CT during arterial portography: diagnostic pitfalls

The Added Diagnostic Value of Transcatheter CT Hepatic Arteriography for Intraprocedural Detection of Previously Unknown Colorectal Liver Metastases During Percutaneous Ablation and Impact on the Definitive Treatment Plan

PURPOSE

This study assessed the diagnostic value of CT hepatic arteriography (CTHA) for the intraprocedural detection of previously unknown colorectal liver metastases (CRLM) and the impact on the definitive treatment plan.

MATERIALS AND METHODS

All patients treated with CTHA-guided percutaneous ablation for CRLM between January 2012 and March 2022 were identified from the Amsterdam Colorectal Liver Met Registry (AmCORE). Radiology reports of the ablative procedure and follow-up imaging were reviewed to see if (a) previously unknown CRLM were detected intra-procedurally and if (b) new CRLM, potentially missed on CTHA, appeared within 6 months following the procedure; three abdominal radiologists re-reviewed the baseline CTHA scans of these patients with early recurrence. To ratify immediate ablations of concomitantly detected CRLM, the upper limit of false positives was predefined at 10%.

RESULTS

One hundred and fifty-two patients were included. With CTHA, a total of 17 additional tumours in 15 patients were diagnosed and treated immediately, two representing disappeared tumours following systemic chemotherapy. Compared to the conventional contrast-enhanced (ce)CT, ceMRI and 18F-FDG PET-CT, adding CTHA was superior for the detection of CRLM (P < .001). Within 12 months of follow-up 121, new CRLM appeared in 49/152 patients (32.2%); retrospective blinded assessment revealed 56 to already be visible on the baseline CTHA scan (46%); four lesions without substrate on follow-up scans were considered false positives (n = 4/60; 7%). Arterial ring enhancement was the most frequently reported imaging characteristic (n = 45/60; 75%).

CONCLUSION

The subsequent use of CTHA has added value for the detection of previously unknown and vanished CRLM. Taking into account the low number of false positives (7%) and the favourable safety profile of percutaneous ablation, we believe that immediate ablation of typical ring-enhancing supplementary tumours is justified and sufficiently validated.

LEVEL OF EVIDENCE

Level 3; individual cross-sectional study with consistently applied reference standard and blinding.

Aberrant gastric venous drainage and associated atrophy of hepatic segment II: computed tomography analysis of 2021 patients

PURPOSE

To investigate the prevalence and patterns of aberrant gastric venous drainage and associated atrophy of the hepatic segment on contrast-enhanced computed tomography (CT).

METHODS

Two radiologists retrospectively reviewed contrast-enhanced CT images from 2021 patients who underwent cone-beam CT-guided chemoembolization between January 2013 and December 2018. They determined the presence or absence of an aberrant gastric vein(s) and its drainage site by consensus, and qualitatively analyzed the presence or absence of atrophy of segments II or III. In cases of disagreement between the two reviewers regarding the presence of atrophy, quantitative analysis was performed using dedicated software.

RESULTS

A total of 31 aberrant right gastric veins were revealed on CT (1.5%), most of which drained into P2 (n = 8), the S2/3 border zone (n = 8), S2 (n = 6), or S4 (n = 5). An aberrant left gastric vein was observed in 21 (1.0%) patients, and P2 was the most common drainage site (n = 13) in these patients. Atrophy of segment II was more frequently observed among patients with aberrant gastric veins than among those without (26.9% versus 4.1%; p < 0.001). In addition, an aberrant gastric vein draining into P2 was most frequently accompanied by segment II atrophy (47.6%).

CONCLUSION

Aberrant right and left gastric veins were observed in 1.5% and 1.0% of patients, respectively. Atrophy of segment II was frequently observed in patients with aberrant gastric veins, especially those that drained into P2.

Computed tomography arterial portography for assessment of portal vein injury after blunt hepatic trauma

PURPOSE

Intrahepatic portal vein injuries secondary to blunt abdominal trauma are difficult to diagnose and can result in insidious bleeding. We aimed to compare computed tomography arterial portography (CTAP), reperfusion CTAP (rCTAP), and conventional computed tomography (CT) for diagnosing portal vein injuries after blunt hepatic trauma.

