malignant in 842 (46%), benign in 771 (42%), suspicious in 154 (9%), and unsatisfactory in 55 (3%) cases. Complete sensitivity (number of carcinomas that were malignant or suspicious by cytopathology) was estimated at 98.5%, whereas full specificity (benign lesions at cytology of the total number of benign lesions) was equal to 94.4%. There were 4 false-positive lesions and 32 false-negative lesions, but all these lesions except one were operated as radiological results were suspicious of malignity. Conclusions: Breast FNAC performed in a dedicated one-stop clinic with immediate on-site diagnosis presented a low rate of unsatisfactory specimens and a very efficient tool for triaging patients candidates for histological evaluation conversely for follow-up by imaging. Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P6-01-05.

Assessment of liver metastases from colorectal adenocarcinoma following chemotherapy: SPIO-MRI versus FDG-PET/CT

This study compared superparamagnetic iron-oxide-enhanced magnetic resonance imaging (SPIO-MRI) and combined fluorodeoxyglucose positron emission tomography and computed tomography (FDG-PET/CT) in evaluating liver metastases from colorectal adenocarcinoma following chemotherapy. Nineteen patients were included in this retrospective study. SPIO-MRI and PET/CT results were compared with surgery, intraoperative ultrasound and pathology results in 11 patients and with the follow-up in eight patients. SPIO-MRI and PET/CT identified 125 and 71 metastases, respectively. False negative lesions were 11 for SPIO-MRI and 65 for PET/CT. In the whole study population, the per-lesion analysis of SPIO-MRI and PET/CT showed a sensitivity of 92% and 52% (p<0.001) and the per-segment analysis a sensitivity of 99% and 79% (p<0.001), respectively. In patients who underwent surgery, the per-lesion analysis of SPIO-MRI and PET/CT showed a sensitivity of 85% and 58% (p<0.05) and the per-segment analysis a sensitivity of 97% and 63% (p<0.05), respectively. In patients who underwent follow-up, the per-lesion analysis of SPIO-MRI and PET/CT showed a sensitivity of 97% and 47% (p<0.001) and the per-segment analysis a sensitivity of 100% and 63% (p<0.007), respectively. For lesions ≥15 and <30 mm and for lesions <15 mm, SPIO-MRI demonstrated a higher sensitivity than PET/CT (p<0.001). SPIO-MRI appears superior to PET/CT in evaluating liver metastases from colorectal adenocarcinoma following chemotherapy.

Performance of FDG PET/CT in postoperative colorectal cancer patients with a suspected recurrence and a normal CEA level

The performance of 2-deoxy-2-[(18)F]fluoro-D-glucose positron emission tomography/computed tomography (FDG PET/CT) has been not established for the evaluation of recurrent colorectal cancer. The aim of this study was to evaluate the diagnostic value of FDG PET/CT in postoperative colorectal cancer patients with normal carcinoembryonic antigen (CEA) levels. This retrospective study was conducted on 63 FDG PET/CT cases, involving postoperative colorectal cancer patients suspected of having recurrent or metastatic lesions with normal CEA levels. The diagnostic performance of FDG PET/CT was evaluated based on diverse suspected conditions, using physical examination, a conventional imaging work-up, and endoscopy. Histopathology, a clinical imaging work-up (including an FDG PET/CT examination), and determination of tumor marker levels during the follow-up served as the reference standard. The sensitivity, specificity, and accuracy for FDG PET/CT were 95, 76.6, and 88.8% for a lesion-by-lesion analysis, and 96.3, 86.1, and 90.5% for a case-by-case analysis, respectively. Three false-negative lesions among 107 suspected recurrent findings were identified as compared with nine false-positive lesions. For radiologically suspected recurrent or metastatic conditions, FDG PET/CT diagnostic performance was superior to radiological image modalities, for both lesion-by-lesion and case-by-case analyses. On follow-up of patients with normal CEA levels, but high CA19-9 levels, the use of FDG PET/CT detected true-positive findings in 63.3% of cases. FDG PET/CT is a valuable tool to distinguish recurrence or metachronous tumor from postoperative changes or other benign lesions in postoperative colorectal cancer patients with normal CEA levels and radiologically or clinically suspicious lesions.

