Bone mineral density measurements of the proximal femur from routine contrast-enhanced MDCT data sets correlate with dual-energy X-ray absorptiometry.

OBJECTIVES: To evaluate the utility of femoral bone mineral density (BMD) measurements in routine contrast-enhanced multi-detector computed tomography (ceMDCT) using dual-energy X-ray absorptiometry (DXA) as the reference standard. METHODS: Forty-one patients (33 women, 8 men) underwent DXA measurement of the proximal femur. Subsequently, transverse sections of routine ceMDCT of these patients were used to measure BMD of the femoral head and femoral neck. The MDCT-to-DXA conversion equations for BMD and T-score were calculated using linear regression analysis. The conversion equations were applied to the MDCT data sets of 382 patients (120 women, 262 men) of whom 74 had osteoporotic fractures. RESULTS: A correlation coefficient of r = 0.84 (P < 0.05) was calculated for BMD(MDCT) values of the femoral head and DXA T-scores of the total proximal femur using the conversion equation T-score = 0.021 × BMD(MDCT) - 5.90. The correlation coefficient for the femoral neck was r = 0.79 (P < 0.05) with the conversion equation T-score = 0.016 × BMD(MDCT) - 4.28. Accordingly, converted T-scores for the femoral neck in patients with versus those without osteoporotic fractures were significantly different (female, -1.83 versus -1.47; male, -1.86 versus -1.47; P < 0.05). CONCLUSION: BMD measurements of the proximal femur were computed in routine contrast-enhanced MDCT and converted to DXA T-scores, which adequately differentiated patients with and without osteoporotic fractures.

Comparison of 3'-deoxy-3'-[¹8F]fluorothymidine positron emission tomography (FLT PET) and FDG PET/CT for the detection and characterization of pancreatic tumours.

PURPOSE: Despite recent advances in clinical imaging modalities, differentiation of pancreatic masses remains difficult. Here, we tested the diagnostic accuracy of molecular-based imaging including 3'-deoxy-3'-[(18)F]fluorothymidine (FLT) positron emission tomography (PET) and [(18)F]fluorodeoxyglucose (FDG) PET/CT in patients with suspected pancreatic masses scheduled to undergo surgery. METHODS: A total of 46 patients with pancreatic tumours suspicious for malignancy and scheduled for resective surgery were recruited prospectively. In 41 patients, FLT PET and FDG PET/CT scans were performed. A diagnostic CT performed on a routine basis was available in 31 patients. FLT PET and FDG PET/CT emission images were acquired according to standard protocols. Tracer uptake in the tumour [FDG and FLT standardized uptake value (SUV)] was quantified by the region of interest (ROI) technique. For FDG PET/CT analysis, correct ROI placement was ensured via side-by-side reading of corresponding CT images. RESULTS: Of 41 patients, 33 had malignancy, whereas 8 patients had benign disease. Visual analysis of FDG and FLT PET resulted in sensitivity values of 91% (30/33) and 70% (23/33), respectively. Corresponding specificities were 50% (4/8) for FDG PET and 75% (6/8) for FLT PET. In the subgroup of patients with contrast-enhanced CT (n = 31), sensitivities were 96% (PET/CT), 88% (CT alone), 92% (FDG PET) and 72% (FLT PET), respectively. Mean FLT uptake in all malignant tumours was 3.0 (range SUV(max) 1.1-6.5; mean FDG SUV(max) 7.9, range 3.3-17.8; p < 0.001). CONCLUSION: For differentiation of pancreatic tumours, FDG PET and FDG PET/CT showed a higher sensitivity but lower specificity than FLT PET. Interestingly, visual analysis of FLT PET led to two false-positive findings by misinterpreting physiological bowel uptake as pathological FLT uptake in the pancreas. Due to the limited number of patients, the clinical value of adding FLT PET to the diagnostic workup of pancreatic tumours remains to be determined.

[Pitfalls in computed tomography for diffuse liver diseases]. / Pitfalls in der CT bei diffusen Lebererkrankungen.

