Liver volume variations as a parameter to assess therapy response in advanced metastatic liver disease.

BACKGROUND: The aim of this study was to evaluate liver volume variations (LVV) as a parameter to assess the therapy response in patients with advanced liver metastasis (aLM). METHODS: Patients with colorectal cancer and consecutive computed tomography (CT) scans were divided into a group with aLM receiving palliative chemotherapy (n = 24) and a control group (n = 21) being followed after curative therapy. Liver volumetry was performed manually. The therapy response was assessed according to the response evaluation criteria in solid tumors (RECIST, n = 69). LVV were compared between groups and to variations in the sum-of-longest-diameter (SLDV). Using receiver operating characteristic (ROC) analysis, LVV were evaluated for distinguishing between progressive disease (PD) and stable disease (SD)/partial remission (PR). RESULTS: Median LVV between patients with aLM (10.0%) and the control group (4.0%) differed significantly (p < 0.01). PD led to a larger median LVV (26.8%) than PR/SD (5.0%, p < 0.01). LVV in aLM patients correlated positively with SLDV (r = 0.71, p < 0.01). A cut-off value of 9.5% allowed distinguishing between PD and SD/PR (sensitivity: 86%, specificity: 88%, p < 0.01). CONCLUSION: LVV are helpful to assess PD in patients with aLM.

Osteoblastic response as a healing reaction to chemotherapy mimicking progressive disease in patients with small cell lung cancer.

The osteoblastic response (OR) phenomenon as a healing reaction during effective chemotherapy-defined by the appearance of new osteoblastic bone lesions while disease response in other tumor sites was well documented-has previously been described for breast and prostate cancer. The purpose of this study was to investigate this phenomenon that could erroneously be interpreted as progressive disease in patients with small cell lung cancer (SCLC) and to establish guidelines for interpretation of follow-up computed tomography (CT) examinations in this situation. Twenty-four patients with newly diagnosed SCLC and bone metastases were retrospectively included in this study. The characteristics of bone lesions in CT examinations were correlated with bone scintigraphy and magnetic resonance imaging, if available. In target lesions the CT density quantified in Hounsfield units (HU) was evaluated at baseline and during follow-up. New osteoblastic lesions occurred during follow-up in 17 of 24 patients. OR was proven in 4 patients and considered most likely in 11 patients; mean density increase in target lesions was 153 HU. The study indicates that osteoblastic response as a healing reaction seems to occur in the majority of patients with SCLC and bone metastases and should not be misinterpreted as progressive disease.

MR-guided liver biopsy within a short, wide-bore 1.5 Tesla MR system.

The purpose of this study was to evaluate the diagnostic efficacy of magnetic resonance (MR)-guided biopsy of focal liver lesions within a short, wide-bore 1.5-T MR system and to determine the duration and accuracy of needle placement using MR fluoroscopy guidance in 25 patients. Accuracy of needle placement was evaluated in two orthogonal planes, and the out-of-plane angle of needle deflection was measured. Needle positioning was characterised subjectively as centred, peripheral, or exterior relative to the lesion. Exterior positioning was corrected by a step-by-step procedure. Surgical resection (n = 6), previous histologies (n = 8), or clinical/radiological follow-up (n = 11) served as the 'gold standard'. The guidance needle could be placed successfully using MR fluoroscopy in 20 of 25 patients (80%). Needle placement was rated as 'centred' in 11 and as 'peripheral' in nine patients. Median needle deflection was 2.6 degrees, with a median deviation of 3.4 mm. In five patients, the direct approach failed or was rated as 'exterior'; therefore, repositioning after needle stabilisation with a stainless-steel stylet was necessary. The diagnostic yield of all biopsies was: sensitivity 95.5%, specificity 100.0% and accuracy 96.0%. In conclusion, MR-guided biopsies in a short, wide-bore MR system yielded highly reliable biopsy results, and in most cases the direct approach with MR fluoroscopy guidance proved to be fast and accurate.

Transhepatic CT-guided radiofrequency ablation of adrenal metastases from hepatocellular carcinoma.

