Case 1: Adrenal adenoma.
(Figs.
1 & 2)
Incidental adrenal nodule identified on routine investigation for alternative pathology. The patient underwent follow up magnetic resonance imaging (MRI) study confirming benign pathology. The retrospective review of the virtual non-contrast (VNC) of the initial CT study demonstrates a lesional Hounsfield unit (HU) of less than 10 (-8.5),
consistent with benign lipid rich adrenal adenoma.
We feel the follow up MRI study would have been superfluous with appropriate review of lesion using the spectral application.
Case 2: Adrenal haematoma.
(Figs.
3 & 4)
Emergency patient presenting following blunt trauma to posterior right chest wall.
CT demonstrated multiple right sided rib fractures and a small right sided haemothorax. An incidental hyperdense adrenal lesion with a HU value of 43 was also identified.
On the portal venous phase abdominal range this density is non-specific for characterisation of the adrenal pathology and a benign adenoma was the presumptive diagnosis.
The reporting radiologist recommended follow up adrenal MRI to further characterise the lesion. Follow-up MRI showed interval resolution of the adrenal lesion; a normal adrenal gland was visualised.
The given explanation was of a post-traumatic adrenal haemorrhage which had resolved during the intervening months.
Retrospective review of the initial trauma CT study with Spectral application including VNC and iodine density post processing show that this transient lesion did not display any enhancement which reinforces the diagnosis of haematoma. This may have possibly saved the patient from undergoing further imaging.
Case 3: Non-enhancing renal lesion.
(Fig.
5)
CT images demonstrate an incidental hyperdense lesion arising from the right kidney mid pole.
Patient underwent interval CT for further characterisation which confirmed stable appearances and lesion was diagnosed as a hyperdense renal cyst.
Following retrospective application of VNC software to the Spectral CT images absence of contrast enhancement is clearly demonstrated. With knowledge of this technique these findings would have likely reassured the initial reporting radiologist and potentially save patient from further imaging and radiation exposure.
Case 4: Hyperdense renal cyst.
(Fig.
6)
Companion case to case 3. Left lower pole hyperdense renal cyst with VNC and ID map images showing no change in the density between VNC and conventional contrast images and a negligible contrast uptake on the ID map.
Case 5: Enhancing renal lesion.
(Figs.
7 & 8)
Acute CT for incarcerated hernia demonstrated an incidental renal lesion. Follow-up MRI was performed with a 4 month interval for characterisation of the lesion which demonstrated features consistent with small renal cell carcinoma.
On review of the spectral CT images available at the time of initial imaging,
the lesion demonstrates avid enhancement. On VNC images the density is approximately 45HU and this increases to 80HU on conventional contrast spectral images.
If this was appreciated at the time,
this may have expedited patients treatment. The patient underwent cryoablation and remains disease free.
Case 6: PUJ obstruction.
(Figs.
9 & 10)
CT performed on a patient with pelvi-ureteric junction (PUJ) obstruction detected on ultrasound. Images demonstrate a non-calcified density lesion at the PUJ,
atypical for ureteric calculi,
this had a density of approximately 75HU on the conventional spectral CT images.
The patient underwent interval ureteroscopy for suspected transitional cell carcinoma of the ureter. No lesion was seen and diagnosis of 'soft' stone or debris was therefore thought most likely.
On image review with spectral software application,
the lesion had an identical density on VNC and no enhancement on the ID map. These findings may have confirmed diagnosis of soft ureteric stone and saved patient from further invasive investigation.