Breast Cancers Not Detected at MRI: Review of False-Negative Lesions

The objective of our study was to determine the sensitivity of cancer detection at breast MRI using current imaging techniques and to evaluate the characteristics of lesions with false-negative examinations. Two hundred seventeen patients with 222 newly diagnosed breast cancers or highly suspicious breast lesions that were subsequently shown to be malignant underwent breast MRI examinations for staging. Two breast imaging radiologists performed a consensus review of the breast MRI examinations. The absence of perceptible contrast enhancement at the expected site was considered to be a false-negative MRI. Histology of all lesions was reviewed by an experienced breast pathologist. Enhancement was observed in 213 (95.9%) of the 222 cancer lesions. Of the nine lesions without visible enhancement, two lesions were excluded because the entire tumor had been excised at percutaneous biopsy performed before the MRI examination and no residual tumor was noted on the final histology. The overall sensitivity of MRI for the known cancers was 96.8% (213/220); for invasive cancer, 98.3% (176/179); and for ductal carcinoma in situ, 90.2% (37/41). In a population of 220 sequentially diagnosed breast cancer lesions, we found seven (3.2%) MRI-occult cancers, fewer than seen in other published studies. Small tumor size and diffuse parenchymal enhancement were the principal reasons for these false-negative results. Although the overall sensitivity of cancer detection was high (96.8%), it should be emphasized that a negative MRI should not influence the management of a lesion that appears to be of concern on physical examination or on other imaging techniques.

Characterization of Metabolic Differences between Benign and Malignant Tumors: High-Spectral-Resolution Diffuse Optical Spectroscopy

To develop a near-infrared spectroscopic method to identify breast cancer biomarkers and to retrospectively determine if benign and malignant breast lesions could be distinguished by using this method. The study was HIPAA compliant and was approved by the university institutional review board. Written informed consent was obtained. By using self-referencing differential spectroscopy (SRDS) analysis, the existence of specific spectroscopic signatures of breast lesions on images acquired by using diffuse optical spectroscopy imaging in the wavelength range (650-1000 nm) was established. The SRDS method was tested in 60 subjects (mean age, 38 years; age range, 22-74 years). There were 17 patients with benign breast tumors and 22 patients with malignant breast tumors. There were 21 control subjects. Discrimination analysis helped separate malignant from benign tumors. A total of 40 lesions (22 malignant and 18 benign) were analyzed. Twenty were true-positive lesions, 17 were true-negative lesions, one was a false-positive lesion, and two were false-negative lesions (sensitivity, 91% [20 of 22]; specificity, 94% [17 of 18]; positive predictive value, 95% [20 of 21]; and negative predictive value, 89% [17 of 19]). The SRDS method revealed localized tumor biomarkers specific to pathologic state.

Optical coherence tomography for bladder cancer - ready as a surrogate for optical biopsy? - results of a prospective mono-centre study

