Changes in spleen volume after resection of hepatic colorectal metastases. Clin Radiol. 2012;67:982-987. [PMID: 22608244 DOI: 10.1016/j.crad.2012.03.013]

Fully Automatic Volume Measurement of the Spleen at CT Using Deep Learning

Purpose

To develop a fully automated algorithm for spleen segmentation and to assess the performance of this algorithm in a large dataset.

Materials and Methods

In this retrospective study, a three-dimensional deep learning network was developed to segment the spleen on thorax-abdomen CT scans. Scans were extracted from patients undergoing oncologic treatment from 2014 to 2017. A total of 1100 scans from 1100 patients were used in this study, and 400 were selected for development of the algorithm. For testing, a dataset of 50 scans was annotated to assess the segmentation accuracy and was compared against the splenic index equation. In a qualitative observer experiment, an enriched set of 100 scan-pairs was used to evaluate whether the algorithm could aid a radiologist in assessing splenic volume change. The reference standard was set by the consensus of two other independent radiologists. A Mann-Whitney U test was conducted to test whether there was a performance difference between the algorithm and the independent observer.

Results

The algorithm and the independent observer obtained comparable Dice scores (P = .834) on the test set of 50 scans of 0.962 and 0.964, respectively. The radiologist had an agreement with the reference standard in 81% (81 of 100) of the cases after a visual classification of volume change, which increased to 92% (92 of 100) when aided by the algorithm.

Conclusion

A segmentation method based on deep learning can accurately segment the spleen on CT scans and may help radiologists to detect abnormal splenic volumes and splenic volume changes.Supplemental material is available for this article.© RSNA, 2020.

Abdominal cross-sectional imaging of the associating liver partition and portal vein ligation for staged hepatectomy procedure

Associating liver partition and portal vein ligation for staged hepatectomy (ALPPS) is a recently introduced technique aimed to perform two-stage hepatectomy in patients with a variety of primary or secondary neoplastic lesions. ALPSS is based on a preliminary liver resection associated with ligation of the portal branch directed to the diseased hemiliver (DH), followed by hepatectomy after an interval of time in which the future liver remnant (FLR) hypertrophied adequately (partly because of preserved arterialization of the DH). Multidetector computed tomography (MDCT) and magnetic resonance imaging (MRI) play a pivotal role in patients’ selection and FLR assessment before and after the procedure, as well as in monitoring early and late complications, as we aim to review in this paper. Moreover, we illustrate main abdominal MDCT and MRI findings related to ALPPS.

Imaging of the postoperative liver: review of normal appearances and common complications

Several benign and malignant liver diseases may require surgical treatment for cure, including anatomical resections based on the segmental anatomy of the liver, non-anatomical (wedge) resections, and surgical management of biliary cysts. The type of surgery depends not only on the location and the nature of the disease, but also on the expertise of the surgeon. Whereas ultrasonography is often the first-line imaging examination in case of suspected postoperative complication, multidetector computed tomography (MDCT) is of greater value for identifying normal findings after surgery, early postoperative pathologic fluid collections and vascular thromboses, and tumor recurrence in patients who have undergone hepatic surgery. Magnetic resonance cholangiopancreatography (MRCP) is the imaging modality of choice for depicting early postoperative bile duct injuries and ischemic cholangitis that may occur in the late postoperative phase. Both MDCT and MRCP can accurately depict tumor recurrence. Radiologists should become familiar with these surgical procedures to better understand postoperative changes, and with the normal imaging appearances of various postoperative complications to better differentiate between complications and normal findings.

Thrombocytopenia due to hypersplenism in oncological disease: partial splenic embolization during palliative treatment

Hypersplenism is excess activity of the spleen, resulting in peripheral pancytopenia that predominates in platelet cell lines. Pancytopenia can be limited by reducing the volume of the functional spleen. However, in patients in very poor general condition, a splenectomy may not be possible, due to the risks of surgery and postoperative infection. Another therapeutic alternative in these patients is to reduce the volume of the spleen by super selective percutaneous splenic embolization. We report three cases of peripheral thrombocytopenia due to hypersplenism with a platelet count between 60,000 and 80,000/mm(3), which made it impossible to continue or start a chemotherapy protocol in these patients. For these patients, super selective partial embolization of the splenic parenchyma, with uncharged microspheres (250 microns) quickly resulted in a platelet count above 150,000/mm(3) so that chemotherapy could be continued or initiated.

