Intraoperative MRI to control the extent of brain tumor surgery

Purpose: The main aim of our study was to find out whether the combined use of neuronavigation and intraoperative MRI can increase the rate of “complete tumor removal”. The second aim was to characterize the different forms of surgically induced enhancement in order to differentiate them from residual tumor. Materials and methods: Surgery was performed in 18 patients with high-grade glioma. Using a neuronavigation device, the surgeons operated up to the point where they would otherwise have terminated surgery. Intraoperative MRI was then performed to determine whether residual enhancing had been left behind and to update the neuronavigation device. If necessary, feasible surgery was continued. On days 1–3 after surgery early postoperative MRI (1.5 T) was performed. The proportion of patients in whom the enhancing tumor was completely removed was compared with a series of 60 patients with glioblastoma multiforme, who had been operated on using neither neuronavigation nor intraoperative MRI . We also looked for and characterized different types of surgically induced enhancement. Results: Intraoperative MRI definitely showed residual tumor in 6 of the 18 patients and resulted in ambiguous findings in 3 patients. In 7 patients surgery was continued. Early postoperative MRI showed residual tumor in 3 patients and resulted in uncertain findings in 2 patients. The rate of patients in whom complete removal of enhancing tumor could be achieved was 50 % at the time of the intraoperative MR examination and 72 % at the time of the early postoperative MR control. The difference in proportion of patients with “complete tumor removal” between the groups who had been operated on using neuronavigation (NN) and intraoperative MRI (ioMRI) and those who had been operated on using only modern neurosurgical techniques except NN and ioMRI was statistically highly significant (Fisher exact test; P = 0.008). Four different types of surgically induced contrast enhancement were observed. These phenomena carry different confounding potentials with residual tumor. Conclusion: Our preliminary experience with intraoperative MRI in patients with enhancing intraaxial tumors is encouraging. Combined use of neuronavigation and intraoperative MRI was able to increase the proportion of patients in whom complete removal of the enhancing parts of the tumor was achieved. Surgically induced enhancement requires careful analysis of the intraoperative MRI in order not to confuse it with residual tumor.      

Punch biopsy or fine needle aspiration biopsy in percutaneous puncture

Purpose: The diagnostic accuracy and rate of complications of CT-guided core biopsies (CB) from suspected tumors of the chest were compared to the accuracy a complications of fine-needle aspiration biopsies (FNAB). Methods: The accuracy in the diagnosis of a benign or malignant lesion of 79 FNAB (19.5 G self-aspirating cutting needle) and of 83 CB (18 G automated core biopsy) and the rates of pneumothorax, pleural drainage and hemoptysis were retrospectively evaluated. Results: With FNAB, the sensitivity for malignant lesions was 62.1 % and the accuracy 68.4 %. With CB the sensitivity amounted to 85.9 % and accuracy to 86.7 %. The rate of pneumothorax was 25.3 % following FNAB, with a drainage rate of 5.1 % compared to 19.3 % and 6.0 %, respectively, following CB. The rate of pneumothorax and drainage increased with increasing path length through aerated lung. In advanced emphysema, the pneumothorax rate did not increase; however, in pneumothoraces, pleural drainage was mandatory in 20 % of FNAB and in 100 % of CB. Hemoptysis without any therapeutic consequences occurred in 3.8 % following FNAB and in 6.0 % following CB. Conclusions: With CB diagnostic accuracy can be clearly increased without an obvious increase in the complication rate. However, in patients with obvious emphysema, the pleural drainage rate of pneumothorax may be higher following CB.      

Crohn's disease: current imaging approach

Purpose: This paper discusses the role of different imaging modalities in the diagnostic work-up of Crohn's disease (CD). Methods: We present a concept, which emphasizes different diagnostic aspects with regard to primary diagnosis, follow-up and assessment of complications of CD. The most effective imaging approach to various diagnostic problems of CD is discussed in detail. Discussion: With regard to the primary diagnosis barium studies should contribute to differentiate between CD and ulcerative colitis. Beyond that, these studies should evaluate location and extent of disease. During the follow-up bowel sonography provides staging of disease and enables the detection of complications at an early stage. CT is a valuable tool in the preoperative assessment of complications, such as fistulae and abscesses.      