The prognosis of patients with adrenal metastases from hepatocellular carcinoma (HCC) has been poor, and aggressive treatment of these tumors is mandatory to improve patients' survival. Since adrenalectomy may be difficult to perform after previous surgery of the right liver lobe, other approaches are required to treat the adrenal mass. This report aims at demonstrating the feasibility of CT-guided transhepatic radiofrequency ablation of right adrenal HCC metastases pretreated with chemoembolization in patients unable to undergo surgical resection.

MR-guided core biopsy with MR fluoroscopy using a short, wide-bore 1.5-Tesla scanner: feasibility and initial results.

PURPOSE: To evaluate MR fluoroscopy in a short, wide-bore 1.5T MRI suitable for near real-time biopsy guidance. MATERIALS AND METHODS: A total of eight consecutive patients underwent MR-guided core biopsy in a 1.5T system with a 70 cm bore diameter. A total of five biopsies were performed in focal liver lesions, three biopsies in soft-tissue tumors. Before biopsy, three different fast MR sequences were compared for image quality (anatomical visibility, lesion visibility, and artifacts), and signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were calculated. In all cases, an MR-compatible guidance needle was positioned under MR fluoroscopy using the most suitable sequence. RESULTS: In each patient the guidance needle could be placed accurately under MR fluoroscopy without having to remove the patient from the isocenter of the magnet during needle movement. All biopsies were technically successful and appropriate specimens could be obtained. In prebiopsy imaging, a T2-weighted single shot turbo spinecho sequence (half-Fourier acquisition single-shot turbo spin-echo [HASTE]) achieved the best rating for lesion visibility and superior SNR and CNR values. CONCLUSION: Findings of this study demonstrate that MR fluoroscopy for biopsy guidance in a short, wide-bore 1.5T scanner is feasible. This scanner combines the patient access advantages of an open-bore system with the superior image quality and speed of a high-field scanner. In our series, the HASTE sequence was best suited for MR-guidance of biopsies.

Diagnostic yield of computed tomography-guided coaxial core biopsy of undetermined masses in the free retroperitoneal space: single-center experience.

The purpose of this study was to evaluate the diagnostic yield of core biopsy in coaxial technique under guidance of computed tomography (CT) for retroperitoneal masses. We performed a retrospective analysis of CT-guided coaxial core biopsies of undetermined masses in the non-organ-bound retroperitoneal space in 49 patients. In 37 cases a 15-G guidance needle with a 16-G semiautomated core biopsy system, and in 12 cases a 16-G guidance needle with an 18-G biopsy system, was used. All biopsies were technically successful. A small hematoma was seen in one case, but no relevant complication occurred. With the coaxial technique, up to 4 specimens were obtained from each lesion (mean, 2.8). Diagnostic accuracy in differentiation between malignant and benign diseases was 95.9%. A specific histological diagnosis could be established in 39 of 42 malignant lesions (92.9%). Correct subtyping of malignant lymphoma according to the WHO classification was possible in 87.0%. Benign lesions were correctly identified in seven cases, although a specific diagnosis could only be made in conjunction with clinical and radiological information. In conclusion, CT-guided coaxial core biopsy provides safe and accurate diagnosis of retroperitoneal masses. A specific histological diagnosis, which is essential for choosing the appropriate therapy, could be established in most cases of malignancy.

CT-guided biopsy of small liver lesions: visibility, artifacts, and corresponding diagnostic accuracy.

