Pulmonary metastasectomy serves as the most efficacious local therapeutic option for stage IV colorectal cancer that has spread to the lungs. In order to properly select patients who will benefit most from pulmonary metastasectomy over other therapeutic options, a multidisciplinary approach should be utilized. The ideal technique is parenchymal-sparing, especially given that there is a high recurrence rate with the most common location being the remainder of the lung. While benefits of pulmonary metastatsectomy are well-documented, further studies are warranted to continue to refine patient selection, timing of surgery, and interplay with other treatment modalities.

Colorectal cancer (CRC) is one of the most common causes of death from cancer. Lung seeding occurs in approximately 10% of patients surgically treated for primary CRC with radical intent: the lung is the most common site of metastases after the liver. While surgical treatment of liver metastases is widely accepted to affect long-term outcomes, more controversial and not standardized is the therapy for CRC patients developing lung metastases. Experience suggests the potential curative role of pulmonary metastasectomy, especially in oligometastatic disease. However, the optimal strategy of care and the definition of prognostic factors after treatment still need to be defined. This review focused on the uncommon scenario of single pulmonary metastases from CRC. We explored pertinent literature and provide an overview of the epidemiology, clinical characteristics and imaging of single pulmonary metastases from CRC. Additionally, we identified the best available evidence for overall management. In particular, we analyzed the role and results of locoregional approaches (surgery, radiotherapy or ablative procedures) and their integration with systemic therapy.

We determined the total amount of diagnostic radiation that a patient with testicular cancer receives during the course of treatment and the associated risk of secondary malignancy.

At a single institution 119 men with seminomatous and nonseminomatous germ cell tumors of the testis were retrospectively identified. Annual and lifetime exposure to radiation was determined for each histological subtype. Values were assessed for compliance with International Commission of Radiological Protection guidelines.

The cohorts included 55 patients with seminomatous and 64 with nonseminomatous germ cell tumor. Between the groups no difference was found in the lifetime (215.5 and 214.1 mSV, p = 0.96) or the annual (104.6 and 104.6 mSV, respectively, p = 1.0) radiation dose. Of the 41 patients with more than 5-year followup 32 (78%) were in violation of guidelines by exceeding 20 mSV per year of radiation. Also, 74 patients (61.7%) received 50 mSV or greater of radiation during a 1-year period. Using the previously calculated excess relative risk for solid cancer and leukemia, excluding chronic lymphocytic leukemia, the RR was 1.06 and 1.33, [corrected] respectively, with a 2.1% lifetime risk of fatal cancer over the baseline risk.

At a tertiary care center with experience with managing testicular cancer 78% of patients with more than 5 years of followup exceeded current national and standard safety limits for radiation exposure. Imaging should be done judiciously in this population at high risk for radiation overexposure.

The aim of surgical treatment of lung metastases is to eliminate all known tumoral disease. After a clinical diagnosis of lung metastases, the criteria for selecting patients who are candidates for surgical treatment, the route of access to the thoracic cavity and the technique for metastases resection are not universally defined. Moreover, half of all patients will show recurrence and the advisability of further surgery will have to be reconsidered. The present article discusses aspects related to the oncological and functional limits of surgical resection of lung metastases, preoperative workup, postoperative follow-up, and the surgical approaches and resection techniques.

The primary imaging modality for the detection of pulmonary metastases is computed tomography (CT). Ideally, a helical CT scan with 3- to 5-mm reconstruction thickness or a volumetric thin section scanning should be performed within 4 weeks of pulmonary metastasectomy. A period of observation to see whether further metastases develop does not seem to allow better patient selection. If positron emission tomography is available, it may identify the extrathoracic metastatic sites in 10 to 15% of patients. Despite helical CT scan, palpation identifies the metastases not detected by imaging in 20 to 25% of patients and remains the standard. No data define the optimal interval for follow-up surveillance imaging.