Function-retaining surgical therapy for head-neck tumors with the CO2 laser

Summary The use of microscopically controlled laser surgery to treat tumors of the upper aerodigestiv tract has as a function maintaining form of treatment gained significance. It is an alternative to conventional surgery, which often makes organ removal necessary. We report on our experience with 85 patients who underwent a laser surgical resection of malignomas of the upper aerodigestive tract. The aim of transoral laser surgery is a histologically confirmed radical tumor resection. Tumor resection can be individually adapted according to the tumor extent. An unnecessary resection of cartilage and muscles can be avoided. Provided the appropriate indication is given, laser surgery yields good oncologic and excellent functional results.      

Diagnosis and therapy for laryngeal cancer

Summary Therapeutic choice in laryngeal carcinoma is influenced by the nature of the tumor and a variety of factors involving the patient and physician. Small (T1) and exophytic (T1, T2) tumors are suitable for radiotherapy. Limited lesions (T1, T2) can be cured by functional endoscopic resection techniques or external partial laryngectomies. Extensive tumors (large T2; T3) are treated by total laryngectomy or by primary irradiation, especially in the case of a good response to induction chemotherapy. When radiation treatment fails, surgery succeeds in more than half of the cases. Tumors infiltrating or transgressing the laryngeal framework (T4) can only be cured by total laryngectomy followed by radiotherapy. Subtotal or circular ablation of the adjacent pharynx or esophagectomy needs repair with visceral or myocutaneous grafts. Lymphatics are preferentially treated with the same modality as used in the primary disease. Inconspicuous lymphatics should be treated electively in most cases, with the exception of early glottic cancer.      

Resectability of pancreatic tumors: Correlation of multidetector CT with surgical and pathologic results

Purpose

The purpose of this study is to evaluate the ability of multidetector CT (MDCT) in predicting resectability of pancreatic tumors.

Patients and methods

Thirty-nine patients were included in this study, there were 29 males and 10 females, and their age range was 44–73 years with a mean age of 58.3 years. All the patients were subjected to contrast enhanced biphasic examinations on 64-slice CT machine.

Results

Twenty-one patients (53.8%) were considered inoperable with unresected tumor, the remaining 18 patients (46.2%) were considered suitable for tumor resection according to MDCT criteria. 15 out of the 18 patients (83.3) had a successful tumor resection while the remaining 3 (16.7%) showed unresectable tumor during operation. On the basis of pathology results 12 patients out of the 18 (66.7%) had successful surgery with negative tumor margin, and a positive predictive value of 66.7% and accuracy of 66.7%.

Conclusions

There is better prediction of resectability of pancreatic tumors with the development of MDCT technology. As compared to Helical computed tomography (HCT) studies, there is a rise in the rate of successful surgical resection. The positive predictive value of multidetector computed tomography for resectable pancreatic tumors is decreased when pathologic results are used as a reference standard.     

Cardiac tumors

Summary Tumors of the heart are very rare. Due to the nonspecific clinical presentation the diagnosis is usually made by radiological procedures. Cardiac myxomas and thrombi are the most common cardiac masses. Two-dimensional echocardiography is the method of choice for the initial evaluation of cardiac tumors, because it permits the accurate determination of the tumor's size, localization, point of attachment, mobility and haemodynamic significance. Inadequate or nondiagnostic ultrasound examination and the need for preoperative assessment are indications for further examinations, such as magnetic resonance imaging (MRI) and computed tomography. Both these methods are helpful in the assessment of paracardiac structures and of the tumor invasion into great vessels and the mediastinum. MRI allows a limited degree of assessment of whether or not the tumor is malignant by soft tissue characterization. In the case of resectable, symptomatic, cardiac tumors surgical excision should be performed. Eingegangen am 23. Dezember 1996 Angenommen am 10. Januar 1997     

