Prospective assessment of MRI for imaging retroperitoneal metastases from testicular germ cell tumours.

AIM: To determine the sensitivity of magnetic resonance imaging (MRI) in the detection of retroperitoneal lymph nodes in patients with testicular germ cell tumours (TGCT). METHODS AND MATERIALS: A prospective study of 52 patients (mean age 34 years, range 18-54 years) was performed. Imaging of the retroperitoneum was performed using multidetector computed tomography (CT) and 1.5 T MRI systems. The CT and MRI images were read independently by three observers. The number, size, and site of enlarged nodes (> or =10 mm maximum short axis diameter) were recorded. Retroperitoneal nodal detection on MRI was compared to CT. RESULTS: Twenty-two (42%) of the 52 patients had no retroperitoneal disease; in remaining 30 patients 51 enlarged nodes were identified. On a per patient basis readers 1, 2, and 3 identified nodal disease in 28 of 29, 29 of 30, and 24 of 30 patients, respectively, using MRI compared to CT. Thus for experienced radiologists (readers 1 and 2) MRI is comparable to CT for nodal detection (i.e., this study excludes MRI being inferior to CT with 80% power and 5% type 1 error). CONCLUSION: MRI offers an alternative method for staging the retroperitoneum in young patients being followed for TGCT and has the major advantage of avoiding exposure to ionizing radiation.

Tumour staging using magnetic resonance imaging in clinically localised prostate cancer: relationship to biochemical outcome after neo-adjuvant androgen deprivation and radical radiotherapy.

AIMS: To evaluate the prognostic significance of magnetic resonance imaging (MRI) tumour stage in clinically localised prostate cancer. MATERIALS AND METHODS: Between 1988 and 1999, 199 men with clinically localised prostate cancer (T -T4, N0/Nx, M0) were treated with neo-adjuvant androgen deprivation and radical radiotherapy, and were staged using MRI. Concordance between clinical tumour (cT) stage, as determined by digital rectal examination, and MRI tumour (mT) stage was assessed. Univariate and multivariate analyses using the Cox proportional hazards model were used to study the prognostic role of cT stage and mT stage in addition to established prognostic factors. RESULTS: Of these 199 patients, 103 (52%) were upstaged on MRI, seven (3%) were downstaged, and in 89 (45%) cT and mT stages were concordant. With median follow-up of 3.8 years, 5-year freedom from prostate-specific antigen (PSA) failure was 48% (95% confidence interval (CI) 39-56%). On univariate analysis, freedom from PSA failure was associated with mT stage (P = 0.009) as well as Gleason score (P < 0.001) and initial PSA (P < 0.001), but not cT stage (P = 0.449). On multivariate analysis, Gleason score (P = 0.001), initial PSA (P < 0.001), but not mT stage (P = 0.112) remained independent determinants of freedom from PSA failure. For the subgroup of 149 patients with cT1-2 disease, mT stage was a significant predictor of increased risk of PSA failure on univariate analysis (P = 0.005), but not multivariate analysis (P = 0.19). CONCLUSION: Freedom from PSA failure was more closely associated with mT stage than cT stage. Future studies are warranted to determine whether mT stage is an independent determinant of treatment outcome.

Evaluating the effect of rectal distension and rectal movement on prostate gland position using cine MRI.

PURPOSE: To evaluate the dynamic interrelationship between rectal distension and rectal movements, and to determine the effect of rectal movement on the position of the prostatic gland using cine magnetic resonance imaging (MRI). METHODS AND MATERIALS: Fifty-five patients with biopsy-proven or suspected prostate cancer were examined in the axial plane using repeated spoiled gradient-echo sequences every 10 seconds for 7 minutes. Twenty-four patients received bowel relaxants before imaging. Images were analyzed for the degree of rectal distension, for the incidence, magnitude, and number of rectal and prostate movements. RESULTS: Rectal movements were seen in 28 (51%) patients overall, in 10 (42%) of those receiving bowel relaxants and in 18 (58%) not receiving bowel relaxants. The incidence of rectal movements correlated with the degree of rectal distension (p = 0.0005), but the magnitude of rectal movements did not correlate with the degree of rectal distension. Eighty-six rectal movements resulting in 33 anterior-posterior (AP) prostate movements were seen. The magnitude of rectal movements correlated well with degree of prostate movements (p < 0.001). Prostate movements in the AP direction were seen in 16 (29%) patients, and in 9 (16%) patients the movement was greater than 5 mm. The median prostate AP displacement was anterior by 4.2 (-5 to +14 mm). CONCLUSIONS: Cine MRI is able to demonstrate near real time rectal and associated prostate movements. Rectal movements are related to rectal distension and result in significant displacements of the prostate gland over a time period similar to that used for daily fractionated radiotherapy treatments. Delivery of radiotherapy needs to take into account these organ movements.

