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Biomedical subjects

Thomas F Hany

Publications and source records attributed to Thomas F Hany.

At least 19 recordsLinked to original sources

Bone involvement in patients with lymphoma: the role of FDG-PET/CT.

PURPOSE: To evaluate the diagnostic impact and clinical significance of FDG-avid bone lesions detected by FDG-PET/CT in patients with lymphoma. METHODS: The study population comprised 50 consecutive patients (mean age 41.7+/-15.5 years; 27 female, 23 male; 41 staging, 9 restaging) with Hodgkin's disease (n=22) or aggressive non-Hodgkin's lymphoma (n=28) in whom FDG-avid bone lesions were detected by FDG-PET/CT. All patients had either direct biopsy of the FDG-avid bone lesion (n=18), standard bone marrow biopsy at the iliac crest (BMB; n=43) or both procedures (n=11). In 15 patients, additional MRI of the bone lesions was performed. All patients underwent FDG-PET/CT after the end of treatment. All CT images of FDG-PET/CT scans were analysed independently regarding morphological osseous changes and compared with FDG-PET results. RESULTS: In the 50 patients, 193 FDG-avid lesions were found by PET/CT. The mean standardised uptake value was 6.26 (+/-3.22). All direct bone biopsies (n=18) of the FDG-avid lesions proved the presence of lymphomatous infiltration. BMB (n=43) was positive in 12 patients (27.9%). In CT, 32 of 193 (16.6%) lesions were detected without the PET information. No additional morphological bone infiltration was detected on CT compared with FDG-PET. All morphological bone alterations on CT scans persisted after the end of therapy. Additional PET/CT information regarding uni- or multifocal bone involvement resulted in lymphoma upstaging in 21 (42%) patients compared with the combined information provided by CT and BMB. CONCLUSION: In patients with FDG-avid bone lesions, FDG-PET is superior to CT alone or in combination with unilateral BMB in detecting bone marrow involvement, leading to upstaging in a relevant proportion of patients.

Adolescent↗

Digital X-ray radiogrammetry better identifies osteoarthritis patients with a low bone mineral density than quantitative ultrasound.

This study assessed the ability of quantitative ultrasound (QUS) and digital X-ray radiogrammetry (DXR) to identify osteopenia and osteoporosis in patients with knee osteoarthritis (OA). One hundred and sixty-one patients with painful knee OA (81 men, 80 women; age 62.6+/-9.2 years, range 40-82 years) were included in this cross-sectional study and underwent dual-energy X-ray absorptiometry (DXA) of both hips and the lumbar spine, QUS of the phalanges and calcanei of both hands and heels, and DXR using radiographs of both hands. Unpaired t-test, Mann-Whitney U test, ROC analysis and Spearman's rank correlation were used for comparisons and correlation of methods. Using DXA as the reference standard, we defined a low bone mineral density (BMD) as a T-score < or =-1.0 at the lumbar spine or proximal femur. In contrast to phalangeal or calcaneal QUS, DXR was able to discriminate patients with a low BMD at the lumbar spine (p<0.0001) or hips (p<0.0001). ROC analysis showed that DXR had an acceptable predictive power in identifying OA patients a low hip BMD (sensitivity 70%, specificity 71%). Therefore, DXR used as a screening tool could help in identifying patients with knee OA for DXA.

Absorptiometry, Photon↗

Impact of integrated positron emission tomography and computed tomography on staging and management of gallbladder cancer and cholangiocarcinoma.

BACKGROUND/AIMS: (1) To evaluate the diagnostic value of integrated positron emission and computed tomography (PET/CT) in comparison with contrast-enhanced CT (ceCT) to detect biliary tract tumors and associated distant and regional lymph node metastases and (2) to evaluate the impact of PET/CT on therapy management. METHODS: From January 2001 to March 2005, each patient who was treated for a malignancy of the biliary tract underwent PET/CT examination in addition to the standard work-up imaging. Data were prospectively collected and analyzed in comparison with ceCT. RESULTS: Sixty-one patients with malignancies of the biliary tract were included into the study. Diagnosis was proven in all patients either by histology or cytology. PET/CT detected all gallbladder cancers (n=14). PET/CT and ceCT provided a comparable accuracy for the primary intra- (n=14) and extra-hepatic cholangiocarcinomas (n=33). All distant metastases (12/12) were detected by PET/CT, but only 3/12 by ceCT (p<0.001). Regional lymph node metastases were detected by PET/CT and ceCT in only 12% vs. 24%. PET/CT findings resulted in a change of management in 17% of patients deemed resectable after standard work-up. CONCLUSIONS: PET/CT is particularly valuable in detecting unsuspected distant metastases which are not diagnosed by standard imaging. Thus, PET/CT staging has an important impact on selection of adequate therapy.