螺旋CT双期扫描对胰腺癌可切除性的评价

目的 评价螺旋ＣＴ双期扫描对胰腺癌可切除性的价值。材料与方法 对４２例拟诊胰腺癌随后又行手术治疗的患者作出前瞻性的诊断和可切除性的评估。病理结果：胰腺癌３３例,非胰腺癌９例。ＣＴ双期延迟扫描时间分别为２５ｓ和６０ｓ。并将ＣＴ判断的结果与手术结果作对比。结果 ４２例中,螺旋ＣＴ正确诊断３９例（９３％）。螺旋ＣＴ判断可切除性的敏感性为８９％,牧场划性为９２％,准确性为９１％。１０例肝转移癌,ＣＴ诊断８     

MRI of the fingers in patients with systemic scleroderma. Early results of contrast-enhanced examinations on a dedicated MRI system

Purpose. To estimate disease activity in patients with systemic sclerosis using contrast-enhanced MRI of the skin. Material and Methods. In a pre-study, sequences of a low-field (0.2 T) scanner (Artoscan, Esaote, Genova, Italy) were optimized for detection of intravenous contrast (0.1 mmol/l Gd-DTPA) in six patients with the autoimmune disease systemic scleroderma. Based on the results of the pre-study, 17 patients with scleroderma (7 sclerotic/10 active inflammatory disease) were scanned using gradient-spoiled 3D GRE sequences (FA 90 °, TR 100 ms, TE 18 ms), which had been established as most sensitive for intravenous contrast. Contrast enhancement of the skin was determined quantitatively by contrast-to-noise ratios (CNR), comparing post- to pre-contrast and dynamic scans (for 6 min, 1 acquisition/min). Patients in the chronic state with sclerodactylia and active inflammation of the hands were considered separately and compared to a control group (n = 10) matched according to age. Results. CNR increase after intravenous contrast was significantly higher in patients with active disease (86 ± 16 % increase) than sclerosing disease (29 ± 3 %, p < 0.05) and the control group (4 ± 2 %, p < 0.05). The dynamic examination showed a significantly slower decrease after the peak rise in the first minute in patients with active disease (CNR 15.4 ± 0.7 to 14.2 ± 1.4) than in those with chronic disease (14.1 ± 0.5 to 11.3 ± 0.9, p < 0.05). Discussion. Capillary leakage is the most likely explanation for the increased enhancement in patients with active scleroderma. Using sequences optimized for contrast detection, disease activity in the course of scleroderma and response to therapy can be determined by MRI in the future.      

Breathhold MRI of the small bowel in Crohn's disease after enteroklysis with oral magnetic particles

Purpose: To evaluate the efficacy of breathhold MRI following enteroclysis with addition of oral magnetic particles to study the extension, detection of stenoses and extraluminal manifestations in Crohn's disease. Material and Methods: 18 patients with Crohn's disease and potential of surgical intervention were studied with enteroclysis with addition of oral magnetic particles. T1-/T2-weighted breathhold MRI w/o spectral fat suppression w/o i. v. Gd-DTPA was applied. Results: Typical findings were marked bowel wall thickening with strong contrast enhancement. 95.8 % of affected small bowel segments and 94.7 % of stenoses were correctly detected by MRI. All four fistulas were detected and important extraluminal findings were seen in 6/18 patients. Additionally, one ileoileal and two ileosigmoidal adhesions, two extraluminal abscesses and affection of the right ureter were delineated. Conclusion: MRI in Crohn's disease offers the potential to avoid radiation exposure in this relatively young patient group. Important additional findings relevant to indication of surgery are seen in approximately one third of cases. The replacement of transduodenal intubation by oral contrast application remains to be further studied.      

Pancreatic adenocarcinoma: A simple CT score for predicting margin-positive resection in patients with resectable disease