IntroductionNew modalities like Optical Coherence Tomography (OCT) allow non-invasive examination of the internal structure of biological tissue in vivo. The potential benefits and limitations of this new technology for the detection and evaluation of bladder cancer were examined in this study.Materials and methodsBetween January 2007 and January 2008, 52 patients who underwent transurethral bladder biopsy or TUR-BT for surveillance or due to initial suspicion of urothelial carcinoma of the bladder were enrolled in this study. In total, 166 lesions were suspicious for malignancy according to standard white light cystoscopy. All suspicious lesions were scanned and interpreted during perioperative cystoscopy using OCT. Cold cup biopsies and/or TUR-B was performed for all these lesions. For this study we used an OCT-device (Niris®, Imalux®, Cleveland, US), that utilizes near-infrared light guided through a flexible fibre-based applicator, which is placed into the bladder via the working channel of the cystoscope. The technology provides high spatial resolution on the order of about 10-20 μm, and a visualization of tissue to a depth of about 2 mm across a lateral span of about 2 mm in width. The device used received market clearance from the FDA and CE approval in Germany. The diagnostic and surgical procedure was videotaped and analyzed afterwards for definitive matching of scanned and biopsied lesion. The primary aim of this study was to determine the level of correlation between OCT interpretation and final histological result.ResultsOf 166 scanned OCT images, 102 lesions (61.4%) matched to the same site where the biopsy/TUR-BT was taken according to videoanalysis. Only these video-verified lesions were used for further analysis. Of all analyzed lesions 88 were benign (inflammation, edema, hyperplasia etc.) and 14 were malignant (CIS, Ta, T1, T2) as shown by final histo pathology.All 14 malignant lesions were detected correctly by OCT. Furthermore all invasive tumors were staged correctly by OCT regarding tumor growth beyond the lamina propria. There were no false negative lesions detected by OCT. Sensitivity of OCT for detecting the presence of a malignant lesion was 100% and sensitivity for detection of tumor growth beyond the lamina propria was 100% as well. Specificity of OCT for presence of malignancy was 65%, due to the fact that a number of lesions were interpreted as false positive by OCT.ConclusionAs a minimally invasive technique, OCT proved to have extremely high sensitivity for detection of malignant lesions as well as estimation of whether a tumor has invaded beyond the lamina propria. However, specificity of OCT within the bladder was impaired (65%), possibly due to a learning curve and/or the relatively low spatial resolution and visualization depth of the OCT technology. Further studies and technical development are needed to establish an adequate surrogate for optical biopsy.

Feasibility study on CT guided percutaneous incisional needle biopsy for deep pelvic masses by different puncture approaches

To explore the feasibility of CT guided percutaneous incisional needle biopsy (PINB) for deep pelvic masses at different locations via various puncture approaches. PINBs under CT guidance were performed in 70 patients with 72 pelvic lesions through different puncture approaches. Their pathological findings and safety were evaluated after follow-up of a period of 1-34 months. PINBs were performed through transpiriform-muscle in 27 cases, 16 through transgluteal approach, 5 through posterior oblique approach in prone position, 8 by anterior or lateral transabdominal route, 8 through iliopsoas muscle and 8 by direct transosseous approach, respectively. Sixty-four malignant lesions were confirmed by pathology, including 30 adenocarcinomas, 19 squamous cell carcinomas, 5 unclassified malignant tumors, 3 small cell carcinomas, 2 malignant giant cell tumors of bone, 2 hepatocellular carcinomas and 3 false negative lesions which were confirmed at the second PINBs as malignant tumors, respectively. Benign neoplasms were confirmed in 8 cases, including fibrosis tissue in 6 lesions, bone tuberculosis in 1 and ovarian cyst in 1. The sensitivity, specificity, and accuracy rate were 95.3% (61/64), 100% (8/8), and 95.8% (69/72), respectively. Twenty-two cases via transpiriform-muscle approach suffered from transient deep pelvic pain which radiated to the lower limbs of the same side. No hematoma, nerve damage, infection, and tumor transplantation in pelvic cavity developed after the PINB procedure. CT guided percutaneous incisional needle biopsy through different puncture approaches is safe and feasible for the patients with deep masses at different locations in the pelvic cavity.