METHODS

Patients with blunt hepatic trauma, who were eligible for nonoperative management, underwent CTAP, rCTAP, and CT. The number and size of perfusion defects observed using the three methods were compared.

RESULTS

A total of 13 patients (seven males/six females) with a mean age of 34.5±14.1 years were included in the study. A total of 36 hepatic segments had perfusion defects on rCTAP and CT, while there were 47 hepatic segments with perfusion defects on CTAP. The size of perfusion defects on CT (239 cm3; interquartile range [IQR]: 129.5, 309.5) and rCTAP (238 cm3; IQR: 129.5, 310.5) were significantly smaller compared with CTAP (291 cm3; IQR: 136, 371) (both, P = 0.002).

CONCLUSION

Perfusion defects measured by CTAP were significantly greater than those determined by either rCTAP or CT in cases of blunt hepatic trauma. This finding suggests that CTAP is superior to rCTAP and CT in evaluating portal vein injuries after blunt liver trauma.

Hepatocellular carcinoma and other hepatic malignancies: MR imaging

Magnetic resonance (MR) imaging surpasses all other imaging modalities in characterizing liver lesions by virtue of the exquisite tissue contrast, specificity for various tissue types, and extreme sensitivity to contrast enhancement. In addition to differentiating benign from malignant lesions, MR imaging generally discriminates between the various malignant liver lesions. Hepatocellular carcinoma constitutes most primary malignant liver lesions and usually arises in the setting of cirrhosis. Intrahepatic cholangiocarcinoma is a distant second and features distinctly different imaging features. Overall, metastases are the most common malignant liver lesions and arise from several primary neoplasms; most commonly gastrointestinal, lung, breast, and genitourinary.

Right gastric venous drainage: angiographic analysis in 100 patients

Objective

To evaluate the pattern of right gastric venous drainage by use of digital subtraction angiography.

Materials and Methods

A series of 100 consecutive patients who underwent right gastric arteriography during transcatheter arterial chemoembolization for hepatocellular carcinoma were included in this study. Angiographic findings were retrospectively analyzed with respect to the presence or absence of the right and aberrant gastric veins, multiplicity of draining veins, aberrant right gastric venous drainage sites, and the termination pattern of aberrant right gastric veins (ARGVs). We also compared the relative size of the right and left gastric veins.

Results

A total of 49 patients collectively had 66 ARGVs. The common drainage sites for the ARGVs included the hepatic segment IV (n = 35) and segment I (n = 15). The termination pattern of ARGV could be classified into 4 different types. The most common type was termination as a superficial parenchymal blush formation in small areas without demonstrable portal branches. A statistically significant difference was found for the dominancy of the right gastric vein in gastric venous drainage between the two groups with or without ARGV (p < 0.05, Fisher's exact test). In the group of patients without ARGV (n = 51), the right gastric vein was equal to (n = 9) or larger than (n = 17) the left gastric vein in 26 patients (26 of 51, 51%).

Conclusion

The incidence of ARGV is higher than expected with four distinct types in its termination pattern. The right gastric vein may play a dominant role in gastric venous drainage.

The incidence of hepatic pseudolesions caused by focal rib compression as seen on multidetector row CT in patients of different hepatic function

OBJECTIVE

To determine whether the incidence of pseudolesions of the liver caused by rib compression is correlated with liver function.

MATERIALS AND METHODS

Multidetector row CT images of 150 consecutive cases were evaluated for the presence of pseudolesions caused by rib compression. Liver function was categorized into two groups mainly using the Child-Pugh classification: Group I-normal liver function and Grade A; Group II-Grades B and C. The number of focal deformities of the liver caused by rib compression was also counted. The incidence of pseudolesions based on number of patients or focal deformities of liver parenchyma by rib compression were compared between the two groups.

RESULTS

There were 108 and 42 patients in Groups I and II, respectively. 169 and 41 focal deformities of the liver caused by rib compression were found in Groups I and II, respectively. Patient-based and deformity-based incidences of pseudolesions were 10.7% (16/150) and 7.6% (16/210), respectively. All pseudolesions were seen in patients of Group I. Both patient-based and deformity-based incidences of pseudolesions were significantly higher in Group I as compared with those in Group II.