PURPOSE: Our study aimed to determine the visibility of small liver lesions during CT-guided biopsy and to assess the influence of lesion visibility on biopsy results. MATERIAL AND METHODS: Fifty patients underwent CT-guided core biopsy of small focal liver lesions (maximum diameter, 3 cm); 38 biopsies were performed using noncontrast CT, and the remaining 12 were contrast-enhanced. Visibility of all lesions was graded on a 4-point-scale (0 = not visible, 1 = poorly visible, 2 = sufficiently visible, 3 = excellently visible) before and during biopsy (with the needle placed adjacent to and within the target lesion). RESULTS: Forty-three biopsies (86%) yielded diagnostic results, and seven biopsies were false-negative. In noncontrast biopsies, the rate of insufficiently visualized lesions (grades 0-1) increased significantly during the procedure, from 10.5% to 44.7%, due to needle artifacts. This resulted in more (17.6%) false-negative biopsy results compared to lesions with good visualization (4.8%), although this difference lacks statistical significance. Visualization impairment appeared more often with an intercostal or subcostal vs. an epigastric access and with a subcapsular vs. a central lesion location, respectively. With contrast-enhanced biopsy the visibility of hepatic lesions was only temporarily improved, with a risk of complete obscuration in the late phase. CONCLUSION: In conclusion, visibility of small liver lesions diminished significantly during CT-guided biopsy due to needle artifacts, with a fourfold increased rate of insufficiently visualized lesions and of false-negative histological results. Contrast enhancement did not reveal better results.

Evaluation of integrated whole-body PET/CT in the detection of recurrent ovarian cancer.

PURPOSE: To assess the usefulness and reliability of integrated whole-body positron emission tomography/computed tomography (PET/CT) in patients in whom recurrent ovarian cancer is suspected. METHODS: Integrated whole-body PET/CT imaging was performed in 19 patients with suspected ovarian cancer recurrence. CT, PET and fused PET/CT images were evaluated separately and imaging results were compared with pathological findings and clinical follow-up after 6 months. RESULTS: Of the 19 patients studied, 11 were found to have recurrent cancer. In 8 of these 11 patients, recurrence was diagnosed by CT, PET and fused PET/CT. In the remaining three patients, only PET and PET/CT showed a recurrent tumour, while CT was negative. Twelve localisations of ovarian cancer recurrence could be detected by CT, 17 by PET and 18 by PET/CT. In one patient with pulmonary metastases in CT and in the CT component of PET/CT, PET was negative. In the case of three metastases in the diaphragm, the spleen and the thoracic wall, respectively, the determination of the exact localisation was only possible by fused PET/CT. CONCLUSION: In patients with recurrent ovarian cancer, PET/CT detects more lesions than PET or CT alone. PET/CT permits the exact anatomical localisation of pathologic tracer uptake and can thus direct further treatment to the precise site of tumour recurrence. Hence, PET/CT should be considered for follow-up of patients with ovarian cancer.

Optimized intravenous contrast administration for diagnostic whole-body 18F-FDG PET/CT.

UNLABELLED: Standard application of CT intravenous contrast agents in combined PET/CT may lead to high-density artifacts on CT and attenuation-corrected PET. To avoid associated diagnostic pitfalls, we designed and compared different intravenous contrast injection protocols for routine whole-body PET/CT. METHODS: Whole-body PET/CT included a topogram and a single spiral CT scan (2-row) with or without intravenous contrast, followed by an emission scan. The CT scan was used for attenuation correction of the emission data. Four groups of 10 whole-body PET/CT referrals each were investigated: (A) no intravenous contrast agent, (B) biphasic injection (90 and 50 mL at 3 and 1.5 mL/s, respectively) of intravenous contrast (300 mg/mL iodine) and CT in the craniocaudal direction with a 30-s delay, (C) triple-phase injection (90, 40, and 40 mL at 3, 2, and 1.5 mL/s, respectively) in the craniocaudal direction with a 50-s delay, and (D) dual-phase injection (80 and 60 mL at 3 and 1.5 mL/s, respectively) in the caudocranial direction with a 50-s delay. CT image quality was assessed on a scale from 1 to 3, and CT and attenuation-corrected PET images were reviewed separately for contrast-induced artifacts. RESULTS: Average CT image quality was poorest for protocol A (1.0) but improved to 2.8 when using intravenous contrast agents (protocols B-D). Only protocols B and C resulted in contrast-induced image artifacts that were limited to the thorax. The most homogeneous intravenous contrast enhancement without high-density image artifacts on either CT or PET after CT-based attenuation correction was achieved with protocol D. CONCLUSION: Dual-phase intravenous contrast injection and CT in the caudocranial direction with a 50-s delay yields reproducible high image quality and is now used routinely for combined diagnostic PET/CT at our hospital.

