Is a preoperative multidiagnostic approach to predict surgical resectability of periampullary tumors still effective?

BACKGROUND: Multimodality staging is recommended in patients with periampullary tumors to optimize preoperative determination of resectability. We investigated the potency of currently used diagnostic procedures in order to determine resectability. METHODS: Ninety-five consecutive patients with periampullary tumors prehospitally staged resectable underwent preoperative diagnostic tests: helical-computed tomography (CT) with maximum intensity projection of arterial vessels (MIP), magnetic resonance imaging (MRI), magnetic resonance cholangiopancreaticography (MRCP), endoscopic ultrasonography (EUS), endoscopic retrograde cholangiopancreaticography (ERCP), digital subtraction angiography (DSA), and positron emission tomography (PET). Diagnoses were verified by surgery and histopathology. RESULTS: In 45 patients with benign and 50 patients with malignant periampullary tumors sensitivity for tumor diagnosis was 89% to 96% in CT, MRI, EUS, and PET. Small tumors were best diagnosed by EUS (100%). Diagnosis of malignancy was made with 85% (EUS), 83% (CT), 82% (PET), and 72% (MRI) accuracy. Arterial vessel infiltration was best predicted by CT/MIP with an accuracy of 85%. For venous vessel infiltration MRI reached 85% accuracy. Accuracy rates for local nonresectability were 93% (EUS), 92% (MRI), and 90% (CT). Two and 4 of 8 patients with distant metastases were identified by CT and PET, respectively. The correct diagnosis of malignancy and determination of resectability was made by CT in 71% and by MRI in 70%. Biliary stenting reduced accuracy of CT diagnosis of malignancy from 88% to 73%. CONCLUSIONS: CT obtained before stenting was the single most useful test, providing correct diagnosis in 88% and resectability in 71% of patients. If no tumor is depicted in CT, EUS should be added. Uncertain venous vessel infiltration can be verified by MRI or EUS. Angiography should no longer be a routine diagnostic procedure. Equivocal tumors or possible metastasis may be further examined with PET.

Ki-67 immunostaining in pancreatic cancer and chronic active pancreatitis: does in vivo FDG uptake correlate with proliferative activity?

UNLABELLED: PET with 18F-FDG has been shown to be useful in the detection and staging of pancreatic cancer. However, whether FDG uptake is dependent on proliferative activity is still unclear. The aim of this prospective study was to evaluate a probable correlation between FDG uptake and proliferative activity in benign and malignant pancreatic tumors. METHODS: Our series consisted of 23 patients with pancreatic cancer and 9 patients with chronic active pancreatitis (CAP). FDG PET was performed within 2 wk before surgery, and standardized uptake values (SUVs) were calculated for benign and malignant pancreatic tumors. Patients were selected when focally increased FDG uptake in previously known pancreatic tumors was present. Proliferation fraction was measured in tissue specimens using the anti-Ki-67 antibody MIB-1. A computer-assisted imaging system was used for quantification of nuclear Ki-67 immunostaining. Immunohistochemical findings were correlated to SUVS: RESULTS: Pancreatic cancer showed both intense nuclear staining of Ki-67 (39% +/- 16%) and high FDG uptake (SUV = 3.6 +/- 1.6). However, no significant correlation was found between in vivo FDG uptake and Ki-67 immunoreactivity (P = 0.65). By contrast, Ki-67 nuclear staining was significantly lower (3.8% +/- 2.7%, P < 0.05) in CAP, whereas FDG uptake was in the same range as for pancreatic cancer (SUV = 3.5 +/- 1.8). CONCLUSION: FDG uptake did not correlate with proliferative activity in pancreatic cancer. Proliferative activity was tenfold higher in malignant pancreatic tumors than in benign tumors associated with CAP, whereas FDG uptake in vivo did not differ significantly. Thus, a PET tracer indicating cellular proliferation should better differentiate between cancer and inflammatory lesions than do metabolic markers such as FDG.

Grading of tumors and tumorlike lesions of bone: evaluation by FDG PET.