Comparison of cytopathological and histological results in 1,053 fine-needle aspiration cytology of breast lesions performed in a one-stop clinic

635 Background: Fine-needle aspiration cytology (FNAC) has been used extensively in the diagnosis of breast lesions, but false-negative rates are a matter of concern. However, immediate onsite evaluation of breast lesions, combining FNAC results with clinical and radiological data allows to improve its diagnostic accuracy. The objective of this study was to evaluate the concordance between cytopathological and histological results in a large series of FNAC performed during the first 3-yr period of the dedicated one-stop clinic set up in our institution since 2004. Methods: We reviewed data of all patients (pts) seen in the one stop clinic between May 2004 and March 2007 who had a lesion diagnosed by FNAC and verified by histology. For benign lesions, histological verification of the lesion was mandatory each time there was no perfect concordance between clinico-radiologic features and FNAC results (such as benign FNAC but BI-RAD 5). Pts characteristics, radiological findings, cytopathological and histological (by per-cutaneous biopsy or surgery) results were extracted from the hospital computerized prospectively registered medical records. Results: A total of 1053 nodular breast lesions (mean size: 24±23 mm, BI-RAD ACR 1/2/3/4/5: 2/10/68/283/684) in 1015 pts (mean age: 59±13 years) were studied. FNAC was US-guided in 521 lesions (49.4%). FNAC classified lesions as malignant in 741 (70.4%), benign in 127 (12.0%), suspicious in 143 (13.6%), and unsatisfactory in 42 (4.0%) cases. Among definitive benign or malignant diagnosis, FNAC and histological results showed concordance in 840/868 (96.7%) cases (738 malignant and 102 benign cases). The numbers of false-negative and false-positive lesions were respectively 25/127 (19%) and 3/741 (0.4%). Among the 143 suspicious and 42 unsatisfactory specimens, 114 and 20 were malignant, respectively. Conclusions: FNAC performed in a one-stop clinic allows obtaining an immediate on-site diagnosis of breast cancer with a good concordance with histological results and low rate of unsatisfactory specimens. However, affirming benign lesion requires a multi-disciplinary team: whenever clinico-radiologic features and FNAC results are non concordant, histologic assessment is mandatory. No significant financial relationships to disclose.

False-negative ultrasound-guided vacuum-assisted biopsy of the breast: difference with US-detected and MRI-detected lesions

The purpose of this study was to retrospectively examine the frequency and causes of a false-negative result of ultrasound (US)-guided vacuum-assisted biopsy. A retrospective review was performed of 835 patients with 986 consecutive lesions who had undergone US-guided vacuum-assisted biopsy (US-VAB) using 11-gauge probes. We divided the lesions into two groups (US-detected and MRI-detected lesions). The sizes of the lesions on US, number of cores taken, rates of repeat biopsy, and the false-negative rate were compared between the two groups. The overall false-negative rate of US-VAB was 7.4% (13/175). The final number of malignant pathologic diagnoses was 175 (18%), including 13 false-negative lesions and 6 upgraded high-risk lesions. The false-negative rate for MRI-detected lesions (26%; 8/31) was significantly higher than that for US-detected lesions (3.5%; 5/144) (P = 0.0002). The causes of a false-negative result in the case of US-detected lesions were considered to be technical error in two cases and difficulty in histologic interpretation in three cases. The average size, as measured by US, average number of core samples, and repeat biopsy rate of US-detected lesions and MRI-detected lesions were 11 vs 9.7 mm (P = 0.0005), 13 vs 13 (P = NS), and 7.0% (43/611) vs 9.4% (18/191) (P = NS), respectively. The high false-negative result for MRI-detected lesions might arise from the difficulties in MRI-US correlation, which indicates the need for MRI-guided biopsy.

