Thin-slice CT Scans Research Articles

Klinische Präzision der C‐Arm-Navigation an der Brust- und Lendenwirbelsäule

The aim of the present study was the verification of the accuracy of 2-D fluoroscopy-based navigated pedicle screws at the thoracic and lumbar spine in a case series of traumatised patients. Within 36 months 111 pedicle screws in 29 patients were instrumented using C-arm based navigation, 60 at the thoracic and 51 at the lumbar spine. All screw positions were evaluated postoperatively by a routine thin slice CT scan using multiplanar reconstruction. The position of a screw in relation to its pedicle was classified in a) screw completely intraosseous, b) screw perforated less than thread level and c) screw perforated more than thread level. In 34 thoracic (56.7%) and 32 lumbar (62.7%) screws complete intraosseous placement was observed, 14 thoracic (23.3%) and 14 lumbar (27.5%) screws perforated less than thread level. Perforations more than thread level were found in 12 thoracic (20%) and 5 lumbar (9.8%) screws. Only medial and lateral perforations of the pedicle were documented (without neurological signs), cranial or caudal ones did not occur. Segmentation of the C-arm navigation into two comparable treatment periods showed a learning curve with a reduction of perforations in the second sequence (after 57 pedicle instrumentations) of about 15%, this was found to be not statistically significant. The fluoroscopic navigation of pedicle screws is a safe procedure at the lumbar spine with equal accuracy compared to the non-navigated conventional instrumentation. Application of C-arm navigation at the thoracic spine showed more inaccuracies, so that 3-D-based navigation seems to be advantageous in this region.

Lung nodule detection in low-dose and thin-slice computed tomography

A computer-aided detection (CAD) system for the identification of small pulmonary nodules in low-dose and thin-slice CT scans has been developed. The automated procedure for selecting the nodule candidates is mainly based on a filter enhancing spherical-shaped objects. A neural approach based on the classification of each single voxel of a nodule candidate has been purposely developed and implemented to reduce the amount of false-positive findings per scan. The CAD system has been trained to be sensitive to small internal and sub-pleural pulmonary nodules collected in a database of low-dose and thin-slice CT scans. The system performance has been evaluated on a data set of 39 CT containing 75 internal and 27 sub-pleural nodules. The FROC curve obtained on this data set shows high values of sensitivity to lung nodules (80–85% range) at an acceptable level of false positive findings per patient (10–13 FP/scan).

Pre-Operative Endovascular Stenting of the Coeliac Trunk

The authors have re-implanted the coeliac axis to ensure adequate vascularisation of the upper abdominal viscera as a part of pancreaticoduodenectomy. This and various other techniques of dealing with an intra-operative diagnosis of either coeliac stenosis or occlusion have been described earlier.1 However, the additional morbidity of major vascular reconstruction procedure needs to be carefully considered. With the availability of thin-slice CT scanning, it should be possible to make a pre-operative diagnosis of coeliac stenosis or occlusion either by direct visualisation of the trunk or by indirect means (abnormally large collaterals). Developments in endovascular stenting technology and expertise allow not only peripheral arterial stenting, but aortic, cerebral and visceral (including mesenteric) arterial revascularisation.2 Thus, if there is a suspicion of occlusion or stenosis on pre-operative CT, mesenteric angiography can also be performed with a view to endovascular stenting prior to performing a pancreaticoduodenectomy. Even if the diagnosis of coeliac occlusion was made intra-operatively, retrograde stenting should still be considered if interventional vascular expertise is available.3 One of our recent patients being worked up for a pancreaticoduodenectomy to treat a pancreatic head malignancy was found to have a coeliac occlusion, detected on staging CT scanning. The give away was an abnormally enlarged gastroduodenal artery (Fig. 1). The diagnosis was confirmed by arteriography and pre-operative endovascular stenting of the coeliac trunk was performed (Fig. 2). At surgery, there was no difference in the CHA pulse or Doppler pressures and waveforms before and after clamping the gastroduodenal artery due to an adequate hepatic arterial inflow from the stented coeliac artery. This technique also allows single-stage pancreaticoduodenectomy with perhaps less morbidity than re-implantation of a major visceral artery. Figure 1 Reconstruction of CT images demonstrating hypertrophic and enlarged gastroduodenal and pancreaticoduodenal arteries. Figure 2 Endovascular stenting across coeliac occlusion.

