A case of synchronous hepatocellular carcinoma (HCC) and intrahepatic cholangiocellular carcinoma
Showa University Fujigaoka Hospital
Drs. Akio Kotake and Nobuyuki Takeyama, Dept. of Radiology
DATE : 2021
Introduction
Patient’s background
Female; 70s; body weight: 43 kg; HCC and intrahepatic cholangiocellular carcinoma
Assessment objectives
The patient, a hepatitis B-carrier, developed two hepatic masses during follow-up by the previous physician. Contrast CT was performed as a thorough test.
Contrast agent used
Iopromide 370 injection syringe, “BYL”, 86 mL
Case explanation
Extrahepatic lateral segmentectomy and S8 subsegmentectomy were performed. On the basis of pathology, the lateral segment tumor was diagnosed as moderately to highly differentiated HCC. The S8 tumor was diagnosed as highly differentiated, peripheral-type, intrahepatic cholangiocarcinoma.
Imaging findings
The HCC in the lateral segment shows early dark staining, and wash-out (red arrow).
The S8 intrahepatic cholangiocarcinoma is difficult to identify other than by simple CT (yellow arrow).
Comparison with previous images showed that both cancers were new.
Fig. 1. Hepatic dynamic CT
Upper row, from left: Plain, 40 s, 70 s, 120 s, 15 min
Lower row, from left: Opposed phase, in phase, diffusion-weighted imaging
The HCC in the lateral segment showed a low signal in the hepatobiliary phase.
No fat content was clearly shown by chemical-shift imaging.
Diffusion restriction was found.
Fig. 2. EOB hepatic dynamic magnetic resonance imaging (MRI) of lateral segment HCC
Upper row, from left: Plain, 40 s, 70 s, 120 s, 15 min
Lower row, from left: Opposed phase, in phase, diffusion-weighted imaging
The S8 intrahepatic cholangiocarcinoma showed a low signal in the hepatobiliary phase.
No fat content was clearly shown by chemical-shift imaging.
Diffusion restriction was found.
Fig. 3. EOB hepatic dynamic MRI of S8 intrahepatic cholangiocarcinoma
Photography protocol
| Equipment used | CT device model | Light Speed VCT/GE |
| Number of CT detector rows / number of slices | 64 rows / 64 slices | |
| Workstation | AW VolumeShare5/GE Medical Systems |
| Imaging conditions | Imaging phase | Simple | Arterial phase (40 s) | Portal phase (70 s) | Equilibrium phase (180 s) |
| Tube voltage (kV) | 120 (currently 100) | 120 (currently 100) | 120 (currently 100) | 120 (currently 100) | |
| Beamwidth | 40 | 40 | 40 | 40 | |
| Slice thickness (mm) | 5 | 5/1.25 | 5 | 5 | |
| Focal-spot size | Large Body | Large Body | Large Body | Large Body | |
| Scan mode | Helical | Helical | Helical | Helical | |
| Scan speed (s/rotation) | 0.4 | 0.4 | 0.4 | 0.4 | |
| Pitch (mm) | 0.516 | 0.516 | 0.516 | 0.516 | |
| Scan range | Upper abdomen | Upper abdomen | Upper abdomen | Upper abdomen | |
| Imaging duration (s) | 4.5 | 4.5 | 4.5 | 4.5 | |
| Imaging direction | Head to foot | Head to foot | Head to foot | Head to foot |
| Reconstruction conditions | Simple | Arterial phase (40 s) | Portal phase (70 s) | Equilibrium phase (180 s) | |
| Routine: Reconstructed slice thickness / interval (mm/mm) | ー | 3/3 (coronal section) | ー | 3/3 (coronal section) | |
| Routine: Reconstruction function / iterative approximation method | ー | ー | ー | ー | |
| 3D / multiplanar reformation: Reconstructed slice thickness / interval (mm/mm) | ー | ー | ー | ー | |
| 3D / multiplanar reformation: Reconstruction function / iterative approximation method | ー | ー | ー | ー |
| Contrast conditions | Simple | Arterial phase (40 s) | Portal phase (70 s) | Equilibrium phase (180 s) | |
| Automatic injector model and manufacturer | Dual Shot GX7 (Nemoto Kyorindo) | ||||
| Contrast agent used | Iopromide 370 injection syringe, “BYL” | ||||
| Contrast agent: Dose | ー | Body weight <50 kg: Body weight × 2 mL Body weight ≥ 50 kg: 100 mL | ー | ー | |
| Contrast agent: Injection speed, injection duration | ー | Fixed for 30 s | ー | ー | |
| Physiological saline solution: Dose | ー | ー | ー | ー | |
| Physiological saline solution: Injection speed, injection duration | ー | ー | ー | ー | |
| Scan timing | ー | Fixation method | ー | ー | |
| Delay time | ー | 40 s | ー | ー | |
| Indwelling needle size (G) | 20 | ||||
| Injection pressure limit (kg/cm2) | 10kg/cm2 | ||||
If the body weight is less than 50 kg, the contrast agent dose is the body weight (kg) × 2 mL. This patient’s body weight was 43 kg, so the dose administered was 86 mL. The infusion duration was fixed at 30 s.
As this imaging was performed a considerable time ago, it was at 120 kV. However, in recent years, in order to improve contrast enhancement, imaging has been performed at the low tube voltage of 100 kV.
Roles of contrast CT in diagnosis of the disease
Contrast CT is indispensable for evaluation of hepatic tumors. As the liver receives nutrition from both arterial and portal blood, blood flow evaluation is essential for detection and qualitative evaluation of tumors. Multiphase imaging enables evaluation of arterial blood flow at an early time, and portal blood flow at a later time. In addition, evaluation that includes EOB-MRI, which indicates hepatocyte uptake, has been performed frequently in recent years.
Development of liver cancer is classified as either de novo or multistage carcinogenesis, and the blood flow changes according to the developmental stage. Moderately or highly differentiated HCC, as with the present patient, shows marked dark staining in the arterial-dominant phase and wash-out in the equilibrium phase. On the other hand, intrahepatic cholangiocarcinoma involves development of fibrous interstitial tissue, and therefore typically shows a gradual increase in dark staining.
With this patient, it was highly difficult to identify lesions at time phases other than those for non-imaging CT, because in the arterial, portal and equilibrium phases absorption level was approximately the same as in the hepatic parenchyma. However, the pattern can be considered to be gradually increasing dark staining. With EOB-MRI, early dark staining and a wash out pattern were shown, and differentiation from HCC was difficult.
Therefore, it can be considered that the imaging pattern with CT was one in which the intrahepatic cholangiocarcinoma showed gradual increase in dark staining. It is essential to perform not just one test, but both tests, and to compare the results.
CT techniques and imaging protocol settings
At the authors’ hospital, standard tests approximately the same as those in the protocol included in Diagnostic Imaging Guidelines 2021 are performed. In addition, arterial contrast enhancement can be expected as a result of using high-concentration contrast media such as iopromide 370.
- Precautions for use [excerpt from Package Insert]
1. Careful administration (particular care should be taken with administration to the following patients)
(11) Elderly patients [see “Administration to elderly people” section]
5. Administration to elderly people
This drug is excreted primarily by the kidneys, but in elderly patients renal function is often depressed, so high blood concentrations may persist. Therefore, it should be administered carefully, at the minimum essential dose, while monitoring the patient's condition.
- *The case introduced is just one clinical case, so the results are not the same as for all cases.
- *Please refer to the Package Insert for the effects and indications, dosage and administration method, and warnings, contraindications, and other precautions with use.