Adult↗

PET/CT of a brodie abscess.

Brodie abscess is a rare, localized type of subacute or chronic pyogenic osteomyelitis, usually of staphylococcal origin. Imaging with standard radiographs, bone scintigraphy, and MRI has been described in the literature. We present the case of a 28-year-old patient with pain in the right knee. Whole-body FDG-PET/CT scan showed a solitary FDG-active (SUV max 5.2) intracortical lesion in the meta-/epiphysis of the proximal tibia. CT demonstrated a sclerotic rim around the lesion. A Brodie abscess was considered a possible diagnosis. Multifocality could be excluded. CT-guided transosseous biopsy and curettage was performed and the diagnosis of a Brodie abscess was confirmed.

Abscess↗

Integrated PET/CT: current applications and future directions.

For the past 5 years, combined positron emission tomography (PET) and computed tomography (CT), or PET/CT, has grown because the PET portion provides information that is very different from that obtainable with other imaging modalities. However, the paucity of anatomic landmarks on PET images makes a consistent "hardware fusion" to anatomic cross-sectional data extremely useful. Clinical experience indicates a single direction: Addition of CT to PET improves specificity foremost, but also sensitivity, and the addition of PET to CT adds sensitivity and specificity in tumor imaging. Thus, PET/CT is a more accurate test than either of its individual components and is probably also better than side-by-side viewing of images from both modalities. The synergistic advantage of adding CT is that the attenuation correction needed for PET can also be derived from the CT data, an advantage not obtainable by integrating PET and magnetic resonance imaging. This makes PET/CT 25%-30% faster than PET alone with standard attenuation-correction methods, leading to higher patient throughput and a more comfortable examination, which typically last 30 minutes or less. Fluorodeoxyglucose (FDG) PET/CT appears to provide relevant information in the staging and therapy monitoring of many tumors, including lung carcinoma, mesothelioma, colorectal cancer, lymphoma, melanoma, and many others, with the notable exception of prostatic cancer. For prostatic cancer, choline derivatives may become useful radiopharmaceuticals. The published literature on the applications of FDG PET/CT in oncology is still limited, but several well-designed studies have demonstrated the benefits of PET/CT.

Forecasting↗

Positron emission tomography/computed tomography influences on the management of resectable pancreatic cancer and its cost-effectiveness.

OBJECTIVE: We sought to determine the impact of positron emission tomography/computed tomography (PET/CT) on the management of presumed resectable pancreatic cancer and to assess the cost of this new staging procedure. SUMMARY BACKGROUND DATA: PET using 18F-fluorodeoxyglucose (FDG) is increasingly used for the staging of pancreatic cancer, but anatomic information is limited. Integrated PET/CT enables optimal anatomic delineation of PET findings and identification of FDG-negative lesions on computed tomography (CT) images and might improve preoperative staging. MATERIAL AND METHODS: Patients with suspected pancreatic cancer who had a PET/CT between June 2001 to April 2004 were entered into a prospective database. Routine staging included abdominal CT, chest x-ray, and CA 19-9 measurement. FDG-PET/CT was conducted according to a standardized protocol, and findings were confirmed by histology. Cost benefit analysis was performed based on charged cost of PET/CT and pancreatic resection and included the time frame of staging and surgery. RESULTS: Fifty-nine patients with a median age of 61 years (range, 40-80 years) were included in this analysis. Fifty-one patients had lesions in the head and 8 in the tail of the pancreas. The positive and negative predictive values for pancreatic cancer were 91% and 64%, respectively. PET/CT detected additional distant metastases in 5 and synchronous rectal cancer in 2 patients. PET/CT findings changed the management in 16% of patients with pancreatic cancer deemed resectable after routine staging (P = 0.031) and was cost saving. CONCLUSIONS: PET/CT represents an important staging procedure prior to pancreatic resection for cancer, since it significantly improves patient selection and is cost-effective.