The findings of bronchial artery change in lung cancer with 16-slice CT

目的 利用多层螺旋CT(MSCT)探讨病灶最大径＜3和≥3 cm肺癌患者及正常人的支气管动脉内径差异.方法 对44例经手术病理证实的肺癌患者资料作回顾性分析,男27例,女17例,年龄19～82岁,中位年龄58岁.其中3 cm以下的小肺癌15例,≥3 cm的肺癌29例,所有患者均进行16层螺旋CT增强扫描,三维重组支气管动脉,测量支气管动脉的内径.正常对照组,男16例,女12例,年龄22～78岁,中位年龄53岁.对3组支气管动脉内径行方差分析.结果 15例小肺癌支气管动脉内径平均值为(1.9±0.4)mm,29例大肺癌支气管动脉内径平均值为(2.5±0.5)mm,28例正常组支气管动脉内径的平均值为(1.6±0.4)mm,大、小肺癌及正常组之间支气管动脉内径差异有统计学意义(P＜0.05).结论 供应肺癌的支气管动脉均增粗,大肺癌较小肺癌显著。

CT evaluation and classification of the Le Fort fracture

目的 探讨Le Fort型骨折的CT表现及其分型.方法 对62例Le Fort型骨折患者进行薄层螺旋CT扫描和三维重组分析.结果 在62例中,Le Fort Ⅰ型10例,Ⅱ型9例,Ⅲ型8例,复合型35例(其中Ⅰ+Ⅱ型18例,Ⅰ+Ⅱ+Ⅲ型7例,Ⅱ+Ⅲ型10例);55例同时伴发颌面部其他骨折.Le Fort型骨折在二维CT上表现为颌面部多发且杂乱的骨折,虽然在发现细小和深部结构的骨折方面优于三维CT成像,但难以作出Le Fort型骨折的诊断;三维CT成像能清晰立体地显示Le Fort型骨折的整体形状及走向,并可明确作出分型.结论 三维CT成像是Le Fort型骨折最有效的诊断方法,对临床制定治疗方案具有指导意义,但是对细小骨折诊断不如二维CT。

CT bronchoscopy in the diagnosis of Williams–Campbell syndrome

Williams-Campbell syndrome, a rare disorder, is characterized by a congenital deficiency of cartilage, typically involving the fourth to the sixth order bronchi, and resulting in expiratory airway collapse and bronchiectasis. The authors report a patient with Williams-Campbell syndrome with type II respiratory failure due to extensive cystic bronchiectasis and secondary emphysema. CT of the thorax showed the affected bronchi had characteristic ballooning on inspiration and collapse on expiration. Three-dimensional images of the tracheobronchial tree were constructed from a volume of data acquired by thin-slice CT scanning. Apart from confirming expiratory collapse of the affected bronchi, these images revealed an absence of the cartilage ring impressions in the bronchial wall, extending bilaterally from the mainstem down to subsegmental bronchi, suggesting cartilage deficiency.