CONCLUSION

Pseudolesions of the liver caused by focal rib compression may be seen more frequently in patients with preserved liver function than in those with impaired function.

Pseudolesões hepáticas na ressonância magnética: ensaio iconográfico

A ressonância magnética é uma técnica de grande importância na avaliação do fígado. Assim como na tomografia computadorizada helicoidal, o emprego de aquisições rápidas, em fases diferentes da vascularização hepática, auxilia na detecção e caracterização de tumores. Contudo, algumas armadilhas podem confundir e dificultar a interpretação do exame, simulando lesões parenquimatosas. Estas armadilhas têm forma, localização e características variadas, sendo denominadas de pseudolesões. Podem ser decorrentes de diversos fatores, como alterações perfusionais, esteatose focal, parênquima hepático preservado na esteatose difusa, artefatos, entre outros. É muito importante que sejam reconhecidas, para que não sejam causas de resultados falso-positivos. O objetivo deste ensaio é classificar e ilustrar as diversas pseudolesões hepáticas na ressonância magnética, com breve descrição delas, e alternativas para diferenciá-las das lesões do parênquima.

Pseudolesões hepáticas na tomografia computadorizada helicoidal: ensaio iconográfico

A tomografia computadorizada helicoidal é largamente empregada na avaliação do parênquima hepático e tem grande importância no planejamento clínico e cirúrgico. O fígado é o órgão que mais se beneficia de aquisições helicoidais, em fases diferentes da perfusão do parênquima, pela sua dupla vascularização e pela diferença de aporte sanguíneo entre tumores e parênquima sadio. Entretanto, várias armadilhas diagnósticas podem ser encontradas, dificultando a análise e prejudicando a diferenciação entre lesões verdadeiras e pseudolesões, principalmente aos olhos de radiologistas menos experientes. Essas pseudolesões têm forma, localização e características variadas, podendo simular lesões parenquimatosas. É de fundamental importância que estejamos aptos a reconhecê-las, no sentido de interpretar corretamente as imagens tomográficas. O objetivo deste ensaio é classificar e ilustrar as diversas pseudolesões hepáticas pela tomografia computadorizada helicoidal, com uma breve descrição dessas lesões e com alternativas para diferenciá-las das lesões do parênquima.

CT during arterial portography: effects of precontrast injection of prostaglandin E1 into the superior mesenteric artery

Prostaglandin E1 (PGE1) is a vasodilator that increases portal venous flow. Hepatic CT during arterial portography (CTAP) was performed in 42 patients with and without PGE1 to compare peak hepatic enhancement and nontumorous abnormalities. Although no significant differences in peak hepatic enhancement were observed (71 +/- 12 HU for CTAP with PGE1; 74 +/- 34 HU for CTAP without PGE1), the number of nontumorous abnormalities for CTAP with PGE1 (n = 11) was significantly lower than that for CTAP without PGE1 (n = 24) (p < 0.01, Wilcoxon signed rank test). CTAP combined with PGE1 therefore represents a useful method to study lesions of the liver, as the number of nontumorous abnormalities observed is significantly reduced and liver parenchyma can be scanned more evenly.

Current techniques of computed tomography. Helical CT, multidetector CT, and 3D reconstruction

The many recent advances in CT technology have secured its position as the modality of choice in routine liver imaging and have improved its performance in several problem-solving applications. In addition, improvements in postprocessing software (e.g., in speed, efficiency, and automated algorithms) have increased their use in clinical practice. Multiplanar reformations, 3D renderings, and high-quality CT angiographic displays have become extremely valuable both in image interpretation and in communicating information to surgeons and referring physicians.

Unusual hemodynamics and pseudolesions of the noncirrhotic liver at CT

Recognition of pseudolesions of the liver at computed tomography (CT) is important because of their close resemblance to primary liver cancers or metastases. Two types of pseudolesion in the noncirrhotic liver include that due to transient extrinsic compression, typically caused by ribs or the diaphragm, and that due to a "third inflow" of blood from other than the usual hepatic arterial and portal venous sources: the cholecystic, parabiliary, or epigastric-paraumbilical venous system. Although the location of both types of pseudolesion are characteristic, their appearances at CT during arterial portography and CT during selective angiography vary from nonenhanced low-attenuation areas to well-enhanced high-attenuation areas, depending on the amount and timing of the inflow and presence or absence of focal metabolic alteration of the hepatocytes. Radiologists need to understand the underlying mechanism of these pseudolesions to better recognize the wide range of their appearances at CT.

