Richard J Johnson

The significance of residual mediastinal abnormality on the chest radiograph following treatment for Hodgkin's disease.

The chest radiographs (CXRs) of 110 patients with mediastinal Hodgkins disease (HD) were reviewed to determine the incidence, degree, and significance of mediastinal abnormalities following treatment. Residual mediastinal abnormalities were defined as either minimal or measurable, and occurred in 64% of all patients at the completion of treatment, but were more common in those with bulky mediastinal disease at presentation (40 of 48, 83%). Fifty-one patients with a mediastinal abnormality at the end of treatment had follow-up films available. Partial or complete regression of the abnormality occurred by 1 year in 30 of these patients (59%). Over a median follow-up of 80.5 months, there were more relapses (13 of 70, 19%) in patients with residual abnormalities following treatment than in those where the mediastinum was considered normal (four of 40, 10%). Measurable abnormality was associated with a higher relapse rate (six of 25, 24%) than minimal abnormality (seven of 45, 16%), but none of these differences were statistically significant. the subsequent relapse rate for patients with persisting abnormality at 1 year was 14%, compared with 17% for patients in whom regression had occurred and 14% in whom the mediastinum had always been considered normal. Considering the whole group, the presence of a mediastinal abnormality following treatment did not predict for relapse, but for the 34 patients treated by chemotherapy (CTR) alone, a residual abnormality was associated with a significantly higher relapse rate (P = .029). We conclude that following mediastinal radiotherapy (XRT) administered either alone or combined with CTR, residual mediastinal abnormalities do not indicate the need for further treatment. However, following CTR alone, such abnormalities may signify persisting disease and we recommend that XRT be considered for these patients.

Gastrostomy insertion: Comparing the options: PEG, RIG or PIG?

AIM To compare percutaneous endoscopic gastrostomy (PEG) with radiologically inserted gastrostomy (RIG) and assess a hybrid gastrostomy technique (per-oral image-guided gastrostomy, PIG). MATERIALS AND METHODS Fifty PEGs and 50 RIGs performed in three centres were prospectively compared and the endoscopic findings of 200 PEGs reviewed. A fluoroscopy-guided technique was modified to place 20 F over-the-wire PEG-tubes in 60 consecutive patients. RESULTS Technical success was 98%, 100% and 100% for PEG, RIG and PIG, respectively. Antibiotic prophylaxis significantly reduced stoma infection for orally placed tubes (p=0.02). Ten out of 50 (20%) small-bore RIG tubes blocked. Replacement tubes were required in six out of 50 PEGs (12%), 10 out of 50 RIGs (20%), but no PIGs (p<0.001). No procedure-related complications occurred. The function of radiologically placed tubes was significantly improved with the larger PIG (p<0.001), with similar wound infection rates. PIG was successful in 24 patients where endoscopic insertion could not be performed. Significant endoscopic abnormalities were found in 42 out of 200 PEG patients (21%), all related to peptic disease. Insignificant pathology was found in 8.5%. CONCLUSION PIG combines advantages of both traditional methods with a higher success and lower re-intervention rate. Endoscopy is unlikely to detect clinically relevant pathology other than peptic disease. PIG is a very effective gastrostomy method; it has better long-term results than RIG and is successful where conventional PEG has failed.

Staging, volume estimation and assessment of nodal status in carcinoma of the cervix: comparison of magnetic resonance imaging with surgical findings.

Pre-operative magnetic resonance imaging (MRI) was carried out in 50 women scheduled for operative treatment of invasive carcinoma of the cervix. The extent of the primary tumour (stage), its dimensions and the presence of lymph node enlargement were assessed and compared with findings at surgery and/or histopathological examination of the resected uterus. In 45 patients undergoing radical hysterectomy, accuracy of MRI staging of the primary tumour was 84.4%. In the group as a whole, including four patients with inoperable disease, staging accuracy was 84%. Most errors were due to difficulty in identifying early vaginal or parametrial invasion by tumour. There was close correlation between the volume of tumour measured from pre-operative MRI scans and measurements made on the hysterectomy specimen (r = 0.95). MRI had a sensitivity of 75% and a specificity of 88% in predicting metastatic lymphadenopathy, based solely on the criterion of enlargement of any pelvic or para-aortic nodes to 1.5 cm or greater. However, retrospective analysis of the presence or absence of metastases by site in 49 patients undergoing lymphadenectomy or lymph node sampling at laparotomy showed that true sensitivity to be 57.1% and the specificity 96.8%. Differentiation between malignant and reactive lymphadenopathy was not reliably achieved on MRI, and in several patients, metastases were present in normal-sized lymph nodes.