This study was undertaken to assess the performance of 16-slice computed tomography (MSCT) using Multi-Planar Reformatting (MPR), Maximum Intensity Projection (MIP) and Volume Rendering (VR) reconstructions to study pulmonary metastases.

CT studies of 32 patients with pulmonary metastases were retrospectively reviewed. Images were assessed for the following parameters: number, size, location, distribution of the nodules and the presence of the "mass-vessel sign". These parameters were evaluated by two observers on axial-source images and on MPR, MIP and VR reconstructions. Sensitivity of each reconstruction and interobserver agreement were calculated.

Two-dimensional (2D) axial images and MIP and VR reconstructions exhibited 100% sensitivity for lesions >10 mm. For nodules 6-10 mm, sensitivity was 49%-55% for the 2D images, 90% for MIP and 80%-85% for VR reconstructions. For metastasis <or= 5 mm, sensitivity was 22% for 2D images, 87%-89% for MIP and 55%-58% for VR reconstructions. Coronal and sagittal MPR, MIP and VR did not improve the detection rate compared with the corresponding axial images. MIP and VR provided overlapping results in detecting the "mass-vessel sign".

MIP are the most sensitive reconstructions for detecting small pulmonary nodules.

Almost 125 years after the first documented case, pulmonary metastasectomy is still poorly understood. No other organ is subject to the wide histologic variety of metastatic insults, and this fact has complicated a complete exposition of when pulmonary metastasectomy may be beneficial. Many physicians still consider pulmonary metastatic disease to be always incurable, and they may underestimate existing surgical options including the benefits of pulmonary metastasectomy. In addition, technological improvements in radiological screening of pulmonary metastases and thoracoscopic resection are fundamentally altering the management of these patients and their surgery. This article reviews the history, form, and future of pulmonary metastasectomy, the literature that supports or refutes its application in various tumor types, and the screening and surgical evaluation that is needed prior to its performance.

Surveillance is a standard management approach for stage I nonseminomatous germ cell tumors (NSGCT). A randomized trial of two versus five computed tomography (CT) scans was performed to determine whether the number of scans influenced the proportion of patients relapsing with intermediate- or poor-prognosis disease at relapse.

Patients with clinical stage I NSGCT opting for surveillance were randomly assigned to chest and abdominal CT scans at either 3 and 12 or 3, 6, 9, 12, and 24 months, with all other investigations identical in the two arms. Three of five patients were allocated to the two-scan schedule. Four hundred patients were required.

Two hundred forty-seven patients were allocated to a two-scan and 167 to five-scan policy. With a median follow-up of 40 months, 37 relapses (15%) have occurred in the two-scan arm and 33 (20%) in the five-scan arm. No patients had poor prognosis at relapse, but two (0.8%) of those relapsing in the two-scan arm had intermediate prognosis compared with 1 (0.6%) in the five-scan arm, a difference of 0.2% (90% CI, -1.2% to 1.6%). No deaths have been reported.

This study can rule out with 95% probability an increase in the proportion of patients relapsing with intermediate- or poor-prognosis disease of more than 1.6% if they have two rather than five CT scans as part of their surveillance protocol. CT scans at 3 and 12 months after orchidectomy should be considered a reasonable option in low-risk patients.

Pulmonary metastasectomy is well accepted in patients with isolated metastases from an extrathoracic malignancy. The standard approach involves careful intraoperative palpation of the lungs because more metastases are frequently found than were seen by preoperative conventional computed tomography (CT). Helical CT detects more nodules than conventional CT, raising the question of whether palpation of the lungs is still necessary if helical CT is used.

Retrospective review was done of medical records of patients undergoing metastasectomy with curative intent at the University of North Carolina (UNC) from 1999 to 2003. During this time at UNC, helical CT was routinely performed using a standardized technique, and all metastasectomy patients underwent manual lung palpation. The primary outcome measure of this study was whether malignant nodules (palpated, resected, and proven histologically) were reliably detected preoperatively by helical CT.