CLINICAL/METHODICAL ISSUE: Misinterpretations in liver diagnostics could result in a false diagnosis, such as a parenchymatous damage or a false focal lesion. STANDARD RADIOLOGICAL METHODS: Computed tomography is a widely used diagnostic tool to visualize liver diseases. METHODICAL INNOVATIONS: Magnetic resonance imaging (MRI) is often used as a second diagnostic test to answer specific questions. PERFORMANCE: The more the condition of changes in liver parenchyma appearance in cross-sectional imaging is known the fewer mistakes will be made in the interpretation. Knowledge of these pitfalls helps to increase diagnostic accuracy. ACHIEVEMENTS: Magnetic resonance imaging could help to depict most of the pitfalls. PRACTICAL RECOMMENDATIONS: By looking at diffuse or focal liver diseases radiologists should be aware of perfusion patterns and structural changes of the liver parenchyma to make a correct diagnosis.

[Endoscopic and percutaneous intervention in the long-term treatment of benign biliary stenosis. A 71-year-old patient with cholestasis following radiotherapy]. / Endoskopische und perkutane Interventionen in der Langzeitbehandlung benigner Gallengangstenosen : 71-jähriger Patient mit Cholestase nach Radiatio.

Benign biliary stenosis can have various causes and requires differentiation from disorders caused by malignant disease. Treatment of benign stenosis is often difficult and includes treatment modalities such as endoscopic, percutaneous or surgical interventions. Exact knowledge of the etiology and localization of the stenosis is essential when selecting the appropriate method of treatment. Here we present the case of a 71-year-old patient admitted to our hospital with cholangitis 13 years after undergoing radiotherapy of the renal bed due to hypernephroma of the right kidney. The patient was diagnosed with common bile duct stenosis due to the secondary effects of radiation, which is rarely reported in the literature. Our case covers a total treatment period of 15 years, enabling us to also discuss a viable sequence of treatment modalities in the treatment of benign bile duct stenosis.

Step and shoot coronary CT angiography using 256-slice CT: effect of heart rate and heart rate variability on image quality.

OBJECTIVE: To evaluate the effect of heart rate variability (HRV) and heart rate (HR) on intra-image "motion" and inter-image "stairstep" artefacts in step-and-shoot coronary CT angiography (CCTA) using a wide detector CT scanner. METHODS: 66 patients underwent step-and-shoot CCTA using 256-slice CT. Patients were divided into two groups (Group 1: HR <65 bpm, Group 2 ≥65bpm). Motion artefacts were quantified using a 5-point-scale. Stairstep artefacts were defined by measurements of misalignment. Image noise, contrast-to-noise-ratio (CNR), signal-to-noise-ratio (SNR), and radiation dose were assessed. RESULTS: Mean HR was 66 ± 16.7 bpm (range: 45-125 bpm) and mean HRV was 10.7 ± 17.5 bpm. A significant correlation between HR and stairstep artefacts (r = 0.46, p < 0.001) and motion artefacts (r = 0.63, p < 0.001) was found. Group 2 showed significantly increased step artefacts with a mean misalignment of 1.4 mm compared to 0.4 mm in Group 1 (p < 0.001). There was no significant effect of HRV on stairstep artefacts (r = 0.15, p = 0.416) and motion artefacts (r = 0.13, p = 0.311). No significant differences in image noise, CNR, SNR, and radiation dose were seen. CONCLUSIONS: Unlike CCTA using narrow CT detectors, HRV has no significant effect on motion and stairstep artefacts using a wide CT detector with high z-coverage. However, a higher HR still increases stairstep and motion artefacts.

[The "invisible" foreign body]. / Der "unsichtbare" Fremdkörper.

A 58-year-old female patient fell down a stairs carrying a plant pot. The bamboo stem penetrated the left lower lip and remained stuck in the throat. The patient pulled the bamboo stem out immediately. The lower lip was sutured and a tear in the mucous membrane in the tonsils was explored and cleansed. A foreign body could not be detected either clinically or by computed tomography (CT) of the neck. After 1 week a control CT of the neck was carried out because the patient complained of odynophagy and a putrid taste. An initially overlooked foreign body was now detected in the "lung window" and lay in an abscess cavity on the prevertebral surface. The foreign body was surgically removed with the patient under narcosis and there were no aftereffects.