Adenocarcinoma↗

Fluorocholine PET/CT in patients with prostate cancer: initial experience.

Institutional review board approval and written informed consent were obtained. Patients with newly diagnosed prostate cancer and patients suspected of having recurrent prostate cancer were prospectively evaluated with fluorine 18 fluorocholine (FCH) combined in-line positron emission tomography (PET) and computed tomography (CT). In 19 patients (mean age, 67 years +/- 8; range, 57-85 years), standardized uptake values of FCH in 17 different tissues were determined by using volumes of interest. In nine patients evaluated at initial staging, histologic findings of the resected prostate were compared to FCH uptake. Only small variations of physiologic tracer accumulation were measured in all organs but the kidneys. Differentiation of benign hyperplasia from cancerous prostate lesions was not possible with FCH PET/CT. However, in patients with recurrent prostate cancer, FCH PET/CT is a promising imaging modality for detecting local recurrence and lymph node metastases.

Adenocarcinoma↗

Integrated PET/CT for the assessment of coronary artery disease: a feasibility study.

UNLABELLED: An accurate, noninvasive technique for the diagnosis of coronary artery disease (CAD) should provide complementary information on coronary anatomy and pathophysiologic lesion severity. We present, what is to our knowledge, the first clinical evaluation of integrated PET/CT for combined acquisition of coronary anatomy and perfusion. METHODS: On an integrated PET/CT scanner, contrast-enhanced CT angiography (CTA) and rest/adenosine-stress myocardial perfusion scanning with (13)N-ammonia were performed on 25 patients with CAD documented by coronary angiography. Contrast-enhanced CTA was performed with retrospective electrocardiography gating after injection of 150 mL of intravenous contrast medium. Decisions on whether to treat with revascularization (anatomic lesion plus ischemia) or conservatively (no lesion or no ischemia) based on PET/CT were compared with those based on PET plus coronary angiography. RESULTS: Of the 100 coronary artery segments (left main, left anterior descending, left circumflex, and right in 25 patients), 7 (in 5 patients) were considered impossible to evaluate by CT because of rapid vessel movement but were correctly categorized by PET alone. In the remaining 93 segments, the sensitivity and specificity of PET/CT versus PET plus coronary angiography were 90% and 98%, respectively. Positive and negative predictive values were 82% and 99%, and accuracy was 97%. CONCLUSION: The data of this preliminary study suggest that PET/CT allows accurate noninvasive clinical decision making about CAD. Because of its high negative predictive value, PET/CT may play an important role in noninvasive selection of CAD patients for revascularization. Integration of higher-performance multislice spiral CT scanners into PET/CT hybrids will accelerate the clinical implementation of this technique.

Adult↗

Non-Hodgkin lymphoma and Hodgkin disease: coregistered FDG PET and CT at staging and restaging--do we need contrast-enhanced CT?