Intraoperative ultrasound

Intraoperative ultrasound is an exciting arena for real-time depiction and evaluation of relevant anatomy and pathology. The information provided by this technique often is pivotal to the surgeon, and not infrequently impacts the nature and extent of the surgical procedure. As more radiologists develop an interest and become facile with IOUS, and as more surgeons appreciate the benefits of this modality, the numbers and applications for this technique will continue to expand. This, coupled with continued commercial and technical improvements, and increasing demand for minimally invasive surgery, ensures that the future of IOUS will be a bright one.

Focal fatty infiltration in the posterior aspect of hepatic segment IV: relationship to pancreaticoduodenal venous drainage

OBJECTIVE

We aimed to investigate the relationship between fatty infiltration in the posterior aspect of hepatic segment IV and pancreaticoduodenal venous drainage.

METHODS

Pancreaticoduodenal arteriography was performed in 21 patients who had nontumorous portal perfusion defects in the posterior aspect of hepatic segment IV, as demonstrated on CT during arterial portography (CTAP).

RESULTS

In 10 patients, pancreaticoduodenal arteriography showed an aberrant nonportal vessel with flow toward the hepatic hilum in the venous phase. Four of the 10 patients with nonportal vessels from the pancreaticoduodenal arterial system had fatty infiltration in segment IV. In three of these four patients, the fatty infiltration was focal and localized to that area. On the other hand, none of the 11 patients without nonportal vessels from the pancreaticoduodenal arterial system had fatty infiltration in the regions corresponding to the nontumorous portal perfusion defects on CTAP. Moreover, three patients with diffuse fatty liver had a focal nonfatty area in segment IV.

CONCLUSIONS

Focal fatty infiltration in the posterior aspect of hepatic segment IV seems to be related to pancreaticoduodenal venous drainage.

A large pseudolesion in the left lobe of the liver caused by inferior vena caval obstruction secondary to metastatic retroperitoneal lymphadenopathy

A rare case with a large pseudolesion in the left lobe of the liver observed on early phase of incremental dynamic computed tomography (CT) caused by inferior vena caval obstruction is presented. Decreased portal perfusion due to increased volume of systemic venous inflow into the left lobe via paraumbilical venous system may be its underlying hemodynamic change. The etiology of this pseudolesion was successfully confirmed by conventional CT with intravenous contrast medium injection via superficial vein of lower extremity.

The aetiology of non-tumorous enhancement in the hepatic hilum shown on CT hepatic arteriography

The causes of non-tumorous abnormalities in the hepatic hilum seen on CT hepatic arteriography were investigated. 13 patients with non-tumorous defects of portal perfusion in the hepatic hilum on CT arterial portography underwent both CT hepatic arteriography from the common hepatic artery and CT obtained during proper hepatic arteriography. The findings of non-tumorous portal defects on these two angiographic studies using helical CT were compared. In the 13 patients, 14 non-tumorous defects of portal perfusion in the hepatic hilum on CT arterial portography were detected as enhanced areas in 10 regions (dorsum of segment IV, 7/10; dorsum of the lateral segment, 3/4) on CT hepatic arteriography via the common hepatic artery, but none were enhanced on CT obtained during proper hepatic arteriography. In conclusion, the main cause of non-tumorous enhancement in the hepatic hilum seen on CT hepatic arteriography is non-portal direct inflow via the parabiliary venous system.

Imaging of hepatocellular carcinoma

Recent improvements in the treatment of hepatocellular carcinoma (HCC) have resulted in a need to identify the disease at an early stage. The wide range of imaging techniques available reflects the difficulty in demonstrating small HCC, particularly in the cirrhotic liver. This article reviews the current imaging techniques available for the diagnosis of HCC.

Spiral CT of the abdomen: increased diagnostic potential

Over the last 10 years, spiral CT has become the optimal method of performing all CT within the abdomen and pelvis. Not only has the technique improved the quality of individual examinations, it has also opened up many new diagnostic possibilities which are currently being evaluated and compared with the concurrent advances in ultrasound and MRI. These new diagnostic possibilities are discussed in this review article. So too are the economic advantages of the shorter data-acquisition times which also make the examination much better tolerated by the patient.