UNLABELLED: Clinical diagnosis of skeletal tumors can be difficult, because such lesions compose a large, heterogeneous group of entities with different biologic behaviors. The aim of this prospective study was to assess the value of PET in grading tumors and tumorlike lesions of bone. METHODS: Two hundred two patients with suspected primary bone tumors were investigated using FDG PET. Uptake of FDG was evaluated semiquantitatively by determining the tumor-to-background ratio (T/B). All patients underwent biopsy, resulting in the histologic detection of 70 high-grade sarcomas, 21 low-grade sarcomas, 40 benign tumors, 47 tumorlike lesions, 6 osseous lymphomas, 6 plasmacytomas, and 12 metastases of an unknown primary tumor. RESULTS: All lesions, with the exception of 3 benign tumors, were detected by increased FDG uptake. Although sarcomas showed significantly higher T/Bs than did latent or active benign lesions (P < 0.001), aggressive benign lesions could not be distinguished from sarcomas. Using a T/B cutoff level for malignancy of 3.0, the sensitivity of FDG PET was 93.0%, the specificity was 66.7%, and the accuracy was 81.7%. CONCLUSION: FDG PET provides a promising tool for estimating the biologic activity of skeletal lesions, implicating consequences for the choice of surgical strategy.

Values and limitations of 18F-fluorodeoxyglucose-positron-emission tomography with preoperative evaluation of patients with pancreatic masses.

The aim of this study was to determine the value and limitations of 18F-fluorodeoxyglucose (FDG)-position-emission tomography (PET) for differentiating benign and malignant pancreatic disease and for staging malignant disease. One hundred fifty-nine patients with 89 malignant and 70 benign pancreatic lesions all received PET, computed tomography (CT), and endoscopic retrograde cholangiopancreatography (ERCP) before pancreatic surgery. The original reports were compared for all patients (group I; N = 159), for a subgroup that neither had fasting plasma glucose levels > or =130 mg/dL or known elevated levels of C-reactive protein ([CRP], group II; n = 123), and for the remaining patients (group III; n = 36). For group I, accuracy values (areas under receiver operating characteristic [ROC] curves) for differentiation of benign/malignant masses were 0.86 (PET), 0.93 (ERCP), 0.82 (CT), and 0.95 for ERCP + PET (N = 159). For group II, ROC areas increased to 0.92 (PET), 0.94 (p < 0.05; n = 123) (ERCP), 0.82 (CT), 0.97 (p < 0.05; n = 123) (ERCP + PET). The results for group III were 0.71 (PET), 0.81 (CT), and 0.93 (ERCP); (n = 36). With 54 patients of group II that either had contradictory or indeterminate/technically unsuccessful CT/ERCP, PET was correct in 43 patients (84%). Sensitivity/specificity for lymph node staging was 49%/63%, respectively. For patients with hepatic metastasis, PET was 70% sensitive and 95% specific, missing some metastasis that were <1 cm. PET detected peritoneal metastasis in 25% of patients, missing poorly localized microscopic spread. For selected patients who have indeterminate pancreatic masses but no hyperglycemia or serologic evidence of active inflammation, FDG-PET is an independent functional assay that significantly adds to the diagnostic accuracy of ERCP and CT in the differentiation of benign and malignant pancreatic disease. PET can reliably detect hepatic, peritoneal, and other distant metastases that are > or =1 cm.

Fluorodeoxyglucose positron emission tomography of soft tissue tumours: is a non-invasive determination of biological activity possible?