BackgroundNegative-margin status is a prognostic indicator for long-term survival following curative intent resection for pancreatic adenocarcinoma. Patients at increased risk for positive-margin resections may benefit from neoadjuvant chemotherapy prior to resection.MethodsWe retrospectively analyzed preoperative computed-tomography (CT) scans in 108 consecutive patients that underwent curative intent resection for a resectable pancreatic ductal adenocarcinoma from 2009 to 2016 in two academic hospitals. Two radiologists independently staged the tumor, including tumor location, size, and tumor-to-superior mesenteric/portal vein (SMV/PV) contact. Uni and multivariate analysis were performed to identify independent predictors of an R1 resection.ResultsTwenty-nine patients had an R1 resection (26.9%). Tumor size, location, and presence of tumor-to-SMV/PV contact were significantly associated with an R1 resection. In multivariate analysis, the independent parameters associated with resection status were: tumor size (R² = 9.7), and tumor location (neck R² = 6.6; pancreaticoduodenal interface R² = 4.4; uncinate process R² = 4.1), but not tumor-to-SMV/PV contact (R² = 0.1, p = 0.7). A simple CT score was built based on tumor size and location. Patients with an R0 resectability score ≥3, i.e. patients with tumor size ≥30 mm (except when tumor location is at the pancreatico-duodenal interface) or patients with tumor size ≥20 mm AND tumor located in the uncinate process or neck, were at high-risk of an R1 resection (AUC, 0.82; sensitivity, 79%; specificity, 76%). This score also showed good diagnostic performances for predicting an R1 resection involving the medial resection margin only (AUC, 0.85).ConclusionsA simple score based on tumor location and size can accurately predict patients at high-risk of an R1 resection.     

Inconclusive findings at mammography: the value of MR imaging

Summary Purpose: To evaluate the usefulness of magnetic resonance (MR) imaging in the assessment of inconclusive findings at mammography, such as indeterminate focal or diffuse breast abnormalities, post-treatment breasts with extensive scarring, dense breasts, and findings suggesting multifocal or multicentric breast cancer. Material and Methods: 254 patients underwent mammography, sonography, and MRI of the breast. Dynamic MR imaging was done using a thin-section three-dimensional gradient-echo sequence (FLASH, TR = 11.8 ms; TE = 5 ms; flip angle = 25 °) which was applied in a dynamic fashion before and every 90 seconds after injection of gadopentetate dimeglumine. Diagnoses were confirmed at biopsy (n = 165) or by follow-up (n = 89). Results: Among various breast anomalies, the highest proportion of breast cancers was associated with dense breast tissue (27.8 %), architectural distortion (26.9 %), and irregular scars (15.8 %). Sensitivity of dynamic MR imaging was 93.7 %, and specificity was 83.3 %. As compared to mammography and sonography, MR detected 6 occult carcinomas, and showed additional malignant lesions in 19/63 women (30.2 %) with biopsy-proven breast cancer. Conclusion: MR imaging of the breast may provide valuable additional information in indeterminate breast anomalies. However, because of its inherent limitations, it should not replace core needle biopsy in all lesions which are amenable to biopsy. Because of its high sensitivity in the detection of invasive carcinomas in any type of breast tissue, MR imaging is considered the modality of choice in the evaluation of dense breasts in high-risk patients or in patients with clinical suspicion of occult breast cancer, and for preoperative tumor staging.      

Hand and wrist imaging using a low-field dedicated MRI system

Summary Purpose of this study was to evaluate the diagnostic value of a low field dedicated MRI system in hand and wrist imaging. All 308 exams of the hand and wrist, that were performed on a low-field dedicated MRI system (Artoscan, Esaote Biomedica, Italy) in our institution in 1996, and high-field MRI exams performed in addition as part of the diagnostic work-up, were evaluated and correlated to final operative (n = 64) and histologic (n = 12) reports. 90 % of all low-field MRI scans stated a diagnosis according to clinical suspicion. In 62 % the clinical question was answered, and in 26 % additional pathologies were identified. An MR-diagnosis completely different from the clinical suspicion was stated in 2 %. High field exams contributed additional information in 6 of 36 patients. In 3 patients a tumor was not shown completely in the limited field-of-view of the dedicated low-field MRI-system. Frequency-selective fat-suppression pulse sequences and a better spatial resolution were the reasons for the additional information obtained in the other three patients. Low-field dedicated MR-imaging is a valuable method in the extensive work-up of the hand and wrist. Osseous, ligamentous and tendinous pathologies are well depicted. Large or infiltrative tumors should be referred to a high-field system.      