The use of CT in radiotherapy treatment planning.

A prospective study is reported comparing conventional localisation with computed tomography (CT) localisation of tumours for radiotherapy treatment planning. One hundred and five out of 320 (33%) patients had an alteration in treatment plan and details are given according to the tumour site. CT planning enables more accurate localisation of both tumour and normal organs in addition to providing an accurate body contour and inhomogeneity corrections. Implications for integration of CT into radiotherapy planning practice are discussed and the impact of CT on treatment policy evaluated.

Thymic rebound in an adult following chemotherapy for testicular cancer.

Thymic hyperplasia is reported in a 27 year old man following combination chemotherapy for metastatic testicular cancer. The occurrence of this phenomenon is reviewed and the implications for management discussed.

The role of CT in the staging and radiotherapy planning of prostatic tumours.

Fifty patients with proven carcinoma of the prostate have been evaluated with CT. The CT studies were carried out for staging and radiotherapy planning and the findings compared with rectal examination and lymphography. CT provided useful additional information to that obtained by rectal examination in 40% of patients and these findings had important implications for radiotherapy planning. There was good correlation between CT and lymphography in the assessment of pelvic lymph node involvement.

Assessment of response following treatment for malignant disease.

Monitoring tumour response to therapy is an increasingly important aspect of oncological radiology. Cancer is increasing in incidence in the UK and recent advances in treatment have resulted in many more patients surviving with treated disease. Concurrent advances in imaging techniques over the past two decades permit us to obtain detailed morphological and functional information from treated tumours. This article reviews clinical strategies for imaging patients following treatment for cancer with particular reference to techniques which are currently under continuing scientific evaluation.

Features of unusual metastases from prostate cancer.

A retrospective study of CT examinations on 508 patients with prostate carcinoma was performed in order to document the presence or absence of uncommon nodal and extranodal metastases according to pre-defined criteria. 45 atypical metastases were demonstrated in 36 patients. There were 23 atypical nodal metastases including unusual distribution (19/23), large volume (7/23) and atypical morphology or contrast enhancement pattern (8/23). 22 atypical extranodal metastases included orbit/skull base (11), pulmonary (4), liver (3), intracranial (2), ocular (1) and adrenal (1). Atypical prostate carcinoma metastases are usually encountered in the presence of known advanced disease but can be the presenting feature of malignancy or the only sign of distant spread. Knowledge of atypical manifestations of metastatic disease will reduce diagnostic delay, allow accurate staging and lead to the effective and timely delivery of appropriate treatment.

The role of computed tomography in the management of soft tissue sarcomas.

Seventy-seven patients with soft tissue sarcoma underwent computed tomography (CT) between 1977 and 1981. The results have been analysed to determine the characteristics of these tumours on CT, the accuracy of CT in predicting resectability and in the detection of distant metastases, and the influence of CT findings on patient management. The majority of tumours appeared as masses which were well-defined, either by surrounding soft tissue planes or because the tumour had a significantly different attenuation value to the surrounding tissues. No correlation was found between the characteristics on CT and the tumour histology. A prediction of operability based on the CT appearances was compared with the surgical findings in 24 patients. This prediction was correct in 22 patients (92%) and further useful surgical information was provided in 11 patients (46%). A comparison of the CT findings with those of chest radiography, including whole lung tomography, showed that CT demonstrated a significantly larger number of pulmonary metastases. CT was also useful in revealing unsuspected local recurrences in four of 18 patients although one false positive diagnosis was made. Overall, the information provided by CT altered the clinical management in 18 patients (23%); the most important change was that surgery was avoided. Computed tomography should be regarded as the investigation of choice for the assessment of the primary or locally recurrent tumour and the detection of "occult" pulmonary metastases.