Correlation of a defect of portal perfusion in the dorsal part of segment IV of the liver on CT arterial portography with inflow of the aberrant pancreaticoduodenal vein

The correlation between an aberrant pancreaticoduodenal vein and a portal perfusion defect in the dorsal part of segment IV as demonstrated on CT arterial portography (CTAP) was investigated. 14 patients with non-tumorous defects of portal perfusion in the dorsal part of segment IV of the liver parenchyma, shown on CTAP underwent CT during pancreaticoduodenal arteriography. The defect on CTAP was shown as an enhanced area resulting from non-portal venous inflow in eight (57%) of 14 patients on CT during pancreaticoduodenal arteriography. In conclusion, the non-portal venous supply via an aberrant pancreaticoduodenal vein occasionally causes a defect of portal perfusion in the dorsal part of segment IV on CT arterial portography.

Multidisciplinary management of metastatic colorectal cancer

When colorectal cancer metastasizes to distant organs, usually multiple sites are involved and treatment consists primarily of systemic chemotherapy and supportive care. Chemotherapeutic agents effective against metastatic colorectal cancer include 5-fluorouracil, often used in combination with leucovorin or methotrexate, and irinotecan (CPT-11). Median survival with optimal chemotherapy regimens ranges from 10 to 15 months. Less frequently, colorectal cancer metastasizes only to the liver or lung. In a minority of these cases, surgical resection can be performed and results in a median survival of 28-46 months for hepatic resections and 24-25 months for pulmonary resections. Five-year survival rates range from 24 to 38% and 21 to 44% for hepatic and pulmonary resections, respectively. For isolated liver metastases that are not surgically resectable, other regional therapies that can be considered are hepatic cryosurgery, radiofrequency ablation, and hepatic arterial infusion chemotherapy. Median survival following cryosurgery is between 26 and 30 months, while median survival following radiofrequency ablation has not been established in large series. Hepatic arterial infusion chemotherapy, especially with newer combination drug regimens, may increase survival in patients with isolated liver metastases compared to systemic chemotherapy, but this must be confirmed in randomized, prospective trials. Colorectal cancer metastases to the brain can be treated with radiation therapy or surgical resection, but median survival with treatment is less than one year.

Nondiseased portal perfusion defects adjacent to the right ribs shown on helical CT during arterial portography

OBJECTIVE

The purpose of our study was to assess the frequency and imaging characteristics of nonpathologic portal perfusion defects in subcapsular liver parenchyma adjacent to the right ribs as seen on CT hepatic arteriography combined with helical CT during arterial portography (CTAP).

MATERIALS AND METHODS

From January 1994 to June 1997, helical CTAP and CT hepatic arteriography were performed in 94 patients with suspected malignant hepatic tumors. The patient group comprised 66 men and 28 women ranging from 37 to 83 years old (mean, 64 years old). Three radiologists retrospectively reviewed the images obtained by CTAP to evaluate portal perfusion defects adjacent to the right ribs for location, shape, size, and correlation with findings seen on CT hepatic arteriography.

RESULTS

We identified 16 nonpathologic portal perfusion defects adjacent to the right eighth (n = 1), ninth (n = 12), and tenth (n = 3) ribs in 12 (13%) of 94 patients. The shapes of the 16 defects were circular (n = 1), oval (n = 7), wedge (n = 3), and irregular (n = 5). The defects were 10-30 mm in diameter (mean, 16.9 mm). In four (25%) of 16 locations, CT hepatic arteriography showed poorly identified, homogeneous, irregularly shaped areas of contrast enhancement corresponding to the defects seen on CTAP. The portal perfusion defects were proven to be nonpathologic on definitive surgery in four patients and on follow-up radiography in eight patients.

CONCLUSION

Helical CTAP may show nonpathologic portal perfusion defects adjacent to the right ribs. Most defects did not appear circular but rather were oval, irregular, or wedge-shaped. CT hepatic arteriography infrequently showed corresponding findings. Radiologists should recognize this potential pitfall when interpreting images obtained by helical CTAP.