Pelvic radiation disease

Radiotherapy is often the treatment of choice for pelvic tumours, particularly cervical, bladder and prostate carcinoma, yet despite careful treatment planning, a radical (curative) course of radiation therapy will result in significant radiation exposure to adjacent normal structures. However, clinically significant pelvic radiation damage occurs in only 5-10% of patients (Allen-Mersh et al., 1986; Schellhammer et al., 1986). Individual organs demonstrate different sensitivities, with the small bowel being most susceptible and the urinary tract, particularly the ureters, relatively tolerant. Moreover, the onset of clinical symptoms, overall severity and progression of changes vary considerably from patient to patient. Several constitutional factors affect individual susceptibility to radiation damage. General medical conditions such as hypertension, atherosclerosis and diabetes mellitus have been implicated, each acting through a mechanism of relative pelvic ischaemia (deCosse et al., 1969; van Nagell et al., 1974). Localized pelvic inflammatory disorders and infection also increase the risk of radiation damage (Graham and Abad, 1967; Stockbrine et al., 1970), and adhesions from prior surgery may cause prolonged exposure of immobilized small bowel loops within a treatment field (Mason et al., 1970). In addition, certain treatment parameters are known to affect the risk of radiation damage. These include the total radiation dose, the volume of irradiated tissue, the size of radiation fractions and the duration of therapy (Hellman, 1989; Fletcher, 1979). Radiation tolerance is also reduced by combination treatment with surgery or chemotherapy. The biological effect of ionizing radiation is to damage intracellular DNA, which is rendered incapable of replication, and this results in cell death. Hence, those tissues with a rapid cell turnover, such as the epithelium of the bowel and bladder, manifest radiation injury before cells which divide more slowly, for example vascular endothelium and connective tissue. Early radiation reactions stem from epithelial necrosis, whereas chronic radiation injury results from damage to vascular and stromal cells, and is the dose-limiting factor in radiotherapy (Hellman, 1989). Vessels undergo endothelial degeneration, fibrinoid necrosis, transmural inflammation and fibrosis. Perivascular interstitial haemorrhage occurs secondary to endothelial damage; inflammation and fibrosis cause the formation of aneurysms, which may rupture and bleed (Haboubi and Hasleton, 1989); and fibrinoid necrosis, together with arterial intimal fibrosis and medial hypertrophy (Hasleton et al., t985), leads to vascular occlusion. The overall pathological effect is one of ischaemia producing a characteristic tissue fibrosis. Clinical radiation reactions are arbitrarily divided into three groups; acute, sub-acute or chronic, depending on the time interval from start of treatment. Acute reactions Correspondence to: Dr R. J. Johnson, Director of Diagnostic Radiology, Christie Hospital Trust, Wilmslow Road, Withington, Manchester M20 9BX. occur in the first 3 months, subacute reactions occur from 3 months to 1 year and chronic effects are seen more than 1 year following therapy. Patients who have a severe acute radiation reaction are more likely to progress to serious chronic radiation damage. In addition, morbidity and mortality are increased when radiation damage involves multiple organs, as occurs in 15 30% of affected patients (Kimose et al., 1989). Although all pelvic tissues within a radiation field are susceptible to radiation damage, clinically significant changes are most frequently encountered in the gastrointestinal and genitourinary tracts.

Prospective study of follow up alone in stage I teratoma of the testis.