Noninvasive therapy of incidental de novo renal cell carcinoma in a kidney allograft 12 years after transplantation: report of a case and review of literature.

BACKGROUND: Immunosuppressive therapy increases the incidence of posttransplantation cancer. Primary renal cell carcinoma (RCC) represents 4.6% of all cancers in transplant recipients. The treatment options for RCC in a renal allograft include radical nephrectomy or nephron-sparing surgery. We report the case of a patient who underwent percutaneous radiofrequency ablation (RFA) of a RCC in the grafted kidney. PATIENT AND METHODS: Twelve years after undergoing heterotopic, allogenic kidney transplantation, a de novo lesion was diagnosed in the upper pole of the kidney graft in a 77-year-old patient during routine duplex ultrasonography. The magnetic resonance image showed a spherical lesion of 17 mm in diameter, which undoubtedly showed radiological signs of a RCC. After adequately informing the patient about alternative treatment strategies and the associated risks, we made an interdisciplinary decision for a percutaneous RFA of the lesion. RESULTS: After the intervention, graft function remained unchanged and is still good at 6 months with no signs of local recurrence on follow-up MRI. A small coagulation defect at the site of the former lesion was the only morphological change. There was also no evidence of distant tumor spread. CONCLUSION: Percutaneous RFA seems an acceptable, allograft-preserving treatment option associated with low morbidity and mortality for RCC in a renal allograft considering the significant risks associated with open partial nephrectomy in a kidney graft.

Gamna-Gandy bodies of the spleen detected with MR imaging: a case report.

We report a case of a female patient with portal hypertension due to liver cirrhosis. In this case, MR imaging revealed small siderotic nodules of the spleen, called Gamna-Gandy bodies. These lesions are found in patients with portal vein or splenic vein thrombosis, hemolytic anemia, leukemia, or lymphoma, patients receiving blood transfusions, acquired hemochromatosis, or paroxysmal nocturnal hemoglobinuria. There are only few reports in the literature about these siderotic nodules which are not very familiar. MR imaging seems to be the superior imaging method for detection of these lesions. It is important to consider Gamna-Gandy bodies in the differential diagnosis of portal hypertension and the other diseases mentioned above.

Direct MR arthrography of the shoulder: 2D vs. 3D gradient-echo imaging.

The aim of this study was to determine the value of a fat suppressed 3D gradient-echo sequence (GRE) data set in comparison to a 2D GRE sequence in direct MR arthrography of the shoulder. For this purpose we examined 50 consecutive patients with subacute or chronic disorders of the shoulder using a 1.5 T scanner: Transverse T1-weighted 2D (slice thickness 4 mm) and 3D GRE (slice thickness 1.5 mm reconstructed from 3 mm), oblique coronal T2- and T1-weighted turbo spin-echo (TSE) and sagittal T1-weighted TSE with fat saturation were applied. Visual image analysis of anatomical and pathological structures was performed by two independent observers. A correlation to surgical results was available in 21 patients. Transverse GRE sequences were well suited for analysis of the anterior/posterior labrum, the middle glenohumeral ligament, and cartilage. 3D GRE with fat suppression was slightly superior to 2D GRE without fat suppression in the evaluation of the anterior/posterior labrum, and the middle glenohumeral ligament, whereas for cartilage no significant differences were found between both sequences. Concerning pathological findings, in most of the cases 2D delivered the same results as 3D. In conclusion, a T1-weighted 3D GRE data set with fat saturation in transverse orientation may be useful for evaluation of the anterior/posterior labrum, and the middle glenohumeral ligament. However, similar measured slice thickness of 3 mm-even if interpolated to 1.5 mm-compared to a 2D sequence with 4 mm does not provide significant diagnostic advantages.

Methods: MRT.