Thirty-four patients were identified who underwent 41 cases of pulmonary metastasectomy with lung palpation. Our analysis revealed that in 22% (9/41), more malignant nodules were found intraoperatively than were detected by helical CT. Of 88 malignant intraparenchymal nodules, 69 were detected by helical CT (sensitivity 78%). Subset analyses of tumor histology, disease-free interval, the presence of a single lesion versus multiple lesions, the interval between the CT and metastasectomy, and the size of the largest lesion were unable to identify a cohort in which lung palpation was no longer needed after preoperative helical CT.

Despite the advent of helical CT, palpation of the lung is necessary if the goal is to resect all detectable disease.

A substernal handport allows palpation of the lung and thus circumvents one of the major limitations of thoracoscopy.

This approach has been used in 24 consecutive patients, primarily during planned metastasectomy or when palpation was needed for deeper or smaller lesions that were difficult to find.

No long-term complications from this procedure were noted, and the 3 early complications were either minor or unrelated to the procedure. This approach allowed adequate resection to be accomplished by a less invasive approach in 67% of patients, although conversion to an open procedure was necessary in 33% of patients for anatomic and technical reasons. Among the 16 patients who underwent this procedure alone, the median length of stay in the hospital was 3 days. The rate of incomplete resection and of recurrence after metastasectomy was comparable to that for an open approach.

Our experience documents that a substernal handport is safe, does not compromise the ability to perform an adequate metastasectomy, and allows biopsy of lesions that are otherwise not amenable to a minimally invasive approach. This technique should be included in the standard armamentarium of approaches for thoracic surgery.

The purpose of this study was to find out if the use of 1.25-mm collimated thin-slice technique helps to detect more small pulmonary lung nodules than the use of 5 mm. A total of 100 patient examinations that allowed a reconstruction of 1.25-mm slice thickness in addition to the standard of 5-mm slices were included in a prospective study. Acquisition technique included four rows of 1-mm slices. Two sets of contiguous images were reconstructed and compared with 1.25- and 5-mm slice thickness, respectively. Two radiologists performed a film-based analysis of the images. The size and the confidence of the seen nodules were reported. We did not perform a histological verification, according to the normal clinical procedure, although it would be optimal regarding research. Statistical analysis was performed by using longitudinal analysis described by Brunner and Langer. In addition, sensitivity, specificity, negative predictive value and positive predictive value were calculated for each reader using the 1.25-mm sections as the gold standard. As an index for concordance the kappa value was used. A value of p<0.05 was regarded as significant. In 37 patients pulmonary nodules were detected. Twenty-four patients showed more than one nodule; among these, 7 patients had disseminated disease and were excluded from the study. Pulmonary nodules larger than 10 mm in size were equally well depicted with both modalities, whereas lesions smaller than 5 mm in size were significantly better depicted with 1.25 mm (p<0.05). Using 1.25 mm as the gold standard, sensitivity for 5-mm reconstruction interval was 88 and 86% for observers A and B, respectively. No false-positive results were reported for 5-mm sections. Interobserver agreement for nodule detection determined for 1.25-mm reconstruction intervals showed a k value of 0.753, indicating a good agreement, and 0.562 for 5-mm reconstruction intervals, indicating a moderate agreement. Brunner and Langer analysis showed significant differences for slice thickness and no significant difference between the observers. Reduced slice thickness demonstrated an improvement of small nodule detection, confidence levels, and interobserver agreement. Application of thin-slice multidetector-row CT may raise the sensitivity for lung nodule detection, although the higher detection rate of smaller nodules has to be evaluated from a clinical perspective and remains problematic about how the detection of small nodules will effect patient outcome.

Our purpose was to assess the incremental effect of maximum-intensity-projection (MIP) image processing on the ability of various observers to detect small (<1 cm in diameter) central and peripheral lung nodules revealed by multidetector CT.