The Subarticular Screw: a New Trajectory for the C2 Screw

Study design: Surgical simulation using CT images and computer software. Objectives: We wanted to determine a new trajectory for the C2 screw, and then we wanted to evaluate its safety and accuracy. Summary of Literature Review: There have been a few suggestions for trajectories of the C2 pedicle screws. However, their safety is somewhat unsatisfactory as all of them have some possibility of vertebral artery injury. Materials and Methods: Using 1 mm-sliced CT scan images of 158 patients and an A-view spine surgery simulator 1.0, we determined a new trajectory for the C2 screw with which 4.0 mm screws can be inserted with a minimal number of breaches of the bone cortices. The percentage of cortical perforations by the suggested trajectory was compared with that by the pedicle screws by means of simulation. Results: The medial angulation of the determined trajectory is the same as that of the pedicle on the axial CT images: it usually is between 30 and 40 degrees. The screw is angled toward the antero-superior end of the superior articular process of C2, as observed on lateral fluoroscopy. The entry point is 3 mm inferior to the posterior aspect of the superior articular surface, and this point should allows the screw (ED note: check this and it wasn't clear.)the screw to be inserted close to the superomedial border of the superior articular process. Using this trajectory, 2.5% (8/316) of the screws breached the vertebral grooves, while 6.0% (19/316) of the pedicle screws breached them (p=0.030, chi-square test). Conclusions: The subarticular screw has improved safety compared with the pedicle screws. However, there are still some cases in which screws can not be inserted without breaching the vertebral groove. Therefore, preoperative thin-slice CT scanning with three-dimensional reconstruction and/or three-dimensional CT-angiography is recommended.

Paired Inspiratory/Expiratory Volumetric Thin-Slice CT Scan for Emphysema Analysis: Comparison of Different Quantitative Evaluations and Pulmonary Function Test

Purpose: The aim of the study was to use three-dimensional high-resolution CT scan data sets in inspiration and expiration for the quantitative evaluation of emphysema. Using an advanced dedicated semiautomatic analysis tool, the functional inspiratory/expiratory shifts of emphysema volume and clusters were quantified. The pulmonary function test (PFT) served as the clinical “gold standard.” Materials and methods: Thirty-one patients (9 women and 22 men; mean [± SD] age, 60 ± 8 years) who had severe emphysema due to COPD (Global Initiative for Chronic Obstructive Lung Disease [GOLD] class III and IV) were included in the study. All patients underwent paired inspiratory/expiratory multidetector CT scans (slice thickness, 1/0.8 mm) and pulmonary function tests (PFTs). CT scan data were analyzed with self-written emphysema detection solftware. It provides lung volume (LV), emphysema volume (EV), emphysema index (EI), and four clusters of emphysema with different volumes (from 2, 8, 65, and 120 mm3). These results were correlated with total lung capacity (TLC), intrathoracic gas volume (ITGV), and residual volume (RV) derived from PFT results. Results: Inspiratory LV correlated with TLC (r= 0.9), expiratory LV with ITGV (r= 0.87), and RV (r= 0.83). Expiratory EV correlated better with ITGV (r= 0.88) and RV (r= 0.93) than with inspiratory EV (r= 0.83 and 0.88, respectively). The mean inspiratory EI was 54 ± 13%, and it decreased to 43 ± 15% in expiration. However, the individuals showed a broad spectrum of changes of EI (mean, 11%; range, 1 to 28%), and no differences in inspiratory/expiratory EI and changes in EI or LV were found between GOLD III and GOLD IV patients. In expiration, there was a change from the large emphysema cluster (-37%) to the intermediate cluster (+15%) and small cluster (+13% and +11%, respectively). The change of volume of the large emphysema cluster after expiration correlated well with the changes in LV (r= 0.9), EV (r= 0.99), EI (r= 0.85), and MLD (r= 0.76). Conclusion: Emphysema volumes measured from expiratory MDCT scans better reflect PFT abnormalities in patients with severe emphysema than those from inspiratory scans. Volumetric cluster analysis provided deeper insights into the local hyperinflation and expiratory obstruction of large emphysematous clusters. Purpose: The aim of the study was to use three-dimensional high-resolution CT scan data sets in inspiration and expiration for the quantitative evaluation of emphysema. Using an advanced dedicated semiautomatic analysis tool, the functional inspiratory/expiratory shifts of emphysema volume and clusters were quantified. The pulmonary function test (PFT) served as the clinical “gold standard.” Materials and methods: Thirty-one patients (9 women and 22 men; mean [± SD] age, 60 ± 8 years) who had severe emphysema due to COPD (Global Initiative for Chronic Obstructive Lung Disease [GOLD] class III and IV) were included in the study. All patients underwent paired inspiratory/expiratory multidetector CT scans (slice thickness, 1/0.8 mm) and pulmonary function tests (PFTs). CT scan data were analyzed with self-written emphysema detection solftware. It provides lung volume (LV), emphysema volume (EV), emphysema index (EI), and four clusters of emphysema with different volumes (from 2, 8, 65, and 120 mm3). These results were correlated with total lung capacity (TLC), intrathoracic gas volume (ITGV), and residual volume (RV) derived from PFT results. Results: Inspiratory LV correlated with TLC (r= 0.9), expiratory LV with ITGV (r= 0.87), and RV (r= 0.83). Expiratory EV correlated better with ITGV (r= 0.88) and RV (r= 0.93) than with inspiratory EV (r= 0.83 and 0.88, respectively). The mean inspiratory EI was 54 ± 13%, and it decreased to 43 ± 15% in expiration. However, the individuals showed a broad spectrum of changes of EI (mean, 11%; range, 1 to 28%), and no differences in inspiratory/expiratory EI and changes in EI or LV were found between GOLD III and GOLD IV patients. In expiration, there was a change from the large emphysema cluster (-37%) to the intermediate cluster (+15%) and small cluster (+13% and +11%, respectively). The change of volume of the large emphysema cluster after expiration correlated well with the changes in LV (r= 0.9), EV (r= 0.99), EI (r= 0.85), and MLD (r= 0.76). Conclusion: Emphysema volumes measured from expiratory MDCT scans better reflect PFT abnormalities in patients with severe emphysema than those from inspiratory scans. Volumetric cluster analysis provided deeper insights into the local hyperinflation and expiratory obstruction of large emphysematous clusters.