Hepatic metastases

Developments in ultrasound, CT scan, and MR imaging have increased our ability to detect and characterize focal liver lesions. Advances in the medical and surgical treatment of secondary liver tumors have continued to challenge these advances in radiology. A successful outcome depends on knowledge of the size and location of the tumor burden, and accurate radiologic assessment is crucial to identify those subgroups who may benefit from surgery and to prevent unnecessary radical surgery in those likely to gain only a short-term benefit.

CT scan of the liver

Since its inception, CT scan has had a dominant role in hepatic imaging. Recent advances including helical CT scan and bolus-triggered scan initiation software packages have had a significant impact. Issues regarding volume, rate of administration, and type of intravenous contrast are being distilled. Workstations for three-dimensional data reconstructions are producing images that compete with conventional angiography in certain areas, while angiographically assisted CT scan is being refined in others.

Aberrant left gastric vein demonstrated by helical CT

PURPOSE

Our goal was to describe the CT findings of aberrant left gastric vein (ALGV) and to evaluate the clinical significance of this vein.

METHOD

Four patients in whom ALGVs were demonstrated by helical CT were examined. Each patient had either intrahepatic cholangiocarcinoma, cirrhosis with gastric varices, chronic hepatitis, or nonspecific abdominal pain. All patients underwent two phase helical CT, and the patient with cholangiocarcinoma underwent CT during arterial portography, and 3D images of the abdominal veins were obtained.

RESULTS

In all patients, the ALGVs ran along the hepatogastric ligament and were directly connected with the left portal branch. In the patient with cholangiocarcinoma, the portal vein had severe stenosis by tumor invasion, and both the ALGV and the aberrant right gastric vein functioned as a collateral pathway of the portal flow into the liver. In the patient with cirrhosis, dilated ALGV with hepatofugal flow caused gastric varices.

CONCLUSION

The ALGV is directly connected with the left portal branch and may play an important role in the collateral pathway of the portal system.

Pseudo lesions on CTAP secondary to arterio-portal shunts

PURPOSE

To clarify the characteristics of the defects on computed tomography (CT) during arterial portography (CTAP) due to arterio-portal shunting (APS).

METHOD AND PATIENTS

The defects in the hepatic parenchyma on CTAP due to angiography proven APS were characterized according to their configuration, size, sharpness of margins, location of the lesion in the liver, and homogeneity of the lesions.

RESULTS

Twenty five patients had non-tumor related APS. The shunts were single on angiography in 15 cases and multiple in 10 cases. The APS were due to liver cirrhosis in 22 patients, and to trauma in the other three. The lesions were irregular in shape in nine cases, wedge shaped in six cases, and round in four cases. In three cases both wedge and round lesions were seen. The margins were sharp in five single defects in five cases. The rest of the lesions were judged to have unsharp margins except for one case in which both clear and unclear lesions were present. In 10 cases, internal enhancement of the lesions were seen on CTAP. The location of the defects were central in five cases, peripheral in nine, and both peripheral and central in eight cases.

CONCLUSION

The parenchymal defects due to APS were typically irregular in shape, with unsharp margins and internal enhancement.

Hepatic parenchymal hyperperfusion abnormalities detected with multisection dynamic MR imaging: appearance and interpretation

On arterial-dominant-phase images in multisection dynamic MR imaging, early-enhancing areas that are perfusion abnormalities rather than tumor deposit are sometimes encountered. The purpose of this article was to determine the frequency, location, and appearance of these hepatic parenchymal hyperperfusion abnormalities and to discuss possible causes of these abnormalities. Multisection dynamic MR images obtained in 415 patients with suspected hepatobiliary diseases were reviewed for the presence of hyperperfusion abnormalities. A total of 96 hyperperfusion abnormalities were identified in 88 (21%) of 415 patients. They were characterised from their shape, distribution, or location as lobar or segmental (n = 36 [38%]), subsegmental (n = 32 [33%]), or subcapsular (n = 28 [29%]) hyperperfusion abnormalities. Presumable etiologies were considered as follows: (a) compression, obstruction, or ligation of the portal vein; (b) siphoning effect by tumor; (c) aberrant cystic venous drainage; (d) percutaneous ethanol injection; (e) percutaneous needle biopsy; (f) rapid drainage by the subcapsular vein; or (g) cirrhosis or unknown. A significant percentage of patients had hepatic hyperperfusion abnormalities. Familiarity with these hyperperfusion abnormalities on multisection dynamic MR images is important to prevent false-positive diagnoses.