MRI has become the imaging method of choice in special regions of the head and neck (e.g. nasopharynx, oropharynx, oral cavity, floor of the mouth). Superconducting MR-equipment with field strengths of 1.0-1.5 T are appropriate for the evaluation of the head and neck region. Signal acquisition is optimal with circular polarized head coils or with specially designed surface coils; the body coil is insufficient.When imaging tumors we need T1 contrast, T2 contrast and contrast medium information (enhancement information). For the T1 contrast T1-spin-echo is and remains the best sequence. For T2-contast T2 turbo-spin-echo with fat suppression has replaced the T2 spin-echo sequences because it is faster and shows good contrast between tumor and saturated fat tissue. Fat saturated T1 turbo-spin-echo enables best tissue contrast after Gd-DTPA application.

Paranasal sinuses and nasopharynx CT and MRI.

Neoplastic disease of the nose, paranasal sinuses, the nasopharynx and the parapharyngeal space requires thorough assessment of location and extent in order to plan appropriate treatment. CT allows the deep soft tissue planes to be evaluated and provides a complement to the physical examination. It is especially helpful in regions involving thin bony structures (paranasal sinuses, orbita); here CT performs better than MRI. MRI possesses many advantages over other imaging modalities caused by its excellent tissue contrast. In evaluating regions involving predominantly soft tissue structures (ec nasopharynx and parapharyngeal space) MRI is superior to CT. The possibility to obtain strictly consecutive volume data sets with spiral CT or 3D MRI offer excellent perspectives to visualize the data via 2D or 3D postprocessing. Because head and neck tumors reside in a complex area, having a 3D model of the anatomical features may assist in the delineation of pathology. Data sets may be transferred directly into computer systems and thus be used in computer assisted surgery.

Oropharynx, oral cavity, floor of the mouth: CT and MRI.

Pretherapeutic staging of tumors of the oropharynx, the oral cavity and the floor of the mouth is important and should be thorough and exact to ensure appropriate therapy. Particularly important is the assessment of infiltration of deeper compartments and the topographic relationship of tumor to vascular structures (lingual artery and vein, hypoglossal nerve), or the presence of spread of the tumor across the midline. As spread of tumor may occur to a large degree underneath normal appearing mucosa, clinical assessment of the true tumor extent is difficult. In the last 20 years computed tomography (CT) has proved its value as a supplementary non-invasive method and established its role in modern diagnostic evaluation. Magnetic resonance imaging (MRI) is an non-invasive scanning method that offers excellent tissue contrast. Ultrasonography (US) is of secondary importance, but provides useful guidance due to its wide availability and its easy use. This paper aims to depict the possibilities of modern CT and MRI to provide 'one-stop-shopping' information to the clinician as a basis for the right therapeutic approach and correct estimation of the individual patient's prognosis. A clear problem oriented imaging strategy with standardized diagnostic criteria will lead to a cost effective evaluation.

[VIBE with parallel acquisition technique - a novel approach to dynamic contrast-enhanced MR imaging of the liver]. / VIBE mit paralleler Akquisitionstechnik - eine neue Möglichkeit der dynamischen kontrastverstärkten MRT der Leber.

PURPOSE: The VIBE (volume interpolated breath-hold examination) sequence in combination with parallel acquisition technique (iPAT: integrated parallel acquisition technique) allows dynamic contrast-enhanced MRI of the liver with high temporal and spatial resolution. The aim of this study was to obtain first clinical experience with this technique for the detection and characterization of focal liver lesions. MATERIALS AND METHODS: We examined 10 consecutive patients using a 1.5 T MR system (gradient field strength 30 mT/m) with a phased-array coil combination. Following sequences were acquired: T 2 -w TSE and T 1 -w FLASH, after administration of gadolinium, 6 VIBE sequences with iPAT (TR/TE/matrix/partition thickness/time of acquisition: 6.2 ms/ 3.2 ms/256 x 192/4 mm/13 s), as well as T 1 -weighted FLASH with fat saturation. Two observers evaluated the different sequences concerning the number of lesions and their dignity. Following lesions were found: hepatocellular carcinoma (5 patients), hemangioma (2), metastasis (1), cyst (1), adenoma (1). RESULTS: The VIBE sequences were superior for the detection of lesions with arterial hyperperfusion with a total of 33 focal lesions. 21 lesions were found with T 2 -w TSE and 20 with plain T 1 -weighted FLASH. Diagnostic accuracy increased with the VIBE sequence in comparison to the other sequences. CONCLUSION: VIBE with iPAT allows MR imaging of the liver with high spatial and temporal resolution providing dynamic contrast-enhanced information about the whole liver. This may lead to improved detection of liver lesions, especially hepatocellular carcinoma.