Since musculoskeletal tumours comprise a large heterogeneous group of entities with different biological behaviour, clinical diagnosis of such lesions can be very difficult. The aim of this prospective study was to assess the usefulness of 2-[F-18]-fluoro-2-deoxy-d-glucose (FDG) positron emission tomography (PET) in the non-invasive evaluation of soft tissue tumours. One hundred and two patients with suspected soft tissue neoplasms were investigated by FDG-PET. The uptake of FDG was evaluated semiquantitatively by determining the tumour to background ratio (TBR). All patients underwent biopsy, resulting in the histological detection of 39 high-grade sarcomas, 16 intermediate-grade sarcomas, 11 low-grade sarcomas, 25 benign tumours, 10 tumour-like lesions such as spontaneous myositis ossificans (n = 6) and one non-Hodgkin lymphoma. All lesions except for two lipomas disclosed an increased FDG uptake. Sarcomas showed significantly higher TBR values than latent or active benign lesions (P<0.001) and aggressive benign lesions (P<0.05). Using a TBR cut-off level of 3.0 for malignancy, sensitivity of FDG-PET was 97.0%, specificity 65.7% and accuracy 86. 3%. From our data there are three main conclusions: (1) Except for patients with pseudotumoral myositis ossificans, lesions with a TBR >3 were sarcomas (91.7%) or aggressive benign tumours (8.3%). (2) Tumours with a TBR <1.5 were latent or active benign lesions, exclusively. (3) The group with intermediate TBR values (<3 and >1. 5) comprised primarily latent or active benign lesions, but also four aggressive benign tumours and two low-grade sarcomas. Our data suggest that FDG-PET represents a useful tool for the evaluation of the biological activity of soft tissue neoplasms.

Detection of liver metastases from pancreatic cancer using FDG PET.

UNLABELLED: We evaluated the potential of the glucose analog [18F]fluorodeoxyglucose (FDG) as a PET tracer for the hepatic staging in 168 patients designated for resective pancreatic surgery. METHODS: Metastatic liver disease was confirmed or excluded during surgery or with CT follow-up for at least 6 mo. Proven metastases were then retrospectively identified on preoperative CT (gold standard). Hepatic PET scans of all patients were interpreted blindly. Any focal FDG uptake was considered malignant. Both proven hepatic metastases and suspicious hepatic PET lesions were then compared, lesion by lesion, with CT. Standardized uptake values (SUV) and tumor-to-liver ratios (T/L) were determined for the most intense lesion of each patient. RESULTS: Sensitivity of FDG PET was 68% (15 of 22 patients). The lesion detection rate was 97% (28 of 29 metastases) for lesions >1 cm and 43% (16 of 37 metastases) for lesions < or = 1 cm. Specificity was 95% (138 of 146 patients). Six of eight patients with false-positive results had marked intrahepatic cholestasis (versus 3 of 15 patients with true-positive lesions), one had an infrahepatic abscess and one had a right basal pulmonary metastasis. The SUV and T/L were 4.6+/-1.4 and 2.3+/-1.1, respectively, for malignant lesions and 4.1+/-1.5 and 1.9+/-0.3, respectively, for false-positive lesions and therefore are of limited value. CONCLUSION: FDG PET provides reliable hepatic staging for lesions >1 cm. False-positive results are associated with the presence of marked intrahepatic cholestasis. For lesions < or = 1 cm, FDG PET can define malignancy in 43% of suspicious CT lesions in the absence of dilated bile ducts.

[Positron-emission tomography of the skeletal system using 18FNa: the incidence, pattern of the findings and distribution of benign changes]. / Die Positronenemissionstomographie des Skelettsystems mit 18FNa: Häufigkeit, Befundmuster und Verteilung benigner Veränderungen.

PURPOSE: We evaluated the frequency, distribution and appearance of benign lesions in 18F-PET scans. METHODS: Between March 1996 and May 1997, 18F-PET scans were performed in 59 patients in addition to conventional planar bone scintigraphy. Eleven patients were subjected to additional SPECT imaging. The main indication was searching for bone metastases (58 pat.). The diagnosis was confirmed radiologically. RESULTS: With 18F-PET in 39 patients (66.1%) 152 benign lesions, mostly located in the spine were detected. 99mTc bone scans revealed 45 lesions in 10 patients. Osteoarthritis of the intervertebral articulations (69%) or of the acromioclavicular joint (15%) were the most common reasons for degenerative lesions detected with 18F-PET. Osteophytes appeared as hot lesions located at two adjacent vertebral endplates. Osteoarthritis of the intervertebral articulations showed an enhanced tracer uptake at these localizations, whereas endplate fractures of the vertebral bodies appeared very typical; solitary fractures of the ribs could not be differentiated from metastases. Rare benign lesions were not studied. CONCLUSION: Most of the degenerative lesions (84%) detected with 18F-PET had a very typical appearance and could be detected with the improved spatial resolution and advantages of a tomographic technique. 18F-PET had an increased accuracy in detecting degenerative bone lesions.