MR arterial portography with gadolinium-DOTA: analysis of nontumoral perfusion abnormalities

The purpose of this article was to determine the frequency and imaging characteristics of nontumoral perfusion abnormalities observed on magnetic resonance imaging (MRI) obtained during arterial portography (MRAP). MRAP examinations done in 23 consecutive patients with malignant hepatic tumors were retrospectively and blindly reviewed by two readers for the presence of nontumoral perfusion abnormalities. MR Images were assessed for the presence, location, shape, and type of nontumoral perfusion abnormalities, and correlated with intraoperative findings or follow-up imaging studies. Fourteen nontumoral perfusion abnormalities were found in 10 patients (43%). Nontumoral perfusion abnormalities were categorized into these five types: triangular nontumoral perfusion defects not associated with a more proximal tumor (n = 6), triangular nontumoral perfusion abnormalities distal to a tumor (n = 2), hypoperfusion involving 1 or >1 segment (n = 2), hyperenhancement of the posterior part of the right hemiliver (n = 2), and gravity-effect-related perfusion abnormality (n = 2). Nontumoral perfusion abnormalities are seen frequently on MRAP examination. Recognition of these abnormalities remains crucial to avoid misdiagnosis.

Malignant liver lesions: comparison of spiral CT arterial portography and MR imaging for diagnostic accuracy, cost, and effect on patient management

We compared two imaging techniques, spiral CT arterial portography (CTAP) and MR imaging, for diagnostic accuracy, procedural cost, and effect on management of 26 patients referred for hepatic surgery for suspected limited malignant liver disease. CTAP and MR imaging were done within a 1-week period (19 within 24 hours); the results of the studies were interpreted prospectively by separate reviewers. Surgical data were evaluated in conjunction with imaging data in 10 patients. Lesion detection and segmental involvement were determined and sensitivity and specificity were calculated. Procedural cost was determined from hospital billing codes. Effect on patient management was determined by the referring oncologic surgeon. CTAP and MR imaging showed 185 and 176 true-positive malignant lesions, 15 and zero false-positive malignant lesions, zero and 18 true-negative malignant lesions, and 13 and 22 false-negative malignant lesions, respectively. CTAP and MR imaging showed 107 and 105 true-positive segments, 11 and zero false-positive segments, 80 and 91 true-negative segments, and four and six false-negative segments, respectively. There was a significant difference in specificity of segmental involvement between MR imaging (1.0 +/- 0) compared with CTAP (0.88 +/- 0.05), P = .03. Total procedural cost was $3,499 for CTAP and $1,224 for MR imaging. CTAP findings did not change patient management over MR imaging findings in any patient, whereas MR imaging findings resulted in a change in patient management over CTAP findings in seven patients (P = .015). The results of our study suggest that MR imaging has higher diagnostic accuracy and greater effect on patient management than CTAP does and is 64% less expensive.

Hepatocellular carcinoma: findings on spiral CT during arterial portography

BACKGROUND

To determine characteristic imaging features of hepatocellular carcinoma (HCC) on spiral CT during arterial portography (SCTAP) and to correlate the presence or absence of spontaneous portosystemic shunts with the degree of hepatic parenchymal enhancement during SCTAP in patients with HCC.

METHODS

SCTAP scans of 20 patients with HCC were retrospectively analyzed for tumor features, degree of hepatic parenchymal enhancement, and presence or absence of spontaneous portosystemic shunts.

RESULTS

Nineteen tumors (95%) were hypoattenuating masses and one (5%) was isoattenuating compared with the liver on SCTAP. In seven patients (35%), the tumor was homogeneous in attenuation. Tumor margins were smooth and regular in 12 patients (60%). Vascular invasion and encapsulation were depicted in 10 patients (50%). A high degree of hepatic parenchymal enhancement was observed in 14 patients; one of them (7%) had spontaneous portosystemic shunts. Poor or moderate enhancement was observed in six patients; five of them (83%) had spontaneous portosystemic shunts (p < .001).