PURPOSE: To retrospectively compare diagnostic value of coregistered fluorine 18 fluorodeoxyglucose positron emission tomographic (PET) and computed tomographic (CT) scans obtained with low-dose nonenhanced CT (PET/CT) with those routinely obtained with contrast material-enhanced CT for staging and restaging of disease in patients with Hodgkin disease or high-grade non-Hodgkin lymphoma. MATERIALS AND METHODS: Sixty patients (mean age, 39.6 years +/- 17.1 [standard deviation]) with Hodgkin disease (n = 42) or high-grade non-Hodgkin lymphoma (n = 18) were included in this retrospective study. All patients underwent PET/CT and contrast-enhanced CT within a maximum of 24 days (mean, 9.1 days +/- 7.0) of each other for staging (n = 19) or first follow-up examination (n = 41). Findings were extracted from original written reports (PET/CT, contrast-enhanced CT) and compared with findings of reference standard, which included biopsy or follow-up with clinical, laboratory, or other imaging findings. For statistical analysis, sensitivity and specificity were calculated with findings of the reference standard. Agreement of both methods was determined with Cohen kappa and McNemar tests on a per-patient basis. RESULTS: For evaluation of lymph node involvement, sensitivity of PET/CT and contrast-enhanced CT was 94% and 88%, and specificity was 100% and 86%, respectively. For evaluation of organ involvement, sensitivity of PET/CT and contrast-enhanced CT was 88% and 50%, and specificity was 100% and 90%, respectively. Agreement of both methods was excellent (kappa = 0.84) for assignment of lymph node involvement but only fair (kappa = 0.50) for extranodal disease. A difference with P <.05 (McNemar test) was considered significant in regard to exclusion of disease with PET/CT, compared with contrast-enhanced CT. CONCLUSION: PET/CT performed with nonenhanced CT is more sensitive and specific than is contrast-enhanced CT for evaluation of lymph node and organ involvement, especially regarding exclusion of disease, in patients with Hodgkin disease and high-grade non-Hodgkin lymphoma.

Adolescent↗

FDG PET for differentiation of infection and aseptic loosening in total hip replacements: comparison with conventional radiography and three-phase bone scintigraphy.

PURPOSE: To compare the diagnostic efficacy of fluorine 18 fluorodeoxyglucose (FDG) positron emission tomography (PET) with that of conventional radiography and three-phase bone scintigraphy in patients suspected of having infection in their total hip replacements. MATERIALS AND METHODS: Thirty-five patients with painful total hip replacements and possible septic prosthetic loosening were examined with FDG PET, conventional radiography, and three-phase bone scintigraphy. PET, radiographic, and scintigraphic images were each evaluated by two independent observers in a blinded fashion. For 32 of 35 patients, serial conventional radiographs were available. Results of microbiologic examinations of surgical specimens represented the standard of reference in 26 patients, and results of joint aspiration plus clinical follow-up of at least 6 months represented the standard of reference in the remaining nine patients. Sensitivity, specificity, accuracy, and interobserver variability (kappa) values were calculated. The imaging modalities were compared in terms of diagnostic confidence by using the sign test. RESULTS: Nine patients had septic and 21 patients had aseptic loosening. In five patients, neither loosening nor infection was confirmed. For diagnosing infection with FDG PET, conventional radiography, and bone scintigraphy, respectively, sensitivity values for reader 1 and reader 2 were 33% and 22%, 89% and 78%, and 56% and 44%, while specificity values were 81% and 85%, 50% and 65%, and 88% and 92% and accuracy values were 69% for both readers, 60% and 69%, and 80% for both readers. PET was significantly more specific (P =.035) but less sensitive (P =.016) than conventional radiography for the diagnosis of infection. CONCLUSION: In a study population of patients suspected of having infected total hip replacements, FDG PET performed similarly to three-phase bone scintigraphy. FDG PET was more specific but less sensitive than conventional radiography for the diagnosis of infection.

Aged↗

Time-resolved 3D MR angiography of the abdomen with a real-time system.

This study reports on the implementation of a real-time MR acquisition, reconstruction, and display system on standard hardware for 3D contrast-enhanced MR abdominal angiography. The system allows for dynamic imaging of the contrast passage with good spatial resolution in a single breathhold. It is capable of synchronously acquiring and processing multiple coil data. Bolus arrival can be detected confidently from the display of MIP images from sagittal 3D slabs with moderate spatial resolution. Upon detection of the contrast agent, the patient is asked to hold their breath and a novel 3D acquisition is started for a coronal volume. Temporal imaging within the breathhold is achieved through applying a modified time-resolved imaging of contrast kinetics (TRICKS) technique with elliptical centric view ordering. The technique displays contrast passage from the arterial phase through enhancement of the hepatic venous system. It also provides the ability to quantify motion of the diaphragm over a long breathhold.

Abdomen↗

Does the novel PET/CT imaging modality impact on the treatment of patients with metastatic colorectal cancer of the liver?