Three-dimensional Imaging of Multi-slice Spiral CT in Bronchial Artery Correlative Study on Blood Supply of Central Lung Cancer and Its Clinical Significance

Objective: To evaluate three-dimensional bronchial artery imaging characters in central lung cancer and applied values with multi-slice spiral CT (MSCT) to provide theoretical evidence on blood supply and intervention therapy. Methods: Eighteen patients with central lung cancer underwent MSCT with real time helical thin-slice CT scanning. Three-dimensional bronchial artery reconstruction was done at the console work-station. The space anatomical characters of bronchial artery were observed through different rotations. Results: For 6 cases, the three-dimensional images of bronchial artery (33.33%) could exactly show the origins, the routes (lung inner segment and mediatism segment) and the diameters of bronchial arteries. Vision rate of bronchial arteries was the highest in pulmonary artery stricture and truncation groups, and the vessels’ diameter became larger apparently. These characters demonstrated blood supply of this kind of central lung cancer come from bronchial artery. Volume rendering images were the best ones among three-dimensional images. Conclusion: Three-dimensional imaging with MSCT in bronchial artery can reveal the anatomical characters of bronchial artery and provide theoretical evidence on blood supply and intervention therapy of central lung cancer.

Pedicle Screw Fixation in Pediatric Spinal Deformities: Results for patients under 10 years old

Purpose: We wanted to determine the efficacy of performing pedicle screw fixation to treat pediatric spinal deformities and we also wanted to evaluate its long-term effects on the growing spine. Materials and Methods: Thirty-eight consecutive spinal deformity patients (25 congenital, 9 idiopathic and 4 other etiologies) under 10 years old at the time of the surgery who underwent pedicle screw instrumentation were reviewed after a minimum follow up of 2 years (range: 2 to 7 years). To evaluate the effect of the pedicle screws on the growing spine, a thin slice CT scan was performed in 27 patients (72%) at the last follow up. The patients were treated by posterior fusion with segmental pedicle screw fixation being performed in 21 patients, vertebral column resection combined with segmental pedicle screw fixation was done in 16 patients and combined anterior and posterior correction was done in 1 patient. Results: The frontal correction was 67.2% in the posterior fusion group, 71.5% in the posterior resection group and 64.7% in the patients who underwent combined anterior and posterior correction. A mean correction of was obtained in the sagittal plane. A total of 341 pedicle screws were inserted (an average of 8.9 screws per patient). The complications were comprised of 7 screw malpositions (2.1%), 1 loss of fixation (screw pull-out), 1 recurrence of deformity and one superficial infection. There were no significant neurological or vascular complications. Any Symptoms or radiological evidence suggestive of spinal stenosis were not detected in any of the patients. Conclusion: Pedicle screw fixation may be used with the same efficacy for pediatric spinal deformities, and even for the patients under 10 years old, without causing any hazard of iatrogenic spinal stenosis.