[Experimental studies on image quality in conventional film screen system, digital phosphor storage plate mammography in mangnification technique and digital mammography in CCD-technique]. / Experimentelle Untersuchungen zur Bildgüte konventioneller Film-Folien-Mammographie, digitaler Mammographie mit Speicherfolien in Vergrösserungstechnik und voll digitaler Mammographie in CCD-Technik.

UNLABELLED: Comparison of image quality between conventional film screen system, digital phosphor storage plate mammography in magnification technique and digital mammography in CCD-technique. MATERIALS AND METHODS: Radiograms of a RMI-mammography phantom were acquired using a conventional film screen system, two digital storage plate systems and two digital systems in CCD-technique. Additionally, the radiograms of one digital phosphor storage plate system were postprocessed emphasizing contrast and included in the comparison. RESULTS: The detectability of details was the best with the digital mammography in CCD-technique in comparison with the conventional film screen technique resp. digital phosphor storage plate in magnification technique. CONCLUSIONS: Based on these results there is the possibility to replace the conventional film screen system by further studies--this has to be confirmed.

[MR imaging of pancreatic lesions with Mn-DPDP. A histopathologic correlation]. / MRT von Läsionen des Pankreas mittels Mn-DPDP - Eine histopathologische Korrelation.

PURPOSE: To examine the diagnostic accuracy of pancreatic lesions using mangafodipir-trisodium (Mn-DPDP) enhanced MR imaging. The imaging results were correlated with the histopathological results. MATERIAL AND METHODS: 40 patients with suspicion of pancreatic carcinoma were examined with MRI before and after i. v. administration of Mn-DPDP (Philips Gyroscan ACS NT 1.5 T, phased array body-coil: TSE T 2 with and without SPIR, TR 2000 ms, TE 120ms; FFE T 1 breathhold, TR 115 ms, TE 4.6 ms; MRCP, TR 6000 ms, TE 1200 ms; Teslascan i. v. 5 micromol Mn/kg; FFE T 1 breathhold SPIR, TR 140 ms, TE 4,6 ms). Two observers evaluated in consensus the number and characteristics of focal pancreatic lesions. The MR findings were correlated with histopathological findings retrospectively. RESULTS: The following lesions were found: adenocarcinoma (19), pancreatitis (8), adenocarcinoma within pancreatitis (3), insulinoma (2), hematoma (1), papillitis stenosans (1), signet ring cell carcinoma (1), metastasis of rectal carcinoma (1), papillary mesothelioma (1). In three patients there was no pathological finding. Mn-DPDP enhanced MRI showed a sensitivity of 100 % and a specificity of 56 %. CONCLUSION: Mn-DPDP enhanced MRI in conjunction with MRCP showed a high sensitivity for the detection of pancreatic lesions. However, the specificity is low, thus recommending Mn-DPDP enhanced MRI only as a complementary imaging method.

Experimental investigations of image quality in X-ray mammography with conventional screen film system (SFS), digital phosphor storage plate in/without magnification technique (CR) and digital CCD-technique (CCD).

Comparison of image quality in X-ray mammography between conventional film screen film system (SFS), digital phosphor storage plate in and without magnification technique (CR) and digital CCD-technique (CCD). Radiograms of an RMI-mammography phantom were acquired using a conventional screen film system, three digital storage plate systems and two digital systems in CCD-technique. Additionally, the radiograms of one digital phosphor storage plate system were post-processed regarding contrast and included in the comparison. The detectability of details was best with the digital mammography in CCD-technique. After confirming these promising results in clinical studies, digital mammography should be able to replace conventional screen film technique.