The Role of 18F-FDG PET/CT in the Evaluation of Ascites of Undetermined Origin

The first aim of our study was to compare the role of (18)F-FDG PET/CT with that of CT alone in detecting the primary cause of ascites. A secondary aim was to compare the value of (18)F-FDG PET/CT with that of CT alone in detecting abdominal cavity metastasis. Finally, we analyzed the receiver-operating-characteristic (ROC) curves of maximal standardized uptake values (SUVmax), serum carcinoembryonic antigen, CA19-9, and CA12-5 for differential diagnostic abilities. The (18)F-FDG PET/CT scans of 40 patients with ascites of undetermined origin, including 30 patients with malignant diseases and 10 with benign lesions, were reviewed for the presence of ascites. Among the 40 patients, 34 had received their diagnosis by pathologic examination and 6 by clinical follow-up. We also assessed the (18)F-FDG PET/CT scans of 20 healthy volunteers for comparison. All (18)F-FDG PET/CT images were visually interpreted, and the SUVmax was measured. We compared the mean diameter of true-positive lesions with that of false-negative lesions. The diagnostic abilities of SUVmax, serum carcinoembryonic antigen, CA19-9, and CA12-5 were compared using the ROC curve. The sensitivity, specificity, and accuracy of PET/CT in detecting the primary cause of ascites were 63.3% (19/30), 70.0% (7/10), and 65.0% (26/40), respectively, and those of CT alone were 36.7% (11/30), 80% (8/10), and 47.5% (19/40), respectively (sensitivity, P < 0.05). The sensitivity of PET/CT was higher than that of CT alone for detecting abdominal cavity metastasis (86.4% vs. 27.3%, P < 0.01). The SUVmax in patients with malignant primary and metastatic lesions was significantly higher than that in healthy volunteers and in patients with benign ascites (P < 0.05). The mean maximal diameter of false-negative lesions was significantly smaller than that of true-positive lesions (P < 0.05). In ROC analysis, the areas under the curve of SUVmax, serum carcinoembryonic antigen, CA19-9, and CA12-5 were 0.803 (P < 0.01), 0.773 (P < 0.05), 0.552 (P > 0.05), and 0.220 (P < 0.01), respectively. (18)F-FDG PET/CT assisted in detecting the original cause of ascites. The differential diagnostic ability of (18)F-FDG PET/CT was superior to that of CT alone, tumor markers, and cytology. More attention should be paid to peritoneal tuberculosis, which can markedly accumulate (18)F-FDG and mimic peritoneal carcinoma.

The clinical efficacy of 18F-FDG-PET/CT in benign and malignant musculoskeletal tumors

Most of the current clinical data on the role of 2-[(18)F]fluoro-2-deoxy-D -glucose positron emission tomography ((18)F-FDG-PET) in musculoskeletal tumors come from patients studied with PET and less frequently with hardware fusion PET/computed tomography (CT). And the number of cases in each report is too small to clarify the exact clinical efficacy of PET or PET/CT. This prompted us to analyze our experience with (18)F-FDG-PET/CT in a relatively large group of patients with musculoskeletal tumors. (18)F-FDG-PET/CT was performed on 91 patients from May 2004 to June 2007. The final diagnosis was obtained from surgical biopsy in 83 patients (91%) and clinical follow-up in 8 (9%). We analyzed the characteristics and amount of (18)F-FDG uptake in soft tissue and bone tumors, and investigated the ability of (18)F-FDG-PET/CT to differentiate malignant from benign tumors. The cutoff maximum standardized uptake value (SUV(max)) was calculated using the receiver-operation characteristic curve method. Sensitivity, specificity, and diagnostic accuracy were calculated with cutoff SUV(max) and the final diagnosis. Unpaired t test was used for the statistical analysis. Final diagnosis revealed 19 benign soft tissue tumors (mean SUV(max) 4.7), 27 benign bone tumors (5.1), 25 malignant soft tissue tumors (8.8), and 20 malignant bone tumors (10.8). There was a significant difference in SUV(max) between benign and malignant musculoskeletal tumors in total (P < 0.002), soft tissue tumors (P < 0.05), and bone tumors (P < 0.02). Sensitivity, specificity, and diagnostic accuracy were 80%, 65.2%, and 73% in total with cutoff SUV(max) 3.8, 80%, 68.4%, and 75% in the soft tissue tumors with cutoff SUV(max) 3.8, and 80%, 63%, and 70% in the bone tumors with cutoff SUV(max) 3.7. (18)F-FDG-PET/CT reliably differentiated malignant soft tissue and bone tumors from benign ones, although there were many false-positive and false negative lesions. Further studies with all kinds of musculoskeletal tumors in large numbers are needed to improve the diagnostic accuracy of (18)F-FDG-PET/CT.