In a prospective surveillance study of 45 patients with stage I teratoma of the testis 34 (76%) required no further treatment. Eleven patients relapsed but were salvaged by chemotherapy and radiotherapy. Seven patients relapsed within three months of the initial assessment and only one after more than 12 months. These preliminary results suggest that a follow up policy in stage I teratoma of the testis is possible but only in a regional centre with facilities for close monitoring of patients.

Computed tomography in adrenal disease

Ninety-eight patients with suspected adrenal disease were examined by computed tomography (CT). In 73 patients adrenal disease was confirmed on biochemical and other grounds (Cushings syndrome (38), primary aldosteronism (8), phaeochromocytoma (12), androgen excess (7), Addisons disease (1) and non-functioning adrenal masses (7)). The CT appearances of hyperplasia and benign and malignant adrenal tumours are described in detail. Ninety-six per cent of the adrenal glands were identified, and all but one of the 39 adrenal mass lesions were correctly identified and localised by CT. The failure to identify some adrenal glands and one adrenal tumour was related to a paucity of intra-abdominal fat. Two abdominal ectopic phaeochromocytoma were not identified (in one patient because the appropriate area was not scanned). The 25 patients examined with unproven adrenal disease had normal glands on CT. That some hyperplastic glands appear normal on CT precludes its use as a screening procedure for biochemically unproven adrenal disease. Computed tomography allows the differentiation of adrenal hyperplasia from functioning adrenal tumours, and the differentiation of benign from malignant lesions with a high degree of certainty; it is the method of choice for the identification and localisation of adrenal tumours.

Quantitative magnetic resonance imaging in rectal carcinoma.

T1 and T2 relaxation times have been calculated in 30 patients with rectal carcinoma and seven patients with a fibrotic pelvic mass. The relaxation times were calculated using a multipoint iterative method with data from seven total saturation recovery and six spin-echo sequences. The results show that the calculated T1 relaxation value is a useful discriminant between carcinoma and pelvic fibrosis and should improve the detection of early tumour recurrence.

Accuracy in staging carcinoma of the bladder by magnetic resonance imaging

Thirty-four patients with a presumptive diagnosis of carcinoma of the bladder diagnosed at EUA and cystoscopy have been staged by MRI and the findings correlated with pathology in 15 patients and clinical follow-up, including repeat cystoscopy, in the remainder. MRI is accurate in identifying tumours confined to the bladder wall or extending beyond the wall to involve perivesical fat or adjacent organs. Whilst it is not possible to distinguish between T1, T2 or early T3a tumours they can be distinguished from advanced T3a lesions and this may affect management. MRI is superior to clinical staging, particularly in detecting lymphadenopathy and provides information for optimal radiotherapy planning. The problem of distinguishing between the effects of radiotherapy and suspected recurrent tumour is discussed.

Staging of colorectal cancer

Colorectal carcinoma remains one of the leading causes of cancer death in the United States and worldwide. In fact, the approximate average lifetime risk of colorectal cancer is a staggering 6%. For this reason, it is important that all radiology and nuclear medicine specialists are familiar with and understand how colorectal carcinoma is accurately staged and the role and benefits of PET/CT in staging this lethal disease.

The diagnostic value of positron emission tomography (PET) with radiolabelled fluorodeoxyglucose (18F-FDG) in head and neck cancer.

Positron emission tomography (PET) scanning has recently been introduced into clinical practice but its usefulness in the management of head and neck cancer is not well defined. The aim of this prospective preliminary study was to examine the clinical value of fluorodeoxyglucose (FDG)--PET in patients with head and neck cancer treated by radiotherapy with surgery in reserve by (i) relating quantitative uptake of isotope to tumour type and histological grade and (ii) comparing the imaging findings of PET and magnetic resonance imaging (MRI) in post-radiotherapy assessment of tumour response. Twenty-one patients had pre-treatment PET and MRI scans and these were repeated four and eight months after treatment if there was no clinical relapse. Pre-treatment uptake of FDG using tumour to cerebellar ratio parameters was significantly related to the histological grade of squamous cancer (p = 0.04) but not to tumour type. Discordance of post-treatment PET/MRI findings in one case indicates a possible role for PET in the early detection of tumour recurrence. Other potential uses of PET scanning in the management of head and neck cancer are discussed.