Location of functioning metastases from differentiated thyroid carcinoma by simultaneous double isotope acquisition of I-131 whole body scan and bone scan

In a young patient with differentiated thyroid carcinoma (DTC), previously submitted to total thyroidectomy and I-131 therapy for ablation of thyroid remnant, a follow-up 1-131 diagnostic whole body scan (WBS) demonstrated four small abnormal I-131 uptake areas. Two of these were projected over the thoracic region and corresponded to lung nodules, as later demonstrated by lung computerized tomography (CT)-scan. The remaining two areas were found in the lumbar-pelvic region, but their precise location could not be determined. Standard bone Rx examination and bone scan were negative. After I-131 therapy, we simultaneously acquired a I-131 WBS and a Tc-99m oxidronate bone scan by setting a dual window on the gamma camera. Comparing the I-131 and bone images we were able to identify the 4th lumbar vertebra and right ilium as the bone segments to be studied by a radiological approach. Eventually, the thin slice CT-scan demonstrated the presence of two small osteolytic lesions in these areas. In conclusion, the simultaneous acquisition of images both from I-131 and a bone-seeking agent may be useful to locate functioning bone metastases from DTC.

The use of forced flexion/extension views in the obtunded trauma patient.

To determine whether forced flexion/extension (F/E) films for "clearing" the cervical spine in unconscious or semiconscious patients are useful or actually dangerous. Of 810 patients admitted for blunt trauma over a 5-year period, 479 patients whose films and charts were available received passive F/E film views of the cervical spine. Of these, 447 were reviewed retrospectively in masked fashion for any exacerbation of neurological changes subsequent to the procedure and with respect to the final neurological status at discharge. Twenty-nine patients (6%) had various abnormalities including fractures and ligamentous injuries seen on the initial films. Following forced F/E films no change was made in the diagnosis of 23 patients. Of the remaining six patients, two required no treatment, two only required the use of a collar but two did have surgical intervention, this decision being based on the findings seen in the initial films. However, 285 films (59%) were judged inadequate due either to inadequate F/E (150 patients, 31%) or poor visualization (194 patients, 40%). There were three false positives all subsequently cleared by other studies and there were no false negatives. From the chart review, there were no complications or deaths attributable to the procedure. Although we were unable to find any complication or deaths directly attributable to the procedure, the clinicians abandoned passive F/E views in obtunded patients on the grounds of expense. Our present method of "clearing" a cervical spine in an obtunded patient is a cross-table lateral radiograph followed by a high-resolution thin-slice CT scan with sagittal and coronal reconstruction. We are against the use of routine MRI studies and of a forced F/E view in these patients.

CT Findings of Aortic Intramural Hematoma with or without associated Penetrating Aortic Ulcer