[Imaging of the normal skeletal system with 18F Na-PET compared with conventional skeletal scintigraphy using Tc99m-MDP]. / Darstellung des normalen Skelett-systems mit 18FNa-PET im Vergleich zur konventionellen Skelettszintigraphie mit 99mTc-MDP.

PURPOSE: We evaluated the feasibility of 18 Fluoride Positron Emission Tomography (18F-PET), investigated the characteristics appearance of bony structures, and compared the quality of 18F-PET images with conventional bone scans (BS). METHOD: 18F-PET scans were performed in 59 patients additional to conventional bone scintigraphy. RESULTS: Even very small details in the spine like the spinous and transverse processes were clearly visible with 18F-PET. Only half of these structures were visualised with BS. When visualising the vertebral bodies of the first rib from the clavicles and the twelfth rib from the kidneys, we arrived at similar results. Hot spots in the skull or at the manubriosternal joint were observed in 29% of the patients without any evidence of trauma, degeneration or metastasis. CONCLUSION: 18F-PET shows more details of the skeleton compared to BS. Some hot spots not occurring with BS must be regarded as physiological.

FDG PET: elevated plasma glucose reduces both uptake and detection rate of pancreatic malignancies.

UNLABELLED: The aim of the study was to evaluate the effects of elevated plasma glucose levels on tumor detection. METHODS: One-hundred and seventy-one fasted patients (100 malignant pancreatic tumors, 46 chronic pancreatitis and 25 patients with other benign pancreatic lesions) were studied with 18F-fluorodeoxyglucose (FDG) PET before planned resective pancreatic surgery. Nineteen of 171 patients had elevated plasma glucose levels above 130 mg/dl, and 24 of 171 had diabetes mellitus. Standard uptake values (SUVs) with and without glucose correction, tumor-to-muscle ratios and tumor-to-liver ratios were measured of the pancreatic lesion respective of the area with the highest uptake within the pancreas. The original qualitative PET reports concerning the dignity of the pancreatic lesion were translated into a five-point malignancy scale. Tumor detection rates and SUVs were compared according to plasma glucose levels above and below 130 mg/dl, the presence of diabetes and by using receiver operating characteristic (ROC) analysis. RESULTS: The detection rates (and mean SUVs) for pancreatic malignancies were 86% and 42% (4.2 and 2.3) if fasted plasma glucose levels were below and above 130 mg/dl, respectively. The sensitivities (and mean SUVs of malignant tumors) were 83% and 69% (3.3 and 2.5) for patients without and with known diabetes. Areas under ROC curves were nearly equal for glucose corrected SUV and visual qualitative results (0.86 and 0.85), followed by uncorrected SUV (0.83), tumor-to-liver ratios (0.80) and tumor-to-muscle ratios (0.79). SUVs for chronic pancreatitis, muscle and liver had a tendency to increase with elevated plasma glucose levels. CONCLUSION: Negative PET results of patients with elevated plasma glucose should be interpreted with caution.

Extranodal malignant lymphoma: detection with FDG PET versus CT.