We retrospectively identified 25 patients with metastatic disease, each having from two to nine nodules that were 3-9 mm in diameter. Two senior and three junior reviewers interpreted all images on a workstation. The observers first reviewed axial images (3.75-mm collimation, 3-mm reconstruction interval, multidetector acquisition) in cine and sequential fashion and recorded the size, lobe, and central or peripheral (within 1 cm of the edge of lung) location of each nodule. MIP images (10-mm slab, 8-mm interval) were then reviewed, and additional nodules detected were recorded. Final counts were established by consensus.

The reviewers found 122 nodules (71 peripheral, 51 central) in the 25 patients. The addition of MIP slabs significantly enhanced reviewer detection of central nodules (p < 0.001) and junior reviewer detection of peripheral nodules (p < 0.001). MIP slabs also reduced the effects of reviewer experience, particularly for peripheral nodules.

MIP processing reduces the number of overlooked small nodules, particularly in the central lung. Observer nodule detection remains imperfect even when lesions are clearly depicted on images.

The standard management approach to stage I testicular non-seminomatous germ-cell tumours (NSGCT) in the UK is a surveillance programme with adjuvant bleomycin, etoposide, cisplatin (BEP) chemotherapy being offered to individuals with high risk disease. Conventionally, computed tomography (CT) scanning of the thorax has formed part of the surveillance programme. This paper evaluates the contribution of routine thoracic CT imaging in the management of this disease.

We retrospectively reviewed the case notes of 168 patients with stage I NSGCT referred to the Wessex Medical Oncology Unit over a period of 13 years (1986-1998). These patients entered onto a surveillance programme that included serial chest X-ray follow up rather than thoracic CT.

Forty-two out of 168 patients (25%) evaluated suffered relapse during the follow up period. Eight of 42 patients (19%) relapsed with intrathoracic disease. Seven out of eight of these patients (87.5%) had at least one other indicator of disease recurrence (elevated serum marker, abnormal abdominal CT). One of 42 patients (2.4%) relapsed with isolated intrathoracic disease with no other indicator of relapse. All patients with intrathoracic relapse had evidence of disease on chest X-ray. Of the 42 relapsing patients, 93% could be categorised as having good prognosis metastatic disease. Seven per cent relapsed with intermediate or poor prognostic disease; relapse in these patients would not have been detected earlier with the inclusion of routine thoracic CT. Only one patient has died giving a cure rate of 98% for relapsing patients.

The elimination of chest CT did not compromise outcome but significantly reduced radiation exposure thereby minimising the risk of radiation-induced secondary malignancy. Continued review of surveillance programmes is essential if we are to optimise management of this disease.

To compare the number of pulmonary nodules detected at helical low- and standard-dose computed tomography (CT) and to investigate the diagnostic value of low-dose CT with a radiation exposure equivalent to that used at chest radiography.

Two radiologists recorded pulmonary nodules at standard-dose (250 or 100 mA, pitch of 1; 200 mA, pitch of 2) or low-dose CT (50 or 25 mA, pitch of 1 or 2) in five postmortem specimens and 75 patients. Nodules were assessed by size (5 mm or smaller, 6-10 mm, or larger than 10 mm) and by diagnostic confidence ("definite nodule," "definite lesion, not classic nodule," or "questionable lesion, possibly representing a vessel") with the Wilcoxon signed rank test. Artifacts depicted at low-dose CT were recorded.

There were no statistically significant differences in the number of nodules detected at standard- or low-dose CT except in nodules 5 mm or smaller that were assessed as definite nodules at standard- or low-dose CT (25 mA, pitch of 2) (472 vs 397, P < .05). Artifacts that possibly interfered with nodule detection were observed exclusively at CT with 25 mA and a pitch of 2.

Pulmonary nodules were detected reliably at CT with 50 mA and pitch of 2 or with 25 mA and a pitch of 1. However, further reduction of the dose to that used at chest radiography was associated with a significant decrease in the number of nodules 5 mm or smaller that were detected, possibly due to artifacts.