Purpose: To analyze the CT findings of aortic intramural hematoma (IMH) with or without associated penetrating aortic ulcer (PAUH), as seen on initial and follow-up CT scans. Materials and Methods: We retrospectively analyzed the CT findings of 36 cases diagnosed clinically and radi-ologically as IMH (n=7) and PAUH (n=29) after initial and follow-up CT scanning. The period between initial and follow-up scanning-which was performed between two and four times-ranged from 1 week to 91 months (mean: IMH, 18.4 months;PAUH, 16.2 months). Results: With regard to maximal thickness and extension of IMH, maximal diameter of the involved aorta, inward displacement of intimal calcification, Stanford type of IMH, and pleural and pericardial effusion between IMH & PAUH, the results were not statistically significant, but PAUH tends to develop in older patients and shows a more frequent incidence of aortic atherosclerosis. Only PAUH involved abdominal aortic aneurysm and focal right renal infarction, each in one case. Penetrating aortic ulcers (PAU) were more frequently found in the proximal descending thoracic aorta (n=24) than in the mid(n=11) to distal(n=10) descending thoracic aorta. Among 53 cases of PAU, seven could not be detected on initial CT scans; this was due to excessive scan thickness (n=4) and masking of the aortic ulcer by IMH(n=3), circumstances which were visualized after resolution of IMH. Follow-up CT scanning showed that PAU progressed to fusiform or saccular aortic dilatation (n=15) or localized aortic dissection (n=4), and that in 34 cases, there was no interval change. Follow-up CT findings of IMH in cases of PAUH were as follows: Type A (n=8), with four resolutions after surgery and four after conservative treatment; Type B (n=21), with 21 resolutions after conservative treat-ment. Follow-up CT findings of IMH were as follows: Type A (n=2), with one resolution after surgery and one after conservative treatment; Type B (n=5), with progression of typical aortic dissection in two cases, and three resolutions after conservative treatment. Conclusion: PAUH is characterized by its occurrence in older patients, a more frequent incidence of aortic atherosclerosis and abdominal aortic aneurysm, but no difference in the extension of IMH and other CT findings between PAUH and IMH. Branch vessel involvement was noted in one case of PAUH but not in cases of IMH. Follow-up CT scanning showed that in the absence of surgery, IMH progressed to aortic dissection or resolution. In all patients who did not undergo surgery, PAU progressed to saccular or fusiform aortic dilatation, localized aortic dissection and no interval change, with resolution of IMH after conservative treatment. Initial and follow-up thin-slice spiral CT scanning can provide correct diagnosis and treatment planning (especially ascending aorta is involved), and permit differentiation between PAUH and IMH.

Planning and surgical strategies for early management of vertebral artery and vertebrobasilar junction aneurysms.

Selection of the approach and technique for surgical repair of aneurysm of the vertebrobasilar artery system is mainly based on angiographic features. This report emphasizes that planning the surgical procedure should also include preoperative evaluation of the individual skull base configuration, as well as the relationship between aneurysm site and surrounding bony structures. These features are evaluated on thin slice CT scans using bone tissue algorithms and are particularly important for adequate exposure of distal vertebral artery (VA) or midline aneurysms, because these cases require drilling of the jugular tubercle. For the use of lateral approaches, the surgeon must be familiar with the extradural and intradural anatomy of the foramen magnum region and may rely on at least five anatomical landmarks for orientation during surgery: 1) the dural entrance of the vertebral artery; 2) the posterior condylar emissary vein; 3) the medial rim of the distal sigmoid sinus; 4) the hypoglossal canal; 5) the jugular tubercle. To increase the safety of the procedure, the authors recommend an individualized tailoring of the surgical approach according to the variable morphological situation of each patient.

CT, MR Imaging and Angiography in Pancreatic Apudomas

Findings at CT, MR imaging and angiography in 29 patients with pancreatic apudomas are presented. CT and angiography were performed in all the patients, MR imaging in 10. Twenty-five patients underwent laparotomy. The ability of the different imaging methods to localize the primary tumor and detect hepatic metastases was compared. CT and MR imaging depicted the primary tumor in 79% and 88% of the cases respectively, angiography in 72%. Enhancement patterns at CT and signal intensity variations at MR imaging were unspecific parameters regarding different types of tumors. CT and MR imaging were considerably more accurate than angiography in evaluating local tumor resectability. Angiography revealed more numerous small hepatic metastases (< 0.5 cm) than CT or MR imaging, but missed metastases in the left lobe in 5 patients. MR imaging seems promising in localizing and characterizing pancreatic apudomas, but further evaluation is needed before any conclusion can be drawn. At present dynamic incremental CT seems mandatory in the evaluation of pancreatic apudomas. Angiography is of value for preoperative and preembolization vascular mapping, and in localizing small pancreatic apudomas not shown at CT or MR imaging. Faster dynamic thin slice CT scanning and fast-sequence MR imaging may increase the sensitivity of detecting small primary pancreatic apudomas.