PURPOSE: To evaluate use of functional imaging with positron emission tomography (PET) versus computed tomography (CT) for detection of extranodal lymphoma spread. MATERIALS AND METHODS: Eighty-one consecutive and previously untreated patients with malignant non-Hodgkin lymphoma (n = 43) or Hodgkin disease (n = 38) were examined with 2-[fluorine-18]fluoro-2-deoxy-D-glucose (FDG) PET and contrast material-enhanced CT. Concordant findings at both CT and FDG PET were regarded as actual locations of disease; discordant results were resolved on the basis of biopsy or follow-up results when possible. RESULTS: Forty-two lesions were identified at both PET and CT, and 19 were verified with biopsy results. PET demonstrated a further 24 lesions. Verification was possible in 15 of these lesions with biopsy (n = 10), magnetic resonance imaging (n = 1), scintigraphic (n = 1), or follow-up (n = 3) results. In 14 of these 15 lesions, PET findings were confirmed (bone marrow, nine; spleen, three; other, two). Seven lesions not visualized at FDG PET were identified at CT, six of which were verified with biopsy (n = 2) or follow-up (n = 4) results. Five of these six CT findings were found to be erroneous. In 13 patients, PET findings led to changes in tumor staging. CONCLUSION: PET may provide more information about extranodal lymphoma than does incremental CT.

Preoperative imaging in a case of molar retention.

The use of high resolution spiral computed tomography with additional 2-D reconstruction is demonstrated for a patient with a deeply impacted first mandibular molar. The precise anatomical localization enabled us to remove the tooth without damaging the inferior alveolar nerve.

Lymphoma: role of whole-body 2-deoxy-2-[F-18]fluoro-D-glucose (FDG) PET in nodal staging.

PURPOSE: To compare 2-deoxy-2-[fluorine-18]fluoro-D-glucose (FDG) positron emission tomography (PET) with computed tomography (CT) in primary nodal staging of malignant lymphoma. MATERIALS AND METHODS: Sixty consecutive patients with untreated, histopathologically proved malignant lymphoma (aged 7-72 years; 33 with non-Hodgkin lymphoma, 27 with Hodgkin disease) underwent FDG PET and contrast material-enhanced CT for nodal staging. Lymph node regions identified at both CT and PET were regarded as actual locations of disease. Discordant results were verified with biopsy or clinical follow-up whenever possible. RESULTS: One hundred sixty of 740 evaluated lymph node regions were identified as diseased at both CT and PET. Of the 25 additional regions seen with PET, seven were true-positive; two, false-positive; and 16, unresolved. CT showed six additional disease manifestations; three were false-positive, and three were unresolved. Staging was changed in the four patients with the seven confirmed additional PET findings: from stage I to II in one patient and from stage II to III in three patients. Staging was changed from stage II to I in one of the three patients with false-positive CT findings. CONCLUSION: FDG PET may be more accurate for detecting nodal lymphoma than incremental CT.

Alveolar reconstruction with splitting osteotomy and microfixation of implants.

This report describes a surgical technique for reconstruction of the buccolingually reduced alveolar process. The technique involves the preparation of an artificial socket with immediate implant placement, which reduces total treatment time compared with two-stage procedures. Alveolar preparation comprises lamellar cortical splitting of the alveolus, interlamellar implant placement, and primary stabilization based on a microfixation technique. It was used for a wide range of indications involving single and multiple alveoli related to the partially dentate and the edentulous alveolar process. The results of 24 Branemark standard implants and 97 ITI implants with 44 consecutively treated patients have been reviewed with a mean observation time of 34.3 months (range 6 to 68 months). The main indicator for alveolar reconstruction was the narrow anterior maxillary arch. The 5-year cumulated success rate was 86.2%. Twelve implants failed during the observation period. The mean marginal bone loss was 1.7 mm (range 0 to 7.5 mm). There was a low infection rate compared with membrane-based GTR techniques. Treatment costs were low as a result of shorter treatment time.

Blurring of vessels in spiral CT angiography: effects of collimation width, pitch, viewing plane, and windowing in maximum intensity projection.