[MR angiography of pelvic and leg arteries: initiation with time-resolved data acquisition of the lower legs]. / MR-Angiographie der Becken-Bein-Arterien: Beginn mit zeitaufgelöster Datenakquisition an den Unterschenkeln.

58 patients suffering from peripheral arterial vascular disease were examined using contrast-enhanced MR angiography with the intention of optimizing the visualization of lower leg arteries. Different from the customary acquisition order, were first the arteries of the lower legs depicted with three time-resolved phases. Afterwards, the iliacal and femoral vessels were imaged by applying the floating-table technique in two steps. In all cases, the lower leg arteries were depicted without overlying veins. By injecting the contrast agent in two phases, imaging quality of the iliofemoral arteries was not significantly reduced.--In conclusion, we would recommend the hybrid technique of peripheral contrast-enhanced MRA with primarily starting the acquisition of the lower legs in cases of foot infections or ulcerations where the transit time is reduced bi- or unilaterally.

Gd-BOPTA: "the MRA contrast agent of choice"?

Gd-BOPTA is a new positive MR contrast agent for intravenous application. In comparison to other gadolinium-chelates it has a nearly two-fold increased relaxivity due to weak protein binding with plasmatic macromolecules. In the papers published yet it has been evaluated to be useful for liver imaging. The purpose of this study was to evaluate, whether Gd-BOPTA is suited as an "magnetic resonance angiography (MRA) contrast agent". We examined four patients (aortic dissection, carotid artery stenosis, portal vein stenosis, exclusion of subclavian artery stenosis) with Gd-BOPTA with a dosage of 0.05 mmol/kg body weight. Furthermore, peripheral MRA of the pelvis and lower extremities was acquired in two healthy volunteers comparing 0.1 mmol Gd-DTPA/kg with 0.1 mmol Gd-BOPTA/kg. There was a delay of one week between the Gd-DTPA and the Gd-BOPTA examinations. In another volunteer Gd-BOPTA was reduced to 0.05 mmol/kg. The patient examinations revealed sufficient quality comparable with Gd-DTPA examinations despite of reduced dosage. In the volunteers Gd-BOPTA proved to be superior especially in the delineation of small pedal arteries which is important for surgical planning. These preliminary results demonstrate the potential of Gd-BOPTA to become a useful contrast agent for MRA. Its efficacy for this purpose has to be evaluated in future prospective studies.

A reliable risk score for stage IV esophagogastric cancer.

BACKGROUND: The role of surgery for patients with metastatic esophagogastric adenocarcinoma (EGC) is not defined. The purpose of this study was to define selection criteria for patients who may benefit from resection following systemic chemotherapy. METHODS: From 1987 to 2007, 160 patients presenting with synchronous metastatic EGC (cT3/4 cNany cM0/1 finally pM1) were treated with chemotherapy followed by resection of the primary tumor and metastases. Clinical and histopathological data, site and number of metastases were analyzed. A prognostic score was established and validated in a second cohort from another academic center (n = 32). RESULTS: The median survival (MS) in cohort 1 was 13.6 months. Significant prognostic factors were grading (p = 0.046), ypT- (p = 0.001), ypN- (p = 0.011) and R-category (p = 0.015), lymphangiosis (p = 0.021), clinical (p = 0.004) and histopathological response (p = 0.006), but not localization or number of metastases. The addition of grading (G1/2:0 points; G3/4:1 points), clinical response (responder: 0; nonresponder: 1) and R-category (complete:0; R1:1; R2:2) defines two groups of patients with significantly different survival (p = 0.001) [low risk group (Score 0/1), n = 22: MS 35.3 months, 3-year-survival 47.6%); high risk group (Score 2/3/4) n = 126: MS 12.0 months, 3-year-survival 14.2%]. The score showed a strong trend in the validation cohort (p = 0.063) [low risk group (MS not reached, 3-year-survival 57.1%); high risk group (MS 19.9 months, 3-year-survival 6.7%)]. CONCLUSION: We observed long-term survival after resection of metastatic EGC. A simple clinical score may help to identify a subgroup of patients with a high chance of benefit from resection. However, the accurate estimation of achieving a complete resection, which is an integral element of the score, remains challenging.