Spot Diagnosis

MDCT for assessing pancreatico-biliary union

This article, by Itoh S et al , in the September issue of the AJR, shows how MDCT (using 4-slice) can depict the pancreatico-biliary ductal anatomy exceptionally well. This allows the diagnosis of the abnormal channel, especially in patients with choledochal cysts.

Because of the superior spatial resolution with multi-slice scanners, it is highly likely that the results with MSCT for this particular purpose, will be better than MRCP.

We have had a similar experience on our 64-slice CT. This is a child with a choledochal cyst (Fig. 1), where the abnormal pancreatico-biliary channel is extremely well seen (Figs. 2, 3).

Solitary pulmonary nodule lecture - slides 7-11

Cervical vertebra biopsy

This 24-yeras old student had neck pain. An MRI revealed a C4 vertebral lesion. A contrast-enhanced CT scan prior to the biopsy showed an expansile osteolytic lesion involving the body and pedicle (Figs. 1, 2) with abnormal soft tissue. Under CT guidance, a core biopsy was performed, both of the soft tissue as well as from within the lesion (Figs. 3, 4).

Adequate tissue was obtained, which was reported to be tuberculosis.

Radiofrequency ablation (RFA) of a lung tumor

This is a 78-years old man, who had a 3.8cm sized mass in the left upper lobe (Fig. 1), which was proven to be a squamous cell carcinoma. There was marked surrounding emphysema and though the lesion was a T1 lesion, with no adenopathy or evidence of spread elsewhere on a PET study, he was not considered to be a candidate for surgery.

He was referred for a radiofrequency ablation (RFA). We had to make sure that we did not penetrate the emphysematous lung. Using the CT fluoroscopy function, it was possible to find an oblique route into the centre of the lesion (Figs. 2-4) and the tines of the electrode were then deployed (Figs. 5,6). A successful ablation was obtained with peri-lesional ground-glass attenuation (Fig. 7).

There was no evidence of a pneumothorax, but a plain-radiograph (FIg. 8) obtained 24 hours later showed fluid-fluid levels, presumably due to hemorrhage into the bullae. The patient however was comfortable and was discharged with due precautions.

Neuroradiology case of the week

Every Friday, we will be putting up a new Neuroradiology case

1. Neuronal ceroid lipofuscinosis

Solitary pulmonary nodule lecture

1. Slides 1-3

2. Slides 4-6

Solitary pulmonary nodule lecture - Slides 1-3

Radiofrequency ablation (RFA) of osteoid osteoma

This is a 15-years old boy with a posterior tibial mid-diaphyseal osteoid osteoma. A radiofrequency ablation (RFA) procedure was performed.

The approach was through the anterior cortex to avoid potential injury to other structures with posterior or lateral approaches. The electrode was placed in the lesion (Figs. 1, 2) and the ablation was performed at 90 deg C for 5 minutes.

A repeat MRI performed a week later shows the tract well (Fig. 3) as well as the zone of ablation (arrow).

RFA is the method of choice for treating osteoid osteomas. The results compare very favorably with surgery, but with hardly any associated morbidity. Since the procedure is performed under deep sedation in an OPD /day care setting, the patient is ready to resume a normal routine within 24 hours.

 

Head injuries Lecture - Slides 51-55

Pyonephrosis

When the infection involves a dilated PC system, there is pyonephrosis, as in this patient with a calculus in the lower third with hydronephrosis. There is reduced function with enhancement of the walls of the pelvis and calyces (Fig. 1). A focal parenchymal lesion is also noted (Fig. 2).