Patients:
A total of 80 focal liver lesions in 59 patients fulfilled the inclusion criteria.
Mean age of these patients was 53 years (range,
4-83 years) with 37 male (63%) and 22 female ( 37%).
Liver lesions:
There were 40 benign and 40 malignant lesions which included 9 hepatocellular carcinoma (11.25%),
30 metastases (37.5%),
1 hepatoblastoma (1.25%),
19 hemangiomas (23.75%),
14 hepatic cysts (17.5%),
2 adenomas (2.5%),
2 FNH (2.5%) and 3 regenerating or degenerating hepatic nodules (3.75%).
Qualitative assessment on DW imaging:
All cystic lesions and hemangiomas showed facilitated diffusion with significant or near complete loss of signal intensity on increasing b value,
and lesions which did not show reduction of signal intensity,
showed high signal intensity on ADC map.
Solid benign hepatic lesions showed facilitated diffusion with mild loss of signal intensity on increasing b value.
On ADC map,
there was lower signal intensity compared to surrounding normal liver parenchyma.
All malignant liver lesions (primary or metastases) showed restricted diffusion with increase in signal intensity on increasing b value.
On ADC map,
they were much darker than the surrounding normal liver parenchyma.
Quantitative (ADC) evaluation:
The average ADC values were 3.07 x 10-3mm²/s for hepatic cysts,
1.86 x 10-3 mm2/s for hemangiomas, 1.71 x 10-3 mm2/s for benign hepatocellular lesions,
0.98 x 10-3 mm2/s for hepatocellular carcinoma and 0.97 x 10-3 mm2/s for metastases (Table 1).
Focal hepatic lesions |
Number of cases |
MeanADC value
(x 10-3 mm2/s )
|
Range of ADC values( x 10-3 mm2/s ) |
Hepatic cyst
|
14 |
3.07 |
1.6 - 4 |
Hemangioma
|
19 |
1.86 |
1.1 -3.3 |
Benign hepatocellular lesion |
7 |
1.71 |
1.5 -2.2 |
HCC
|
9 |
0.98 |
0.2- 1.5 |
Metastases
|
30 |
0.97 |
0.5 -1.5 |
Table 1.
Focal liver lesions with their ADC values.
ADC values of benign hepatic lesions (2.25 x 10-3mm2/s ± 0.81) were significantly higher than the malignant hepatic lesions ( 0.97 x 10-3 mm2/ ± 0.30).
The ROC curve was generated to determine the cut off point for ADC value that best differentiated the malignant and benign liver lesions.
The cut off ADC value of 1.5 x 10-3mm2/s was best able to differentiate malignant focal lesion from all benign lesions including hepatic cysts with accuracy of 96.5%,
sensitivity of 87.5% and specificity of 92.5% (Fig.
1).
Fig. 1: ROC curve to determine the cut off point of ADC to discriminate malignant and benign liver SOL's including hepatic cysts: 1.5 x 10-3mm2/s with accuracy of 96.5%
References: Basvatharkam Indo-American Cancer Hospital, Hyd/In.
When ROC curve was generated for only solid benign and malignant lesions (excluding hepatic cysts),
the cut off ADC value was 1.4 x 10-3mm2/s with accuracy of 94.7%,
sensitivity of 88.5% and specificity of 85% (Fig.
2).
Fig. 2: ROC curve to determine cut off point of ADC value to distinguish malignant and solid benign liver lesions: 1.4 x 10-3mm2/s with accuracy of 94.7%.
References: Basvatarkam Indo-American Cancer Institute Hyd,India
Cases:
Fig. 3: 60 year male with Hepato-cellular carcinoma: (a.) CECT arterial phase showed an enhancing mass in the liver with neovascularity and central necrosis. (b & c.) DWI at b0 and b800 revealed increase in signal intensity on increasing b value. (d.) Very low ADC value
References: basvatharkam Indo-American Cancer Hospital, Hyd/In.
Fig. 4: 62year female with hepatic metastasis from carcinoma cervix: (a.) Well defined hyperintense SOL on T2WI in right lobe of liver. (b.) Restriction on DWI.(c.) low ADC value.
References: Basvatharkam Indo-American Cancer Hospital, Hyd/In.
Fig. 5: 55 year old female with liver hemangioma in known c/o carcinoma ovary: (a.) Intensely hyperintense lesion on T2WI. (b &c.) persistence of hyperintense signal on increasing b value. (d.) High ADC value compared to surrounding liver parenchyma. (e.) Peripheral nodular enhancement in arterial phase of CECT, typical of hemangioma.
References: Basvatharkam Indo-American Cancer Hospital, Hyd/In.
Fig. 6: 70 year old male with degenerating nodule in right lobe of liver in a known c/o rectosigmoid carcinoma: (a.) Mildly hypointentse on T1WI compared to normal liver parenchyma. (b.) Hypointense on T2WI. (c.) Mild restriction on DWI. (d.) ADC value of 2.2 x 10-3 mm2/sec. (e.) Metabolically inactive on PET-CT.
References: Basvatharkam Indo-American Cancer Hospital, Hyd/In.