Existing methods used to simulate pulmonary metastases are unsatisfactory. The aim of this study was to create a simple in vivo model of pulmonary metastases by endobronchial deployment of small high-density beads in anesthetized dogs.

Commercially available decorative beads measuring 2 and 4 mm in diameter and of high density (600 to 1200 Hounsfield units) were deployed in the peripheral airways of anesthetized dogs using catheter and guide wire manipulations through an endotracheal tube.

A total of 65 beads were placed in five dogs. Computed tomography demonstrated that 41 (63%) were satisfactorily located in the lung periphery, 9 (14%) were unsatisfactorily located in large airways, and 15 (23%) were not visible.

The endobronchial deployment of small high-density beads in the peripheral airways of anesthetized dogs is a novel and effective technique for creation of an in vivo model of pulmonary metastases.

To evaluate role of chest computed tomography (CTC) and chest radiography (CXR) in management of patients with testicular germ cell tumours (GCT).

An analysis was undertaken of staging and re-assessment CTC and CXR examinations performed on patients with GCT over a 4.5-year period. Data were obtained on clinical presentation, tumour histology, tumour marker levels and clinical course. Consensus review interpretation was combined with these data to obtain a 'standard of reference'. Sensitivity, specificity and predictive values were derived by comparison of original imaging reports to 'standard of reference'.

Six hundred and twenty-three CTC examinations on 207 patients with GCT were included. Intrathoracic metastases were identified in 1% of seminoma patients compared with 20% of non-seminoma (NSGCT) patients. CTC was more accurate than CXR in the detection of intrathoracic metastases at 0.97, 0.96-0.98 (95% CI) compared with 0.91, 0.89-0.93. The agreement between imaging techniques and the standard of reference (determined by Kappa statistic) was respectively 0.96 for CTC and 0.65 for CXR. In GCT patients undergoing re-assessment with both CXR and CTC, CXR never detected unknown intrathoracic metastatic disease. Abdominopelvic lymphadenopathy was associated with intrathoracic metastases (P < 0.001), however re-assessment CTC did identify intrathoracic metastases in 27 cases without concurrent abdominopelvic disease. CXR was negative in 19 of these.

Routine interval CXRs are unnecessary in NSGCT patients undergoing regular re-assessment CTC due to the low additional yield and limited effect on management. Re-assessment should still include CTC. In low risk, pure seminoma patients (abdominal CT and marker negative) re-assessment CTC can be safely avoided. Baseline CTC is advocated with CXR alone for re-assessment.

Volumetric CT data acquisition has had a major impact on the practice of computed tomography. This article reviews the current state of knowledge of the applications of this technique to the chest disease summarising its clinical impact on the assessment of lung and airways diseases, mediastinal abnormalities (excluding vascular disorders which are covered elsewhere), and in the evaluation of lung cancer patients. The impact of spiral CT on the non-invasive detection of pulmonary thrombo-embolic disease is also considered.

To determine the effect of breathing on the detection of small dense pulmonary nodules of threshold conspicuity by spiral computed tomography (SCT).

Forty pulmonary nodules of high density were created by endobronchial deployment of 2 and 4mm diameter beads in the peripheral airways of five anaesthetized dogs. SCT was performed during induced breath-hold and quiet breathing, using 5 mm collimation, pitch 2 and reconstruction of contiguous 5 mm slices. Scans were reviewed by six radiologists. Detection rates were measured as the number of nodules seen by at least one reader. The data was modelled using ordinal logistic regression for repeated measures, and the Wald Chi-square statistic used to test if there was a breath-hold vs. breathing effect on reader confidence level.

There was no difference in detection rates for breath-hold vs. breathing SCT (28 vs. 25, respectively; P=0.48). This was also true when only the 2 mm nodules (n=24) were considered (12 vs. 11, respectively; P=0.77). Reader confidence level was significantly higher for breath-hold vs. breathing SCT (Wald Chi-square statistic with 6 degrees of freedom=19.0; P=0.0041).

