A. Kalovidouris

MR imaging of tuberculous vertebral osteomyelitis: pictorial review

Abstract Vertebral osteomyelitis is one of the most common manifestations of tuberculosis. Magnetic resonance imaging is considered the main imaging modality for the diagnosis, the demonstration of the extent of the disease, and follow-up studies. Vertebral destruction involving two consecutive levels with sparing of the intervertebral disc, disc herniation into the vertebral body, epidural involvement, and paraspinal abscess are the most common MRI findings suggestive of tuberculous vertebral osteomyelitis.

Abdominal retained surgical sponges: CT appearance

Abstract. Retention of surgical sponges is rare. They cause either an aseptic reaction without significant symptoms or an exudative reaction which results in early but nonspecific symptoms. Computed tomography is very useful for recognition of retained sponges. The appearance of retained sponges is widely variable. Air trapping into a surgical sponge results in the spongiform pattern which is characteristic but unfortunately uncommon. A low-density, high-density, or complex mass is found in the majority of cases, but these patterns are not specific. Sometimes, a thin high-density capsule may be seen. Rim or internal calcification is a rare finding. Finally, a radiopaque marker is not a reliable sign. Differentiation from abscess and hematoma is sometimes difficult.

MRI of abdominal hydatid disease

Seventy hydatid cysts in 30 patients were studied with magnetic resonance imaging (MRI) and computed tomography (CT); all cases were confirmed surgically. MRI detected all cysts when confined to solid organs, whereas small-sized cysts (≤2 cm) may be missed when located in the peritoneal cavity. Hydatid cysts of less than 3 cm (noncomplicated) present no specific findings of hydatid disease. MRI findings suggesting hydatid disease demonstrate a relatively thick hydatid cyst wall, daughter cysts, and germinal membrane detachment. T2-weighted images proved to be superior to T1 or PD-weighted images in demonstrating hydatid cyst wall thickness, germinal membrane detachment, and daughter cysts. In all spin-echo sequences, the maternal cystic content presented much higher signal intensities than that of daughter cysts. This difference in signal intensity is more obvious in T2 weighted images, except in complicated, infected cases. CT proved to be superior to MRI in demonstrating wall calcifications.

A comparative study between Gd-DTPA and oral magnetic particles (OMP) as gastrointestinal (GI) contrast agents for MRI of the abdomen

In the present study we compared two gastrointestinal contrast agents--Gd-DTPA, a positive signal, and oral magnetic particles (OMP), a negative signal contrast agent--in patients who were referred for MR imaging of the abdomen. Altogether 60 patients were examined with the former and 28 patients with the latter contrast before and after the administration of contrast media. Gd-DTPA was given either per os or per rectum. In comparing the results, it was shown that the diagnostic accuracy of postcontrast MRI in both groups was more or less similar to CT but much higher as compared with plain MRI. In the OMP series, first the contrast between the GI-filled lumen and the surrounding fat was much superior to that of the Gd-DTPA and, second, there was no evidence of any artifacts from bowel motion. However, the overall accuracy of the Gd-DTPA group was better compared with that of the OMP group. This was due to underfilling of the distal bowel because the OMP in those patients was administered only per os. Finally, Gd-DTPA had a more pleasant taste and fewer side effects. It is concluded that both contrast media are suitable for the upper abdomen because the results are comparable, whereas for the lower abdomen Gd-DTPA is superior because it can be used from both routes.

Comparative study between ultrasound, computed tomography, intra-arterial digital subtraction angiography, and magnetic resonance imaging in the differentiation of tumors of the liver

Forty-one patients with liver tumor have been evaluated with ultrasound (US), computed tomography (CT), intra-arterial digital subtraction angiography (IA-DSA), and magnetic resonance imaging (MRI) in order to establish the accuracy of each technique. In group A (24 patients), in which all four imaging modalities were performed, our results show that MRI detected all hemangiomas (25/25) compared to 22/25, 21/25, and 20/25 with US, CT, and IA-DSA, respectively. No difference between the various methods was seen in the case of hepatoma. Finally, in the patients with metastases, all four techniques had the same sensitivity (100%) but the specificity of MRI was also 100%, compared to 33% for IA-DSA and 66% for US and CT.

Computed tomographic localization of pelvic hydatid disease.

Nine patients with history of hydatid disease have been examined by CT. Localization of the hydatid cysts in the pelvis was established by anatomical criteria. Occasionally, the transverse plane can be confusing for the precise localization of a lesion. A central location, close to the boundaries of the bladder and rectum, can define peritoneal location. Further posterolateral retrovesical location can be considered retroperitoneal. Using these criteria, 8 cysts were situated within the peritoneum and 1 within the retroperitoneum.

Correlation between spinal cord MRI and clinical features in patients with demyelinating disease

Localisation of spinal cord lesions by MRI was correlated with neurological symptoms and signs in 16 patients with clinical and laboratory evidence of multiple sclerosis. There was good correspondence between spinal cord lesions and motor tract signs. On the other hand, superficial or deep sensory disturbances correlated with spinal cord lesions in only about a quarter of the patients. MRI of the spinal cord appeared to explain the myelopathy in 11 patients, while in 3 there was strong clinical evidence of more extensive demyelinating lesions. In 7 of the 16 patients MRI of the brain was normal.

Gd-DTPA as an intestinal contrast agent for MR imaging of the lower abdomen: phase III clinical trial.

Thirty-one patients were investigated with magnetic resonance (MR) imaging of the lower abdomen before and after the administration of gadopentetate dimeglumine (Gd-DTPA) solution per os or per rectum or from both routes for the opacification of the intestinal tract. The parameters evaluated were: (a) contrast medium distribution, (b) degree of filling of the bowel lumen, (c) contrast between the bowel lumen and the surrounding normal or pathological structures, and (d) whether the administration of the contrast agent improved the diagnostic ability of MR compared to computed tomography (CT) or plain MR of the same region. Gd-DTPA, at a concentration of 1 mmol/L, produced a positive signal irrespective of its dilution in the bowel and good contrast between the bowel lumen and the adjacent tissues or any possible pathological lesions. From the diagnostic point of view, after the administration of contrast medium, MR is comparable to CT and much superior to plain MR. It is concluded that opacification of the bowel with Gd-DTPA solution will improve the diagnostic yield of MR imaging of the lower abdomen.

Low back pain due to extramedullary hemopoiesis.

SummaryTwo cases of extramedullary hemopoiesis in the lower spinal column are reported. One of them was due to thalassemia major and the other to thalassemia intermedia. CT and MRI studies showed paraspinal and presacral masses respectively which caused nerve root compression. It is concluded that the differential diagnosis of low back pain and radicular or pseudoradicular pain should include extramedullary hemopoiesis.

MRI in the investigation of patients with myelopathy thought to be due to multiple sclerosis

The role of cerebral and spinal cord MRI was investigated in 65 patients with myelopathy suspected of having demyelinating disease. Cerebral MRI demonstrated lesions compatible with demyelination in 80% and spinal cord MRI in 68.6%. In 28.5% of our patients brain lesions were present with normal spinal cord images, but in 17% spinal cord lesions were depicted with a normal brain MRI. The combination of the two examinations demonstrated lesions in 97% of the patients. The frequency of coexistent cerebral lesions in patients with spinal cord lesions was over 85% in patients with chronic disease but only 28.5% in patients with acute myelitis.