Value of CT volume imaging for optimal placement of radiofrequency ablation probes in liver lesions.

PURPOSE: To determine the value of multiplanar and volume-rendered modes of analysis versus axial imaging for the optimal placement of probes in spiral image computed tomography (CT)-guided radiofrequency (RF) ablation of liver lesions. MATERIALS AND METHODS: Thirty-two malignant hepatic lesions in 21 patients with hepatocellular carcinoma (n = 10) or metastases (n = 11) were treated with percutaneous RF ablation. After axial CT-guided placement (biopsy mode) of the probe in the tumor, a contrast-enhanced spiral image set was obtained and data were viewed in contiguous axial sections and the multiplanar and volume-rendered modes. The position of the probe was characterized as "central," "marginal," or "outside," corresponding with its position in the lesion. Outside positioning was corrected before ablation was performed and, in cases of "marginal" positioning, the probe was redirected after initial ablative therapy in the same session. RESULTS: Multiplanar and volume-rendered analysis reclassified the needle position before 14 of 32 RF ablation procedures (44%; P =.0034, McNemar test). In 10 cases, probe positions considered "central" on biopsy-mode images were found to be "marginal" with multiplanar/volume-rendered analysis. In three cases, probe positions considered "marginal" on biopsy-mode images were found to be "outside" with multiplanar/volume-rendered analysis. In one lesion, multiplanar/volume-rendered analysis upgraded the probe position from "marginal" to "central." Comparison of multiplanar and volume-rendered analysis revealed no difference in probe positioning. The time requirements to obtain additional data were 159 seconds +/- 49 for multiplanar analysis and 434 seconds +/- 78 for volume-rendered analysis. CONCLUSION: A contrast-enhanced spiral CT image data set with multiplanar reformations to verify an optimal probe location after axial CT-guided needle placement should be obtained before RF ablation of liver lesions.

Whole-body positron emission tomography-CT: optimized CT using oral and IV contrast materials.

OBJECTIVE: Our objective was to show that oral and IV contrast materials improve CT image quality in dual-modality positron emission tomography (PET) and CT, resulting in an increase in diagnostic capacity. We also present a standardized scanning protocol for whole-body PET-CT with oral and IV contrast materials. SUBJECTS AND METHODS: To evaluate the use of whole-body PET-CT in clinical practice, we examined 30 patients according to the protocol. The CT images were evaluated quantitatively by signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) analyses and qualitatively by two radiologists in consensus. PET quality was assessed quantitatively by measurements of standard uptake values that were compared with standard uptake values in 10 PET-CT examinations without contrast agents. RESULTS: . The application of oral and IV contrast materials led to a highly sufficient delineation of vascular and intestinal structures in 26 of 30 patients. Quantitative analysis revealed a mean vascular SNR of 15.8 +/- 7.71 for the 30 patients who received contrast materials compared with 4.79 +/- 1.45 for the 10 control group patients (p < 0.001). Similarly, the mean intestinal SNR of 17.06 +/- 7.96 far exceeded that seen in the control group of 3.83 +/- 1.16 (p < 0.001). Analyses led to a vessel-to-muscle CNR of 10.78 +/- 5.89 (control group, -1.21 +/- 0.89; p < 0.001) and an intestine-to-muscle CNR of 12.04 +/- 6.07 (control group, -2.17 +/- 1.22; p = 0.001) in the 30 patients. An evaluation of PET quality in patients who received contrast materials showed a mean standard uptake value of 2.09 +/- 1.16 compared with 2.04 +/- 0.83 in the control group (p = 0.702). CONCLUSION: Our whole-body PET-CT protocol provided good vascular and intestinal enhancement without compromising PET quality, leading to a potential improvement in the diagnostic capacity of the combined PET-CT examination.