SCT can be performed during quiet breathing without a significant reduction the overall detection rate for small dense pulmonary nodules, though reader diagnostic confidence level is reduced.

We sought to determine the accuracy of helical CT in the detection of pulmonary metastases.

Four anesthetized dogs with metastatic osteosarcoma underwent helical CT with a collimation of 5 mm, a pitch of 2, and a reconstruction interval of 5 mm. All macroscopically evident metastases were recorded at autopsy. CT images were independently reviewed by 10 radiologists and compared with pathologic results. Alternate slices in the dog with the most metastases were microscopically examined in their entirety.

Pathologic examination of the lungs revealed 132 macroscopically evident pulmonary metastases, of which 74 (56%) were detected by at least one reader. Forty-four of the 99 (44%) metastases of < or = 5 mm in diameter were detected by at least one reader compared with 30 of 33 (91%) metastases of > 5 mm in diameter (p < 0.0001). The 10 readers reported a total of 107 false positives. Complete microscopy of alternate slices in the dog with the most metastases (n = 68) revealed an additional 38 micrometastases of < or = 3 mm in diameter. None of the 32 micrometastases of < or = 1 mm were detected by CT.

Helical CT has some limitations in the detection of pulmonary metastases.

This study was undertaken to investigate the use of maximum intensity projection (MIP) images in the detection of pulmonary nodules by spiral CT (SCT). 40 pulmonary nodules of high density were created by endobronchial deployment of 2 and 4 mm beads in the peripheral airways of five anesthetized dogs. Standard SCT was performed with 5 mm collimation, pitch 2 and reconstruction of contiguous slices. MIP images were generated from overlapped slabs of seven consecutive 3 mm slices, reconstructed at 2 mm intervals and acquired at pitch 2. Scans were reviewed by six radiologists. The data were modelled using ordinal logistic regression for repeated measures, and the Wald chi 2 statistic used to test if there was a difference in nodule detection and reader confidence level between the two techniques. MIP imaging increased the odds of nodule detection by 2.18 (p = 0.0002). Reader confidence level for nodule detection was significantly higher with MIP images (p < 0.00001). MIP images improve the detection rate for small high density pulmonary nodules and increase reader confidence level, when compared with standard SCT.

A prospective evaluation of spiral CT angiography (SCTA) as the sole pre-operative imaging modality for abdominal aortic aneurysm repair.

Spiral CT angiography was compared with conventional transfemoral angiography in 30 patients and results correlated with surgical findings in 22 patients. The following features were assessed: renal artery number and disease; upper and lower aneurysm extent; aneurysm size; perianeurysmal inflammation; iliac artery disease; radiation dose; and contrast usage.

Spiral CT angiography agreed with conventional angiography in all cases of severe stenosis or occlusion of renal arteries and had 90% agreement overall for renal artery disease. Two of nine accessory renal arteries seen at conventional angiography were missed. For showing aneurysm extent SCTA was 100% sensitive, and performed better than conventional angiography. Aneurysm size was better shown with SCTA. In iliac disease SCTA, as performed in this study, was poor for mild-moderate disease, but detected four of six severely stenosed/occluded iliac arteries seen at conventional angiography. Prospective sensitivity for perianeurysmal inflammation was 33%. Radiation dose for SCTA was approximately twice and contrast dose approximately three times that for conventional angiography.

Spiral CT angiography can provide all the necessary imaging information to plan aneurysm repair in the non-claudicant.

To clarify the role of pelvic CT in the imaging of patients with germ cell testicular tumours (GCTT).

A retrospective analysis was undertaken of all CT examinations performed on patients with GCTT at a regional oncological centre over a 3-year-period. Patient notes were reviewed and data on histology, tumour marker levels, therapy and clinical course obtained. The review interpretation was combined with the original radiological report and clinical data to arrive at a consensus result.