OBJECTIVE: To compare the diagnostic value of contrast-enhanced CT (ceCT) and 2-[18-F]-fluoro-2-deoxyglucose-PET/CT in patients with metastatic colorectal cancer to the liver. BACKGROUND: Despite preoperative evaluation with ceCT, the tumor load in patients with metastatic colorectal cancer to the liver is often underestimated. Positron emission tomography (PET) has been used in combination with the ceCT to improve identification of intra- and extrahepatic tumors in these patients. We compared ceCT and a novel fused PET/CT technique in patients evaluated for liver resection for metastatic colorectal cancer. METHODS: Patients evaluated for resection of liver metastases from colorectal cancer were entered into a prospective database. Each patient received a ceCT and a PET/CT, and both examinations were evaluated independently by a radiologist/nuclear medicine physician without the knowledge of the results of other diagnostic techniques. The sensitivity and the specificity of both tests regarding the detection of intrahepatic tumor load, extra/hepatic metastases, and local recurrence at the colorectal site were determined. The main end point of the study was to assess the impact of the PET/CT findings on the therapeutic strategy. RESULTS: Seventy-six patients with a median age of 63 years were included in the study. ceCT and PET/CT provided comparable findings for the detection of intrahepatic metastases with a sensitivity of 95% and 91%, respectively. However, PET/CT was superior in establishing the diagnosis of intrahepatic recurrences in patients with prior hepatectomy (specificity 50% vs. 100%, P = 0.04). Local recurrences at the primary colo-rectal resection site were detected by ceCT and PET/CT with a sensitivity of 53% and 93%, respectively (P = 0.03). Extrahepatic disease was missed in the ceCT in one third of the cases (sensitivity 64%), whereas PET/CT failed to detect extrahepatic lesions in only 11% of the cases (sensitivity 89%) (P = 0.02). New findings in the PET/CT resulted in a change in the therapeutic strategy in 21% of the patients. CONCLUSION: PET/CT and ceCT provide similar information regarding hepatic metastases of colorectal cancer, whereas PET/CT is superior to ceCT for the detection of recurrent intrahepatic tumors after hepatectomy, extrahepatic metastases, and local recurrence at the site of the initial colorectal surgery. We now routinely perform PET/CT on all patients being evaluated for liver resection for metastatic colorectal cancer.

Colorectal Neoplasms↗

CT attenuation correction for myocardial perfusion quantification using a PET/CT hybrid scanner.

UNLABELLED: In routine PET, a 10- to 20-min transmission scan with a rotating (68)Ge source is commonly obtained for attenuation correction (AC). AC is time-consuming using this procedure and could considerably be shortened by instead using a rapid CT scan. Our aim was to evaluate the feasibility of CT AC in quantitative myocardial perfusion PET using a hybrid PET/CT scanner. METHODS: (13)N-labeled NH(3) and PET were used to measure myocardial blood flow (MBF) (mL/min/g) at rest and during standard adenosine stress. In group 1 (n = 7), CT scans (0.5 s) of the heart area with different tube currents (10, 40, 80, and 120 mA) were compared with a standard (68)Ge transmission (20 min) and with no AC. In group 2 (n = 3), the repeatability of 8 consecutive CT scans at a tube current of 10 mA was assessed. In group 3 (n = 4), emission was preceded and followed by 3 CT scans (10 mA) and 1 (68)Ge scan for each patient. For reconstruction, filtered backprojection (FBP) was compared with iterative reconstruction (IT). RESULTS: For group 1, no significant difference in mean MBF for resting and hyperemic scans was found when emission reconstructed with (68)Ge AC was compared with emission reconstructed with CT AC at any of the different tube currents. Only emission without any correction differed significantly from (68)Ge AC. For group 2, repeated measurements revealed a coefficient of variance ranging from 2% to 5% and from 2% to 6% at rest and at stress, respectively. For group 3, similar reproducibility coefficients (RC) for MBF were obtained when (68)Ge AC(FBP) was compared with (68)Ge AC(IT) (RC = 0.218) and when CT AC(FBP) was compared with CT AC(IT) (RC = 0.227). Even better reproducibility (lower RC) was found when (68)Ge AC(FBP) was compared with CT AC(FBP) (RC = 0.130) and when (68)Ge AC(IT) was compared with CT AC(IT) (RC = 0.146). CONCLUSION: Our study shows that for the assessment of qualitative and quantitative MBF with a hybrid PET/CT scanner, the use of CT AC (with a tube current of 10 mA) instead of (68)Ge AC provides accurate results.