Quantitative assessment of lung damage due to bleomycin using computed tomography.

Visual assessment and density measurements of the lung using computed tomography (CT) were made in 18 patients undergoing treatment with bleomycin for malignant teratoma of the testis. The results of both visual assessment and density measurements were compared with changes in gas transfer per unit lung volume (KCO). Visual assessment of severity of damage to the lungs caused by bleomycin is unrelated to changes in KCO but is characteristic of bleomycin damage and allows a confident diagnosis to be made. Quantitative density measurement by CT, however, is inversely related to changes in KCO and may therefore be used to monitor the physiological effect on the patient. Examination of the lung by CT in these patients can not only characterise and define the extent of lung damage due to bleomycin but can be used to give a quantitative measurement on which to monitor treatment.

Comparison of ultrasound and computer-assisted tomography in pancreatic diagnosis.

In a series of patients suspected of having pancreatic disease both ultrasound and computerized tomography (CT) were performed. The diagnosis has been confirmed in 50 patients. Computerized tomography visualized the pancreas in all 50 (100%) whereas ultrasound was successful in 40 patients (80%). The ultrasound failures were due to bowel gas anterior to the pancreas. The overall diagnostic accuracy was 84% for computerized tomography and 64% for ultrasound; however, in those cases where ultrasound successfully detected the pancreas the diagnostic accuracy was 80%.

Pneumomediastinum complicating bleomycin related lung damage.

We describe two patients who developed spontaneous pneumomediastinum without pneumothorax against a background of bleomycin-induced pulmonary interstitial disease whilst on treatment for metastatic germ cell tumours of the testis. Pneumomediastinum is a rare but recognized complication of bleomycin-induced lung toxicity, which has previously only been described in association with pneumothorax.

A preliminary investigation of dynamic transmission computed tomography for measurements of arterial flow and tumour perfusion.

An assessment of the meaning and accuracy of CT numbers in dynamic CT has been made using data obtained from both phantom and patient investigations. Following an injection of contrast material, a series of 5-s scans (at 125 kVp, 230 mAs) were taken of the same slice at a rate of 6 scans min-1 using a Siemens Somatom 2 scanner. In order to study rapid changes of CT number, each 5-s scan was split into three segmented and overlapping images of 3-s duration. The variation of the mean CT number within small regions of interest (ROIs) were displayed as density-time curves and the errors associated with the artery and tumour curves were studied. In order to investigate the errors in the arterial curve which are associated with the timing sequence, blood flow through a large vessel was simulated in an experimental model. The results show that the largest error is associated with the peak CT value but this error can be reduced by a factor of approximately 2 if the images are split. Dynamic CT has been carried out on six patients with retroperitoneal or pelvic lesions in a preliminary study to investigate its use as a tool for monitoring the effectiveness of therapy. The results demonstrate that this technique can provide useful information regarding tumour vascularity and perfusion. In the studies on patients, a large spread in the CT numbers within a ROI was found to be a useful indicator of an uneven iodine distribution. For example, in two tumours, necrotic centres which were not apparent on the pre-contrast scan were identified from the dynamic study.

The role of computed tomography in the management of children with advanced neuroblastoma.

Computed tomography (CT) was found to be a valuable method of assessing the extent of local disease in 36 patients with advanced neuroblastoma. Precise predictions on the operability of tumours can be made so that the timing of primary or "second look" surgery may be optimised. However, intraspinal extension of tumour is not detected on CT examinations without intrathecal contrast medium and plain radiographs are not a reliable guide to the presence of intraspinal disease; the examination should include intrathecal contrast medium (CT myelography) when patients undergo pre-operative staging by CT. The majority of neuroblastomas appear calcified on CT. During chemotherapy the most common change in tumour morphology is decrease in size and increase in calcification. There is however no correlation between tumour size or behaviour during chemotherapy and eventual survival but an increase in size during or after treatment is a serious prognostic sign.

Radiation induced liver injury detected by particulate reticuloendothelial contrast agent.

Radiation induced liver injury detected by a particulate reticuloendothelial MR contrast agent is described in a patient with metastatic colon cancer. The irradiated hepatic parenchyma failed to darken after ferumoxide administration. This finding suggests that detection of metastatic disease after ferumoxide contrast agents may be impaired in patients who have previously received upper abdominal radiation treatment.