Four hundred and forty-three examinations on 167 patients were included. One hundred and nineteen examinations (27%) demonstrated abdominal and/or pelvic lymph node enlargement. Nodal metastasis was entirely or predominantly ipsilateral in 73/77 examinations from left-sided primary tumours (95%) and 35/42 examinations from right-sided tumours (83%). Pelvic nodal enlargement was identified in 37 examinations from 16 patients. Thirteen of these sixteen patients possessed an identifiable risk factor for pelvic nodal metastasis; the remaining three had unequivocal nodal metastases in the abdomen. Combined abdominopelvic CT increased the effective dose equivalent (EDE) by 2.6 mSv (74%) compared with abdominal examination alone. Three hundred pelvic CT examinations were performed on 117 patients without risk factors for pelvic nodal metastasis. For this cohort the radiation burden from pelvic CT was 0.78 manSv, giving a risk of induction of a single fatal cancer of 3.9%.

We advocate pelvic CT only at the time of staging, except in patients with a risk factor for pelvic nodal metastasis. Any unequivocal abdominal lymph node enlargement should be regarded as a risk factor. Implementation of this policy would safely reduce pelvic CT examinations in patients with testicular tumours by nearly 50%, with a consequent reduction in patient radiation exposures and a resource saving.

Computed tomography (CT) delivers a substantial proportion of the medical radiation dose to the population. The National Radiological Protection Board (NRPB) recommends that "CT examinations should only be carried out after there has been proper clinical justification for the examination of each individual by an experienced radiologist". The aim of this study was to review the indications for body CT in a large acute hospital in order to identify groups of patients in whom CT might not be "clinically justified". We reviewed the age, sex and diagnosis of all patients undergoing CT of the abdomen and pelvis (including lumbar spine) in our department in 1992. All requests had been checked by a senior radiologist before booking. CT was performed in 1078 male patients and in 990 females. Patients examined for benign disease were younger (mean age 52 years) than patients with malignant disease (mean age 57 years). Of 915 examinations performed for benign disease, 293 (32%) were orthopaedic in nature and included 255 (87%) for back pain. CT was carried out for benign non-orthopaedic disease in 97 women under 50 years old, usually following other tests with inconclusive or normal results. 49 of these examinations were reported as normal. Of 191 patients who had more than one CT examination, 158 (83%) were undergoing follow-up for malignant disease. All 39 patients who underwent CT on three or more occasions had life-threatening conditions, either malignancy or complicated acute pancreatitis. We have been unable to find substantial numbers of patients in whom CT was performed inappropriately. Substitution of magnetic resonance imaging (MRI) for CT of the spine will help population dose reduction. The benign condition responsible for the largest radiation dose from CT is complicated acute pancreatitis, and it may be possible to substitute MRI for CT in these patients. Women under 50 years old with normal CT form an important group for clinical audit.

To evaluate the use of spiral/helical computed tomography (CT) in the preoperative evaluation of pediatric leukocoria.

A total of 34 patient charts and imaging studies were reviewed from a consecutive series of children referred with the diagnosis of presumed retinoblastoma. Of these patients, 31 had a confirmed diagnosis of retinoblastoma. Three patients had simulating lesions, including one patient with persistent hyperplastic primary vitreous and two with Coats disease.

In all patients, a diagnosis of intraocular retinoblastoma could be established or excluded at the same clinical level by spiral CT as by conventional CT. Spiral CT of the eye, orbit, and midline structures was performed without a requirement for patient anesthesia. This technique resulted in a reduced volume of contrast material required for evaluation of the central nervous system and a small decrease in total radiation exposure. There was an attendant reduction in the amount of monitoring equipment required and the necessity for attending anesthesia staff.

The primary advantage of spiral CT is reduced anesthesia risk in small children. In addition, this technique provides necessary clinical information with a reduction in image acquisition time, monitoring equipment, and monitoring staff.