Somatostatin receptor scintigraphy in advanced renal cell carcinoma

Objective of this prospective study was to evaluate the role of somatostatin receptor scintigraphy (SRS) in advanced renal cell carcinoma (RCC) with respect to potential therapy with somatostatin analogue (SST-A) and to assess the response rate under therapy with SST-A. 16 patients with documented progression of histologically confirmed advanced RCC were included. Planar whole-body SRS was performed 4, 24 and 48 h post i.v. injection of 175-200 MBq 111In-pentetreoide. 5 and 25 h p.i. SPECT of thorax and abdomen were performed. Documentation of somatostatin receptor expression via SRS in >50% of known tumour lesions was the criteria for treatment start with SST-A (Sandostatin LAR-Depot 30 mg i.m. every four weeks). In 9/16 of the patients SRS showed at least one metastasis with moderate (n = 5) or intense (n = 4) tracer uptake. Lesion-based SRS evaluation showed only 12.1% (20/165) of all metastases. Most false-negative lesions were located in the lungs. In two patients, the majority of the known metastases was SRS positive and these patients received SST-A therapy. The first radiographic evaluation after a two-month interval showed progressive disease in both patients. We conclude that SRS is of limited value in staging of advanced RCC. In our patients SST-A did not result in a growth control of RCC. Consequently, the use of SST-A in advanced RCC seems to be no relevant therapeutic option.

Hepatocellular Carcinoma in Patients Undergoing Living-Donor Liver Transplantation

Objective: To compare 8-detector row helical computed tomography (CT) findings with histopathology in patients with hepatocellular carcinoma (HCC) who had undergone living-donor liver transplantation (LDLT). Materials and Methods: This institutional review board-approved prospective study was performed between February 12, 2003 and November 12, 2004; of the 78 candidates for LDLT due to HCC who underwent preoperative multidetector CT (MDCT), 48 transplant recipients met our criteria and in 41 of them, HCCs were diagnosed with <15 lesions on MDCT; these patients represented the study population. Results of preoperative CT were correlated with histopathological results after 5-mm sagittal slicing of the explanted liver. Following the injection of contrast medium (2 ml/kg body weight of 300 mg I/ml), triple-phase contrast-enhanced images were obtained. CT was performed using the following parameters: detector row configuration, 8 × 1 mm, reconstruction interval, 1 mm, 200 mA s and 120 kVp. Image analysis was performed in consensus by three abdominal radiologists using 1-mm-thick slices with 0.5-mm overlap with paging as well as multiplanar reformatting (MPR; i.e. axial, coronal and sagittal images). Results: A total of 134 HCCs were identified by pathological examination. The mean lesion size was 21 mm. Sensitivity, positive predictive value and accuracy for HCC detection were 87, 96 and 84% for all lesions, respectively, and 99, 100 and 97% for lesions >1 cm, respectively, but only 46, 76 and 41% for tumors <1 cm, respectively (n = 28). There were 12 false-negative lesions but only 5 false-positive findings. Conclusion: MDCT combined with the paging method and MPR images is very effective in the detection of HCCs >1 cm in diameter with a very low false-positive rate.