Macromolecular contrast media. A new approach for characterising breast tumors with MR-mammography

Summery The value of macromolecular contrast agents (MMCM) for the characterization of benign and malignant breast tumors will be demonstrated in this review. Animal studies suggest a high potential of MMCM to increase the specificity of MR-mammography. The concept of tumor differentiation is based on the pathological hyperpermeability of microvessels in malignant tumors. MMCM show a leak into the interstitium of carcinomas, whereas they are confined to the intravascular space in benign tumors. Capabilities and limitations of the MMCM-prototype. Albumin-Gd-DTPA, for breast tumor characterization will be summarized and compared to the standard low molecular weight contrast agent Gd-DTPA. Initial experience with new MMCM, such as Dendrimers, Gd-DTPA-Polylysine and MS-325 will be outlined. The potential of “blood-pool“-iron oxides, such as AMI-227 for the evaluation of tumor microvascular permeabilities will be discussed.      

CT angiography in carotid stenosis

Purpose: Prospective evaluation of the accuracy of CT angiography (CTA) with different postprocessing for extracranial carotid artery in comparison with DSA. Method: one hundred patients were studied with standarized CTA. For postprocessing, MPR, MIP, and 3D reconstruction based on segmentation with upper and lower threshold were used. Intravascular density profiles were considered. All CTA studies were correlated with intra-arterial angiography. The degree and classification of stenoses was determined using the guidelines established by the NASCET collaborators. Results: Measurement of stenosis was possible by MPR in 82.5 %, by MIP in 85 %, and 3D in 100 %. Correct classification was found in 65.5 % for MPR, 66 % for MIP and 88.5 % for 3D. The sensitivity for severe stenoses was 74 % for MPR, 82 % for MIP, and 93 % for 3D. The specificity of these methods was 98 %, 96 %, and 97 %, respectively. All carotid occlusions were correctly identified, no carotid artery was wrongly classified as occluded. Conclusions: CT angiography allows reliable examinations in carotid artery stenoses and occlusions. 3D reconstruction based on threshold segmentation is superior to MPR and MIP. In some circumstances, e.g., carotid occlusion, further investigation by invasive procedures is not necessary.      

螺旋CT双期增强对胰腺癌病人的术前评估

目的 探讨螺旋CT双期增强对胰腺癌可切除性术前评估的价值。方法 对1999年5月～2003年3月期问行螺旋CT双期增强扫的45例诊断为胰腺癌病人的CT图像与22例手术结果进行对比研究，通过显示胰腺癌的部位、大小以及肿块对周围血管侵犯程度、远处器官转移以及后腹膜淋巴结转移，作出能否切除的术前评价。结果 45例胰腺癌病人中18例位于胰头，16例位于胰体尾，11例位于胰尾；27例患接受手术治疗，其中22例术前SCT认为肿瘤可切除，实际成功切除17例，成功切除的阳性预测值达77％，其他5例SCT认为肿瘤不能切除，实际手术均不能切除。结论 螺旋CT双期增强扫描可作为一种评价胰腺癌术前能否手术切除的有效方法。     

Therapeutic profile of outpatient radiosurgery with the Gamma Knife system. Part 2: First clinical experiences

Summary Gamma Knife radiosurgery (GKRS) was applied in 500 consecutive treatments for 445 patients within 2 years. Indications were arterio-venous malformations (93 patients), schwannomas of cranial nerves (75 patients), meningiomas (79 patients; 73 of the tumors involving the skull base), pituitary adenomas (40 patients), craniopharyngiomas (13 cases), gliomas (13 cases), rare indications (12 cases), and brain metastases (126 patients). In arterio-venous malformations two complications were observed whereas two other patients underwent surgery due to intracranial hemorrhage in the latent period after GKRS. In all cases follow-up with MRI showed evidence of an active obliteration process. Out of 24 patients with a follow-up over 1 year, angiography revealed complete obliteration in 9 patients so far. A partial obliteration was evidenced by MRI in 15 cases. In benign tumors (meningiomas and vestibular schwannomas) tumor control rates of 88 % and 89 % were achieved, respectively. Treatment related side effects were mild and rare; no facial palsy occured after primary Gamma Knife treatment. GKRS was particularly effective in inoperable skull base meningiomas. Cerebral metastases were controlled in 89.5 % by a single Gamma Knife treatment. The mean survival period was 11.8 months. In patients receiving a single Gamma Knife treatment the mean survival time was 9.1 months. For patients undergoing multiple (up to 5) sessions of GKRS (because of new tumors) the mean survival period was 17.2 months. MRI showed evidence of adverse radiation reactions in 10/124 patients (8.1 %) which were symptomatic in 3 patients (0.8 %). The results obtained in patients with cerebral metastases emphasize that GKRS alone is as effective as the combined treatment of these lesions by surgery and fractionated radiotherapy. Our results demonstrated an attractively high therapeutic gain factor of Gamma Knife treatment in key indications of radiosurgery.      

