A 41-year-old patient with latent porphyria cutanea tarda is described; 8 years after mastectomy for carcinoma, sonography and CT showed multiple hepatic foci, which were at first interpreted as liver metastases. A liver biopsy was carried out during laparoscopy and u/v fluorescence and subsequent laboratory tests confirmed the diagnosis of porphyria cutanea tarda. Treatment with resochin produced almost complete resolution of the liver abnormalities within 9 months. Magnetic resonance tomography using proton-weighted SE sequences showed a few foci of high signal intensity.

In-vivo and in-vitro checks on measurements of relaxation times in MRI have been carried out as part of quality control. For the in-vitro experiments we used 13 reagents consisting of varying concentrations of copper sulphate manganese sulphate, gadolinium solutions and various oils as well as water. For in-vivo measurements we used liver parenchyma and fat in three subjects. Eight different sequences were performed; intra- and interindividual variations and comparison of three similar MRI units showed average variations of 2-3% for T1 and 3-4% variations for T2 relaxation times. This margin of error makes quantitative MRI acceptable for clinical use.

MR is the only noninvasive procedure that can demonstrate changes in the medullary space. If it is combined with bone marrow scintigraphy and conventional x-ray film diagnostics, it can yield a comprehensive diagnosis of bone marrow infiltrations in the regions of the pelvis, thighs and lumbar vertebral column in leukaemia or malignant lymphomas. The T1 relaxation times of the malignant infiltrations are enhanced compared with normal fatty marrow. MR tomography of the bone marrow is particularly suitable for determining the therapy or follow-up control of a malignant systemic disease.

The arterial system can be demonstrated after intravenous contrast injection by means of DVSA. The abdominal aorta, pelvic and lower limb arteries were examined in this way in 152 patients. Occlusions, stenoses and areas of dilatation could be recognised. In 8% of the patients the aortic bifurcation or common iliac arteries were not adequately visualised. In other respects, the results of DVSA were comparable with conventional arteriography. Because of limited image size, DVSA is particularly indicated where the vascular changes can be localised accurately by clinical means. The method is well suited for observing the results of surgery or percutaneous angioplasty. The indications for arteriography have been reduced as a result of DVSA.

56 patients with head and brain trauma and in coma were studied prospectively by means of MRT, CT, EEG and neurological examination. All patients had initial CT and EEG admission. MRT showed that in our patients morphological return to normal was the exception. Patients with head and brain injuries should be examined by MRT during the course of their illness. The use of special sequences, such as gradient-echo sequences for the diagnosis of haemorrhagic contusions, is indicated. CT should be retained for evaluating bone injury and cerebral damage during the acute stage.

A linear array colour Doppler sonographic method was used experimentally on a vessel phantom in order to determine flow velocity, and the results were compared with DSA. Both the Doppler and the DSA method showed very good agreement with true velocities (r greater than 0.97). The Doppler method underestimated flow velocity. Early clinical results indicate that colour Doppler sonography is able, at the same time, to demonstrate morphology and function (direction flow and flow velocity) of significant vascular abnormalities by a non-invasive method.

Report on a huge mucocele of the right maxillary sinus extending into the ethmoid and sphenoid sinuses, and protruding into the contralateral left posterior cranial fossa. The patient, a 45-year old male, had no history of paranasal sinus energy, nasal or paranasal symptoms. He went to his physician because of a slowly developing deafness in his left ear and because of episodes of loss of consciousness when blowing his nose. A reversible episode of vertigo and reversible paresis of the left abducent nerve 17 years previously, were later assumed to have been the first symptoms of endocranial extension of the mucocele. The diagnosis of a mucocele was made by MRI. MRI in T2 weighted spin-echo sequences is the best imaging technique for diagnosing a mucocele. The mucocele was treated primarily with endonasal surgery of the paranasal sinuses, using telescopes and an operating microscope. After opening the right maxillary sinus via the middle meatus liquid contents of the mucocele poured into the nasal cavity. The sack of the mucocele was removed partially. Three months later the patient was reoperated with a combined transfacial and endonasal approach, because of progression from partial hearing loss to total deafness. Postoperatively hearing improved nearly completely and compression of the pons and the posterior fossa had disappeared on MRI. It is concluded that in mucoceles no longer the extirpation of the sack, but endonasal marsupialization, using the operating microscope and telescopes, is the therapy of choice.

Intravenous digital subtraction angiography is often used for evaluation of the extracranial and major intracranial vessels. The information obtained by this examination concerning cerebral perfusion is usually judged visually. In 50 patients a time-density curve at a specific point was analysed using 128 X 128 matrix. The level of grey scale at the moment of arrival of the bolus permits estimation of the haemodynamics of the intracranial vessels and provides a simple demonstration of differences of perfusion.