18F-FDG PET/CT in Evaluating Non-CNS Pediatric Malignancies

We reviewed our experience of (18)F-FDG PET/CT in noncentral nervous system (CNS) pediatric malignancies and evaluated if PET/CT provided additional information to conventional imaging (CI) examinations to determine the efficacy of this new imaging modality in the clinical setting. One-hundred fifty-one consecutive FDG PET/CT examinations in 55 pediatric patients with non-CNS malignant tumors were reviewed. Among them, 108 PET/CT examinations were accompanied by CI, such as contrast CT or MRI, performed within a month of PET/CT in our hospital. Two radiologists reviewed the indication, purpose, and PET/CT findings and compared the findings with those of CI, if available, on the representative lesion in each of the 6 separate body regions. Positive findings included abnormal findings related to malignant lesions (suspected) as well as equivocal findings, in which the presence of malignancy could not be denied, but excluded findings considered to relate to past treatment. Accuracy of the findings was determined on the basis of the reference standard comprising histopathologic findings or informative follow-up of >1 y. An examination-based analysis was also performed in terms of additional information of PET/CT to CI. There were 56 PET/CT-positive-CI-positive, 26 PET/CT-positive-CI-negative, and 54 PET/CT-negative-CI-positive lesions in 108 PET/CT examinations accompanied by CI, of which 54, 20, and 52 exhibited accurate PET/CT findings, respectively. Seventeen of the 20 PET/CT true-positive-CI false-negative lesions represented small lymph nodes diagnosed as negative on CI. All 52 PET/CT true-negative-CI false-positive findings were observed in lesions in a posttreatment status including 30 mediastinal masses in lymphoma. Examination-based analysis revealed that additional information of PET/CT to CI was found in 37 (34%) of the 108 examinations: 23 (21%) as negative and 14 (13%) as positive PET/CT findings. PET/CT exhibited better diagnostic performance than CI and showed accurate findings in 90% (72/80) of lesions with discordant findings between them. Additional information of PET/CT to CI was observed in more than one third of examinations compared. PET/CT was demonstrated to be an accurate imaging modality in evaluating pediatric patients with non-CNS malignancies.

Assessment of local control after laser-induced thermotherapy of liver metastases from colorectal cancer: contribution of FDG-PET in patients with clinical suspicion of progressive disease

Management of patients after locally ablative treatment of liver metastases requires exact information about local control and systemic disease status. To fulfill these requirements, whole-body imaging using positron emission tomography with (18)F-fluorodeoxyglucose (FDG-PET) is a promising alternative to morphologic imaging modalities such as computed tomography (CT) and magnetic resonance imaging (MRI). To evaluate FDG-PET for the assessment of local control and systemic disease in patients with clinical suspicion of tumor progression after laser-induced thermotherapy (LITT) of colorectal liver metastases. In 21 patients with suspicion of progressive disease after LITT, whole-body FDG-PET was performed. The presence of viable tumor within treated lesions, new liver metastases, and extrahepatic disease was evaluated visually and semiquantitatively (maximal standard uptake value [SUV(max)], tumor-to-normal ratio [T/N]). The standard of reference was histopathology (n = 25 lesions) and/or clinical follow-up (>12 months) including contrast-enhanced MRI of the liver. Among 54 metastases treated with LITT, 29 had residual tumor. Receiver operating characteristic (ROC) analysis of SUV(max) (area under the curve (AUC) 0.990) and T/N (AUC 0.968) showed a significant discrimination level of negative or positive lesion status with an equal accuracy of 94% (51/54). The overall accuracy of visual FDG-PET was 96% (52/54), with one false-negative lesion among six examined within 3 days after LITT, and one false-positive lesion examined 54 days after LITT. In the detection of new intra- and extrahepatic lesions, FDG-PET resulted in correct alteration of treatment strategy in 43% of patients (P = 0.007). FDG-PET is a promising tool for the assessment of local control and whole-body restaging in patients with clinical suspicion of tumor progression after locally ablative treatment of colorectal liver metastases with LITT.