CONCLUSION

The presence of a low attenuated homogeneous intrahepatic mass with associated vascular invasion on SCTAP scans should raise the possibility of HCC. The presence of spontaneous portosystemic shunts is associated with poor or moderate parenchymal enhancement.

Quantitative indices for ranking the severity of hepatocellular carcinoma

A method for quantifying the severity of tumour burden based on fractional affected areas, weighted by their mean attenuation values relative to normal tissue, is presented. The procedure was applied retrospectively to routine computerized tomography (CT) scans of patients with hepatocellular carcinoma, and produced severity indices that reliably followed the ranking of an expert panel.

Computed tomographic portography in preoperative imaging of hepatic neoplasms

Preoperative selection of suitable patients for liver resection is dependent on the quality of radiological imaging. Computed tomography (CT) identifies approximately 70 per cent of lesions. Computed tomographic arterial portography (CTAP) during contrast enhancement of the liver via the portal vein may be superior to conventional CT. Preoperative CTAP was evaluated in 60 patients with hepatic neoplasm (48 having colorectal metastases) who subsequently underwent laparotomy. The preoperative images were compared with intraoperative palpation, intraoperative ultrasonography and histology of the resected liver. Fifty-six patients (93 per cent) underwent partial hepatectomy. The detection rate sensitivity for CTAP was 110 of 116 lesions in the 56 patients (95 per cent) and for intraoperative ultrasonography was 114 of 116 (98 per cent). CTAP correctly identified all lesions found at histology in 50 of 56 (89 per cent) resected specimens. At laparotomy four of 60 patients (7 per cent) were inoperable; two of these had been predicted to be so by this technique. CTAP correctly identifies and locates the majority of hepatic tumours, particularly metastases, and is the procedure of choice for selection of suitable candidates for partial hepatectomy.

MR portography: preliminary comparison with CT portography and conventional MR imaging

Magnetic resonance (MR) imaging with arterial portography (MRAP) was compared with computed tomography with arterial portography (CTAP) and conventional MR imaging for preoperative evaluation of hepatic masses in eight patients (nine studies). Twenty contiguous, 10-mm-thick-section CTAP images were obtained. MR imaging included T1- and T2-weighted spin-echo and fast multiplanar SPGR (spoiled gradient-recalled acquisition in the steady state) techniques. For MRAP, 0.1 mmol/kg gadopentetate dimeglumine was injected into the superior mesenteric artery. Portographic-phase, 8-mm-thick-section, axial SPGR images were first obtained, followed by "systemic phase" SPGR images. Lesions were seen best on the portographic-phase MRAP images and were less conspicuous on the systemic-phase MRAP, CTAP and conventional MR images. Of 19 visualized lesions, 18 were seen with MRAP; however; five subcentimeter lesions seen with MRAP were not seen with conventional MR imaging or CTAP. Systemic recirculation of iodinated contrast material from the bolus and from previous angiography is a potential limitation of CTAP. For both CTAP and MRAP, optimal results are expected if all images are obtained during a single breath hold, within seconds of the onset of contrast agent administration.

Intrahepatic cholangiocarcinoma: findings on spiral CT during arterial portography

To attempt to determine the characteristic imaging features of intrahepatic cholangiocarcinoma on spiral CT during arterial portography (CTAP), spiral CTAP examinations of 17 patients with pathologically confirmed intrahepatic cholangiocarcinoma were reviewed in consensus by three radiologists. The diameter of the tumors ranged from 1 to 12 cm (mean diameter, 6.6 cm). All tumors (100%) were hypoattenuating masses on spiral CTAP. In 11 cases, the tumor was homogeneous in attenuation (65%). Tumor margins were smooth and regular in 11 cases (65%). Vascular invasion was found in 14 cases (82%). Intrahepatic bile duct dilatation was present in seven cases (41%). This review shows that intrahepatic cholangiocarcinoma is associated with a constellation of findings on spiral CTAP. The presence of a low attenuation homogeneous intrahepatic mass with vascular invasion and intrahepatic bile duct dilatation on spiral CTAP images should raise the possibility of intrahepatic cholangiocarcinoma. However, these findings can be associated with other types of primary and secondary malignant hepatic tumors.