傍正中VA Aneurysmに対する (Trans-) Condylar Approach

The surgical technique of the transcondylar approach (TCA) for midline vertebral aneurysms is presented, and the differences in the surgical fields between TCA and the lateral suboccipital approach (LSA) are highlighted. Extradural resection of the lateral wall of the foramen magnum, from the occipital condyle to the jugular tubercule, was the most important element for exposure of the aneurysm in this area. Effective bone resection using the TCA enlarged the subarachnoid space around the lower cranial nerves, and offered more surgical space than that of LSA for aneurysm clipping between the nerves. The total length of the vertebral artery was observed with minimal retraction on those nerves. Resection of the JT was necessary when the aneurysm was located close to the vertebro-basilar junction (VBJ), in the area less than 10 mm from the midline on the A-P view of the angiogram, and closer than 12 mm to the internal auditory meatus on the lateral X-ray. One of the shortcomings of the TCA was the necessity of sacrificing or exposing the cervical venous plexus, which continues from the jugular bulb through the supracondylar emissary vein. A preoperative thin-slice bone CT scan offered important information about the variation of the venous system and the size of the JT in each case.

Comparative treatment planning: Proton vs. x-ray beams against glioblastoma multiforme

The survival of patients with glioblastoma multiforme is extremely poor, the 5-year survival rate being almost zero. The cause of failure is almost exclusively local progression of tumor, the remainder is due to complications of treatment. Although this tumor is clearly radiation resistant, there is evidence of a dose response relationship. Using a thin slice CT scan of the entire head of a patient with glioblastoma mutiforme, 3-dimensional radiation treatment plans were developed for treatment to a dose of 90 cobalt-Gray-equivalent (CGE). Dose distributions using protons were compared to those using x-rays. The results showed advantages for the proton beam technique. Namely the proton plan irradiated less non-target brain than the x-ray plan; this was especially so in the decrease of coverage of deep-seated structures. The volume of non-target brain that received more than 70 CGE was 175 ml for the x-ray plan and 94 ml for the proton plan. This study indicates that for a subpopulation of patients with glioblastoma multiforme, at least 90 CGE could be delivered with proton beam techniques to the target with only small volumes of normal brain structures receiving more than 70 CGE.

CT-scan and intraocular tumours: detection and assessment of size and extrascleral growth of uveal melanomas

Twenty-two patients, who were suspected of an intraocular tumour, were examined with the high resolution thin slice CT-scan (1.5 or 3 mm slices). The final diagnosis in 14 cases was an uveal melanoma, and in 3 cases in which an uveal melanoma was suspected a chorioretinal haemorrhage, an exudative macular degeneration type Junius Kuhnt and an intrascleral foreign body were respectively found. In 2 cases intraocular metastases were demonstrated, and in 2 other cases malignant lymphomata. One patient had a haemangioma. In 10 of the 14 patients with uveal melanomata enucleation was performed and 4 were treated by ruthenium application. The CT-scan was compared with ultrasonographic, operative and histological findings. From the study it appears that the CT-scan is useful for screening uveal melanomas. It is however difficult to distinguish the uveal melanoma from a secondary retinal detachment; differentiation from an exudative macular degeneration was not possible. The size of the tumour was only represented correctly on the CT-scan in half the cases. CT examination fails to demonstrate or exclude epi- and extrascleral growth. The multiple metastases and the haemangioma could only be seen with difficulty on the CT-scan; the latter was however clearly visible after the injection of contrast. The foreign body could be clearly seen without contrast.