Chemotherapy-induced splenic volume increase is independently associated with major complications after hepatic resection for metastatic colorectal cancer

BACKGROUND

In patients with colorectal cancer liver metastases (CRCLM), chemotherapy-induced hepatic injury is associated with increased splenic volume, thrombocytopenia, and decreased long-term survival. The current study investigates the relationship between change in splenic volume after preoperative chemotherapy and development of postoperative complications.

STUDY DESIGN

The study group consisted of 80 patients who underwent resection of CRCLM; half received neoadjuvant chemotherapy for 6 months before resection (n = 40) and the other half did not (n = 40). The study group was compared with two control groups: a normal group composed of patients undergoing cholecystectomy for benign disease (n = 40) and a group of untreated, nonmetastatic colorectal cancer (CRC) patients (n = 40). Splenic volume was measured by CT/MRI volumetry. In the study group, the nontumoral liver was graded for steatosis and sinusoidal injury; operative and outcomes characteristics were also analyzed.

RESULTS

Before chemotherapy, CRCLM patients had normalized spleen volumes of 3.2 ± 1.1 mL/kg, significantly higher than normal (2.5 ± 0.8 mL/kg; p < 0.001) and nonmetastatic CRC (2.6 ± 1.3 mL/kg; p < 0.05) patients, with higher splenic volume after 6 months of chemotherapy (4.2 ± 1.7 mL/kg; p < 0.01). After chemotherapy, splenic volume increase was associated with any perioperative complication (p < 0.01) and major complications (p < 0.05). Patients with ≥39% splenic volume increase (maximal chi-square test) were significantly more likely to have major complications (p < 0.01). Spleen volume changes were not correlated with change in platelet count (R(2) = 0.03; p = 0.301).

CONCLUSIONS

In patients with CRCLM, the presence of liver metastases and chemotherapy are associated with higher splenic volume. Percent splenic volume increase after 6 months of chemotherapy can aid preoperative risk stratification, as it was an independent predictor of major postoperative complications.

Mechanisms of splenic hypertrophy following hepatic resection

BACKGROUND

Following hepatic resection, liver regeneration has been associated with concurrent splenic hypertrophy. The mechanisms of this phenomenon are unknown, may be multiple and include: splanchnic sequestration caused by a reduction in the hepatic mass; hepatic growth factors that may indirectly act on the spleen, and the redistribution of the total reticuloendothelial system.

METHODS

Seventy-five patients (40 males; median age: 60 years) who underwent minor (16%) or major (84%) hepatectomy between September 2004 and October 2009 were included. Prospective measurements of liver and spleen volumes were obtained preoperatively and postoperatively 1 month after hepatectomy using computed tomography (CT). The future remnant liver volume (RLV) was calculated on preoperative CT and the extent of resection was expressed as the RLV divided by total liver volume (TLV). Liver and spleen hypertrophy were expressed according to the absolute gain or relative increase in the initial volumes (%).The presence of fibrosis >F1, associated extrahepatic resection (except minor resections), and previous hepatectomy (major or minor) within 3 months represented exclusion criteria.

RESULTS

Mean ± standard deviation (SD) liver volume at 1 month was higher than RLV (1187 ± 286 cm(3) versus 764 ± 421 cm(3) ; P < 0.001). Mean ± SD splenic volume increased from 252 ± 100 cm(3) preoperatively to 300 ± 111 cm(3) at 1 month (P < 0.001). Liver and splenic hypertrophy were significant after major hepatectomies (+100% and +26%, respectively; P < 0.001), but not after minor hepatectomies. Liver hypertrophy was inversely correlated to RLV/TLV (r = -0.687, P < 0.001). Splenic hypertrophy was not correlated to RLV/TLV. Liver and splenic hypertrophy were linearly correlated (r = 0.495, P < 0.001). Neoadjuvant chemotherapy (n = 37), preoperative portal vein embolization (n = 10) and postoperative complications (overall: n = 25; major: n = 10; infectious: n = 6) had no impact on hepatic or splenic hypertrophy.

CONCLUSIONS

Splenic hypertrophy occurred after major hepatectomy, but was not correlated to the extent of resection, by contrast with liver hypertrophy. Nevertheless, there was a linear correlation between splenic and liver hypertrophy. This correlation suggests the hypothesis of a splenic action of hepatic growth factors or a redistribution of the total reticuloendothelial system rather than an effect of reduction of the portal bed or hepatic outflow.