Fast magnetic resonance imaging of intracerebral metastatic disease.

The appearance of intracerebral metastases imaged with a multi-slice fast imaging sequence (FLASH) is described. Images were obtained using a Siemens 2.0 T Magnetom operating at 1.5 T. Results of the FLASH imaging sequence at different values of repetition time, different values of "flip angle" and different numbers of acquisitions are described both qualitatively and quantitatively. At low flip angles, both tumour and oedema appear brighter than surrounding white matter. Increasing the flip angle tends to make oedema brighter than both tumour and white matter and increasing the flip angle still further makes tumour and oedema darker than white matter. A major limitation of this technique is that the low flip angle images, in particular, suffer from low signal-to-noise ratios. High flip angle FLASH images have higher signal-to-noise ratios but show similar contrast behaviour to T1-weighted spin-echo images and are likely to be no better as a screening sequence for intracerebral metastases. All the FLASH sequences showed a sensitivity to changes in magnetic susceptibility. This made small intratumoral haemorrhages and basal ganglia "calcification" easier to detect than on spin-echo images but also caused susceptibility artefacts in images around the base of the skull.

The value of thoracic computed tomography in the detection of recurrent Hodgkin's disease.

Fifty chest radiographs and concurrent thoracic computed tomography (CT) scans obtained in a total of 44 patients with 50 separate episodes of suspected recurrent Hodgkin's disease were reviewed. Recurrent disease was present in 18 episodes, involving the mediastinum in 12, the lung parenchyma in five and both mediastinum and lung parenchyma in one. In four episodes, mediastinal recurrence was demonstrated on both the chest radiograph and CT scan. In a further two cases, the chest radiograph appeared normal but CT detected recurrence in the mediastinum. In 20 cases, the mediastinal appearances on chest radiography were suspicious but not diagnostic of recurrence, usually because of previous radiotherapy resulting in residual mediastinal widening. Computed tomography diagnosed recurrent disease which was subsequently proven in seven of these cases. Recurrent disease was suggested by CT in a further case, subsequently shown to be radiation fibrosis. Of the 12 remaining chest radiographs in which the mediastinal assessment was indeterminate, CT was true negative for recurrent disease in 10 cases and was also indeterminate in two. Recurrent disease in the lung parenchyma was demonstrated on the chest radiograph and CT scan on five occasions. There was one incident in which the chest radiograph was normal but CT detected recurrent parenchymal disease. The appearances of the lung parenchyma were indeterminate for recurrent disease on three chest radiographs but CT was helpful in only one case in which radiation change alone was diagnosed. In eight cases the diagnosis of recurrent disease by CT resulted in a decision to initiate treatment. Computed tomography is of value in detecting relapse in patients with suspected recurrent Hodgkin's disease when the chest radiograph is inconclusive, and may enable differentiation of radiation change from recurrent disease in the mediastinum.

The appearance of the inferior thyroid veins on computed tomography.

Computed tomography (CT) scans of the mediastinum in 80 patients were reviewed retrospectively to determine the nature of small opacities which are identified on contiguous cuts. These structures varied in number from one to five. The pattern of enhancement, appearance on contiguous CT sections and position in the mediastinum led us to believe that these represent inferior thyroid veins. To our knowledge their appearance on CT has not been reported previously.

Magnetic resonance imaging in recurrent carcinoma of the cervix.

Twenty patients with suspected recurrent cervical carcinoma were evaluated with computed tomography (CT) and high-field magnetic resonance imaging (MRI). Histological verification of the imaging findings were available in all cases. Computed tomography and MRI were equally effective in making the diagnosis of disease recurrence. The extent of vaginal recurrence and involvement of pelvic floor muscles was better shown on MRI than on CT.

Focal sparing in fatty infiltration of the liver.

Four cases of focal sparing in otherwise diffuse fatty infiltration of the liver are reported. The characteristic features are described as shown at sonography, computed tomography (CT) and scintigraphy. It is emphasised that, with ultrasound, if the increased echogenicity of the majority of the liver is not appreciated, then the area of normal hepatic parenchyma may be misinterpreted as a pathological hypoechoic lesion.