Algorithms↗

Staging of non-small-cell lung cancer with integrated positron-emission tomography and computed tomography.

BACKGROUND: We compared the diagnostic accuracy of integrated positron-emission tomography (PET) and computed tomography (CT) with that of CT alone, that of PET alone, and that of conventional visual correlation of PET and CT in determining the stage of disease in non-small-cell lung cancer. METHODS: In a prospective study, integrated PET-CT was performed in 50 patients with proven or suspected non-small-cell lung cancer. CT and PET alone, visually correlated PET and CT, and integrated PET-CT were evaluated separately, and a tumor-node-metastasis (TNM) stage was assigned on the basis of image analysis. Nodal stations were identified according to the mapping system of the American Thoracic Society. The standard of reference was histopathological assessment of tumor stage and node stage. Extrathoracic metastases were confirmed histopathologically or by at least one other imaging method. A paired sign test was used to compare integrated PET-CT with the other imaging methods. RESULTS: Integrated PET-CT provided additional information in 20 of 49 patients (41 percent), beyond that provided by conventional visual correlation of PET and CT. Integrated PET-CT had better diagnostic accuracy than the other imaging methods. Tumor staging was significantly more accurate with integrated PET-CT than with CT alone (P=0.001), PET alone (P<0.001), or visual correlation of PET and CT (P=0.013); node staging was also significantly more accurate with integrated PET-CT than with PET alone (P=0.013). In metastasis staging, integrated PET-CT increased the diagnostic certainty in two of eight patients. CONCLUSIONS: Integrated PET-CT improves the diagnostic accuracy of the staging of non-small-cell lung cancer.

Aged↗

Cause and magnitude of the error induced by oral CT contrast agent in CT-based attenuation correction of PET emission studies.

UNLABELLED: CT images represent essentially noiseless maps of photon attenuation at a range of 40-140 keV. Current dual-modality PET/CT scanners transform them into attenuation coefficients at 511 keV and use these for PET attenuation correction. The proportional scaling algorithms hereby used account for the different properties of soft tissue and bone but are not prepared to handle material with other attenuation characteristics, such as oral CT contrast agents. As a consequence, CT-based attenuation correction in the presence of an oral contrast agent results in erroneous PET standardized uptake values (SUVs). The present study assessed these errors with phantom measurements and patient data. METHODS: Two oral CT contrast agents were imaged at 3 different concentrations in dual-modality CT and PET transmission studies to investigate their attenuation properties. The SUV error due to the presence of contrast agent in CT-based attenuation correction was estimated in 10 patients with gastrointestinal tumors as follows. The PET data were attenuation corrected on the basis of the original contrast-enhanced CT images, resulting in PET images with distorted SUVs. A second reconstruction used modified CT images wherein the CT numbers representing contrast agent had been replaced by CT values producing approximately the right PET attenuation coefficients. These CT values had been derived from the data of 10 patients imaged without a CT contrast agent. The SUV error, defined as the difference between both sets of SUV images, was evaluated in regions with oral CT contrast agent, in tumor, and in reference tissue. RESULTS: The oral CT contrast agents studied increased the attenuation for 511-keV photons minimally, even at the highest concentrations found in the patients. For a CT value of 500 Hounsfield units, the proportional scaling algorithm therefore overestimated the PET attenuation coefficient by 26.2%. The resulting SUV error in the patient studies was highest in regions containing CT contrast agent (4.4% +/- 2.8%; maximum, 11.3%), whereas 1.2% +/- 1.1% (maximum, 4.1%) was found in tumors, and 0.6% +/- 0.7% was found in the reference. CONCLUSION: The use of oral contrast agents in CT has only a small effect on the SUV, and this small effect does not appear to be medically significant.

Administration, Oral↗