Efficacy of Mammographic Evaluation of Breast Cancer in Women Less Than 40 Years of Age: Experience from a Single Medical Center in Taiwan

Mammography is the standard imaging modality for breast cancer diagnosis. However, the value of mammographic diagnosis in breast cancer patients aged less than 40 years old has not been well assessed. The goal of our study was to determine the diagnostic efficacy of mammography for the detection of breast cancer in women under 40 years of age in a single medical center in Taiwan. Of 1766 women diagnosed with breast cancer in one medical center between 1999 and 2005, 227 (12.9%) who were younger than 40 years of age were enrolled, and 105 of these 227 patients had pre-biopsy mammograms available for analysis. The sensitivities for mammography at first (prospective) and second (retrospective) readings and for corresponding ultrasound were calculated. The distribution of different breast composition between the mammographic true-positive (TP) and false-negative (FN) lesions at the first and second readings was analyzed. Of the 105 patients, 104 presented with a palpable mass and the other one was asymptomatic. There were 109 pathologically proven breast cancers from the 105 patients; 92 of 109 cancerous lesions were detected at the first mammographic reading (sensitivity 84.4%), and the most common mammographic sign was microcalcifications (40.2%). The second reading detected seven additional cancers (99 of 109 lesions; sensitivity 90.8%). There was no significant difference between mammographic TP and FN lesions for the different breast composition on first and second readings. Ninety patients also had ultrasound available for correlation with 94 cancers diagnosed from them. The diagnostic sensitivity of ultrasound was 94.7% (89 of 94 lesions). Mammography has an acceptable sensitivity for the detection of breast cancer in women aged less than 40 years, regardless of different breast composition. Breast ultrasound can offer a higher sensitivity for such a population.

Contrast-enhanced MR Mammography for Evaluation of the Contralateral Breast in Patients with Diagnosed Unilateral Breast Cancer or High-Risk Lesions1

To prospectively evaluate accuracy of gadobenate dimeglumine-enhanced magnetic resonance (MR) mammography for depiction of synchronous contralateral breast cancer in patients with newly diagnosed unilateral breast cancer or high-risk lesions, with histologic analysis or follow-up as reference. The study had ethics committee approval; all patients provided written informed consent. One hundred eighteen consecutive women (mean age, 52 years) with unilateral breast cancer or high-risk lesions and negative findings in the contralateral breast at physical examination, ultrasonography, and conventional mammography underwent gadobenate dimeglumine-enhanced 1.5-T MR mammography. Transverse three-dimensional T1-weighted gradient-echo images were acquired before and at 0, 2, 4, 6, and 8 minutes after gadobenate dimeglumine administration (0.1 mmol per kilogram body weight). Breast Imaging Reporting and Data System (BI-RADS) was used to categorize breast density and the level of suspicion for malignant contralateral breast lesions. Results were compared with histologic findings. Sensitivity, specificity, accuracy, and positive and negative predictive values for contrast-enhanced MR mammography were evaluated. Contrast-enhanced MR mammography revealed contralateral lesions in 28 (24%) of 118 patients. Twenty-four lesions were detected in patients with dense breasts (BI-RADS breast density category III or IV). Lesions in eight (29%) of 28 patients were BI-RADS category 4; patients underwent biopsy. Lesions in 20 (71%) patients were BI-RADS category 5; patients underwent surgery. At histologic analysis, 22 lesions were confirmed as malignant; six lesions were fibroadenomas. No false-negative lesions were detected; none of the fibroadenomas were BI-RADS category 5. The sensitivity, specificity, accuracy, and positive and negative predictive values of contrast-enhanced MR mammography for depiction of malignant or high-risk contralateral lesions were 100%, 94%, 95%, 79%, and 100%, respectively. Follow-up findings (12-24 months) confirmed absence of contralateral lesions in 90 of 118 patients with negative contrast-enhanced MR mammographic findings in the contralateral breast. Contrast-enhanced MR mammography is accurate for detection of synchronous contralateral cancer or high-risk lesions in patients with newly diagnosed breast cancer or high-risk lesions.