PURPOSE: Our goal was to examine the effects of collimation width (CW), pitch, viewing plane, and windowing on the display of in-plane vessels in maximum intensity projection (MIP). METHOD: A theoretical concept based on partial volume averaging of vessels was developed to describe the contents of voxels (densities) in MIP and to derive cross-sectional vessel diameters and blurring. To validate the concept and to describe the influence of pitch, a Plexiglas cone submerged in water was scanned with varying CW and pitch. Binary MIP with three representative window levels was chosen so that definitive vessel diameters could be quantitated. RESULTS: The theoretical concept correctly predicted voxel contents and blurring for CW > or = 3 mm and low pitch. For high pitch, actual blurring was larger; however, for a given table speed, blurring of the cone decreased with pitch while increasing with CW. Overall blurring was most effectively reduced by using a thin CW and the transverse viewing plane. In the transverse viewing plane, the least blurring was found using binary MIP with a low window level. On the contrary, in the longitudinal viewing plane, blurring was minimized using a window level halfway between the density of the cone and that of the surrounding water. CONCLUSION: For CW > or = 3 mm, blurring of in-plane vessels can be explained with a simple geometrical concept based on partial volume. For accurate display, the transverse viewing plane should be used, a proper windowing must be chosen, and the CW should be kept below vessel size while raising the pitch to cover a reasonable volume.

Must radiation dose for CT of the maxilla and mandible be higher than that for conventional panoramic radiography?

We evaluated the feasibility of performing preoperative spiral CT of the maxilla and mandible with a radiation dose similar to that used for conventional panoramic radiography. The skin entrance doses of radiation used for spiral CT (collimation, 1 mm; pitch, 2; tube voltage, 80 kV; tube current, 40 mA) and for panoramic radiography (75 kV, 8 mA, 15 seconds) were measured in one patient by using thermoluminescent dosimeter chips. Results were 0.56 +/- 0.06 mGy for CT and 0.59 +/- 0.04 mGy for radiography. Image quality was adequate for preoperative implant planning. Spiral CT of the mandible and maxilla may therefore be feasible with a radiation dose of similar magnitude as that used for conventional panoramic radiography.

[Spiral CT with reduced radiation dosage]. / Spiral-CT mit reduzierter Strahlendosis.

PURPOSE: To examine the clinical use of a reduced dose in high-resolution spiral-CT (HR-SCT) in combination with a multiplanar volume reconstruction technique (MPVR) to decrease image noise. MATERIAL AND METHODS: Facial bones, skull and extremities of 33 patients with different pathological findings were examined with spiral-CT using a slice thickness of 1 mm (pitch 1.7-2.0), a tube amperage of 40 mA and tube voltages of 80 or 120 kV. Additionally, 2-D, 3-D, and MPVR images reconstructions were performed. MPVR takes advantage of displaying planar volumes of variable thickness. RESULTS: Increased image noise was negligible if high contrast structures like bones were examined. However, very small bony structures like the stapes of the middle ear were not seen. Soft tissues could also be imaged by using the MPVR-technique. This technique did reduce image noise while at the same time partial volume averaging was increased. The skin entrance dose per investigation did not exceed 3 mGy, which is based on twelve dose measurements in two patients. CONCLUSION: It is feasible to perform HR-SCT with secondary reconstructions of facial bones, skull and extremities using reduced skin entrance doses by 10 to 20 fold to below 3 mGy. With the exception of imaging very small structures, sufficient image quality can be accomplished in routine examinations without relevant diagnostic compromise.

[The acetabular prosthesis: detection of a migration using ruler and pencil? Measurements on a pelvic phantom in comparison with a 3D computer simulation]. / Hüftpfannenprothese: Nachweis einer Migration mit Lineal und Bleistift? Messungen am Beckenphantom im Vergleich mit einer 3D-Computersimulation.

Conventional X-ray films were made with varying degrees of tilt of a pelvic phantom containing an acetabular prosthesis. The position of the prosthesis was then reconstructed graphically. The measurement errors were calculated and an estimate was made for the tilt. There is a linear correlation between the measurement error and the tilt of the prosthesis. Therefore a tilt dependent maximum error can be calculated. This error is very small for small degrees of tilt, so that acetabular migration can in this instance be evaluated with greater confidence than with other graphical methods. The error also correlates with the determination of the selected region of the acetabulum, but not with the position of the central focus spot or image magnification.