Value of contrast-enhanced 3D MR angiography of the renal arteries

Summary Purpose: To determine the value of gadolinium-enhanced, three-dimensional breathhold Magnetic Resonance Angiography (MRA) in the assessment of the aorta and renal arteries in comparison to conventional arteriography (CA). Patients and methods: 49 patients were evaluated with both CA and 3D MRA. 0.3 mmol/kg BW gadolinium-DTPA was administered intravenously in a bolus, using an automated injector. A test bolus method was used for timing of the bolus and beginning of the data acquisition. The intraarterial CA was used as the gold standard. Results: MRA-based assessment of renal artery stenosis was identical with CA in 31 of 45 stenoses (68.8 %). Sensitivity and specificity for assessment of renal arterial disease by MRA were 84 % and 96 %; for clinically relevant lesions they amounted to 90 % and 98 %. Conclusion: The presented contrast-enhanced 3D MRA technique allows for the reliable assessment of renal arterial morphology and pathology.      

Magnetic resonance imaging on a low-field system (0.2 T): comparison with a 1.0-T system

Summary Aim of the study: Using phantom studies, a dedicated low-field MR system with 0.2 T and a whole-body MR-scanner with 1.0 T were compared. Methods: A spin-echo sequence was performed on the 0.2-T MR unit using the knee coil and on the 1.0-T MR unit with the head coil. In a water-filled phantom, signal-to-noise ratios (SNR) were calculated and contrast measurements on gels with well-defined relaxation times were obtained and compared to nominal relaxation times. Measurements of T1 and T2 relaxation times on the low-field system were compared to the 1.0-T unit. As a parameter for geometrical image quality, magnetic field distortions were calculated. In theory, influence of field strength and and receiver bandwidth on the minimal echo time and on chemical shift artifacts were calculated. Results: The SNR was 63.2 on the 0.2-T and 179.6 on the 1.0-T MR unit (difference factor 3, against a theoretical difference of 5–16). Relaxation times on the low-field system were significantly (around 40–50 %) lower. Measurements of contrast were similar on both systems. On the low-field system geometrical distortions of several pixels were recorded. The minimal echo time on the low-field system was 21.3 ms with the low receiver bandwidth and 4.3 ms on the 1.0-T MR unit. The amount of chemical shift artefacts was the same on both systems. Discussion: On low-field MR systems SNR is markedly improved by small read-out gradients and a low receiver bandwidth (factor 3 vs 5–16 in comparison with the 1.0-T MR unit). However, an optimal homogeneous magnetic field is required, since inhomogeneities may create severe geometrical distortion.      

多层螺旋CT对胰腺癌的术前评估

目的:探讨多层螺旋CT双期增强扫描及图像后处理在胰腺癌手术可切除性研究中的应用价值。方法:对63例胰腺癌患者进行MSCT双期增强薄层横断位扫描,结合多平面重组(MPR)、最大密度投影(MIP)、三维容积演示(VR)等后处理技术,对胰腺癌作出能否切除的术前评估,并以手术结果作为对照和分析。结果:35例患者进行了手术,19例MSCT认为可切除的,实际术中切除15例(可切除率79%);16例MSCT认为不可切除的,实际术中不可切除15例(不可切除率94%)。结论:MSCT对胰腺癌术前可切除性的评估具有重要的临床指导意义。